EPA-600/2-76-134
June 1976
Environmental Protection Technology Series
             WASTEWATER RECLAMATION PROJECT,
                    ST.  CROIX,  U.S. VIRGIN  ISLANDS

                                  Municipal Environmental Research Laboratory
                                        Office of Research and Development
                                       U.S. Environmental Protection Agency
                                               Cincinnati, Ohio 45268

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                RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped  into five series. These five  broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
     1.    Environmental Health Effects Research
     2.    Environmental Protection Technology
     3.    Ecological Research
     4.    Environmental Monitoring
     5.    Socioeconomic Environmental Studies

This report  has been  assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate  instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new  or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                      EPA-600/2-76-134
                                      June 1976
      WASTEWATER RECLAMATION PROJECT,

      ST. CROIX, U.S. VIRGIN ISLANDS
                    by

            Oscar KM sen Buros
      Black, Crow and Eidsness, Inc.
        Gainesville, Florida  32602
           Project No. GAK 11010
              Project Officer

               Robert Mason
      Research and Development Branch
   U.S. Environmental Protection Agency
                 Region II
         New York, New York  10007
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
    OFFICE OF RESEARCH AND DEVELOPMENT
   U.S. ENVIRONMENTAL PROTECTION AGENCY
          CINCINNATI, OHIO  45268

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                              DISCLAIMER
        This report has been reviewed by the Research and Development
Branch and the Municipal Environmental Research Laboratory, U.S. Environ-
mental Protection Agency, and approved for publication.  Approval  does
not signify that the contents necessarily reflect the views and policies
of the U.S. Environmental Protection Agency, nor does mention of trade
names or commercial products constitute endorsement or recommendation
for use.
                                    ii

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                               FOREWORD
        The Environmental Protection Agency was created because of
increasing public and government concern about the dangers of pollution
to the health and welfare of the American people.   Noxious air, foul
water, and spoiled land are tragic testimony to the deterioration of
our natural environment.  The complexity of that environment and the
interplay between its components require a concentrated and integrated
attack on the problem.

        Research and development is that necessary first step in problem
solution and it involves defining the problem, measuring its impact,  and
searching for solutions.  The Municipal  Environmental  Research Laboratory
develops new and improved technology and systems for the prevention,
treatment, and management of wastewater and solid and  hazardous waste
pollutant discharges from municipal and community sources, for the
preservation and treatment of public drinking water supplies, and to
minimize the adverse economic, social, health, and aesthetic effects  of
pollution. This publication is one of the products of  that research;  a
most vital communications link between the researcher  and the user
community.

        The study described here was undertaken to demonstrate the reuse
of municipal wastewater as a means of conserving valuable water resources
in a water-short semi-arid area by recharging groundwater supplies with
treated effluents.
                                   Francis T.  Mayo
                                   Director
                                   Municipal  Environmental
                                   Research Laboratory
                                   ill

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                                    PREFACE
     With a burgeoning population and a concomitant insufficiency of
potable water, the United States Virgin Islands is continually faced with
the necessity of constructing additional desalinization plants.  The
freshwater supply is a combination of rainwater collected in cisterns, a
rather meager amount of groundwater, and a rather large proportion of
desalinated water.  To conserve potable water, saltwater flushing is
resorted to in some areas.  Since the rainfall is unpredictable and highly
nonuniform during the year, with either substantial rain or none at all
for months at a time, the aquifers are generally either full or empty.

     Because of the tremendous importance of the water problem, with its
social and economic implications, it is obvious that any reasonable
alternative to a once-through-use-and-discharge-to-the-ocean must be
investigated.  In the present work, recharge of suitably treated wastewater
is addressed experimentally.  The selection and preparation of a recharge
site, study of the nature of the aquifer, and techniques of recharge are
all discussed against the background of a semiarid, subtropical island
environment.

     As a comprehensive geologic and sanitary engineering study of St. Croix
from the standpoint of groundwater recharge, this report will  serve as a  •
foundation for the development of a water management master plan for the
island, as well as the model for studies of other similar islands and
selected coastal  areas.

                                        Robert W. Mason, Ph.D.
                                        Research and Development
                                        Representative, Region II
                                     iv

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                         TABLE OF CONTENTS
                                                                    Page
FOREWORD                                                            <11
PREFACE                                                              1v
LIST OF FIGURES                                                     vii
LIST OF TABLES                                                        x
ABBREVIATIONS AND SYMBOLS                                            xi
SECTION
   I      INTRODUCTION                                                1
          Description of St. Croix                                    1
          Outline of the Wastewater Reclamation Project               8
   II     SUMMARY                                                    14
   III    CONCLUSIONS                                                16
   IV     RECOMMENDATIONS                                            17
   V      PRELIMINARY INVESTIGATIONS OF THE RECHARGE AND
          STUDY AREA                                                 28
          Selection of the Recharge and Study Area                   28
          Description of the Study Area                              39
          Golden Grove Recharge Area                                 45
          Negro Bay Recharge Area                                    49
          Hydrological Developments in the Study Area                51
          Water and Wastewater Systems on the Island                 53
   VI     DESCRIPTION OF THE PROJECT FACILITIES                      59
          Advanced Wastewater Treatment Plant (AWWTP)                59
          Recharge Areas                                             76
   VII    MONITORING ACTIVITIES DURING THE PROJECT                   87
          Water Quality                                              87
          Groundwater Quantity and Movement                          90
          Rainfall Data                                              91
          Advanced Wastewater Treatment Plant                        91

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                  TABLE OF CONTENTS (CONTINUED).


SECTION                                                            Page

   VIII   RESULTS AND DISCUSSION                                    95

          Water Quantity Changes Due to Recharging                  95
          Water Quality Changes Due to Recharging                  113
          Water Quality in Future Operations                       119
          AWWTP Operations                                         119
          Cost Factors                                             120

   IX     MAJOR PROBLEM AREAS ENCOUNTERED IN THE  PROJECT           122

          Conceptual                                               122
          Coordinated Planning                                     123
          Changing Conditions                                      123
          Project Location                                         124
          Delays                                                   124
          Equipment Outages                                        125
          Natural Disasters                                        125
          Summary                                                  125

   X      OTHER ACTIVITIES ASSOCIATED WITH THE WASTEWATER
          RECLAMATION PROJECT                                      126

          Irrigation                                               126
          Clam Culture                                             127
          Pisciculture                                             127
          Interrelationship                                        128

REFERENCES                                                         130

APPENDIX                                                           133

PART A    LOGS OF PROJECT WELLS                                    135

PART B    PRIMARY WELLS-ANALYTICAL DATA                           144

PART C    SECONDARY WELLS—ANALYTICAL DATA                         178

PART D    STREAM SAMPLES-ANALYTICAL DATA                          200

PART E    AWWTP OPERATIONAL DATA                                   206

PART F    SOIL BORING INFORMATION                                  208

PART G    WATER LEVELS IN PROJECT WELLS                            210

PART H    ENGLISH-TO-METRIC CONVERSION                             244
                                  vi

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                          LIST OF FIGURES

Number                                                             Page
   1      Location of St.  Croix, U.S.  Virgin Islands                 2
   2      St.  Croix, U.S.  Virgin Islands                             3
   3      Rainfall and groundwater potentiometric levels
          in central St. Croix                                       5
   4      The cost of desalinized water purchased during
          the period 1972 to 1975                                    7
   5      The project study area in central St.  Croix               10
   6      The Golden Grove and Negro Bay area in central
          St.  Croix                                                 11
   7      Schedule of the phases of the wastewater
          reclamation project                                       12
   8      Future well field development in the Golden
          Grove recharge area                                       22
   9      Future expansion of the spreading basins in
          the Golden Grove recharge area                            24
  10      Proposed horizontal well                                  26
  11      Public-owned lands in central St. Croix                   30
  12      Soil limitations for septic tanks in central
          St. Croix                                                 31
  13      Geological conditions in central St. Croix                32
  14      Results of percolation tests made at recharge
          sites under investigation                                 34
  15      Surface geological features in the Golden
          Grove area                                                38
  16      Well locations in the study area                          40
                                 vii

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                   LIST OF FIGURES (CONTINUED).

Number                                                             Page
  17      Geological  cross section of the coastal  plain             43
  18      Geological  cross section of the Golden Grove
          area at right angles to the streambed                     44
  19      Geological  map of the coastal  plain                       46
  20      Geological  cross section of the Golden Grove
          area along  the plane of the streambed                     47
  21      Geological  cross section of the Negro Bay area            50
  22      The source  of wastewater flows in June,  1974              56
  23      The source  of wastewater flows in September,
          1975                                                      57
  24      Chloride content of the incoming wastewater to
          the AWWTP in 1974                                         58
  25      Flow diagram of the AWWTP                                 62
  26      Aerial  view of the AWWTP                                  63
  27      AWWTP production utilized for  artificial
          groundwater recharging                                    72
  28      The Golden  Grove recharge area                            78
  29      Aerial  view of the Golden Grove recharge  area             80
  30      The Negro Bay recharge area                               85
  31      A typical page from the AWWTP  operator's  log
          showing the effluent flow chart                           93
  32      A typical page from the AWWTP  operator's  log
          showing flow data and electric power consumed             94
  33      Infiltration rates in the recharge basins                 96
  34      Hypothesized flow of groundwater in the upper
          aquifer in  Golden Grove                                  101
  35      Comparison  of wells GG-3 and GG-5,  1973-1974             103
                                  viii

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                   LIST OF FIGURES (CONTINUED).


Number                                                             Page

  36      Comparison of wells A-18,  GG-3,  GG-13,  and
          PW-8,  1974                                               104

  37      Comparison of wells GG-3 and PW-6,  1974-1975              106

  38      Comparison of wells GG-3,  PW-8,  and PW-9, 1974            107

  39      Potentiometric groundwater levels in Estate
          Golden Grove, 1972-1974                                  109

  40      Potentiometric groundwater levels in Estate
          Golden Grove, 1974-1975                                  110

  41      Water balance in Golden Grove with and  without
          artificial recharging                                    111

  42      Chloride content of monitor wells in the study
          area                                                     114

  43      Proposed interrelationships between water use
          and reuse activities on St. Croix                        129

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                          LIST OF TABLES

Number                                                             Page
  1       SOIL CLASSIFICATIONS IN THE PROJECT AREA                  36
  2       MAJOR WATER SOURCES ON ST.  CROIX                          55
  3       EQUIPMENT USED IN THE ADVANCED WASTEWATER
          TREATMENT PLANT                                           64
  4       DESIGN AND ACTUAL PARAMETERS FOR THE
          BIOLOGICAL SECTION OF THE AWWTP                           65
  5       OPERATING DATA FOR THE AWWTP                              68
  6       WATER AND WASTEWATER QUALITY MONITORING
          SCHEDULE                                                  89
  7       PROJECTED COSTS FOR THE PRODUCTION AND
          RECOVERY OF RECLAIMED WASTEWATER BY
          GROUNDWATER RECHARGE                                     121

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                        ABBREVIATIONS AND SYMBOLS

Standard Abbreviations
AWWTP             Advanced wastewater treatment plant
BOD               Five-day biochemical oxygen demand
C                 Centigrade
cm                Centimeters
cu                Cubic
E                 Estate Envy
EPA               Environmental Protection Agency
FCR               Free chlorine residual
ft                Feet
FTU               Formazin turbidity units
gal               Gallons
gpcd              Gallons per capita per day
gpd               Gallons per day
gpm               Gallons per minute
ha                Hectares
in.               Inches
kg                Kilograms
km                Kilometers
1                 Liters
Ib                Pounds
m                 Meters
mgd               Million gallons per day
mg                Mi 11i grams
                                  xl

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mil gal           Million gallons
MLSS              Mixed liquor suspended solids
PVC               Polyvinyl chloride
PWD               Public Works Department
SAR               Sodium absorption ratio
sec               Seconds
sq                Square
Std Dev           Standard deviation
SVI               Sludge volume index
IDS               Total dissolved solids
USDA              U.S. Department of Agriculture
USGS              U.S. Geological Survey
V.I.              Virgin Islands
WAPA              Water and Power Authority
wk                Weeks
Well Abbreviations and Symbols
A                 Adventure
BMW               Bethlehem Middle Works
E                 Envy
F                 Fountain
FP                Fair Plains
GG                Golden Grove
GP                Grove Place
LL                Lower Love
MB                Manning Bay
                                 xii

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Rain gage
Public well—pumped
Public well—not pumped
Private well--pumped
Private well—not pumped
Sampling station on a stream
              xiti

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                              SECTION I

                             INTRODUCTION
DESCRIPTION OF ST. CROIX
        St. Croix is the largest of the more than 50 islands and cays
which comprise the Territory of the U.S. Virgin Islands.   The Virgin
Islands are located 1,100 miles (1,770 km) southeast of Miami, Florida,
and have been a possession of the United States since 1917 when they
were purchased from Denmark (see Figure 1).

        St. Croix is 84 sq miles (217 sq km) in area.  It is about
20 miles (32.2 km) long and 6 miles (9.6 km) wide at its broadest
point (see Figure 2).  A range of low mountains forms a spine along
its longer east-west axis.  The Northside Range at the western half of
the island hugs the northern shore and a flat coastal plain has been
formed from the foothills of the range to the south shore.  It is on
this coastal plain between the two major towns of Frederiksted and
Christiansted that the majority of the people of the island live.  The
island has about 40,000 inhabitants and the major sources of employment
are in alumina processing, petroleum refining, watch assembling,
tourist-related services, or government agencies.  Agriculture, which
used to be the largest source of income on the island, has dwindled
considerably in the last decade.  The growing of sugarcane has been
phased out, leaving beef cattle and dairy products as the major
agricultural enterprises.

        In the latter part of the eighteenth century when agriculture
was the only industry, the entire island was divided up into plots of
about 150 to 300 acres (61 to 122 ha).  Each plot was called an estate
and given a name.  This system of estate division remains today and
forms an important function in the location of any point on the
island.  These names, such as Golden Grove, Adventure, and Negro Bay,
are used throughout this report to aid in the location of areas for
those familiar with the island.

Water Supply

        Along with this shift from a rural agricultural economy
towards industrial growth and tourism, there has been a rapid increase
in population and a rise in the standard of living.  With these
changes has come a massive increase in total water consumption.
Unfortunately the low topography of the island does not promote the

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                                                                                                                               0    100  200  300
                                                                                                                                    MILES
                                                                                                                                 0  ~50  100 150
                                                                                          VENEZUELA
                                                       Figure 1. Location of St. Croix, U.S. Virgin Islands.

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                                                                    Figure 2. St. Croix, U.S. Virgin Islands.

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formation of rain clouds as reliably as on the larger, higher islands in
the Caribbean.  The average rainfall is only 40 to 45 in. (102  to  114 cm)
per year.  This combined with the extremely high evapotranspiration rate
restricts the amount of surface and groundwater on the island available
for water supply usage.

        Although each dwelling is still required by law to be
constructed so as to catch and store the rainwater from its roof as a
basic source of water, it has been necessary for the government to
augment this supply through a water distribution system.  This
additional water was originally derived from wells located in the
central part of St. Croix, and is now supplemented by large seawater
desalinization plants located in Christiansted and mid-island at the
Martin Marietta Alumina Company.

        The combination of rainwater catchments and groundwater could
go a long way in satisfying the demand for water on the island, but
they are very much dependent on the pattern of weather in the area.
In the past few years this pattern has tended to minimize the benefits
to be derived, directly or indirectly, from the rainfall.  Figure 3
compares rainfall and the water levels in two wells in central St.
Croix over the past 4 years.  Although the average rainfall  over this
short period approaches the norm expected, the distribution of
rainfall throughout the individual years has made it difficult for
efficient cistern storage and has detrimentally affected the efficient
natural recharge of the groundwater.

         The combination of reduced rainfall, a diminished groundwater
supply, and increased individual consumption has caused the demand to
exceed the production of water from these traditional  sources.
Although only about 70 percent of the populace is connected to the
public distribution system, it has been necessary to use increasing
amounts of desalinized water in the system until presently the
groundwater contribution to the total water supply picture is only
about 30 percent.  This is discussed in further detail in Section V
under the topic, Water and Wastewater Systems on the Island.

        The desalinized water for the potable system is produced by
two distillation plants, one operated by the Virgin Islands  Water and
Power Authority (WAPA) and the other by the Martin Marietta  Alumina
Company.  Each provides about 0.65 mgd (2,460 cu m/day) to the system.
The average amount of water being distributed in the public  system
during the spring of 1975 was about 1.8 mgd (6,813 cu  m/day)f

        This amount represents the supply and not the  demand, as the
demand for water exceeds this figure by possibly as much as  30 percent
for just the existing hookups.  Additionally, in the past year or so
at least 14 miles (22.5 km) of water mains have been added to the
system.  Connections to these new mains have been almost nil  as there
is insufficient water in the system to properly service any  new
consumers.   It has been quite normal to wait 2 to 3 years for

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                                          Figure 3. Rainfall and groundwater potentiometric levels in central St. Croix.

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individual homes to obtain permission to hook up to the potable
distribution system and even after the connection is made there is no
assurance that a steady supply of water will be available.

Hater Costs

        As the price of petroleum has increased so has the cost of
producing desalinized water, which requires oil-fired boilers to
produce the steam used in the distillation process.  Since almost two-
thirds of the water in the public potable system is derived from
distillation plants the aggregate cost has increased drastically.  The
changing cost to the public system for this water over the past three
years is shown in Figure 4.  This shows the cost to the government
from both the WAPA and the Martin Marietta plants.  In June, 1975, the
cost of water from these plants was $5,16/thousand gal ($1.36/cu m)
and $6.86/thousand gal ($1.81 cu m) respectively, for an average of
0.75 mgd  (2,839 cu m/day).  This is compared to the estimated cost of
$0.30/thousand gal ($0.08/cu m) for groundwater produced on the
island.

        Although water is sold to the general public for $4.00/
thousand gal ($1.05/cu m), which is about ten times the cost in the
mainland United States, the government is still losing money in
distributing it due to the high proportion of expensive desalinized
water used.

        At present the WAPA is increasing its water supply capacity by
the construction of a new 2.25 mgd (8,516 cu m/day) desalting plant
which should be on line sometime in the latter part of 1975.  Although
this could possibly give  the  island a surplus of water, it is realized
that the Martin Marietta Alumina Company will soon be phasing out  its
sales of water to the government and that in the past the consumer
demand has always risen to match the amount of water that the
government has been able to distribute.

Water Reuse

        With the water supply system based mainly  on desalted water,
the water  is converted from seawater to fresh water at great expense,
used once, and then returned  to the ocean as wastewater.  Not only is
it expensive, but also the expansion of the desalination  facilities
creates a  situation where there is a greater dependency upon water
from a single source  instead  of the more versatile multiple-source
concept which the island  still possesses.   If this desalted water
could be  used once, processed for reuse, and utilized again before
being completely degraded by  discharge back  into  the ocean, the cost
of the processing between uses should be significantly below the
expense currently required to recover fresh water  from the ocean  by
distillation.
                                    6

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        The potential source of this reusable water, public wastewater
flows, receives only primary or no treatment at all before being
discharged into the ocean.  However, in accordance with the current
implementation of federal environmental legislation, it may soon be
necessary to provide secondary treatment to all wastes discharged from
the island.  All of these steps require progressively higher quality
effluent, and very little extra processing is required to adapt these
effluents to various water reuse programs on the island.  Among these
programs would be reuse for agricultural irrigation, pisciculture,
groundwater augmentation, fire control, prevention of saltwater
intrusion, and various industrial purposes.

        The idea of wastewater reclamation is not new, the inadvertent
reuse of wastewater being rather widespread throughout the United
States and the rest of the world.  It is a major factor necessitating
the treatment of water before distribution to the public.  Koenig
(1966) in a study of 155 communities in the United States served by
surface water found that, including industrial wastewaters, the median
reuse factor was about 50 percent.  Throughout the world there are
areas where deliberate reuse of wastewater is being practiced.  These
are predominantly in the arid regions where the cost of procuring new
water exceeds that of processing wastewater for reuse.  Localities in
California, Texas, Israel, and South Africa are utilizing wastewater
reclamation plants for various purposes.


OUTLINE OF THE WASTEWATER RECLAMATION PROJECT

Project Description

        The concept of wastewater reclamation and its subsequent reuse
for groundwater recharge on St. Croix has been studied and suggested
by the U.S. Geological Survey (Robison, 1972; Jordan, 1973) and
engineering consultants (Engineering-Science Inc., 1968).  This report
covers a study entitled "Wastewater Reclamation Project on St. Croix,
U.S. Virgin Islands," which was sponsored by the U.S. Environmental
Protection Agency (EPA) and the Virgin Islands Government, Division of
Natural Resources Management.  In this project-a portion of the flow
normally discharged to the sea from the island's new primary treatment
plant at Bethlehem Middle Works was used for reclamation purposes.
The flow was diverted and processed in an advanced wastewater
treatment plant (AWWTP) adjacent to the primary plant.  Processing was
by biological and physiochemical means and produced a treated
wastewater which was-conveyed by a force main to recharge areas
located about 1-1/4 miles (2 km) away.  Here it was stored in a
holding tank and introduced into the groundwater aquifers by various
methods.  This was for the purpose of improving the yield of wells in
the area and assisting in preventing further seawater intrusion which
threatens Fair Plains, one of the government's major we'll fields on
the island.
                                   8

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        The project was handled for the government by the consulting
engineering firm of Black, Crow and Eidsness, Inc., of Gainesville,
Florida.  Project personnel worked on the island continuously from
April, 1971, to October, 1975, studying the problem, supervising the
construction, operating all of the facilities involved, and evaluating
the results.  Early in the project the recharge sites were located and
a study area of about 8 square miles (23 km) was defined, which
included the drainage basins where the recharge activities would take
place.  Wells and surface water throughout this study area were
monitored for 2-1/2 years in order to clarify the hydrological
characteristics of the region and to establish baseline data for the
project before recharging began.  The study area is outlined in
Figures 2 and 5.  The most important portion of the region is shown in
detail in Figure 6.

Project Objective

        The overall objective of this project was to determine the
feasibility of increasing the freshwater reserves on St. Croix by the
use of wastewater reclamation.  This consisted of the artificial '
recharge of the groundwater on the island using tertiary-treated
wastewater effluent.  The project entailed not only the operation of
the treatment and recharge facilities but the study of the wastewater
collection system; the geohydrological character of the recharge area
and the subsequent water distribution; evaluation of the effects on
the groundwater regime; and the costs associated with the production
of fresh water in this manner.

Project Phases

        The project was divided into four phases:  initiation,
investigation, operation, and evaluation.  A diagrammatical outline of
these phases and their scheduling during the project is shown in
Figure 7.

        Phase 1  - Initiation.  This included the discussions and
efforts made in formulating a proposal that outlined the steps of the
investigation and proposed a budget to match these plans.  During this
time the grant application and approval  were obtained and a
contractual  agreement between the parties involved was defined and
finalized.  This phase ended in March, 1971, with the assignment of a
full-time engineer to the project who began field work on St. Croix
the following month.

        Phase 2 - Investigation, Design,  and Construction.  This phase
covered the investigation of the conditions that affect the recharging
operation and included the selection of the sites for recharging and
the area to be monitored during the project.  Studies were made of the
hydrology, geology, soils, land use, groundwater, and surface water,
in the study area.  A monitoring program was begun to establish
baseline data on water quality and quantity.  An advanced wastewater
                                   9

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STUDY AREA
 BOUNDARY
  Figure 5. The project study area in central St. Croix,

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                                     PUBLIC SAFETY
                                     HEADQUARTERS
                                               CHECK DAMS
                                               	GUT
                                           FISH
                                          PONDS
                60     GG-5
        GOLDEN GROVE
        RECHARGE AREA
               I    \
                                                          SPUR LINE ^
             SPREADING BASINS
                 (TYPICAL)
NEGRO BAY
RAIN GAGE
SPREADING BASINS
                                                                                             FAIR PLAINS
                                                                                             WELL FIELD
    NEGRO BAY
 RECHARGE AREA
           SURGE TANK
   SPRAY \\ ^rz
1000
    MAIN TO CONVEY
RENOVATED WASTEWATER
   TO RECHARGE AREA
         Scale Feet
       0     500
       0   100  200 300
       Scale in Meters
                                                                                  PRIMARY WASTEWATER^X
                                                                                  TREATMENT  PLANT    \\
                           Figure 6.  The Golden Grove and Negro Bay area in central St. Croix.

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INVESTIGATION DESIGN
I INITIATION i AND CONSTRUCTION I OPERATION
1
INITIAL MEETINGS
OF EPA, TERRITO-
RIAL. AND
ENGINEERING
OFFICIALS
V

1 1
ENGINEER
ASSIGNED FULL
TIME ON
PROJECT
(MARCH, 1971)
x

SALINE WASTE-
WATER AND
FLOODS HALT
RECHARGING
OPERATIONS

EVALU-
ATION

EVALUATION
AND FINAL
REPORT
                                                                       NOTE: SHADING INDICATES THE ASSUMPTION OF CONTROL
                                                                            BY THE VIRGIN ISLANDS GOVERNMENT
to
                  PROJECT INITIATION.
                  GRANT PROPOSALS,
                  AND CONTRACT
                  FINALIZATION
                                                               DESIGN AND
                                                               CONSTRUCTION  OF
                                                               RECHARGE FACILITIES
                INVESTIGATION OF THE SOILS, GEOLOGY.
                HYDROLOGY, WATER, AND WASTEWATER ON
                ST. CROIX INCLUDING WATER QUALITY
                MONITORING
                                                           OPERATION
                                                              OF
                                                           RECHARGE
                                                           FACILITIES
                                                          REPAIR.
                                                          UPKEEP
                                                          RE-
                                                          CHARGE
                                                          FACIL-
                                                          ITIES
                                            CONTINUED MONI-
                                            TORING OF WATER
                                            QUALITY AND
                                            QUANTITY
DESIGN
OF
AWWTP


CONSTRUCTION
OF THE AWWTP


OPERATION OF S
THE AWWTP S
            1969
1970
1971
1972
1973
1974
1975
                                   Figure 7. Schedule of the phases of the wastewater reclamation project.

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treatment plant (AWWTP), force main, holding tank, and recharge
facilities were designed and constructed.  All facilities were tested
for operation.  This phase was completed in January, 1974.

        Phase 3 - Operation.  Phase 3 began in February, 1974, and
consisted of operating the plant and recharge facilities.
Improvements and modifications were made to the AWWTP and recharge
facilities as required during the operational phase.  Recharging
operations continued until October, 1974, when they were curtailed due
to the high total dissolved solids (TDS) in the incoming wastewater.
The high TDS was caused by the saltwater flushing system employed in the
town of Frederiksted which was connected to the central wastewater
interceptor system during that month.  In November, 1974, the primary
plant and wastewater collection network were rendered inoperative by
heavy rains and flooding.  Also damaged were the recharge facilities in
Estate Golden Grove.  Repairs to all facilities were completed by May,
1975.  However, further recharge operations were restricted by the high
TDS in the collected wastewater due to the use of salt water for
flushing in the town of Frederiksted. The operational phase of the
project ended in May, 1975, with the complete transfer of the project
facilities to the Virgin Islands Government, Division of Natural
Resources Management.

        Phase 4 *• Evaluation.  The data gathered throughout the
project were evaluated to determine the actual feasibility of the
project, both on a technical and economical basis.  This final report
contains the results of the evaluation and contains recommendations
for further development of the wastewater reclamation project.  Phase
4 was completed in November, 1975, with the completion of this report.
                                   13

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                              SECTION II

                               SUMMARY
        The wastewater reclamation project on St. Croix has
demonstrated that it is possible to economically augment the island's
freshwater reserves through the use of reclaimed wastewater for the
artificial recharge of groundwater.  The most successful method of
recharge has been with the use of spreading basins in Estate Golden
Grove.

        The project has spanned close to 5-1/2 years from its
initiation to the publication of this final report.  It has resulted
in the construction and operation of an advanced wastewater treatment
plant and recharge facilities which can process up to 0.5 mgd (1,892
cu m/day).  Investigation of the geology, hydrology, and groundwater
movement in the area and the compilation of considerable data on
treatment plant operations, recharge activity, well water quality, and
groundwater quantity has been completed.

        After numerous delays in the construction of the treatment
plant, recharging operations began in February, 1974.  During the
subsequent 8 months various minor problems in the system were resolved
and plant production steadily increased until in October, 1974, it was
possible to recharge an average of 1 mil gal/wk (3,785 cu m/wk).  The
restriction at that point was caused by a lack of treated wastewater
effluent, rather than the capacity of the recharge areas.

        Of the two recharge sites utilized it was possible to
eliminate one and focus all attention on the most feasible site at
Estate Golden Grove.   At the recharge rate used in Golden Grove, no  -
significant adverse effects were observed among the parameters examined
in the groundwater extracted downstream of the project.   There was,
however, evidence of a notable increase in available groundwater in the
vicinity of the recharge activities.

        The major problems experienced during the project's
operational phase were:

            The lack of sufficient wastewater for treatment and
        subsequent recharge.

            The mechanical failure of equipment associated with the
        treatment process.
                                   14

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             The transfer, to the central treatment plant, of
        wastewater containing a high percentage of seawater.

        This last problem, followed immediately by a record flood on
the island, caused the premature termination of the recharge
activities in October, 1974.  Although the flood damage nas been repaired,
it is not expected that the saltwater problem will be resolved until the
latter part of 1975.  At that time it will be possible to resume the
artificial recharge activities.

        Using the present facilities for treatment and recharging it is
estimated that recoverable groundwater could be increased by  at least
0.35 mgd (1,351 cu m/day) at the recovered water cost of about $2.15/
thousand gal ($0.56/cu m).

        Although this is considerably higher than the $0.30/thousand gal
($0.08/cu m) estimated for recovering the limited amount of groundwater,
it is much cheaper than the cost of $5.16/thousand gal ($1.36/cu m)  for
water produced by the government's desalinization plant on the island
and additionally it will provide a dependable source of fresh water  for
St. Croix.

        In addition to the work on artificial recharge, the project
personnel worked with other public and private entities on the island to
foster the use of reclaimed wastewater for other purposes. This proved
to be successful and broadened community support and participation in
the idea of water reuse.  Among the other reuse projects that are being
carried out on St. Croix are agricultural irrigation, pisciculture,  and
the raising of freshwater clams.

        Continuing research on the project will be carried out by the
territory's Water Resources Research Center located at the College of
the Virgin Islands in St. Thomas.
                                    15

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                             SECTION III

                             CONCLUSIONS
        It is economically feasible to use reclaimed wastewater to
artificially recharge the groundwater on St. Croix.  However, it can
only be accomplished successfully at carefully selected areas on the
island.  A site in the alluvial valley at Estate Golden Grove was
demonstrated to be highly suitable for recharge by the use of
spreading basins.

        With the AWWTP operating at design capacity of 0.5 mgd (1,892
cu m/day) and allowing for down time and losses in groundwater
recovery, it will be possible to recover groundwater for a cost of
about $2.15/thousand gal ($0.57/cu m).  With expansion of the existing
plant and recharge areas to a capacity of 1 mgd (3,785 cu m/day) the
cost can be reduced to about $1.64/thousand gal ($0.43/cu m).

        It is not economical to artificially recharge and recover any
of the subsequent groundwater from the marl formation in the recharge
area in Estate Negro Bay on St. Croix.  Infiltration and percolation
rates were too low and eyapotranspiration rates were too high to
warrant further efforts in this type of soil structure.

        With the existing AWWTP it is possible to treat the incoming
wastewater, as it was constituted during the 8 months of recharge
activity, so that with normal operation the effluent will have a
turbidity of less than 3 Formazin turbidity units (FTUs) and a free
chlorine residual of over 3 mg/1, after a 30-minute contact time (see
Section VIII).

        The use of an effluent low in organics and turbidity with a free
chlorine residual for artificial recharge in the recharge basins in
Estate Golden Grove will permit the operation of-the basins with a
minimum of odor or algae problems and a high rate of infiltration into
the soil.  The average sustained rate of infiltration experienced in the
Golden Grove basins was about 14 gpd/sq ft (0.57 cu m/day/sq m) on a wet
cycle basis.

        The recharging activities which took place in Golden Grove and
Negro Bay, during the 8-month period of project operations in 1974, did
not significantly affect the water quality of any pumped well in the
area on the basis of the parameters examined (see Section VII).

        The use of seawater for flushing purposes must be terminated in
areas where the wastewater is to be processed for reuse.
                                   16

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                              SECTION IV

                           RECOMMENDATIONS
Continue the Project

        The reclamation of wastewater for artificial  groundwater
recharge should be continued on St.  Croix.  It has proved to be an
economically feasible enterprise and should be a benefit to the island
not only for groundwater augmentation but other uses  as well.

Strengthen the Organization

        The entire reclamation project is of sufficient importance and
complexity that it requires careful  organization and  staffing to
ensure its future success.  If the operation continues within the.
Division of Natural Resources Management, it should be organized with
one person having the responsibility for operations,  monitoring,
distribution, and coordination with other agencies.  This person
should be an engineer with experience and/or training in both the
fields of water supply and wastewater treatment.  He should probably
hold the title of Assistant Director.  There should continue to be a
separate superintendent for the AWWTP since this, in itself, is a
full-time job.

        The AWWTP and recharge facility must be adequately manned.  It
presently is understaffed and will not be able to sustain full
production for very long without additional staff.

        Coordination with other departments and individuals concerned
with the reuse of water is vital to the efficient utilization of this
resource.  The program of expansion and promotion of water reuse for
beneficial purposes must continue to stress the multiuse concept of
the project.

Coordinate Future Planning

        The concept of the reuse of water must be incorporated into
all aspects of planning for water supply and wastewater collection on
St. Croix.  Although it may not be advantageous to recycle all of the
water on the island, all new water and wastewater installations and
changes, both public and private, must be reviewed as to their effect
on the reclamation project.  A master plan for water management on St.
Croix, which will be published about March, 1976, will aid in this
evaluation process.
                                  17

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 Control  Saltwater Usage

         The use of seawater as a source of fire and flushing water
 must be  carefully evaluated since its use is not compatible with the
 reclamation of wastewater at a reasonable cost.  It must be
 remembered, though,  that salt water is a very inexpensive source of
 water.   The complexity and expense of attempting to eliminate all
 saltwater discharges to the wastewater collection system on the  island
 may not  be commensurate with the benefits derived from a 100 percent
 reuse capability.

         At the present time, it is recommended that the saltwater
 usage in Frederiksted be eliminated by the direct use  of fresh water
 in  the saltwater system.   This will  require about 0.08 mgd (300  cu
 m/day) of fresh water.   This will  permit the use in the AWWTP of at
 least 0.5 mgd  (1,892 cu m/day) of low chloride wastewater for
 reclamation purposes.   The additional  fresh water produced through
 artificial  recharge  and recovery can be returned to the system to make
 up  the flushing water.   This will  permit the reclamation project to
 operate  until  about  June,  1977,  when the wastewater interceptor  system
 is  completed to Christiansted and  the wastewater containing  salt water
 from Christiansted will  be delivered to the central  treatment plant on
 the south shore.   Christiansted  uses an estimated 0.6  mgd (2,271 cu m/day)
 of  seawater for flushing  purposes,  which is over 7 times the  amount used
 in  Frederiksted and  hence  difficult  to replace with fresh water.

         If,  by approximately June,  1976,  plans for the elimination  of
 all  the  salt water in  the  Christiansted area  have not  been finalized
 and agreed  to  in plan and  principle  by the  Public Works  Department,
 V.I.  Housing Authority, and  the  owners  of the  major  hotels,
 condominiums,  and  restaurants  using  salt water,  then it  is doubtful
 that  the  wastewater  coming  from  the  area  can  be  used for  reclamation
 purposes  and without further modifications  the project would  probably
 be  shut down again in 1977.  The unilateral  prohibition  of saltwater usage
 in  the area  without  an  immediately available,  cheap alternative would
 probably  create an extremely  negative  reaction against  the concept  of
water reuse.

Split the Wastewater Flow at the Primary  Plant

        If  the  salt water cannot be  eliminated from the Christiansted
area, then  it  is recommended that a  new  pumping station be built
adjacent  to  the collection structure at  the primary treatment plant.
This pumping station would pick up a percentage of the wastewater
entering  the structure from the central and western portions of the
island before it is contaminated by  the salty wastewater from
Christiansted.   The pumping station would then transfer the wastewater
directly to  the AWWTP with provisions for screening and degritting
enroute or via one of the primary settling tanks.  In the latter  case,
the primary facility would need to be altered to permit the splitting
                                    18

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of flows within the plant so that the high and low IDS wastewaters
could be treated separately.

        With this plan, reclamation efforts could be continued and
expanded to the capacity of the influent available.  If successful
extended operation at that level indicated that the usage could be
expanded to efficiently utilize most of the wastewater from
Christiansted; then careful, coordinated plans could be made and
carried out to initiate the needed changes to smoothly incorporate
this additional supply into the water reuse system.

Promulgate Regulations Concerning Reuse

        As soon as practicable, the proper territorial agency or
agencies should promulgate regulations specifically governing the use
of reclaimed wastewater for groundwater recharge,  agricultural
irrigation, and any other activity involving water reuse.  These would
provide guidelines for the planners and operators associated with the
facilities.  As the EPA has gained additional knowledge and experience
in the field of water reuse since it initiated this project in ]969, it
is advised that the EPA be consulted for guidance and assistance in
reviewing the regulatory and monitoring portions of the project in the
future.

Monitoring Future Operations

        Monitoring in the study area should be continued.  This should
include chemical and biological analysis and the gaging of water
levels in selected wells.  A thorough review of the type of analyses
run should be made and modified where appropriate.  It is suggested
that BOD and COD measurements of the wells be suspended and that, at a
minimum, all the tests covered in the proposed new EPA drinking water
standards (Environmental Protection Agency, 1975) be instituted.

Disinfection of Recovered Water

        All water extracted from the Golden Grove well field in
association with the recharge operation should be monitored and
thoroughly disinfected, as a safety precaution, before distribution.
The Fair Plains collection tank and pumping station should be the
focal point for monitoring, disinfection, and distribution of this
water.  The two direct taps onto the force main connecting the Golden
Grove well field to the Fair Plains tank should be either
disconnected or altered in a way that will assure proper disinfection
of any water used.  These two taps feed the adult correctional
facility and the Public Safety Headquarters.

        The disinfection operation at Fair Plains must be carefully
monitored to ensure that it is being carried out properly at all
times.  Consideration needs to be given to the installation of a gas
chlorinator instead of the current dry chemical chlorinator system.
                                   19

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 Prohibit  Industrial Wastes

        Industrial wastes should  not be added to  the wastewater
 ultimately used for reclamation purposes unless they have been
 carefully analyzed and evaluated.  This is to ensure that no harmful
 exotic  substances are introduced  into the reuse system.

 Monitor Coagulants' Effectiveness

        The effectiveness of using aluminum sulfate as a coagulant and
 filter  aid should be continually monitored as the project continues.
 The projected changes in the major water source in the western portion
 of the  island from groundwater to distilled water may have a
 detrimental effect on the alum reaction.  Other chemicals, including
 polyelectrolytes, may be required in the future.  Any chemicals
 employed  should be approved by the EPA for water  treatment usage.

 Improve Groundwater Recovery

        The existing recharge facilities were not intended to maximize
 the recovery of recharged water.  Additional groundwater extraction
 facilities should be constructed  in Estate Golden Grove to facilitate
 this.

        The emphasis should be on the removal of the groundwater from
 the upper aquifer which is the one being artificially recharged.
 Figure  8  is a sketch of the Golden Grove recharge area and shows the
 sequence  of well field development that should take place.  Initially,
 at least  the first six recovery wells should be installed.  These wells
 are located so as to permit rapid removal of water from under the
 scattered recharge basins.  The additional wells are planned to coincide
 with the  expansion of the recharge basins as shown in Figure 9.  A
 feature of this development should be a horizontal collection system
 constructed along the northwest property boundary between wells RW-12,
 RW-6, PW-1, RW-1, and PW-4.   At this point the upper aquifer is close
 enough  to the surface to permit excavation and installation of the
 necessary collectors.  A sketch of this system is shown in Figure 10.
 As information is gained through the construction and pumping of the
wells,  the proposed locations of the additional wells and basins should
 be continually reevaluated.

        All extraction facilities, wells, or collectors shown have been
 located so as to maintain the minimum 50 ft (15 m) horizontal  distance
 between the wells and the recharge facilities as required by the V.I.
 Division of Natural  Resources Management (Stolz, 1975).  This  placement
affords a high degree of hydraulic efficiency for the removal  of
 recharged water from below the basins,  but these wells should be
carefully monitored to ensure that the desired groundwater quality can
be maintained.
                                   20

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Expand the Recharge Area in Golden Grove

        Expansion of the spreading basins should take place as shown
in Figure 9.  The area suitable for surface methods of recharging is
rather limited in size and expansion in Estate Golden Grove beyond the
areas shown will probably be uneconomical.

Improve the Performance of the AIMTP

        The performance and production of the AWWTP would
significantly improve if a steady flow rate to the plant could be
maintained.  This can be accomplished by relocating the influent pumps
from the present wet well to the primary clarifier along with the
installation of a new, larger diameter pipeline.  This is described in
detail in the section on project facilities under the subheading Plant
Expansion.  The majority of the work can be accomplished by local
government personnel and the materials required would cost less than
$10,000.  It is urged that this change be instituted as soon as
possible.

Consider AIMTP Expansion

        The present plant and installed equipment have the capability
to permit considerable expansion of plant capacity with a relatively
low amount of capital investment.  However expansion should only be
carried out if there is full utilization of the present production and
a reasonable prospect for the use of additional reclaimed water.
Plant expansion is discussed in further detail in the section,
Description of the Project Facilities.

Expand Local Research

        Research projects on water reuse as they apply to conditions
within the territory should be encouraged.  The newly established
Water Resources Center at the College of the Virgin Islands should
take a leading role in directing and funding this research.  Some of
the following are suggested topics for research.

            The long- and short-term effects on the various local
        soils as the result of using reclaimed wastewater for recharge
        and irrigation purposes.

            The fate of nutrients, organics, and microorganisms in
        reclaimed wastewater as it moves through the various types of
        local soils.

            Viral studies in the reclaimed wastewater and recovered
        groundwater.
                                  21

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          *rft
   TO NEGRO BAY VM FROM THE NEGRO BAY
                  WELLFIELI
    METER

   TO
   STORAGE
   TANK
                                 DIRT ROAD
                                                 BURIED 4" WELL WATER
                                                 COLLECTOR LINE
                                  BURIED 6" FORCE MAIN
                                  FOR TERTIARY EFFLUENT
                                                           FORCE MAIN
                                                           STANDPIPE
                                                           AND VALVE
                                   BURIED 6"
                                   WATER LINE
                                  AIR RELEASE
                                  VALVE
                                                        CONCRETE FORD
       WELL
       TO BE
      DRILLED
              FORCE MAIN
              STANDPIPE
              AND VALVE
     DRILLING
     PRIORITY
                                                   .BASIN
                                                    NO. 5
 RW-1 = FIRST
RW-2 = SECOND
    ETC.
RW= RECOVERY WELL
                                \ BURIED VALVE
                                                    DRAINAGE DITCH
               FROM RECLAMATION ป' TO FAIR PLAINS
               PLANT         -ป- 1 STORAGE TANK
                                  k

          Figure 8. Future well field development in the Golden Grove recharge area.
                                   22

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          WESTERN LIMIT
            F GOVT. PROPER!
                                    I V V I I ^K     ^
                                    POLE*  ^MONUMENTS
• •'••• *'-J
	• • *-^
FORCE
MAIN
STANDPIPE
AND
VALVE
                                                        PAVED PARKING LOT;
                          "li             ^*.
                          I             \
                          4 !• BASIN NO. 3 I

                                                          PUBLIC SAFETY
                                                           HEADQUARTERS
                                           BURIED 6"
                                           UUATFR MAIN    GRAVIIY
                                                         WASTEWATER
                                                         INTERCEPTOR
                                                    PWR FROM
                          DRAINAGE DITCH 7^-—  POLE GROVE PLACE

                               I
                              OUTER FENCE
                              OF ADULT
                              CORRECTIONAL
                              FACILITY
0   50   100

0  10  20  30
                              Figures. (Extended)
                                     23

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TO NEGRO BAY

 METER

TO
STORAGE
TANK
'FROM THE NEGRO BAY
WELLFIEL
                   DIRT ROAD
                                    BURIED 4" WELL WATER
                                    COLLECTOR LINE
                                   PWR POLE

                                BU~RIErT6" FORCE MAIN X
                                FOR TERTIARY EFFLUENT
                                                           FORCE MAIM
                                                           STANDPIPE
                                                           AND VALVE
    RECOVERY WELL
    TO BE DRILLED
    BASINS TO BE
    CONSTRUCTED
    CONSTRUCTION
    PRIORITY
      1=FIRST
      2=SECOND
                 BURIED
                 WATER
              FORCE MAIN
              STANDPIPE
              AND VALVE
                                4" ALUMINUM
                                IRRIGATION
                               BURIED VALVE
            FROM RECLAMATION H TO FAIR PLAINS
            PLANT          -ป-  I STORAGE TANK
   Figure 9. Future expansion of the spreading basins in the Golden Grove recharge area.
                                24

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                                     PWR/
                                    POLE/
— ^  r
  (.  BASIN NO.
 I     NEW BASIN
         NO. 5      |
                             PAVED PARKING L

11- BASIN NO. 3  \

    OUTER FENCE
    OF ADULT
    CORRECTIONAL
    FACILITY
                            xx CORNER OF
                                PUBLIC SAFETY
                                HEADQUARTERS
                 BURIED 6"      rRAVITY
                 WATER MAIN    GRAVMY
                               WASTEWATER
                               INTERCEPTOR
                       • PWR  FROM
DRAINAGE DITCH /		  POLE  GROVE PLACE
                                                  0   50  100

                                                  0  10 20 30
    Figure 9. (Extended)

-------
'ฑt.'. :t.y.'.Kj.'.'.VPfrff-
    EXISTING •:
      WELL  Jj
                                     150 ft (46 m)
                                                                  i
APPROX. 15
   (4.6m)  .
                                 •xrfftaxfXfWfa*
                                            ปvx^ซซ4es^^S5^iป^xซปปSBป^5Mr•^:•ซ":<•:•ปK
                                                 HORIZONTAL
                                       EXISTING
                                        UPPER
                                       AQUIFER
     UNDISTURBED SOIL
                            WIDTH OF EXCAVATOR
                            lซ    BUCKET    ป|
                             >.,..•?..,•: •
                             •.;.;<ป;.-;o.-.  CLEAN  ',.•.
                                                     TWO SHEETS OF HEAVY
                                                          TAR PAPER   ::;;;
                            ' •  ••  . ป• •  ซ • * •ป o *.
                            • •'•ฐ.'i -„••'*! •* • • ป .  • .• i
                            i-ซ.'vi •">•••.•••.•—ป'.y--'
                            ^1^" ,* •rrr^ej. - ._ฃ.ป • t > J
                        8-in. (20 cm) PVC PIPE
                      'SLOTTED ON TOP EVERY
                             4-in. (10cm) ,<ฑm&.
                                         UNDISTURBED SOIL
                                  SECTION A-A
                             Figure 10.  Proposed horizontal well.
                                          26

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            The uptake of nutrients, heavy metals, microorganisms,
        etc., in local plant materials as a result of the use of
        reclaimed wastewater for irrigation purposes.

            Quantification of the loss of groundwater by the
        transpiration of subtropical vegetation in the territory.

            Evaluation and revisions, where necessary, of regulations
        and guidelines governing the use of reclaimed wastewater.

        A review of the areas of research needed in the field of water
reuse has been made in the paper, "Research required to establish
confidence in the potable reuse of wastewater," (English et al., 1975).
This paper provides additional  topics for investigation.

Reduce Costs

        The best method to reduce costs would be to combine the  staffs
of the adjacent primary treatment plant with that of the AWWTP.   The
present arrangement where each  plant has a separate staff is an'
inefficient use of manpower and equipment.  Combining them under one
government agency with one head would reduce overall labor costs and
permit coordinated operation to the benefit of the wastewater
reclamation project.
                                  27

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                               SECTION V

       PRELIMINARY INVESTIGATIONS OF THE RECHARGE AND STUDY AREA


 SELECTION OF THE RECHARGE AND STUDY AREA

         The key decision in the project was the selection of the
 recharge area.   If an unsuitable site had been selected and developed,
 then the remainder of the effort on the project would have been
 largely wasted.  Therefore the preliminary investigations centered
 around the selection of a suitable site and the definition of its
 hydrogeological features.

         In the  selection of the areas which were used for recharging,
 there were two  major constraints involved.   The first was financial  in
 that the budget for  the project only provided  sufficient funds  for  up
 to  2 miles (3.2 km)  of force main.   Thus,  the  maximum distance  of the
 recharge area from the advanced wastewater treatment plant was
 predetermined.

         The second major constraint was  that the basic decisions as  to
 the pattern of  wastewater interceptors  and  the location of the  central
 primary treatment  plant were made  by others  before  this project was
 begun.   Since the  influent for  the  advanced  wastewater treatment plant
 (AWWTP)  would come directly from this  primary  plant,  the location of
 that  plant determined  the site  of  the advanced  wastewater  treatment
 plant.

         The budget for  development  of the recharge  areas was based
 upon  the understanding  that  the  land utilized must  be  obtained at
 little  or  no cost.  At  the  time  when the original proposal was
 outlined in 1969,  local  officials had indicated  that  there would be
 little  problem  in  using  land at  Estate Barren Spot  in  central St.
 Croix.   This probably seemed natural at the  time as the area then
 consisted of abandoned  fields of sugarcane.  The recharge areas were
 proposed for a  location which was on alluvial soil and  in the same
 hydrological basin as one of the larger public well fields on the
 island.

         However, between  1969 and the start of the project in 1971,
the fields  in question and almost all of the surrounding land were
purchased or optioned by a local developer who began to construct
homes on the site.  Despite this, it was hoped that perhaps the
operation could  be handled in certain greenbelt areas within the
                                  28

-------
development which would be beneficial for both the project and the
developer.  Subsequent negotiations on this subject proved otherwise, as
the financial and operational conditions that were suggested by the
developer did not appear feasible.  The costs would have vastly exceeded
the funds available for purchase of the lands and the restrictions would
have seriously hindered the success of the project.

        Investigations were then conducted to find a new site for the
recharge operations.  One important criterion for the alternative site
was that it be located on government-owned or controlled land.  This
would avoid the necessity for the purchase or lease of the property, and
would give the government control over the operation and full possession
of the facility upon completion of the project.

        In selecting an alternate site, the new primary treatment plant
was used as a center and all the government holdings within a radius of
three miles were determined from tax records.  These included territorial
government, federal government, and Virgin Islands Port Authority lands
(see Figure 11).  The current and future uses for the land were determined.
Much of the land, although presently not used, was scheduled for develop-
ment in the immediate future.

        A study was then made of the general soil and geological
conditions existing at each site.  For the soils investigations, two
reports published by the Soil Conservation Service of the U.S. Depart-
ment of Agriculture (USDA) proved extremely useful.  These were: Soils
and Their Interpretations for Various Uses, St. Croix, American Virgin
Islands (McKinzie et al., 1965) and Soil Survey. Virginlslands of the
United States (Rivera et al., 1970).  They delineated the soils and
their engineering and agricultural uses throughout the island. Their
concern has been with the characteristics of the profile of the upper 60
in. (152 cm) of the soil.. This layer is of primary interest to the
project due to its ability to permit infiltration and percolation of the
water to be recharged.  An interpretive map in the first publication
which was of great value was entitled, "The soil limitations for resi-
dences with individual septic tanks." These limitations were based on
many of the characteristics such as percolation rate, shrink-swell
behavior, depth to water table, etc., that would also apply to the arti-
ficial  recharge operation.  On this map the soil conditions were inter-
preted as providing slight, moderate, or severe limitations to the use of
individual septic tanks.  This information is shown on Figure 12.  Areas
showing slight limitation were those considered most suitable for the
project, although others  were considered.

        Geological conditions have been characterized by Cederstrom
(1950)  and Robison (1972) in separate U.S.  Geological Survey (USGS)
publications concerning groundwater on St.  Croix.  This geological
information, modified by  observations in the field, is shown in Figure
13.  This was an aid in outlining the possible groundwater flow, the
                                    29

-------
BOUNDARY OF
 STUDY AREA
                                                            ORIGINAL SITES*-*
                                                            OF RECHARGE,   /i
                                                            AREA  ^VซsrU
                                                                       Hill
                                                               BARREN SPOT
                                                               WELL FIELD
 Ctoflซh.
r OJd Worl
 ADVENTURE
       FIELD
    Soirl
                                                                                           •"ja—vy  OkHitrBb-La
                                                                                       \   REFINERY CORpAr/./
                                     ซ—=--%-,
                 1r   f :J*-?^^^^^^^^^^P
                 t:'      ;  ~~~~  **ป*
-------
      BOUNDARY
       OF STUDY
'VTป
 ซ,  /  l/si\ป.
                                            DRAINAGE BASIN BOUNDARIES
 3 MODERATE LIMITATIONS


-3 NOT CLASSIFIED
SEVERE LIMITATIONS


SLIGHT LIMITATIONS
                                      -.--*^ STUDY AREA AND DRAINAGE
                                            BASIN BOUNDARY
                                     Figure 12. Soil limitations for septic tanks in central St. Croix.

-------
                                                                                        .
BOUNDARY OF
 STUDY AREA

                       _    _	_
    ^^^^^^^
    gex^   g^^^^^si^^^H^ฎ^^^
                                                      ES2P-&

                                                        N
                                    B
           DRAINAGE BASIN
           BOUNDARIES
           STUDY AREA
j""*   *-'" AND DRAINAGE
           BASIN BOUNDARY
                                      .'/.•/.•.•) ALLUVIUM
                                      >V'.y'/>J (MARLS, SAND & GRAVEL.
                                          AND/OR CLAYSI
                                          MODERATELY PERMEABLE.
                                          TYPICAL REPORTED YIELDS
                                          5 TO 40 GPM
JEALOUSY FORMATION
(GREY CLAY) • NOT WATER
BEARING

ALLUVIUM
(GREY TO BROWN CLAY)
POORLY PERMEABLE.
TYPICAL REPORTED YIELDS
1/2 TO 2 GPM
MOUNT EAGLE VOLCANICS
SUPPLIES SMALL QUANTITIES
OF WATER

DIORITE EXTRUDED INTO
MT. EAGLi VOLCANICS
WEATHERED PORTION ISA
GOOD WATER BEARER
(MARL. CLAY & LIMESTONE)
MODERATELY PERMEABLE
TYPICAL REPORTED YIELDS
10 TO 40 GPM
                           Figure 13. Geological conditions in central St. Croix.

-------
 relative  subsurface  permeabilities and  the  type of water-bearing
 formations  to  be  expected.  Observations made  in  the  field  produced
 specific  information on  soil  conditions, current  land usage, and
 existing  facilities  such as wells, roads, available power,  etc.
 Several temporary roads  were  built and  a trailer-mounted  boring rig
 was  used  to make  soil  borings at  various locations.   Samples were
 evaluated in the  field to determine  the soil profile.  Borings were
 made at three  different  depths—4, 7, and 20 ft (1.2,  2.1,  and 6.1 m).
 The  resulting  20-ft  (6.1 m) holes were  used for the placement of
 piezometric tubes while  the 4-  and 7-ft (1.2 and  2.1  m)  holes were
 utilized  for percolation tests.   These  latter  two depths  were selected
 to give information  on percolation capabilities of shallow  ponds
 versus a  deeper trench arrangement.  The results of the tests were
 used to indicate  the relative capacity  for  percolation between sites.
 The  data  derived  from  the percolation tests in the four areas—Golden
 Grove, Negro Bay,  Adventure, and  Barren Spot—are illustrated in
 Figure 14.

        Three  sites  were intensively investigated.  These were in
 Estates Adventure, Golden Grove,  and Negro  Bay.  The  site at Adventure
 was  discarded  due  to unfavorable  soil conditions.  The Negro Bay site
 indicated some good  percolation values  and  no water table but appeared
 to contain  some hard horizontal rock layers at depths from  8 to 20 ft
 (2.4 to 6.1  m).  The presence of  a hard limestone layer is  a situation
 very typical of the  Kingshill marls  in  which this site is located.

        The  Golden Grove  site was very  similar to the one at Barren
 Spot.  Both  are located  in alluvial valleys above a major public well
 field and had  relatively equivalent percolation results.  However, the
 groundwater  at Golden  Grove is closer to the surface  than that at
 Barren Spot.

        The  recharge area finally selected was one which  made use of a
 dual-site concept.   Two  separate  sites  were used, one at  Negro Bay and
 the  other at Golden  Grove.  The sites selected were made  up of two
 entirely different soil  and geological  conditions but are located
 quite close  to each  other.  This permitted the use of one force main
 and  holding  tank to  supply both areas with only a slight  additional
 amount of piping.   As  these two formations comprise the bulk of the
 geological composition of the coastal plain, the data obtained are
 quite valuable in planning any expansion of the project to other areas
 of the island.

        The Golden Grove portion was the primary site of recharging
 operations with the  Negro Bay area used only for secondary
experimentation.   The Golden Grove project area is part of a larger
parcel owned by the  territory which is  being developed into a
 governmental complex.  The entire parcel is 94 acres (38 ha) and will
 ultimately be the site of a large building complex including an  adult
correctional facility, a juvenile detention center,  and the Public
Safety Headquarters.   At the time of the initial  studies the entire
                                  33

-------
LLJ

S
u.
cc

to


I
o
cc
uj

ffl

_J

LLJ

>

UJ

_!


QC

UJ
                                              NOTE:  7-ft GRAVEL-PACKED HOLES

                                                      PRESOAKED FOR 48 hr BEFORE

                                                      PERCOLATION TEST ON JUNE

                                                      13, 1971.
                                                                A ESTATE ADVENTURE


                                                                | ESTATE BARREN SPOT



                                                                0 ESTATE GOLDEN GROVE



                                                                   ESTATE NEGRO BAY
                  20
40
60            80

        TIME (minutes)
100
120
140
                                                                                                                    160
                           Figure 14. Results of percolation tests made at recharge sites under investigation.

-------
 area appeared untouched and was overgrown with scrub growth.
 Presently, the adult correctional facility and the public safety
 building have been constructed.

         In using this parcel, the permanent installations involved
 with the recharging operations were located so that they will not
 interfere with any of the future buildings planned for the area.  This
 again acted as another imposed restriction in the selection of land
 for recharging.  After extensive discussions, several small areas of
 the parcel were set aside for project use by Lieutenant Governor Maas
 who was supervising the development of the parcel at that time.  These
 areas were generally adjacent to the course of a meandering stream,
 River Gut, which winds through the parcel.

         The basic geological  formation is an alluvial valley with the
 soil types classified as being in the Coamo, Fraternidad, and
 Fredensborg series (see Table 1).  The actual  soil boundaries are not
 sharp in this area and the existence of some nonconforming lenses in
 the soil profiles is common.   The topographic features in the area
 where the groundwater recharge operations in Estate Golden Grove will
 take place are shown in Figure 15.

         About one mile (1.6 km)  down the alluvial valley is the Fair
 Plains  well  field which is the major well field on the island with an
 average production of about 0.24 mgd (908 cu m/day).   It is this well
 field that will  be ultimately affected by the  recharging operations at
 Golden  Grove.

         The  Negro Bay site consists  of about 8 acres  (3.3 ha) spread
 over a  slight saddle between  two low hills.   The underlying formation
 is  the  Kingshill  marl.   The major soils in this area  are classified in
 the Fredensborg  and  Aguilita  series  (see Table 1).  Borings made on
 the site indicated that a  hard layer of limestone existed under most
 of  the  area  at a  depth  of  8 to 20 ft (2.4 to 6.1  m).   This has a mild
 anticlinal shape  with an axis  in a northeasterly direction and a slope
 of  about 3 degrees.   Recharging  operations took place on the south
 side  of the  axis.

         Work  in  this  secondary site  was largely of an  experimental
 nature  to see  if  the  marls  would have  any potential for  artificial
 recharge as  they  are  predominant along  the coast  of the  central  plain.
 Although the major soil types  in the area are  classified  as  having
 moderate to  severe limitations for septic tank  installations,  initial
 on-site  percolation tests produced favorable results.

        After  the selection of the recharge area  was accomplished,  a
 study area was defined for  the project.   This consisted of  the  surface
 drainage area  both above and below the  recharge sites plus some
 additional area to the south which was  thought  to  be related  by
 groundwater flow.  Within the  study  area, wells were selected for
monitoring water quality and water levels.  These  included wells which
                                   35

-------
          TABLE 1.  SOIL CLASSIFICATIONS IN THE PROJECT AREA
Soil Classification
                    Description
Aguilita Series
Coamo Series
Fraternidad Series
Gently sloping to steep, well drained soils that
are shallow over soft limestone or marl.  These
soils formed in residuum derived from limestone.

In a typical profile the surface layer is very dark
grayish brown and light brownish gray gravelly clay
loam about 6 in. (15 cm) thick.  Below this is
mixed very dark grayish brown firm calcareous
gravelly clay loam that is 50 to 70 percent lime-
stone fragments.  The substratum, at a depth of
about 10 inches, is mostly soft limestone but
contains hard limestone concretions.  The soft
limestone material can be penetrated with a spade.

Drainage is good, and the permeability is moderate.
The water table is low.

Gently sloping well-drained soils that are deep
over volcanic and limestone rocks.  These soils
occur on alluvial fans and terraces.  They formed
in sediments derived from these rocks.  The sedi-
ments range in texture from clay to sand.

In a typical profile the surface layer is very dark
grayish brown clay loam about 8 in. (20 cm) thick.
It contains a few rock fragments.  The subsoil is
very dark grayish brown and yellowish brown, firm
clay. It also contains a few rock fragments.  The
substratum, beginning at a depth of about 24 in.
(61 cm), is yellowish brown, friable, calcareous
clay loam stratified with sand and gravel.

Moderately well drained soils that formed in clayey
sediments derived from volcanic and limestone hills.

In a typical profile the surface layer is very dark
grayish brown clay about 13 in. (33 cm) thick.
Below this, to a depth of about 62 in. (157 cm),
is light olive brown calcareous, very firm clay.

Drainage is moderately good.  Permeability is slow.
                                    36

-------
                            TABLE 1 (CONTINUED).
Soil Classification
                    Description
Fredensborg Series
Well drained soils that formed in clayey, cal-
careous sediments over soft limestone or marl.
These soils occur near coastal areas, in valleys,
and on foot slopes below the limestone hills.

In a typical profile the surface layer is very pale
brown, very friable, calcareous silty clay loam.
At a depth of about 20 in.  (51 cm)  is a very pale
brown, soft marl or limestone.
The information for this table was adapted from the publication,  Soil
Survey. Virgin Islands of the United States -1970.
                                   37

-------
                                     PUBLIC SAFETY
                                 / HEADQUARTERS
                               G G-6^1*^ —^ CHECK DAMS
                                                                            6 IN. (15 CM)
                                                                             SPUR LINE
                                                                            TO C.V.I.
                                                                                 V
              60
      GOLDEN GROVE
      RECHARGE AREA
             I    \
             SPREADING BASINS
                 (TYPICAL)
NEGRO BAY
RAIN GAGE
SPREADING BASINS
                                                                                             AIR PLAINS
                                                                                              ELL FIELD
                           100,000 GAL
                             (380 CUM)
                            SURGE TANK
    NEGRO BAY
 RECHARGE AREA
                                                         6IN. (15 CM) FORCE
                                                          MAIN TO CONVEY
                                                       ENOVATED WASTEWATER i\
                                                         TO RECHARGE AREA   \\\
                    SPRAY
                    /AREA
                 1000
       0   100  200 300
       Scale in Meters
I    I ALLUVIUM

       / /     /
                                                                                  PRIMARY WASTEWATER
                                                                                  TREATMENT  PLANT
                                Figure 15. Surface geological features in the Golden Grove area.

-------
 were above  and  below  the  recharge  sites  and  some which were entirely
 out of  the  drainage basin to  use as  controls.
 DESCRIPTION OF THE STUDY AREA

         The study area is outlined in Figures 11, 12, 13, and 16.
 Figure 16 shows the area in detail including the existing wells and
 recharge sites.  This study area is about 8 sq miles  (20.7 sq km) and
 consists mainly of the drainage area for an intermittent stream called
 River Gut.  The main portion of this stream, referred to as the East
 Branch, originates from springs located within Fountain Valley and
 flows south-southeast through the area for a distance of about 6 miles
 (9.7 km).

         The northern part of the study area begins at the ridges of
 the hills which surround Fountain Valley where they delineate the
 drainage into the valley and downstream through River Gut.   The ridge
 line here ranges from 300 to 1,000 ft (91  to 305 m) in elevation, and
 the slopes fall  off sharply to the undulating valley floor.

         Once south of the line which  runs  from the villages  of Grove
 Place to Coble,  the study area becomes  a gently sloping  flat plain
 that continues to the shore  about 3 miles  (4.8 km) to the south.

         Low eroded hills  on  the southern end of the area divert  the
 flow of River  Gut slightly  to  the east  as  they direct its course
 through a  gap  in  the  hills  known as Fair Plains.   It is  at this  gap
 where one  of the  government's  largest well  fields,  the Fair  Plains
 well  field,  is located.

        The  east  and  west branches  of River  Gut wind through  the  study
 area  in a  streambed that  is  generally depressed 2  to 10  ft (0.5 to 3 m)
 below the  land surface.   Along  its  banks are  older more  established
 trees which were  left untouched  during  the years of cultivation.   A
 wide  variety of trees are represented including, but not limited  to,
 mango  (Mangifera  indica), hog plum  (Spondias mombin),  West Indian
 almond  (Terminalia catappa), royal  palm  (Roystonea  borinquena), and
 licorice (Pithecel'lobium saman).  These  trees  range  from 40 to 50  ft
 (12 to  15 m) in height and tower over the lower scrub  growth of the
 adjacent fields.

        Visually, the animal density and diversity has appeared low  in
 the study area with the most frequently seen animals being the
mongoose (Herpestes auropunctatus) and the white-tailed  deer
 (Odocoileus virgimana).

        Until about 1968 almost all of the flat portions of the study
area were used for pasture and for the cultivation of sugarcane by the
Virgin Islands Corporation.   Aside from the golf course which occupies
the upper end of the study area, most  of the rest of the land has  been
                                  39

-------
                                      Mount
                             .  ,       la?I,;



    BODKIN
    RAIN GAGE

                                                           Blue' (
                                                           Mountain "V\_
               .
                        i         rnu u n lu i M
           o,

                         ''

                                   v)r
                 \\   STUDY     i
GUT-        /   '\   AREA BOUNDARY
FOUNTAIN    V        \m ^ \ \
                                        Bel/y •,  l


                                        ^

      ny s.
\f,
                                Ril



           GUT7
           RIVER
                                   Upper)
                                                                                   Fredensborc
    > ,
 STUDY
 AREA BOUNDARY
                                         GUT-
                                         HOLY CROSS'
                          >'ce  .
                          V
                       GROVE PLACE         I  r ACXI F
                       RA.NGAGE       f^ Su|KE

                                    L""'vL t* /S>
                            Co
-------
  allowed to naturally shift from pasture and cane to scrub growth.
  This process has almost completely driven out the ratoon crops of
  sugarcane by the rapid growth of Guinea grass (Pancium maximum) and
  the spread of acacia (Acacia tortuosa), tan-tan (Leucaena glauca),  and
  thibet (Albizia lebbek) trees throughout the area.   The change in
  vegetation has been assisted by several fires which often sweep the
  area during the dry seasons.

          The main activity in  the study area over the past 5 years has
  been the clearing of land by  bulldozing.   Generally only a small
  section  of land is affected  at  a time  but probably  the whole  area has
  been cleared once and  some parts several  times.   Fires have also
  occurred in the area during times  of drought.   These usually  will burn
  entire fields  and act  as  a clearing agent.   Regrowth from both  causes
  is  rapid and with the  proper  rainfall  the main  effects of clearing  can
  disappear  within  3 to  6 months.

          In  1972 a  major wastewater interceptor  was  built  alongside  the
 main  and west  branches of  River  Gut to  serve  the village  of Grove
 Place.  About  the  same time a 100-unit  multistory housing  project,
 Croixville,  was built just north of the Adventure well  field  and two
 large governmental complexes, the Public  Safety Headquarters  and an
 adult correctional facility, were constructed in Estate Golden Grove.
 In conjunction with the construction of the correctional facility,
 about 1,000  ft  (305 m) of River Gut was widened, straightened, and the
 trees removed as part of a flood control plan.

         Portions of the Golden Grove recharge area have been  cleared
 and planted in Bermuda grass, which gives better service and   is easier
 to maintain than the native Guinea grass.   During clearing operations
 the larger more desirable thibet and licorice trees  were preserved on
 the site.

         The Negro Bay site, which is  on the Kingshill marl, has
 probably  not been used  agriculturally for  at least 35 years.   The  soil
 is  not as rich  as  other parts  of the  coastal plain and the area had
 been part of the U.S. Army base  during  World War II.  Here the scrub
 growth was  lower in height but much denser and predominantly in  thorn
 trees such  as acacia.   The cleared  areas have quickly moved to
 revegetation with  Guinea grass.

 Groundwater Geology

        Study Area.  The knowledge  of the  groundwater geology  in the
 study area  is somewhat fragmentary  since it  depends  largely on
 gathering information through actual coring  of the mantle,  either for
 intellectual  gratification  or the actual construction  of a  well.  This
has always been  a rather expensive pursuit and currently costs
approximately $10/ft ($32.80/m) for a 6-inch  (15 cm)  uncased hole
using a cable tool drilling rig.
                                  41

-------
        An interpretive sketch of the geological formations in the
coastal plain that probably affect the flow and location of
groundwater in the study area is presented in Figure 17.  This sketch
is based on a variety of source information but most notably on
observations by project personnel, Public Works Department well logs,
and publications by Cederstrom (1941, 1950) and Whetten (1963).

        The major portion of the study area is in the coastal plain
which gently slopes up from the south shore to the hills of the
Northside Range.  The geological base for this plain in the study area
is the Jealousy formation.  Cederstrom (1950) mentions that this is a
gray clay, or mudstone, which contains some calcareous conglomerate in
its makeup.  This formation is referred to locally as blue clay and it
has a reputation, not unfounded, for being an impermeable nonwater-
bearing stratum.  Test drillings by Cederstrom found that this
formation had a thickness, adjacent to the study area, of over 1,398
ft (426 m) and hence when a local well driller encounters this
formation, he generally drills no further.

        Lying on the Jealousy formation is the Kingshill marl which
Cederstrom (1950, p. 21) describes as consisting of "buff-to-white
moderately thick bedded limestone, alternating with soft cream or
white marl."

        The limestone portion is generally quite hard while the marl
is comparatively soft and easily cut with a knife.  The vertical
permeability of this formation is extremely low due to the intact
limestone layers, while the horizontal permeability can be quite high
due to solution cavities or other voids in the formation.

        On the coastal plain the hills at Jealousy and Lower Love are
made up only partially from Kingshill marl while all of the hills
south of the Centerline Road consist of this formation.  It probably
formed the entire plain but has been eroded by streams and the eroded
beds replaced by local alluvial deposition.  This can best be seen in
the geological cross section of Estate Golden Grove, in Figure 18,
where a U-shaped valley has been eroded from the marl and filled with
the alluvial clays, sands, and gravels that make up the upper, most
recent formation on the plain.

        This alluvial material becomes thinner as it proceeds
northward to the lower slope of the Northside Range.  Within the
alluvium a number of defined gravelly aquifers exist separated by
thicker layers of silty clay.   This clayey soil  ranges from moderately
to highly impermeable, depending on the location.   The existence of
alluvium is no guarantee of an underlying aquifer, as apparently the
deposition of sands and gravels has been nonuniform both horizontally
and vertically, which has resulted not only in the lack of aquifers in
the alluvium in some locations but isolated sand and gravel lenses in
others.
                                  42

-------
            600
            500
                                                                    NORTH NORTHWEST
CO
                SOUTH SOUTH EAST
                                                                                       VILLAGE OF
                                                                                       GROVE PLACE
                                                                                  CROIXVILLE
                                                                                  HOUSING
                                                                                  PROJECT
CARIBBEAN SEA
       SOUTH SHORE OF ST. CROIX
   MT. EAGLE I
   VOLCANICS^
ADVENTURE
WELL FIELD
                                                     GOLDEN GROVE
                                                     RECHARGE AREA
                                         FAIR PLAINS
                                         WELL FIELD
                                                                                                  JP SEAJ
                                                                                           EXACT
                                                                                         INTERFACE
                                                                                         UNKNOWN
                                              JEALOUSY FORMATION
                                                   (BLUE CLAY}
                                                                                   :%a^en
                                                                                    Vy^*~ v^'
            300
                               4,000
                            8,000
                                                                12,000

                                                    HORIZONTAL DISTANCE (ft)
                                                              16,000
20,000
                                        Figure 17. Geological cross section of the coastal plain.

-------
     80
     60
     40
<
uj    20
 SEA
 LEVEL
     20
                    KINGSHILL MARL-APPARENTLY NONWATER BEARING
                    EXCEPT IN FRACTURES, JOINTS, AND CAVITIES.
                    SANDY GRAVELLEY ALLUVIUM-MAJOR WATER
                    BEARING STRATA IN THE ALLUVIUM.
                    ALLUVIAL FINES-GENERALLY MONTMORILLONITIC CLAYS
                    AND SILTS. POORLY PERMEABLE.
                    INDICATES POTENTIOMETRIC SURFACE DURING THE FALL, 1972.
                    INDICATES PERMEABLE MATERIAL ENCOUNTERED.
               EXCAVATION
               FOR SEWER
                   1972
         INTERCONNECTION MAY?
         NOT EXIST AT THIS POINT.

                                                        &W8S8@&ms^G BASINS 'ffivy&jg -  \
                                                                             V 5$7^tj
                                                                                 wM^%
                200
                         400
600
800
1,000
1,200
1,400
1,600
1,800
                                     HORIZONTAL DISTANCE (ft)
              Figure 18. Geological cross section of the Golden Grove area at right angles to the streambed.

-------
         As seen in Figure 17 the alluvium and Kingshill  marl
 formations terminate in the north by contact with the  Mount Eagle
 volcanics.  Cederstrom (1950, p. 16) mentions that "a  large part of
 the material  is volcanic in origin,  that much of it is stratified,  and
 that some limestone beds are interbedded with volcanics.   Dark  fine-
 grained massive, laminated or slaty  rocks,  hard  thin-  to thick-bedded
 limestone, and spotted or porphyritic rocks are  most common." The
 Mount Eagle volcanics generally yield minor amounts of groundwater  in
 their weathered portions and in the  rock fractures and crevices.  The
 Mount Eagle volcanics make up the vast majority  of the Northside Range
 and it is believed that much of the  water in the aquifers  of the
 coastal plain has its origin in these hills.  The exact  structure of
 the interface, defined by the dashed circle in Figure  17,  between the
 coastal plain and the Northside Range is unknown and merely
 hypothesized  in this sketch.   It is  certainly a  subject  worthy  of
 further research efforts on the part of local  geologists.

         Not shown in Figure 17 is the geological  structure of Fountain
 Valley, which is in the northernmost part of the study area and
 contains the  springs which initially supply River Gut.   Fountain
 Valley has an alluvial  valley floor  but its walls are  made up of not
 only Mount Eagle volcanics but an intrusive igneous rock referred to
 by  Whetten (1968)  as Fountain Gabbro.   A plan  view of  the  geological
 formations exposed at the surface in central  St.  Croix is  shown  in
 Figure 19.

         Naturally the geology of the recharge  areas is of  great
 concern to the project since  this determines the ultimate  disposition
 of  the recharged water after  it enters  the  soil.   As was mentioned,
 two  recharge  areas were selected which  are  adjacent to each other but
 yet  geologically dissimilar.   One contains  alluvial  deposits and  the
 other  marls.   These areas,  Golden Grove and Negro Bay, contain the
 geological  formations that make up the  vast majority of  the land  held
 by  the local  government and  therefore would be available for future
 groundwater recharge utilization.


 GOLDEN GROVE  RECHARGE AREA

         Using  information  obtained from  old well  logs, potentiometric
 data plus  borings,  and  new wells  constructed in  the  area as part  of
 this project,  three  diagrams  of the  assumed geological configuration
 in the  Golden  Grove  area  have  been constructed.   These are  shown  in
 Figures  15, 18,  and  20.   Basically the area  consists of alluvial
 deposits  laid  down  on  top  of  the  Kingshill  marl.   The alluvial  deposit
 is the  one  of  concern  in  this  area as far as recharging is  concerned.
 As shown  in Figure  18 the deposit  varies  in  thickness up to about 70
 ft  (21.3 m).   Its  predominant  constituent is a montmorillonitic clay
which  tends to  be  somewhat impervious.
                                   45

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BOUNDARY

                                                                                                                         MOUNT EAGLE VOLCANICS
                                                                                                                         SUPPLIES SMALL QUANTITIES
                                                                                                                         OF WATER
                                                                                                                         DIORITE EXTRUDED INTO
                                                                                                                         MT. EAGLE VOLCANICS
                                                                                                                         WEATHERED PORTION IS A
                                                                                                                         GOOD WATER BEARER
JEALOUSY FORMATION
(GREY CLAYI - NOT WATER
BEARING
                       •S       DRAINAGE BASIN   p.-V.^/
                        1 '	BOUNDARIES       fe**''
                               KINGSHILL MARL
                               (MARL. CLAY & LIMESTONE!
                               MODERATELY PERMEABLE
                               TYPICAL REPORTED YIELDS
                               1QT040GPM
                                                                                          ALLUVIUM
                                                                                          (GREY TO BROWN CLAYI
                                                                                          POORLY PERMEABLE.
                                                                                          TYPICAL REPORTED YIELDS
                                                                                          1/2T02GPM
AND/OR CLAYS)
MODERATELY PERMEABLE.
TYPICAL REPORTED YIELDS
5 TO 40 GPM
      STUDY AREA
*—• AND DRAINAGE
      BASIN BOUNDARY
                                         Figure 19. Geological map of the coastal plain.

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  I KINGSHILL MARL-APPARENTLY NONWATER BEARING
33 EXCEPT IN FRACTURES. JOINTS .AND CAVITIES .

  I SANDY  GRAVELLEY ALLUVIUM-MAJOR WATER
  I BEARING STRATA IN THE ALLUVIUM.
                                           plpjj ALLUVIAL FINES-GENERALLY MONTMORILLONITIC CLAYS
                                           r----::,v;::< AND SILT. POORLY PERMEABLE.

                                            -*- INDICATES POTENTIOMETRIC SURFACE DURING THE FALL, 1972.
                                             ฃ  INDICATES PERMEABLE MATERIAL ENCOUNTERED.
          60
          20 •
        SEA
       LEVEL
          20
          40
              15) BORING
               vBOTTOM OF GUT
         WELL
          pvvi   WELL BORING
              X    P
                                                          WELL
                                                                                                                 WELL
                                                                                                                  FP8
                              1000
                                                                                      4000
                               2000               3000
                                HORIZONTAL DISTANCE (ft)
Figure 20. Geological cross section of the Golden Grove area along the plane of the streambed.
                                                                                                        5000

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        Spaced within the alluvial clays are  thin horizontal aquifers
of clayey-sandy-gravelly material.  These aquifers are usually no more
than 2 ft  (0.61 m) in thickness and are probably not well
interconnected except due to boreholes in the vicinity and possibly at
the junction of two streambeds near the Fair  Plains well field.

        Groundwater studies have demonstrated that the potentiometric
head throughout the valley reflects the confined condition of the
water within the aquifer and does not represent a free water table.
In most of the study area and the island in general, an unconfined
water table does not exist.  The water in the aquifers moves from
northeast to southeast below the recharge area.  It must be kept in
mind that Figure 17 has the vertical scale exaggerated 15 times for
clarity and that the actual slope of the ground surface and aquifers
is less than 1 degree from the horizontal.

        The upper aquifer, in Figure 18, is the aquifer mainly
affected by the surface recharge activities in the area.  The material
between this aquifer and the ground surface tends to be a
nonhomogeneous soil with great variations taking place in the soil
types across the valley floor.  The upper 18  inches of soil is a dark
clay with the lower material being lighter in color and containing a
higher percentage of silt and sand.  This sand is of the silica
variety, which is rare on the island since calcareous sand is the
predominant form on the shoreline.  Several beds of sand have been
encountered in the region but unfortunately they were not extensive in
area nor is it certain that they are interconnected.  The gut which
winds through the valley depends on a base flow from springs located
at the head of the stream and other areas where the streambed cuts
into an aquifer and thus flows when the groundwater level is above -the
elevation of the bed.

        The method of recharging proposed in the Golden Grove area was
by the use of spreading basins and existing streambeds.  The limiting
factor was expected to be the permeability of the soil between the
recharging activity and the upper aquifer.  The bottoms of the
spreading basins were therefore excavated below the extremely clayey
surface layer to utilize the increased permeability of the lower silty
horizons.  This scheme did prove feasible and the recharge operations
were conducted mostly in the basins.
                                                                ft
        The streambed in the Golden Grove area is below the
surrounding land from 2 to 8 ft (0.6 to 2.4 m) and thus somewhat
closer to the aquifer in question.  Six small check dams 2 to 3 1,
(0.6 to 0.9 m) high were constructed in'the streambed to hold the
recharge water to facilitate infiltration and percolation.
Unfortunately the floods in October, 1974, severely damaged all of
these check dams before recharge experiments in the streambed could be
carried out.
                                  48

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 NEGRO BAY RECHARGE AREA

         The  geology of this  area  consists  of calcareous  material  of
 various  types.   Explorations in  the  recharge area  were carried  out  by
 shallow  borings,  to a  depth  of about 15  ft (4.6  m),  and  wells were
 constructed  to  a  maximum of  150  ft (46 m).   A hypothesized
 geological cross  section of  the  Negro Bay  recharge area  is  shown  in
 Figure 21.

         The  surface layer of about 6 to  12 in.  (15 to 30 cm) is a dark
 clay  while the  subsoil  is of a calcareous  nature,  white  to  buff in
 appearance and  composed of a combination of a soft powder!ike material
 interspersed with cemented nonstratified marl.   Beginning at about  10
 ft  (3 m)  below  grade there are alternate hard and  soft stratifications
 of  limestones and marl  which continue to a depth of  about 150 ft  (46
 m).   Here  the Kingshill  marl  rests on a  montmorillonitic mudstone .
 geologically designated as the Jealousy  formation  and commonly
 referred  to  on  the island as blue clay.  Stratifications within the
 Kingshill marl  in this  area  are about 2  to 6 in. (5  to 15 cm) thick.
 The movement of groundwater  through  the  marl  is  by solution cavities
 which apparently  are rather  small, generally having  cross sections  of
 no more  than about 20  sq in.  (129 sq cm).   These solution cavities
 seem  to  run  in  specific strata in the formation  but  are  not always
 interconnected  within  the same strata.

        During  the summer of 1972 two wells  were drilled, PW-2 and
 PW-3,  which  confirmed  the existence  of alternate hard and soft layers
 within the Kingshill marl.   The formation  was  dry  until  the drilling
 operation penetrated a  hard  limestone layer  at an  elevation of about  2
 ft  (0.61 m)  below sea  level  and encountered  water.   This water proved
 to be  under  pressure and rose  in  the well  to about 15 ft (4.6 m)  above
 sea level.   The two  wells were constructed  250 ft  (76 m) apart and
 encountered  water at the same  elevation.   The  groundwater was confined
 in both cases but production  in one  well was  estimated at a rate  of
 only  2 gpm (0.13  I/sec)  while  the other  produced at  about 60 gpm  (3.8
 I/sec).  Currently the  latter  well is being  used by  the  Virgin
 Islands' government  as  part  of its public  supply.

        Recharging  in the Negro Bay  area involved  the use of the
 unconsolidated marls in  the  upper 10 ft  (3 m)  of the existing
 formation.   Numerous soil  borings  were made  by the project in this
 area  to map  out the  extent of  the  unconsolidated marl and the
 underlying limestone anticline.   Long-term percolation tests indicated
 that the upper softer marls were  capable of  receiving large quantities
 of recharge water.  This  concept  was  tested on a full scale with
 reclaimed wastewater, using  surface  methods  such as spray irrigation
 and spreading basins.

        The  recharged water from  the  site was expected to percolate
 down to the first  hard  layer about 10 ft (3 m) below the surface which
would  place  it on  the south slope  of a mild anticline which has  a
                                   49

-------
en
o
            80
                                                                                   ESTATE GOLDEN GROVE
 ESTATIE NEGRO BAY
    NEGRO BAY
RECHARGE AREA
                                                                     mm ALLUVIUM
                     Xi^Vfi^t^&t-Q U NCONSO LI DATE D MARL
                                                                  i^l^ym AQUIFERS
                                                   DRY STRATA :•':•'
                                                                  HARD LIMESTONE;
                                                                  AQUICLUDE ^xovx
                                               ,:.:: WATER CONFINED
                                               SijS: BELOW
                                                                     KINGSHII .MARL
                                  1,000
                             2,000                  3,000
                        HORIZONTAL DISTANCE (ft)
4,000
                                           Figure 21. Geological cross section of the Negro Bay area.

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 northeasterly axis.   Indications were that this  hard layer  was
 contiguous and probably impermeable.   The water  would then  mound and
 be available for recovery.   This system would not involve any mixing
 with the existing groundwater in the  area as  the groundwater is
 located in strata about 80  ft (24 m)  below the surface where it  was
 extremely improbable that the recharged water could  reach.

         Unfortunately the rate of infiltration and percolation of the
 recharged water in Negro Bay did not  prove to be up  to expectation and
 recharging operations were  suspended  in August,  1974.
 HYDROLOGICAL  DEVELOPMENTS  IN  THE  STUDY AREA

 Groundwater

         In the  normal groundwater recharge cycle  on  St.  Croix,  the
 heavier  rains occur  between August and December;  these tend  to  fill  up
 the aquifers which then  slowly  empty  until the  following  fall when
 they are refilled.   There  is  also a short rainy season in the spring
 and occasionally other times  of heavy rains which aid in  recharging,
 but basically the aquifers must depend on these fall rains or any long
 series of heavy rains which come  in a pattern to  permit maximum
 infiltration and minimum runoff to the sea.  Large amounts of rain
 alone are unsatisfactory as much  of the water can be lost in runoff.
 The long-term relationship between the rain pattern  and  the water
 levels in some wells in  the study area is shown in Figure 3.

         The groundwater  in the  study  area at Golden  Grove is entirely
 dependent on infiltration possible from a tributary  area  of about 5.6
 sq miles  (14.4 sq km).   Much  of this  area is surfaced with tight clays
 and hence is limited as  to its  potential for infiltration and
 permeability.  The major aquifers  in  the Golden Grove area are  of
 gravelly  sand with a thickness  of  less than 2 ft  (0.6 m)  and an
 estimated width which varies  from  250 to 1,000  ft (76 to  305 m).
 There are several individual  aquifers interspaced by clayey strata.
 The major recharge activity appears to take place in the  area north of
 Center!ine Road after which the groundwater flows south-southeast to
 the ocean.

        This water is tapped  in numerous places by government and
 private wells which draw down on  the  stored water.  A measure of the
 amount of water existing in the aquifer at any  time  is the
 potentiometric head on the aquifer at various points along the flow
 network to the sea.  Water level recorders were installed in various
 key locations along the flow  route which monitored the water levels in
these wells.   Some accuracy is  lost in these measurements since the
wells generally penetrate, and  thus interconnect, more than one
aquifer.
                                  51

-------
        At the time of the first interim report  (Black, Crow and
Eidsness, Inc.)  in June,  1972, the study area was affected by a
surplus of groundwater.   This hindered borings and required the
formulation of plans to reduce the amount of groundwater in the
recharging area  to provide capacity in the aquifers to test the
feasibility of recharging.  Plans to alleviate this situation were
carried out, but by the time of the second interim report (Black, Crow
and Eidsness, Inc.), in October, 1973, a contrary situation had
occurred in that a general deficit of precipitation during the
preceding 17 months had produced a circumstance where some of the
aquifers were nearly empty and others were producing at a reduced
capacity.

        This deficit condition continued for an additional year and
marked one of the worst droughts in recent history.  On July 22, 1974,
the island was proclaimed a federal drought disaster area.  Many wells
went dry during  this time and others, near the sea, had a significant
rise in salt content due  to saltwater intrusion.  Although the drought
condition was alleviated  in August, 1974, by the first significant
rains in months, it definitely came to a close by November, 1974, when
record rains caused severe flooding over large portions of the island.
On November 15,  1974, the island was again declared a federal disaster
area, only this  time it was due to flooding.   Half the average annual
rainfall was received within a period of 25 days and the soil could
not handle the disposal of the water by infiltration.  As a result,
billions of gallons of water ran off into the surrounding sea.

        Although some recharge of the aquifers did occur during this
period, it was not concomitant with the amount of precipitation
experienced.  Piezometric levels rose, but in the subsequent 8 months
only scant rainfall occurred and the levels rapidly dropped again.   By
July, 1975,  many of the piezometric levels had dropped close to the
previous spring's drought level.   Although the quick shift from one
extreme to another in the water situation was caused by an unusual
rain condition,  the overall long-range pattern of going from a surplus
to a deficit of water seems to be a regular,  though unpredictable,
phenomenon for the island.  This points up the utility of having a
method of artificial  groundwater recharge working on the island which
will permit the  leveling off of groundwater production at a constant,
predictable high rate,  regardless of the climatic conditions.

Surface Water

        The only significant surface flow in  the study area occurs  in
River Gut.   In general, its base flow is dependent on the groundwater
level in the area.   Runoff from storms makes  up its flow on only a
small percentage of its total  flow days.   However, these runoffs can
be quite considerable and only a  few days of heavy runoff can
represent the majority of the total  annual  flow.   The amount of this
runoff contributing to streamflow is dependent on the rainfall
pattern, soil  moisture, land surface,  and vegetation conditions.
                                  52

-------
During 1971 through early 1972 there was a continuous base flow in
River Gut as it passed through Golden Grove.  But then due to the
depressed water table and lack of adequate precipitation, there was no
flow in the lower half of River Gut from March, 1972, to October,
1974, with the exception of two days of storm runoff and one week as a
result of a broken water main near the Adventure well field.  A flash
flood occurred in October, 1974, and an even larger flood came again
in the following month.  A sustained flow followed in River Gut which
continued until the latter part of December, 1974.  From then until
September, 1975, there has been no flow in the streambed in the Golden
Grove area.
WATER AND WASTEWATER SYSTEMS ON THE ISLAND

        The potable water distribution system on the island of St..
Croix has developed in small stages as finances permitted and politics
dictated.  Its initial function was to service the two towns of
Christiansted and Frederiksted and the central sugar factories built
at several locations in the island.  From this it was expanded or
converted to serve the expanding needs of the populace.  Currently
both towns are supplied with potable water and portions of the central
coastal plain are included in the system.

        The wastewater collection system was relatively simple up to
1970.  Both towns collected and discharged their untreated wastewater,
via outfalls, into their respective harbors.  Inland, most homes used
septic tanks while large housing developments employed small package
plants with discharge onto the fields or out to sea.

        In 1966 a consultant surveyed the obvious defects in the
existing system and submitted a report and master plan (Camp, Dresser
and McKee, Inc.) for the collection, treatment, and ultimate disposal
of wastewater on St. Croix.  This plan has been followed with only
minor deviations and today is well on its way toward completion.

        Basically the plan called for a single treatment facility on
the south shore about midway between Christiansted and Frederiksted.
The wastewater from the two towns and the central portion of the
island would be transported to this facility by gravity interceptors
and force mains, given primary treatment, and discharged to sea via a
long ocean outfall.  The system and its design are excellent; however,
since the designers were apparently neither informed by the local
government of its desire for eventual water reuse nor able to foretell
the generally unpredictable future on the island, the system was not
designed to cope with the complex problem of wastewater reclamation.
This fact, combined with the system of water distribution, has caused
considerable problems for the reclamation project.

        The system of water distribution and wastewater collection on
the island is crucial to the successful reuse of water on St. Croix.
The distribution system has a variety of point sources which add water
                                  53

-------
of differing qualities to the system at various locations.  Table 2
names  these point sources and lists the quantity and quality of the
water  added to  the system.  Figures 22 and 23 show the sources of
wastewater and  outline the relationship between chloride content from
these  sources and the flows in the entire collection system on the
island.   Figure 22 shows the situation as it was in June, 1974, when
the reclamation project was in operation.  At this time only the
central portion of the island was contributing wastewater to the
treatment plant at Bethlehem Middle Works.

        This limited area of collection is the reason that the amount
of wastewater available for processing in the AWWTP was so limited
during the operational phase of the project.  The water used in this
area is a combination of groundwater from the Adventure, Barren Spot,
and Fair  Plains well fields plus some of the desalinized water from
the Martin Marietta Company.  Additionally, of course, each building
in the island supplies collected rainwater from its own cistern.

        The most serious problem with the reuse of water on the island
comes from the  total dissolved solids (TDS) in the waste stream.  Most
notable are the chlorides which affect the taste of the water and its
suitability for agricultural purposes.  Table 2 shows the great range
of chloride concentrations from the various sources.  Some of this
groundwater for the central area is mixed in the 10 mil gal (37,850 cu m)
storage tank at Kingshill before distribution; but the final chloride
content of water used, and hence wastewater produced, is really a
function of the day-to-day production of each source.  Figure 24 is a
graph of the chloride content of the influent to the AWWTP during the
operational phase of the project.  The chloride content ranged from
about 300 to 2,500 mg/1 during this operational period.

        Figure  23 shows the relationship of the chlorides in the
various sources of wastewater and the flows in the entire collection
system which went to the central primary treatment plant in September,
1975.   The sources of wastewater have been increased by flows from the
town of Frederiksted.  Aside from a large increase in wastewater,
there was now the addition of about 0.08 mgd (300 cu m) of seawater
which is used in Frederiksted for flushing purposes in several  of the
major housing projects.  This collection configuration became
effective in October, 1974, with the activation of the wastewater pump-
ing station in  Frederiksted.  The chloride content in the wastewater
being processed at the AWWTP increased immediately to about 2,000 mg/1.
This made the reclaimed wastewater unsuitable for present reuse
purposes.  The  artificial recharge of groundwater was discontinued
while the local government tried to resolve the problem.  Although
progress has been made towards resolution, the situation still  existed
in September, 1975.

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                 TABLE 2.  MAJOR WATER SOURCES ON ST. CROIX
Source
Desalinized water
WAPA Stern Rogers plant
Martin Marietta Alumina Co. plant
Groundwater
Fair Plains well field
Barren Spot well field
Adventure well field
Concordia well field
Mahogany Road-La Grange well field
Rainwater collected in cisterns
Total of homes on island (estimate)
Average daily
contribution to
the water supply
(mgd) (cu m/day)

0.74 2,800
0.65 2,460

0.22 830
0.14 530
0.09 340
0.07 265
0.13 490

0.3 1,135
Average
chloride
content
(mg/1)

2
4

1,100*
670
230
390
250

10
*Extremely variable, this value is based on a mean of the samples taken
1971-1974.
                                    55

-------
en
as
           FREOERIKSTED TOWN
           HARRIGAN COURT HD
           HODGE PAVILLIONHD
           MARKOE SCHOOL
              GROVE PLACE VILLAGE
              SiU HOUSING
              LORRAINE VILLAGE HD
              WILLIAM'S DELIGHT HD
              PARADISE Ml LLSHD
              PUMPING
              STATION
                NOT
             OPERATIONAL
FREDERIKSTED
  BYPASS
(FORCE MAIN)
          CAMPO RICO
              HD
            WHIM HD
              1
           2% OF
           TOTAL FLOW
           220mg/l
           CHLORIDES
    GROVE PLACE VILLAGE
    CROIXVILLE HD
    CENTERLINE HD
    GOLDEN GROVE PARK
    TERRITORIAL PRISON
                 95% OF
                 TOTAL FLOW
                  450 mg/l
                  CHLORIDES
              DIAMOND
              INTERCEPTOR
             ]
                           SOUTHWEST "*
                           INTERCEPTOR
          MON BIJOU HD
          FREDENSBURG HD
          STRAWBERRY HILL HD
          AUREO DIAZ HEIGHTS HD
          CENTRAL HIGH SCHOOL
        1%OF
        TOTAL FLOW
        190 mg/l
        CHLORIDES
                2% OF
                TOTAL FLOW

                 300 mg/l
                 CHLORIDES
GOLDEN
GROVE
INTERCEPTOR
                                                                     BETHLEHEM GUT
                                                                     INTERCEPTOR
                   FUTURE INTERCEPTOR
                   TO CHRISTIANSTED
                 RECLAIMED ^
                 WASTEWATER"
                              CENTRAL \/
                              COLLECTION^
                              STRUCTURE
  IONS
  REj-
                                                                     AWWTP
PRIMARY
TREATMENT
PLANT
                                                                        HD = HOUSING DEVELOPMENT
                                                                      TO OCEAN
                                                                      OUTFALL
                                     Figure 22. The source of wastewater flows in June, 1974.

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en
-q
          FREDERIKSTEDTOWN
          HARRIGAN COURT HD
          HODGE PAVILLION HD
          MARKOE SCHOOL
             GROVE PLACE VILLAGE
             SIU HOUSING
             LORRAINE VILLAGE HD
             WILLIAM'S DELIGHT HD
             PARADISE MlLLSHD
             50% OF
             TOTAL FLOW
             3,300 mg/l
             CHLORIDES
GROVE PLACE VILLAGE
CROIXVILLE HD
CENTERLINE HD
GOLDEN GROVE PARK
TERRITORIAL PRISON
                45% OF
                TOTAL FLOW

                 350 mg/l
                 CHLORIDES
FREDERIKSTED
   BYPASS
 (FORCE MAIN)
          CAMPO RICO
              HD
            WHIM HD
              i
            1%OF
            TOTAL FLOW
             220 mg/l
             CHLORIDES
               DIAMOND
               INTERCEPTOR
                            SOUTHWEST
                            INTERCEPTOR
                               MON BIJOU HD
                               FREDENSBURG HD
                               STRAWBERRY HILL HD
                               AUREO DIAZ HEIGHTS HD
                               CENTRAL HIGH SCHOOL
    2% OF
    TOTAL FLOW

     380 mg/l
     CHLORIDES
                                      2% OF
                                      TOTAL FLOW

                                      320 mg/l
                                      CHLORIDES
                                                          GOLDEN
                                                          GROVE
                                                          INTERCEPTOR
           BETHLEHEM GUT
           INTERCEPTOR

             FUTURE INTERCEPTOR
             TOCHRISTIANSTED


CENTRAL \/
COLLECTION^
STRUCTURE
ioJn
RE_J—
                                                    RECLAIMED
                                                    WASTEWATER
                               AWWTP
                                                      PRIMARY
                                                      TREATMENT
                                                      PLANT
                                 i
                                   TO OCEAN
                                   OUTFALL
                      HD = HOUSING DEVELOPMENT
                                    Figure 23. The source of wastewater flows in September, 1975.

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O1
oo
           3,000 .
           2,500 •
            2,000' •
         UJ
O
O
UJ  1,500
Q

OC
O
         X
         o
            1,000
             500
               0
                                TESTING FREDERIKSTED

                                PUMPING STATION

                                (SALTWATER)
                                                                               INFLUENT DILUTED

                                                                               BY FLOODWATERS
                                                      START OF REGULAR

                                                      OPERATION
                                                               FREDERIKSTED PUMPING

                                                               STATION

JAN

FEB

MAR
APR
MAY
JUN
JUL

AUG

SEP


4 	 ^— H

I . I

                                                       TIME (months)


                             Figure 24. Chloride content of the incoming wastewater to the AWWTP in 1974.

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                               SECTION VI

                 DESCRIPTION OF THE PROJECT FACILITIES


 ADVANCED WASTEWATER TREATMENT PLANT (AWWTP)

 Purpose

         The purpose of the AWWTP within the project framework was to
 upgrade the quality of the wastewater to a level  where it could be
 safely and efficiently used for artificial recharge of the groundwater
 on St. Croix.

 Goal

         The goal  of the AWWTP was to produce a clear,  odor-free
 effluent which would be extremely low in organics,  suspended  solids,
 and microorganisms.   Certain operational guidelines were  drawn up and,
 aside from normal  organic reduction, it was desired that  the  effluent
 have  a turbidity  of less than 3 Formazin Turbidity  Units  (FTUs)   and
 preferably less than 1.   At the same time, the effluent should have  a
 free  chlorine  residual  (FCR) after a 30-minute contact time of 1  mg/1
 or more,  at 1  FTU;  and  3 mg/1  or more,  at 3 FTUs.

         The purpose  of  using these guidelines  was two-fold.   One  was
 the protection of  public health and  hence the  desire to reduce
 exposure  of the public  to possible pathogenic  organisms to a
 negligible degree.   Additionally it  was  realized that  the soil  in the
 main  recharge  area was  predominately clays and,silts and  that this
 type  of  soil could be expected to clog  readily if any  significant
 biological  activity  or  mechanical  entrapment took place.  By  adhering
 to the guidelines,  it enabled  the project to minimize  these problems
 and efficiently utilize  the  small  amount of land available for
 recharging.

 Design Assumptions

         In  the  design of the plant,  certain assumptions were  made.   A
 discussion  of  the most significant of these follows with pertinent
 comments on their validity.

        Assumption 1.  The primary plant and the associated wastewater
 collection  system in the western and central portions of the  island
would  be completed and operating with a  total flow of about 1  mgd
 (3,785 cu m/day) by the  time the reclamation of wastewater began.
                                  59

-------
         In actuality the construction of the plant and interceptor
network  was delayed at all stages, with the primary plant not being
placed in operation until August, 1972, and the  important western end
of the collection system not being completed until October, 1974.
Thus  incoming wastewater flows were below expectation during the
operational phase of the project.

         Assumption 2.  The incoming wastewater to the primary plant
would have a high biochemical oxygen demand (BOD) and ammonia-nitrogen
(NH3-N)  content.

         The local environmental health officials on St. Croix were
quite insistent on designing for a high incoming BOD.  The basis for
this  idea, at the time, was quite reasonable.  Several package
treatment plants had been recently constructed in the territory to
service  various large housing developments.  Although different types
of plants were used, the results were often very poor as the high
organic  loading to the plants had caused them to operate badly and, in
many cases, such as the package plant at Mon Bijou, to become a
community nuisance.  This high BOD was the result of low water usage,
often only 15 to 40 gpd/person (57 to 151 1/day/person) due to the
severe shortage and high cost of fresh water.  A health department
report (Grigg et al., 1971) on package treatment plants on neighboring
St. Thomas, which has similar water problems, showed a range in BOD of
incoming wastewater from 6 to 693 mg/1.

         Since no interceptors existed at the time of design in the
central  portion of the island, with the exception of the vicinity of
Mon Bijou, opportunities for testing were limited; and in view of the
package  plant problems, it does not seem like an unreasonable
assumption.  Samples of the incoming wastewater at the Mon Bijou plant
and the  Frederiksted pumping station in July, 1971, were analyzed and
had a BOD of 1,000 and 260 mg/1, respectively; while the NH3-N level
was 90 and 56 mg/1, respectively.  For design purposes it was
estimated that the BOD to the secondary portion of the plant would
range from 200. to 750 mg/1.

         In actuality at the same time as the design of the AWWTP was
taking place, construction began on numerous multistory housing
projects in central and western St.  Croix.   These were completed in
late 1973 and had a capacity for about 8,000 residents, which is about
20 percent of the population of the island.  A decision was made to
connect these units to the public potable water system and in most
cases to supply unmetered water to the tenants as part of the basic
monthly rental.

        The result was a tremendous increase in the average water
usage and a concomitant reduction in the BOD of the wastewater which
entered the collection system from the central and western portions of
the island.  The mean value of the BOD, determined on a bimonthly
                                   60

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 basis during 1974, for incoming effluent for the AWWTP ranged from 68
 to 140 mg/1.  Hence the plant has plenty of excess aeration capacity.

         Assumption 3.   Surface methods of artificial  recharge would be
 employed.

         In actuality that is what happened.

         Assumption 4.   The saltwater flushing system  in  Frederiksted
 would be converted to  fresh water to avoid contaminating the
 wastewater to be used  for reclamation.

         In actuality although the local  government knew  of  the
 situation, steps were  not taken to alleviate the potential  conflict.
 Since the  Frederiksted wastewater system was not connected  to the
 central  collection until  October, 1974,  there was  not really a problem
 until  then.   After the connection, due to flooding damage on the
 island,  no positive action was taken on  removing the  salt water until
 a  governmental  study group was formed by the governor in June, 1975,
 to look  into the problem.   It is  hoped that  this saltwater  situation
 will  be  resolved during the fall  of 1975.   Until  then, the  project
 cannot use its  product water for  agricultural  irrigation or for
 groundwater  recharge.

 Basic Design

         The  plant was  designed to be an  extended aeration activated
 sludge plant followed  by  units to permit chemical  coagulation,
 filtration,  and  disinfection.   A  block diagram of  the plant is  shown
 in  Figure  25 and an aerial  photo  of the  facility appears in  Figure 26.
 A  list of  major  components  with their specifications  is  shown  in Table
 3 while  the  major design  parameters for  the  activated sludge  section
 are shown  in  Table 4.

         These parameters make  it  apparent  that this is basically a
 standard extended aeration  plant,  but with a  higher volumetric  loading
 and aeration  capacity  to minimize  the size of  the  aeration  tanks.  The
 use of a completely mixed extended  aeration  plant  with sludge  recycle
 gave  the facility an inherent  ease  of operation  and the  ability to
 handle moderate  shock  loads.   The  prolonged  residence time  and  excess
 aeration capacity were  expected to  provide the environment  for  the
 growth of  nitrifying organisms which  would act to  convert ammonia
 compounds  to  nitrates.   This,  in  turn, would reduce the ultimate
 chlorine demand at  the  time of disinfection.

        After being aerated and continously agitated, the mixed liquor
moves  from the aeration tanks  to a  circular clarifier for solids
 separation, with  provisions for a maximum of 100 percent sludge
 recycling.  After clarification the flow goes  to a solids contact unit
 (a reactor-clarifier) where chemical  addition facilitates the removal
                                  61

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 INCOMING
    RAW
WASTEWATER
  PRIMARY
TREATMENT
   PLANT
OS
to
                    LIFT
                   STATION
                  "I
TO OCEAN
OUTFALL
                              AERATION BASIN
                              AERATION BASIN
                         HEAVY LINE
                         REPRESENTS
                        NORMAL FLOW
                          PATTERN
                           PUMPING
                           STATION
                            T
                                                             CONTROLLED
                                                             OVERFLOW
                                                                           SOLIDS
                                                                           CONTACT
                                                                            UNIT
                                                               CXD
                                                     CHLORINE
                                                     CONTACT
                                                     CHAMBER
                        TO RECHARGE
                           AREAS
MONITORING FOR:
  TURBIDITY
  CHLORINE RESIDUAL
  FLOW
  CONDUCTIVITY
                                                                      GATE OR VALVE
                                                    LIMITS OF
                                                   RECLAMATION
                                                     PLANT
                                   Figure 25. Flow diagram of the AWWTP.

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Figure 26. Aerial view of the AWWTP.
                 63

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                         TABLE 3.    EQUIPMENT  USED  IN THE ADVANCED WASTEWATER TREATMENT PLANT
           Equipment
                          Quantity    Manufacturer
                                Additional  Information
Oi
Influent sewage pumps        2

Aerators, surface            4

Clarifier                    1
Sludge return pumps          2

Solids contact unit          1
Chemical feed pumps          2
Filters, mixed media         2
Backwash pump                1

Chlorinator                  1
Chlorine analyzer            1
Effluent pumps               2

Total effluent flow meter    1
Turbidity meter              1
Conductivity meter           1
Flygt

Mixco (Lightning)

Eimco
Morris

Eimco
Wallace & Tiernan
Jet Flo  (Reyco)
Worthington

Wallace & Tiernan
Wallace & Tiernan
Worthington

Leopold & Stevens
Hach
Beckman
4 in. (10 cm) CP-3126, 350 gpm at 60 ft TDH  (22
I/sec at 18 m), 1,750 rpm.
25 hp (18.6 kw), Transfer 1,800 Ib (817 kg)  of
oxygen/day/unit.
Type C, 35 ft (10.6 m) ID x 11 ft (7.6 m)  SWD.
3 in. (7.6 cm) 3HS10, 175 gpm at 25 ft TDH (11
1/sec.at 7.6 m), 880 rpm.
Type HRB, 22 ft (6.7 m) ID x 11 ft (3.3 m) SWD.
Model A747.
Gravity, 10 ft (3 m) ID.
Model 12M90, 40 hp (30 kw), 950 gpm at 115 ft
TDH (60 I/sec at 35 m), 1,750 rpm.
Series 91-100, 100 Ib (45.4 kg)/day.
Model A-767, with recorder.
Model 10L22, 40 hp (30 kw), 350 gpm at 300 ft
TDH (22 I/sec at 91 m), 1,750 rpm
Model 61R, recorder and totalizer, 90ฐ V-notch.
Model 1720, Rustrak recorder.
Model RQ1-7-CHIC-R1K, recorder.

-------
                TABLE 4.   DESIGN AND ACTUAL PARAMETERS FOR THE
                           BIOLOGICAL SECTION OF THE AWWTP
              Parameters
     Design
     Actual*
  Flow through the aeration  tanks
    (mgd)
    (cu m/day)



 Aeration  tank capacity
    (mil  gal)

    (cu m)

 Detention time (hr)

 Aeration tank MLSS (mg/1)

 BOD (mg/1)

 Food-to-microorganism ratio
 (Ib BOD/lb MLSS)  or (g BOD/g MLSS)

 Rated oxygen transfer of aerators
   Ib/hr

   kg/hr
    0.5



   1,892




    0.6

   2,270

      29

4,000 - 6,000

     750


    0.13


     350

     160
 0.25  -  0.4
 0.33  Estimated
      Averaget
 945 - 1,515
 1,250 Estimated
      Averaget

 0.3t,#

 l,135t,#
1,350$

  133$


0.1$


  175ง,.#

   80ง,#
 *Based on averages for the period January,  1974,  through October,  1974.

 tThe plant flow meter was  located at  the  effluent portion of the AWWTP.
 Since February, 1974, a portion  of the  influent entering the operation
 tanks was bypassed back to the primary  plant after the clarifier,  but
 before the flow meter.   Thus  the total  influent could not be measured.
 Meters have now been  installed to measure the  influent flow.

 $Based on the  average for  the 8-month period.

 ง0nly 2 of the plant's  4 surface aerators* were used.  During the
 majority  of operation only 1  of  these aerators was used at one time and
 hence the actual operating value  would be one-half of this.

#0nly one aeration  tank was used  during actual operations.
                                   65

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of remaining suspended matter including colloidal material.  This
chemical, aluminum sulfate (alum), is mixed in the reactor turbine
section of the unit.  Solids removal is by coagulation and
flocculation, which results in precipitation in the clarifier section
and agglomeration aiding filtration in the subsequent sand filters.

        The filtration unit is composed of two gravity sand filters
which operate in parallel.  The design filter loading rate is
approximately 2.2 gpm/sq ft (90 1/min/sq m) when both filters are in
operation.  Backwash water is obtained from the chlorine contact
chamber and the backwashing is controlled by automatic timers.

        Detention time is a minimum of 30 minutes in the chlorine
contact chamber before the effluent passes over a weir to the wet well
for transfer to the recharge areas by two vertical turbine pumps.

Special Design Features

        Certain features were built into the AWWTP to increase its
flexibility and usefulness to the project.  The most important of
these are discussed in the following paragraphs.

             The aeration unit is separated into two equal tanks with
        the water surface of one being 2 ft (0.61 m) above the water
        surface of the other.  This permits the tanks to be operated
        singly, in parallel, or in series without additional pumping
        required.

             There are provisions for bypassing either the solids
        contact unit, the filter, or both.

             The effluent from the plant can be directed to either the
        recharge areas, the head of the primary plant, or into the
        ocean outfall.

             The plant is monitored by recording instruments to give a
        continuous record of the effluent turbidity, conductivity,
        residual chlorine, and flow.

Plant Construction

        Bids were opened in January, 1972, for the construction of the
AWWTP.  The award was made to the Pizzagalli Corporation of South
Burlington, Vermont, and construction began in April, 1972, with a
contract completion date of January, 1973.  The bid price was
$6.98,400.

        Although the original structural work on the project proceeded
rapidly, there were delays in the fabrication and delivery of some of
the proprietary devices for the plant and additional delays on the
                                   66

-------
site involving subcontractors,  scheduling, quality control etc   The
olant was  provisionally accepted  in October of 1973 while  final
^cceptanceTd not take place until May, 1974.  Start-up began during
the fall of  1973 with the plant operational by January,  1974.
Operation
        The plant mode of operation was  dictated by two important
factors-  low flows and a low BOD.   In early 1974 the flows through
the Plant averaged less than 0.25 mgd (946 cu m/day) and the influent
  Ds raned below 100 mg/1.  In order to compensate for this  the
  ^rซ^
 solids contact unit (SCU)  in maintaining a chennca  sludge blanket in
 thP reaction zone   To  correct this problem,  the  flow pattern was
 m  iffeS Dฐ spmiing the  cUrifier effluent  "d  returning a por ion
 of the high flows back  to  the primary P ant.   This return flow was
                                                               "ป•
 by dilution and a reduced production level from the  plant.
        Successful operation of  the plant was very sensitive to the
 (g/g).
         A comparison of the actual  average 1ปซฃwftctors with the
                      s
          operation     toxic materials, the sludge concentration was
  reduced in the aeration tank.
                                  67

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TABLE 5.  OPERATING DATA FOR THE AWWTP (AVERAGE VALUES FOR THE
          PERIOD JANUARY TO OCTOBER, 1974)
Parameter
BOD
COD
Total P
N03-N
NH3-N
C03
HC03
Total Hardness
Ca
Mg
Chlorides
Conductivity
PH
Turbidity
MLSS
SVI
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1 as CaC03
mg/1 as CaC03
mg/1 as CaC03
mg/1 as CaC03
mg/1 as CaC03
mg/1
umhos/cm2 at 25ฐ C

FTU
mg/1
ml/g
Influent Effluent
113 12
206 31
12.3 9.0
0.6 12.9
22.6 6.8
0 0
318 123
289
114
172
456
1,778
7.4 6.7
1.3
—
—
Aeration Tank
—
—
—
—
—
—
—
—
—
—
—
—
—
--
1,351
75

-------
         Nitrification did occur within the secondary units,  as shown
 by the ammonia and nitrate data in Table 5.   But this process,
 especially reinforced by excess aeration and possibly other  factors,
 made solids separation difficult in the clarifier.   The amount of
 aeration was always a compromise between enough to  keep the  aeration
 tanks mixed and hold a reasonable dissolved  oxygen  content,but not too
 much to induce bulking and subsequent excess solids carry-over in the
 clarifier.

         The modification of the plant to permit the addition of alum
 to the effluent of the aeration tanks improved  settling
 characteristics considerably.   A dose rate of from  14 mg/1 to 25 mg/1
 was  found to be effective.

         While nitrification did reduce the chlorine demand during
 disinfection, it also created  a problem by setting  the stage for
 denitrification in the clarifier.   This problem is  noted  by  Sawyer
 (1967)  and  Busch (1971)  who suggest the expeditious removal  of the
 sludge before it can be  buoyed to the surface by entrapped or attached
 nitrogen gas bubbles.  This problem would generally occur in the early
 morning hours when the flow from the primary plant  was reduced.   This
 often permitted the sludge underflow in the  clarifier to  jam in  the
 telescope valve,  if the  latter was not set exactly  right, causing the
 sludge  to start to build up at the bottom of the tank.  This soon was
 buoyed  up and drastically increased the solids  loading to the solids
 contact unit and  the filters,  generally clogging the  latter.
 Continuation of this process for any length  of  time usually  resulted
 in a  serious reduction of MLSS and,  in general,  unsatisfactory  plant
 performance.

         In  operating the solids  contact unit, an alum dose of between
 20 mg/1  and 35  mg/1  was  found  to produce  a good  sludge  blanket.
 Automatic sludge  withdrawal was  adjusted  to  keep the  top of  the  sludge
 blanket at  least  5  ft (1.5  m)  from the  surface.

         Alum was  used  as it was  relatively inexpensive, functioned
 without pH  adjustments,  was simple in  operation,  and  worked.   Some
 experimentation was  made using  commercial polymers  but  the results did
 not justify the extra  cost  and  problems.

         While alum worked quite  well during  the  project's operational
 period,  it  may  be that in the  future when the mineral content of  the
 wastewater  changes due to shifts  in  the water source  to desalinized
water,  other  coagulants  and filter aids will   need to  be employed.

         Not  only does  alum  react with  the bicarbonate  in the
wastewater  as follows:
                A12(S04)3 + 6HCQ',1* 2A1(OH)3  + 350?+ 6CO

-------
to form a voluminous, gelatinous floe to aid in clarification, but it
also combines with phosphates in this reaction:
                    Al 2(504)3 + 2PO"43 + 2A1P04 + 3SO;2


Gulp  (1971, p. 27) mentions that the "two reactions  compete for
aluminum ions.  At pH values above 6.3, the phosphate removal
mechanism is either by incorporation in a complex with aluminum or by
adsorption on aluminum hydroxide floe."

        The pH of the wastewater at  the point of alum application was
about 7.2.  The pH was reduced in the AWWTP by approximately 0.6 units
due to alum addition and disinfection.  Total phosphorus reduction did
occur but the removal rate was not consistent.  Removals ranged from
about 10 to 60 percent within the plant.  Phosphorus removal was not a
goal of plant design and only occurred as a by-product of
clarification.  Phosphorus was expected to cause no  problems in
recharging and would be removed in the upper soil layers by the clays
and silts in the area.

        Disinfection was accomplished by the use of  gas chlorination.
Originally 150-lb (68 kg) cylinders were used to supply the gas but
early in the project this system was converted to 1-ton (908 kg)
cylinders.  This reduced the cost of the chlorine from approximately
$0.50/lb ($0.23/kg) to about $0.25/lb ($0.11/kg).  Dosage varied with
effluent quality but generally ranged from 20 to 30  mg/1 .  This was
more than was actually needed since a steady rate of chlorine feed was
used to maintain the minimum FCR desired at all flow levels.  Thus the
selected rate chlorinated the high flows and organic surges at the
proper FCR and overchlorinated during the low flows.  A programmed
proportional feeder could reduce the usage of chlorine considerably.

        The results of disinfection were excellent,  with a reduction
of coliform bacteria from a magnitude of 107 colonies/100 ml in the
AWWTP influent to a value of 0 and occasionally 1 colony/100 ml in the
effluent.

Plant Production

        When the interim report for this project was published in
October, 1973 (Black, Crow and Eidsness, Inc.), it predicted that it
would only be possible to produce a maximum of 750,000 gal/wk (2,839
cu m/wk).  This was attributed to the expected low wastewater flows to
the primary plant, the pattern of pumping associated with the primary
plant, and the lack of personnel to man the AWWTP on a 24-hour basis.

        This situation would have been substantially improved with the
addition of the wastewater flow from Frederiksted,but it was decided
                                  70

-------
 to continue ahead with the project without waiting for completion of
 that phase of the wastewater collection system.  As it was, work was
 not completed on the crucial Frederiksted pumping station, whose
 operation about doubled the flow to the primary plant, until October,
 1974.

         However, by making certain modifications to the basic plant
 design and operations schedule, it was possible to exceed the
 estimated maximum production level; and by the time the recharge work
 was suspended, in October, 1974, the plant was averaging over 1 mil
 gal/wk (3,785 cu m/wk) and had boosted its maximum daily production to
 about 300,000 gpd (1,135 cu m/day).  This represents effluent actually
 delivered to the recharge areas.  Actual production in sections of the
 plant was higher.

         A bar graph showing the actual weekly production and delivery
 of reclaimed wastewater to the recharge area is shown in Figure 27.
 These data exclude water produced and not pumped to the recharge area
 and water used for backwashing.

         Delivery of water to the recharge areas was  halted if the
 guidelines for turbidity or free chlorine residual  were exceeded or if
 the chloride content exceeded 500 mg/1 to 550 mg/1.   Generally the
 plant operated at a turbidity level  of about 1.5 FTU and a FCR of 4
 mg/1.

 Operational  Problems

         Aside  from  the  low flows to  the pi ant,power  input problems
 plagued  the  plant throughout  its operation.   Failures  in  the  island's
 power distribution  system  are  common.   The manner  in which the  power
 would be  cut off  to  the  plant would  often  cause the  control circuits
 to  register  an overload  and to  open  their  automatic  circuit breakers,
 which required manual resetting.   If this  occurred on  weekends  or
 evenings  when  the plant was not manned,  then  the plant would  not
 function  properly and production was  lost.

        Difficulties with  various pumps  posed  the next most
 troublesome problem  in the operation of  the plant.  The reliability of
 the pumps was probably affected  by their remaining idle for a long
 period of time when the plant was delayed in completion and then
 operating under a salty tropical condition.  More production was lost
 due to pump difficulties than from any other mechanical cause.
 Initial troubles centered around the submersible pumps on the influent
 station.  These initially had two manufacturing defects which took
 considerable time to finally locate.  Then one of the  pumps had  to be
 completely overhauled due to a seal failure.   However for the past 18
months they have been operating without problems.

        The plant water pump has burnt out once and lost its impeller
on another occasion.  The vertical turbine effluent pumps had a series
                                   71

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                                 TIME-1974
Figure 27. AWWTP production utilized for artificial groundwater recharging.
                                   72

-------
 of problems during the summer of  1974.  The motor on one of the pumps
 shorted out and required rewinding, and the pump assembly on the other
 required a complete overhaul.  Since these incidents occurred within a
 few days of each other in July, it adversely affected the plant's
 ability to transfer treated effluent to the recharge area for about 5
 weeks until repairs were effected.  The distance from the mainland and
 the difficulty in obtaining spare parts and service turns a small
 incident like this into a major problem.

         An algal problem was experienced in the clarifier, solids
 contact unit, filters, and chlorine contact chamber.  In the clarifier
 the algae formed on the effluent trough and baffle.  This was handled
 by scrubbing down the affected area twice a week before the algae
 built up to an unmanageable degree.  The problem was severe in the
 solids contact unit and the final  solution was to cover the unit with
 an opaque polypropylene fabric which was custom-made by a local
 sailmaker.   This has worked excellently and has solved the difficulty.
 The algal  buildup in the filter was controlled by the chlorine in the
 backwash water and a plywood cover over the splitter box.

         The direct sunlight on the chlorine contact chamber not  only
 created an  algal  problem but it caused a higher chlorine demand  during
 the daylight hours.   Initially a temporary opaque plastic cover  was
 placed over the chamber but this was later replaced by the
 construction of a  50 x 20 ft (15 x 6 m) steel  building  over the
 chamber.  This not only served the purpose of  covering  the  chamber  but
 it provided extra  storage room for chemicals  (alum)  and  tools  plus  an
 office and  shower  area for  the operators.

 Plant  Expansion

        The present  capacity of  the  AWWTP  is adequate to permit  the
 artificial  recharge  and  recovery of  sufficient  groundwater  to
 economically justify  its  operation.   If there  is  a  viable market for
 additional  reclaimed wastewater and  if  there is a reliable  long-term
 supply of wastewater of a quantity that merits  treatment, then the
 expansion of the AWWTP should  be considered.

        However extensive capital  outlays should not be  made on
 expansion until a reasonable plan  has been agreed to for the
 disposition of the high chloride wastewater from both the Frederiksted
 and the Christiansted  areas.

        The AWWTP has  the capability for inexpensive expansion of
 capacity built into many of the units,  so that outright duplication of
 the units would not be necessary.  The  following is a discussion of
each major unit operation as it applies to future plant expansion.

        Influent Pumping.  This is  an item that needs correction
 immediately^The influent to the AWWTP is erratic due to the diurnal
                                  73

-------
pattern of flows in the interceptors and the nature of the high
capacity pumps used in the primary plant lift station.  With  their
present installation the flat rate 350 gpm (22 I/sec), AWWTP influent
pumps either do not get enough to pump or cannot handle all that is
available from the ocean outfall line.

        It is suggested that the present AWWTP lift station be
abandoned and the pumps be relocated at the effluent end of the
primary clarification basins.  These basins will act as large
equalization tanks permitting the pumps to deliver a continuous flow
to the AWWTP.

        The proper location of the pumps will allow the rakes to
function unimpaired, although 'the surface skimmers will be inoperative
while the level of the tank is below the effluent weir.  Certain
adverse currents may be induced during low flow operations; but since
the product will be receiving additional treatment in the AWWTP, it
should not be a great disadvantage.

        It is suggested that 8-in. (20 cm) cast or ductile iron pipe
be used from the pumps to the AWWTP along with throttling valves to
adjust the head.  This will reduce the friction head over the longer
distance so that the original pumps can still be used.  It will also
provide capacity so that the pumps can be operated at higher rates
when desired.  When in dual, parallel operation using the new
pipeline, it is believed that the present pumps will be able to
deliver up to 550 gpm (35 I/sec).

        The installation of this change now could probably increase
the reliable output of the AWWTP by about 0.1 mgd (378 cu m/day).  The
need to bypass and return a portion of the flow in the secondary
clarifier would be largely eliminated.  A smooth flow, steady organic
loading, and efficient chemical addition could be maintained 24 hours
per day.

        Aeration.  The aeration section of the plant is overdesigned
for the wastewater now being processed; and by operating both aeration
tanks, there should be little problem in handling up to 700 gpm (44
I/sec) both from a hydraulic and oxygen transfer standpoint.  This is
assuming that the wastewater characteristics do not change in the
future.

        Clarification.  The design loading is about 540 gpd/sq ft (22
cu m/day/sq m) of surface area in the clarifier.  However with the use
of coagulants such as alum and the proper operation of the aeration
tank, this loading can probably be exceeded without problems.  The
higher level must be determined by actual experimentation since it
will depend on the makeup of the wastewater and the selection and
dosage of coagulants used.
                                   74

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         During  plant  operations  extended  trial  runs  were  made  adding
 alum  to  the  effluent  from  the  aeration  tank  to  improve  solids
 separation  in the  clarifier.   This  enabled plant  personnel  to  bypass
 the solids  contact unit  (SCU)  and transfer the  clarifier  effluent
 directly to  the filters.   This eliminates the SCU from  use  and it
 could be utilized, with  some modifications,  as  an additional clarifier
 to work  in  parallel with the present  one.  Keeping the  same design
 surface  loading rate,  this would allow  the clarification  of an
 additional  0.2  mgd (757  cu m/day) of  mixed liquor suspended solids.
 However  there are  some disadvantages  to keep in mind.

         The  SCU acts  as  a  backup for  the  clarifier.   If the clarifier
 malfunctions and permits solids  carry-over,  the solids  are  usually
 handled  in  the  SCU.   Without the SCU  the  solids would rapidly  clog  the
 filter.

         The  second major disadvantage is  that there  are no  provisions
 for surface  skimming  nor underflow  solids return  to  the aeration tank
 from  the SCU.

         Filtration.   It  is doubtful that  this unit can  increase its
 production capacity.   It is suggested that if additional  filtration
 capacity is  needed, another filter  unit capable of handling at least
 350 gpm  (22  I/sec)  be  purchased  and installed.

         Effluent Pumps.  To increase  production it would  be necessary
 to purchase  new pumps  with a higher capacity.   These could  be
 installed in the same  location as the old pumps.   These should  be
 selected and equipped  with throttling valves so that the  rate  of
 discharge can be matched to the  production level  of  the plant.  This
 will  prevent the wet well  from being  emptied too  rapidly  and thus
 reducing the cycling of the pumps.  The old  pumps  could be utilized,
 at a  later time, at a  booster  station to  transfer  reclaimed water from
 a storage facility at  the  Department  of Agriculture's Lower Love
 facility to various points for irrigation purposes.

         Expansion  Plan.  It is recommended the  expansion  of plant
 capacity be carried out in 3 phases.  After each  phase, performance of
 the system should  be reevaluated and modifications made,  as necessary
 to the next phase.   These  phases, along with a  generalized cost
estimate are discussed in  the following paragraphs.

             Phase 1 - 0.5 mgd (1,892 cu m/day)  - Move  the influent
        pumps to the effluent end of  the primary settling tanks.
        Construct the  line to transfer the wastewater from the primary
        plant to the aeration tank.    Install  throttle valves on the
        influent and effluent pumps.  Expand the recharge area.
        Estimated cost $30,000.

             It  is  suggested that these improvements be made as soon
        as possible.
                                   75

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              Phase  2-0.75 mgd  (2,725 cu m/day)  -  Install an
        additional  350 gpm  (22 I/sec) gravity filter.   If the
        clarifier cannot  handle  the new  load, then  repipe the solids
        contact unit  in parallel.  Install effluent pumps with a
        capacity of 700 gpm (44  I/sec).  Expand recharge areas.
        Estimated cost $70,000.

              Phase  3  - 1  mgd  (3,785 cu m/day) - Install an additional
        clarifier,  new influent  pumps, and expand the recharge area.
        Make  general  plant  improvements  to handle higher loading.
        Estimated cost $140,000.
RECHARGE AREAS

        The development of the recharge facilities took place in
stages during the construction and operational phases of the project.
The initial facilities developed covered those types of surface
recharge methods which appeared to offer the most promise as far as
recharge in the existing soil strata was concerned.  As noted
previously, it was expected that the AWWTP would produce about 750,000
gal/wk (2,840 cu m/wk) in the period following start-up and the
recharge facilities were sized to handle this capacity.

        As operations continued and information was collected, the
data were evaluated and the facilities were modified, expanded, or
phased out as the situation dictated.  The original recharge
facilities consisted of spreading basins, spray irrigation, and
spreading in a dry streambed.  All of these facilities were built with
flexibility to permit modification to ensure maximum efficiency.
Although the effluent from the AWWTP was conveyed to the recharge
areas in a permanent ductile iron force main, the final portion of the
piping from the force main to the basins, etc.,-employed portable
aluminum and PVC pipe so that changes could be readily made by project
personnel with a minimum of effort and expense.

        As discussed in the section on preliminary investigations,
recharge was planned to take place in two separate areas, Golden Grove
and Negro Bay, which were geologically different but located very
close to each other and hence easily served by the same force main and
storage tank.  Golden Grove was to be the major facility, with the
Negro Bay site to be used for secondary experimentation.

        As part of the final selection and location process for the
recharge sites, a series of wells were drilled in the two areas to
further define the geological strata.  The logs of these wells and a
chart of the soil borings appear in the Appendix and the well
locations are shown on Figure 6.

        Three of these nine wells, PW-1, PW-2, and PW-4, were
transferred to the Public Works Department (PWD), which activated them
                                    76

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 for  use  in  its  potable  water  system.   At  the  time  of  drilling and
 initial  pump  tests  these  wells  had  a  demonstrated  aggregate  total
 capacity of about  100 gpm (6.31  I/sec).   This  addition  of
 approximately 140,000 gpd (530  cu m/day)  to the  potable water system
 was  meant to  aid the PWD  in building  up its freshwater  reserves  so
 that it  would be able to  switch  the saltwater  flushing  system in
 Frederiksted  to fresh water when the  town's wastewater  was diverted to
 the  new  primary treatment plant  at  Bethlehem Middle Works.

         However as  drought conditions  persisted  on the  island, the
 yield of the  wells  decreased  to  approximately  60 percent of  their
 initial  rates.  Still,  this would be  sufficient  production to allow
 substitution  of potable water for salt water  in  Frederiksted where the
 saltwater usage is  approximately 75,000 to 80,000  gpd (284 to 302 cu
 m/day).

         The active  project well  in  Negro  Bay,  PW-2, was located where
 it should not,  due  to the geology of  the  area, be affected by the
 recharging operations at  the  Negro  Bay site.   However the two wells in
 Golden Grove, PW-1  and  PW-4,  should be affected  to some degree by the
 recharge  operations in  that area.   PW-1 was located approximately 200
 ft (61 m) from  the  edge of the nearest spreading basin, while PW-4 was
 about 300 ft  (91 m) from  the  same basin.  Although the wells were
 hydrologically  upstream of the recharge site,  they were expected to
 extract  a small diluted portion  of  the artificially recharged water.
 The  recharging  was  also expected to increase the yields of these wells
 since water was being added to one  of  the aquifers being pumped.  This
 increase, however,  would  not  necessarily  be directly and entirely from
 the  recharged water but most  probably  would be due to a combination of
 recharge  flows  and  impounded  aquifer flows resulting from the damming
 up of the aquifer by the  artificial mound created at the recharge site
 immediately downstream.

        The recharge areas were  developed and  constructed within the
 project by renting  heavy  equipment  for the earth-moving portions and
 performing the minor work remaining using project personnel.  The
 development and operation  of  the two areas are described in  the
 following discussion.

 Golden Grove Recharge Area

        Description.  The  Golden Grove recharge area consists of six
spreading basins and six  small check dams in the adjacent riverbed.  A
sketch of the facility  is  shown  in  Figure 28 and an aerial  photograph
 showing a portion of the  basins  is  seen in Figure 29.

        The six spreading  basins were  constructed with a total bottom
area of about 45,000 sq ft (4,180 sq m).  During construction the
upper layer of the soil was removed in each case to expose the more
porous lower horizons.   Due to the  extremely clayey soil between the
                                  77

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                                                        BURIED 4" WELL WAT.ER
                                                        COLLECTOR LINE
*$ TANK ......
           ?;
                                     BURIED 6" FORCE MAIN
                                H*"...FOR TERTIARY
                                                            *:.:.:.,.. FORCE MAIN
                                                            j-I-" STANDPIPE
                                                            >ฃ&. AND VALVE
                                      BUR I ED 6"
                                      WATER LINE
                  FORCE MAIN
              ..... r- STANDPIPE
             -•>.  \  AND VALVE
         '/'
                   lit y
                                     : IRRIGATION PIPE
                                                         BASIN'
                                                         NO. 6i
                                    BURIED VALVE
FROM RECLAMATION
PLANT
                                      STORAGE TANK
             \\
             \ .*%&> $$&MM*  ^
Figure 28. The Golden Grove recharge area.
                                       78

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    PWR
          WESTERN LIMIT
          OF GOVT. PROPERTY
.i t4" MET!2
FORCE •>&.
MAIN  4ฃ
STANDPIPE
AND  3B
VALVE $$
BASIN
NO. 4
                 PW-9
       BASIN A
      BASIN B
                                   PWR *    SURVEY
                                   POLE   •MONUMENTS
                                         m(TYP)
                           4" ALUMINUM
                           IRRIGATION PIPE
                                     .•••A:-:*
                                     W&
                               BASIN NO. 1
                                                            MH
                              BASIN NO. 2
                         • •!• BASIN NO. 3
                                                     JpAVED PARKING LOT
                                                               POLE
                             i
                                               "PWR
                                               POLE
    [POND
    ho. si
[FISH'
[POIS
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                 PONI

                 [NO.
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                                              CORNER OF
                                              PUBLIC SAFETY
                                              HEADQUARTERS
           :plRT]
                                          BURIED 6"
                                          WATER MAIN
         PAVED ROAD,
                          DRAINAGE DITCH_

                              t
                         FENCE
                   OF ADULT    „
                   CORRECTIONAL

                   FACILITY

                 Figure 28. (Extended)
                                             GRAVITY
                                             WASTEWATER
                                             INTERCEPTOR
                                        PWR FROM
                                        POLE GROVE PLACE
                                                                 N
                                                             METERS

                                                          0  10 20 30
                                    79

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Figure 29. Aerial view of the Golden Grove recharge area.

-------
 upper aquifer and the one  immediately below  it, the upper one acts as
 a conduit to move the new  water horizontally with minimal leakage
 between the two.

         Bermuda grass was  developed in the recharge basins and
 surrounding areas.  This grass was selected  as it is tolerant to a
 high level of dissolved solids and is quite  resistant to dry periods,
 prolonged flooding, and heavy traffic.  The  grass aids in stabilizing
 the soil, reducing erosion while creating root channels to encourage
 infiltration and percolation.  Due to normal uptake and metabolism, a
 portion of the nutrients contained in the recharged water is
 incorporated in the plant material.  This low grass is easily cut,
 harvested, and mechanically removed from the recharge area.   This
 effectively removes some of the nutrients from the system.  No
 definitive studies were undertaken on the nutrient uptake by the
 Bermuda grass but the grass grew luxuriantly during a time of severe
 drought on the island.

         Water was brought to each spreading basin  by a 4-in.  (10 cm)
 diameter aluminum irrigation pipe.   The water was  discharged  into the
 basin by impinging it upon a splash block and a pile of large stones.
 This dissipated  the  energy in the water so that it could  enter the
 basin without eroding the bottom.

         Each  pond was first tested  for a  short period  to  ascertain its
 relative ability for  infiltration  and  percolation.   After this,  two
 ponds were selected  to  determine  how  long the wet  cycle of operation
 could be extended  without a noticeable drop  in  infiltration
 efficiency.

         During recharging  operations the  selected  basin,  or basins,
 were filled to a  height  of 3  to 3.5 ft (0.9  to  1.1 m).  Then  the  flow
 to the pond was adjusted to maintain the  same water depth.  This  meant
 that the water was entering the pond at the  same rate that it was
 being  lost by infiltration  and evapotranspiration.   It  proved
 relatively easy,  in practice, to hold  the depth to within 0.5 ft  (0.15
 m) through the use of adjustable valves at the force main standpipes.
 The  results of the operation are outlined in  the section on results
 and  discussion.

        The work using the  check dams  in Golden Grove was scheduled to
 begin in November, 1974.  Unfortunately recharge operations were
 suspended due to the high TDS of the wastewater and the floods during
 that month; therefore no data were  collected  on that phase of the
 project.

        Design Considerations.  One of the best guides to the design
and operation of a groundwater recharge system using wastewater
effluent is a report entitled "Soil  Mantle as a Wastewater Treatment
System" by McGauhey and Krone (1967).   This was based on considerable
                                  81

-------
experience with septic tank studies and was broadened to  include other
soil-oriented treatment systems involving wastewater.  Aside from an
extensive literature review and discussion of the the theoretical
aspects of the subject, the authors present some recommendations for
the design and operation of an engineered soil  system.  As part of
these recommendations they developed eight criteria for optimizing
such a system.  These criteria from the report  (McGauhey, 1967, p.
144) are quoted below; and following each one is a discussion of its
application to the system constructed  in Golden Grove on  St. Croix.

        In reviewing these criteria and subsequent discussions it must
be kept in mind that they were developed for a  soil-aquifer system
which was meant to act as a treatment  process for wastewater.  In the
St. Croix project the soil-aquifer system is meant to be  a treatment
process only in the sense of a polishing of the extensive processing
that has already taken place in the AWWTP.  The system also acts as a
safety barrier against any occasional  deficiencies in the treatment
process.  Hence it is expected that the soil system will  reduce
nutrients and remove most organics, bacteria, and viruses,but it is
not to be expected to bear the brunt of the oxidation and filtration
processes that a system using settled  wastewater or septic tank
effluent might experience.

        "Criterion 1:  The infiltrative surface should be no less
permeable than any undisturbed parallel plane within the  system."

        As part of the construction of the basins the upper, less
permeable, layer was removed to expose a more permeable soil horizon.
Soil borings in the area indicate that permeability does  not decrease
below the newly exposed horizon before the upper aquifer  is reached.

        "Criterion 2;  The soil surface should  be managed in such a
manner as to disperse clogging material."

        One of the suggestions made by McGauhey and Krone was to grow
vegetation on the areas to provide root channels and expand the soil.
This was done using Bermuda grass which additionally stabilized the
banks of the basins to permit foot traffic and  incorporated a portion
of the applied nutrients in their plant material for removal by
harvesting.

        "Criterion 3:  There should be no abrupt change in particle
size between coarse trench fill or surface cover material and soil at
the infiltrative surface."

        Since the existing soil structure is the infiltrative surface,
this is no problem as no larger material, such as gravel, is applied
to this surface.

        "Criterion 4:  The infiltrative system should provide a
maximum of sidewall surface and a minimum of bottom surface."
                                  82

-------
        The use of a basin design entirely violates this criterion.
The cost of construction, ease of maintenance, and simplicity in.
operation were deciding factors in selecting spreading basins over
trenches.  Additionally the use of vegetation for dispersing any
clogging material (Criterion 2) and nutrient uptake can be maximized
with the basin configuration.

        "Criterion 5;  Continuous inundation of the infiltrative
surface must be avoided."

        By using a system design, such as the one in Golden Grove,
containing many basins; the flow can be diverted to any of the basins,
allowing some to be utilized while others are allowed to dry out.
Successful management of the facility depends on having sufficient
basin area so as to provide for alternative loading and drying cycles
during operation.  The area required in the future has been
reevaluated on the basis of the results obtained and is discussed
under the section on monitoring activities.

        "Criterion 6:  Aerobic conditions should be maintained in the
soil system."

        This is to promote aerobic metabolism by the soil biota to
prevent the buildup of undesired anaerobic by-products such as
clogging slimes or taste and odor-causing compounds.  This can be
maintained in several ways.  The first is to use alternate loading
cycles, wet and dry, in the operation of the spreading basins.
Another is to remove the water accumulating in and above the aquifer
under the spreading basin as rapidly as possible so as to prevent the
groundwater mound from building up until it reaches the bottom of the
basin.  The section on recommendations for future development covers
this situation.

        "Criterion 7:  The entire infiltrative surface should be
loaded uniformly and simultaneously."

        Since the bottom area of the spreading basins is the primary
infiltrative surface, it will be loaded rather uniformly as the
bottoms are relatively level.  The sidewalls, however, are loaded
differentially, but they do not contribute as much to the total
recharge effort.

        "Criterion 8:  The amount of suspended solids and nutrients in
the applied water should be minimized."

        The design of the treatment process for this project was
oriented towards a high reduction of suspended solids and organic
material.  The problem of a mat forming on the surface of the soil and
clogging the pores did not manifest itself to any noticeable extent in
the project during normal operations.
                                  83

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        Nutrients were not fully removed in processing at the AWWTP,
with ammonia generally converted to the nitrate form and the
phosphates only partially removed.  Undoubtably the growing and
harvesting of Bermuda grass in the spreading basins aided in the
removal of additional nutrients while the soil itself is capable of
handling phosphate removal.

Negro Bay Recharge Area

        Description.  In the Negro Bay area two types of recharge
met iods were tested:  spreading basins and spray irrigation.  A sketch
of the facilities is shown in Figure 30.  The spray irrigation portion
consisted of a gently sloping (0.031) field 250 ft by 250 ft (76 m by
76 m).  The water was transferred from the permanent standpipe to the
field by 4-in. (10 cm) aluminum irrigation pipe.   In the spray area
grids containing 8 spray heads each were set in the field.  The feed
in the grid loops was by 2-in. (5 cm) PVC pipe.  The spray heads were
Rainbird 30 B-TNT with an 11/64 x 3/32 nozzle that was rated for a
92-ft (28 m) diameter circular spray pattern at 40 psi (258 kg/sq cm)
with an individual feed of about 7 gpm (0.44 I/sec).  These spray
heads were placed on 2.5-ft (76 cm) risers at 60 ft x 60 ft (18 m x 18
m) spacing.  The actual rate of surface loading was about 2 gpd/sq ft
(0.08 cu m/day/sq m).

        The normal mode of operation was to run the entire system 3.5
to 13 hours at a time with the total loading ranging from 0.3 to 1.1
gal/sq ft (0.012 to 0.044 cu m/sq m).  Higher loading than this caused
surface runoff and erosion of the soil.

        The entire area was seeded with Bermuda grass which, due to
the poor soils in the area, did not fill out as thickly as it did in
the Golden Grove spreading basins.

        The results of the tests were not encouraging.  Water did not
build up in the various piezometric tubes installed in the area.  If
the spraying time or amount of water applied at a single time was
increased, runoff occurred.  The rate of application was far below
that of the ponds.  What apparently occurred is that the soil  moisture
in the upper layer was increased during spraying periods; but in the
periods between spraying, the water was removed by evapotranspiration
aided by the capillary nature of the marly soil which acted as a wick
for the water incorporated in the soil.  To decrease erosion a better
vegetative cover could have been developed by leaving more of the
clayey soil on the surface.  However this would also act as a further
barrier to the infiltration of water applied by spraying.

        The two spreading basins in the Negro Bay section were run on
an alternating wet and dry cycle.  Each pond has an average bottom
area of about 2,500 sq ft (232 sq m).  The ponds are built on a slight
slope so that the water depth is limited by the downslope side.  The
                                  84

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                                                                       FORCE MAIN
                                                                       STANDPIPE
                                         DIRT ROAD
                                                        4-in. DIAMETER ALUMINUM
                                                        IRRIGATION PIPE
    BASIN NO. 8
                      BASIN NO. 7
                                   2-in. DIAMETER
                                   PVC PIPE
                   DIRT
                   WINDROW
  SPRAY
IRRIGATION
   AREA
     10  20  30
                                                                             POWER POLE
POWER POLE
                                          16 SPRAY HEADS
                                          MOUNTED ON 30-in
                                          PVC RISERS
                                                                             DIRT ROAD
                                 POWER POLE
                             Figure 30. The Negro Bay recharge area.

-------
marls neither lend themselves well to the construction of berms around
the ponds nor to stabilized banks as do the soils in Golden Grove.
Erosion of the sidewalls contributed to the plugging of the bottom
surface of the basins.

        Each pond was initially run on a constant-head basis where the
ponds were filled to a certain depth and then the flow was throttled
down to try to maintain that depth.  This was not satisfactory over a
long-term basis as the ponds took so little water that the setting had
to be too low for effective operation.  The average percolation rate
based on bottom area was so low that work in the Negro Bay area was
suspended and the remaining efforts were applied in the Golden Grove
area.
                                  86

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                              SECTION  VII

               MONITORING ACTIVITIES  DURING THE PROJECT
        As  part of  the  project an extensive monitoring program was
 established to provide  data for a "before, during, and after" look at
 the various parameters  that might be affected by the recharge
 operations.   It was desired to carefully monitor surface and
 groundwater quality and quantity in the study area and, in addition,
 monitor the operation of the AWWTP.
WATER QUALITY

        A water quality laboratory was established within 3 months of
project operation on St. Croix.  This was first located in the field
office, then in laboratory space donated by the Martin Marietta
Alumina Company, and finally  in February, 1973, in the permanent
laboratory which was constructed as part of the AWWTP facility.

        The number of parameters analyzed was increased as laboratory
facilities improved.  Initially a chemist was brought in from the
mainland to do the work and to train local people for the work so that
he could phase himself out.

        In addendum No. 1 of the original project proposal (FWPCA-
1970), a list of analyses to be performed during the project was noted
and is as follows:

          Specific conductivity
          Chemical oxygen demand
          Biochemical oxygen demand
          Total nitrogen
          Ammonia nitrogen
          Nitrite nitrogen
          Nitrate nitrogen
          Phosphate
          Total organic carbon
          Chloride
          Coliform

To these tests  were added those for alkalinity,  calcium,  and total
hardness plus operational tests for the AWWTP.
                                  87

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        All of these analyses were performed on St. Croix with the
exception of the total organic carbon and total nitrogen measurements
which were performed in the Black, Crow and Eidsness laboratory in
Gainesville, Florida.

        A survey of the entire study area was made and wells, both
public and private, were selected for monitoring purposes.  These were
located above and below the theorized groundwater flow at the proposed
recharge areas.  Only active wells were selected for water quality
monitoring purposes.  These were wells that were being actively
pumped, thus assuring a fresh sample of the groundwater for analysis.
Additionally sampling points were selected along the course of River
Gut where surface water could be sampled.  These sampling stations are
shown on Figure 16.

        To avoid needless duplication of sampling and analysis, the
selected wells were divided into two groups, primary and secondary,
with the primary wells being considered the most important.

        A sampling schedule (see Table 6) was then devised which
included all of the sampling stations and all of the analyses
scheduled in a systematic fashion that included all of the sampling
points in a full analytical time cycle.  These time cycles were 4
weeks in length and permitted the chemist time to sample and perform
the analyses with a minimum of storage time, and sufficient extra time
to maintain the laboratory, prepare reagents, and do the necessary
paperwork associated with the laboratory.

        In sampling, problems were encountered throughout the project.
The greatest was in simply obtaining the samples.  Most wells had no
provision for sampling taps and these had to be added where
permissible so as to sample the water before it-was mixed in a storage
cistern.  Often it was not possible to add these taps, or if they
existed, they sometimes were removed at a later time by the owner or
alterations were made to the premises which then prevented access to
the taps.  One has to keep in mind that sampling has continued at some
stations for over 4 years.

        It was easy to install  taps on most of the government-owned
wells but these were soon discovered by people who used them during
dry periods to either fill  up drums of water to take home to fill
their cisterns, to provide water to wash cars, or both.  This abuse of
the government wells often provoked the Public Works Department to
remove the sampling taps altogether.

        The wells that were drilled adjacent to the Golden Grove
recharge area for the purpose of monitoring the changing water levels
during recharging were also sampled.   Since these had no pumps
installed nor easily available power; they were simply dipped, using a
project-constructed torpedo sampler.   Despite being dipped a few times
                                  88

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      Conductivity,  free chlorine  residual and turbidity levels of the wastewater ts continually monitored.

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at each sampling, this was obviously an inferior method of sampling
and the data obtained from these wells should be viewed with this in
mind.

        The water quality data for the project are presented in
tabular form in the Appendix.


GROUNDWATER QUANTITY AND MOVEMENT

        A study of groundwater quantity and movement was made using
water level data from wells selected in the study area.  These wells
were generally inactive nonpumping wells on public and private
property.  Water level recorders were placed on a series of wells to
ascertain what continual variations took place while other wells were
simply measured by using a tape measure at regular intervals.  Since a
free water table does not exist in the study area south of the Center!ine
Road, these water levels represent the potentiometric surface of the
groundwater rather than the actual depth of the aquifer.

        Aside from these data, additional information on the
potentiometric surface was gathered by installing small diameter, 3/4-
in. (1.9 cm) PVC, tube wells in the vicinity of the proposed recharge
area.  Holes for these wells were dug using a 4-in. (10 cm) soil
boring rig with an auger bit.  This gas-powered drilling rig was
mounted on a trailer which could be moved rapidly from site to site.
Although the rig could drill holes quickly in the tight clayey soil,
it could not penetrate far below the existing water in the soil as the
sides of the holes in the vicinity of the water would collapse as the
sectioned auger was being removed to clear the hole.  Since all of the
holes were drilled during a period of excess groundwater in the area,
the resultant tube wells were not deep enough to toe usable during the
extended period of dry weather that occurred during the last 2.5 years
of the project.  Additionally the majority of the tube wells
downstream of the recharge area were destroyed during the construction
of the adult correctional facility.  Most of the tube wells upstream
of the recharge area were lost in two fires which swept the area and
those that survived went down to the blades of a large government-
owned cane cutter which made intermittent unpredictable forays into
the area to cut forage for the island's cattlemen.

        However, the tube wells did furnish useful information in
initially calculating the flow pattern of groundwater in the area,
which aided in the final placement of the recharge structures.
Moreover the actual boring of the holes produced valuable data on the
soil horizons in that part of the study area.

        The water level data for wells in the study area are presented
in graphical form in the Appendix.
                                    90

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 RAINFALL DATA

         Initially three  recording  rainfall  gages  of  the weighed bucket
 type were installed  in various  parts  of  the study area to collect
 rainfall  data.

         On the  aggregate this data collection  system was not even a
 moderate success.  The gages suffered from  mechanical breakdown, human
 abuse,  and animal  interference.

         The clock portion of the gages continually broke down.
 Repairs were difficult to procure  on  the island and  the replacement
 spring-driven clocks  cost close to $100  each.  Several replacements
 were purchased  but they  soon failed in operation.

         Additionally, the rain  gages  seemed to exude a magnetic pull
 for  human curiosity and  at two  of  the locations the  security lock was
 frequently twisted off the case and the  gage thoroughly examined.  At
 the  Negro Bay location the gage was located adjacent to a government
 well  and  was repeatedly  broken  into to obtain  the bucket, which
 apparently was  used in conjunction with  the well  to  wash cars.

         Another problem  was animal  interference,  which at the Bodkin
 location  above  Fountain  Valley, took  the form of  the gage being used
 as a rubbing post by  cattle.  There was  also the  general problem of
 the  local  tree  lizards,  Anolis acutus, which would occasionally be
 found living in the gage.  This selection of dwelling place was no
 doubt accidental  on their part and probably the result of falling
 through the  narrow funnel-shaped opening which directs the rain to the
 weighing  bucket.   Once trapped inside, the  lizard would repeatedly
 jump on the  recording needle, thus  distorting the recording.  They
 would eventually  die, attracting large numbers of ants who would
 invade  the  gage to consume the body.

        The  only  gage remaining after the first 3 years was the one
 installed  at the  fire station in Grove Place.  This gage remained
 relatively  unscathed but  has suffered from  numerous and continuous
 clock failures.

        Fortunately, the  U.S. Department of Agriculture maintains a
 rain gage at Bethlehem Upper Works, which is on the eastern edge of the
 study area on a hill just above the Golden  Grove recharge area.  This
 gage, which  is  protected  and attended daily, has produced far more
 reliable  information and  its data  have been  used in this report.
ADVANCED WASTEWATER TREATMENT PLANT

        The operation of the advanced wastewater treatment plant was
monitored as to flow, power consumed, chemicals used, influent and
                                   91

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effluent quality, etc.  This work was performed by both the plant
operators and the project chemist.

        The sample log pages displayed in Figures 31 and 32 show how
the various plant functions were recorded.  These logs required a fair
portion of the operator's time to complete every day; but in filling
them out and examining the various recorded data that had to be
entered into the log, he obtained a better understanding of the
plant's operation.  The effluent flow chart, Figure 31, was especially
helpful in recognizing small problems in operation before they became
major disasters.  The operating data for the plant have been
statistically analyzed and presented in the Appendix of this report.
                                  92

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                                                                                                                 REATMENT PL&HJT &T
                                                                                                                 ST. CROIX.  U.S. V.I
                      Figure 31.  A typical page from the AWWTP operator's log showing the effluent flow chart
                                                                                                                C16TE I To" /  ~T / *VJ |

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-------
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                              SECTION VIII

                         RESULTS AND DISCUSSION


 WATER QUANTITY CHANGES DUE TO RECHARGING

 Infiltration and Percolation

         A key factor in the economic success  of  a  surface method of
 artificial  recharge  is the rate of infiltration.   This  determines  the
 land  area required per unit of recharged water.  On  the Virgin  Islands
 land  is  expensive, averaging about $10,000/acre  ($4,050/ha).

         In  comparing the rates  of infiltration between  the 8 basins as
 shown on Figure 33,  it is  apparent that  there is a distinct difference
 between  the rates in the 2 basins in Negro  Bay and the  6 basins in
 Golden Grove.   The sustained infiltration rate in  Negro Bay was less
 than  5 gpd/sq ft (0.2 cum/day/sq  m)  while infiltration  rates in the
 Golden Grove basins  ranged from 10 to 28 gpd/sq ft (0.4 to 1.1 cu m/
 day/sq m).

         Negro Bay.   In the Negro  Bay area,  which is  located on the
 Kingshill marl,  two  methods  of  surface recharge were tried:  spray
 irrigation  and spreading basins.   Neither method of surface application
 proved to be sufficiently  successful  to  warrant further investigations.

         The  spray irrigation was  limited in the rate and extent of
 application  by surface runoff on  the  spray  area.   The spray area was
 constructed  on a location  with  a  gentle  slope  of about  0.031.   The water
 was applied  at the rate  of approximately 2  gpd/Sq  ft (0.08 cu  m/day/sq
m) and once  the  loading  reached about 0.4 to 0.6 gal/sq ft, (0.016 to
 0.024  cu m/sq  m), any  additional water would tend  to runoff down the
 Slope  causing  soil erosion.  This meant  that spraying periods  were
 limited  to between 5 and 7 hours  in a 24-hour  period if erosion was to
 be controlled.  During  the  intervening drying period,  evapotranspiration,
 through  the vegetation and the capillary action of the marl,  removed the
water  in the upper soil  horizons.  The result was no  net gain  in water
entering the marl formation.

       . One of the main reasons for this infiltration problem  is the
structure of the upper soil horizon in the spray area.   Covering the
                                   95

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   30
         BASIN NO. 3
       (GOLDEN GROVE)
~
in
a>
<
cc
H
ii.
z
UJ

cc
   20 -.
                    *~BASIN NO. 1
                    (GOLDEN GROVE)
                     NO. 6
                    (GOLDEN GROVE)
   10
           \    BASIN NO. 8
           \   (NEGRO BAY)
         .  AX
           •^&ซt
                      fc BASIN NO. 7
                       (NEGRO BAY)
                                                                          BASIN NO. 5
                                                                        (GOLDEN GROVE)
   BASIN NO. 2
.(GOLDEN GROVE)
                                                                                              \
                                                                                                \
                                                                                                  I
                                                                                  LENGTH  OF  DRY  PERIOD
                                                                                  BETWEEN  REUSE  OF BASIN
                                                                                  FOR RECHARGING
              100       200       300       400       500        600       700
                               CUMULATIVE AMOUNT OF INFILTRATION(gal/sq ft)
                                                                                     800
       900
                                  Figure 33. Infiltration rates in the recharge basins.

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 actual marl formation is a cap of soil approximately 8 in. (20.3 cm)
 thick.  All but 2 to 3 in. (5 to 7.6 cm) of this clayey organic material
 was removed and windrowed to prepare the area for surface application.
 It was realized that when wet the clay would swell and tend to be
 impervious.  However, this upper top soil was necessary to serve as a
 base for growing grasses.  The grasses would aid in preventing soil
 erosion while at the same time they would remove a portion of the
 nutrients in the applied effluent.

         Adjacent to the spray area (see Figure 30) two spreading basins,
 basins 7 and 8, were each operated for approximately 2 weeks.  The
 resulting sustained rate of infiltration was less than 4 gpd/sq ft (0.16
 cu m/day/sq m).  This was a better infiltration rate than for the spray
 irrigation site, but it was not high enough when compared to  the rates
 in Golden Grove to justify continued operation.   Additionally, the banks
 of the marl  basins were unstable when wet.   The fine material  from the
 banks was eroded to the bottom of the basin, which contributed to the
 sealing of pore spaces in the exposed marl.   Marl, by itself,  will
 support only sparse vegetation to a very limited degree so the use of
 grass for stabilization was not possible.

         In summary the results of the work  in Negro Bay showed that
 artificial  recharge by spray  irrigation or  spreading basins in that
 area  was  not justified when compared to the  alternative available.
 This  alternative is in Golden Grove where the sustained recharge rates
 are 4 to  7 times higher and hence the land area  required  would be
 proportionally  less.   Recharge operations in Negro Bay  were abandoned
 in  August,  1974,  and  all  subsequent efforts  were concentrated  on  the
 Golden  Grove facility.

        Golden  Grove.   This recharge area, which is  located in an
 alluvial  valley, was  in operation from  February  through October,  1974.
 All the recharging  work  in  this  area  was accomplished by  the use  of
 spreading  basins.   The  resulting  rates  of infiltration  for the  various
 basins  are shown  in Figure  33.  These data show  a  high  sustained  rate
 for infiltration and  percolation  for  all of  the  basins  with the minimum
 rate  being in the order of  11  gpd/sq  ft  (0.45 cu m/day/sq m).    The best
 infiltration rate was encountered  in  operating basin 5  which had a
 maximum sustained rate of infiltration  in the range of  25 gpd/sq ft
 (1.0 cu m/day/sq m).

        The rate of infiltration  is a function of both  the soil
 structure on, and immediately below,  the bottom of the  basins  and the
 inherent ability of the underlying formation to conduct the percolating
water away from the vicinity.  If the underlying formation will not
remove the introduced water at the same rate that it is being  applied,
then ponding will occur.
                                   97

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        In order to test the long-term ability of the underlying
formation to handle recharging, basin 2 was operated continuously for
60 days.  A sustained decline in infiltration rate was not apparent
until the final 10 percent of the run.  By that time a cumulative
loading of about 660 gal/sq ft (26.9 cu m/sq m) had been applied  to
the basin for a total flow of about 6.6 mil gal (24,981 cu m).

        Basin 5 was also operated for an extended period of time  to
test its capabilities.  After a dry cycle of 126 days the basin was
operated at a high rate of loading for 18 days.  During this time the
rate of infiltration averaged about 22 gpd/sq ft (0.9 cu m/day/sq m)
compared with 11 gpd/sq ft (0.45 cu m/day/sq m) for basin 2 discussed
in the preceding paragraph.  The total loading for the run was  about
400 gal/sq ft (16.32 cu m/sq m).  The infiltration rate dropped off
drastically during the final portion of the run and there were  indi-
cations of ponding at that time.  These were manifested by some
dampness at the bottom of the adjacent structure, basin 6.

        The decrease in infiltration rates which occurred in both
basins 2 and 5 could be caused by clogging of the soil in the  basin
due to deposition of suspended solids and/or biological growth; or,
to the mounding of the water table to the point where it reached  the
bottom of the basin.  Based on observations, examination of water
level information, and comparison of infiltration rate data, it is
believed that clogging of the soil was involved in both cases  but that
the mounding water level under the basins also played a part.   This is
especially true in the case of basin 5 during its final extended  run.

        The clogging condition of the soil due to deposition of organic
suspended solids and biological activity is readily reversed by a
period of drying so that stable aerobic conditions are restored to the
upper soil horizons.  This permits aerobic metabolic activity  to  occur
in that area.

        The low turbidity and organic content of the wastewater effluent
used in this recharging reduced considerably the potential suspended
solids involved in mechanical entrapment, while also reducing  the food
available for microbial growth.  In order to continue the long  periods
of inundation which are vital to the economics of the recharge
operations, it is important to continue the operation of the AWWTP
so that the present low levels of turbidity and organic content are
maintained, or reduced.

        The short span of recharge operations in 1974 did not  permit
sufficient data to be collected to determine the most efficient time
period to use for either the inundation of the ponds (wet days) or the
intervening drying period (dry days).  It will probably take several
years of operation and careful monitoring to correctly arrive  at  the
                                   98

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 answer.   It  is  likely that  there  will  be  different values for each pond
 due  to  the difference in  underlying  strata.

         For  the present,  however,  operations  should be carried out on
 the  basis  of 10 wet  days, followed by  5 dry days.  This will give a
 complete cycle  of  15 days for which  an average value for the entire
 cycle of 8 gpd/sq  ft (0.33  cu m/day/sq m) can be used for loading
 purposes.  When operations  are  renewed then these figures can be
 updated  as experience dictates.

 Groundwater  Movement in the Golden Grove  Area

         St.  Croix's  physiography  in  general and stratigraphy in
 particular create  some problems for  the groundwater hydrologist.  The
 island's  groundwater situation  is  studied most easily on a broad plane
 where  generalizations can  be made on  well yields, aquifer flows, and
 transmissibility.  The USGS has done this in  useful reports such as
 those recently  published by Jordan (1973) and Robison (1972).  These
 reports  combined collected  data to present an overall view of the
 groundwater  potential  on the island.

        As the  area  of study in St. Croix is  reduced to a single
 drainage basin, or portion  thereof, the difficulties involved in accurate
 analysis can  increase drastically.  This  project has intensively studied
 the  portion of  River Gut where  it  passes  through Golden Grove.   The area
 of interest  is  the alluvium in  the valley into which the artificially
 recharged water is introduced.  Information about the alluvium has been
 gained mainly by soil  borings, well construction, pumping tests, water
 level monitoring, chemical  analysis of water  samples, and field
 observations.

        The results  of all  of these investigations have shown that
 this area is one of  extreme  complexity when studied as a separate
 small system.  The alluvium is of  recent geologic origin and its
 placement has been a  result  of years of deposition of material
weathered from the basin's  surrounding hills.   This was deposited by
 both normal stream sediment  transport and by occasional  turbulent
 flooding conditions.   The result has been a formation of an alluvial
material which is generally  heterogeneous and  anisotropic in character.
 It is estimated that  field  permeability (Kf)  values for the alluvium
 range from 0.01 to 10,000 gpd/sq ft (0.0004 to 410 cu m/day/sq  ft)
and vary in both horizontal   and vertical  planes.   While all  of  the
material will conduct water  to some extent,  the main aquifers composed
predominately of sand and gravel conduct the major portion  of the flow.
Based on borings, well construction samples, and observations,  these
aquifers are neither consistent in thickness,  material  content,  nor
horizontal extent.   Their thickness ranges from 0.5 to 15 ft (0.15 to
4.57 m)  but generally in the order of 1 to 2 ft (0,3 to 0.6 m)  thick.
                                   99

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         Pumping Test Analysis.  Pumping tests were performed on selected
wells  in the  area.  However, analyzing the data to provide valid,
meaningful  results as to permeability (K), transmissibility (T), and
the coefficient of storage  (S), for each well is not possible to any
reasonable  degree of accuracy.

         The reason for this is that many of the assumptions on which the
accepted theories and calculations for these parameters are based are
not valid in  the situation at hand.  Of the 7 assumptions listed by
Kruseman and  DeRidder (1970, p. Ill) which are basic to any conventional
analysis, 3 of them cannot be fulfilled.  These are:

              The aquifer has an apparently infinite areal extent.

              The aquifer is homogeneous, isotropic, and of uniform
         thickness over the area influenced by the pumping test.

              Prior to pumping, the piezometric surface and/or phreatic
         surface are (nearly) horizontal  over the area influenced by the
         pumping test.

         In  the first assumption, the aquifers in Golden Grove have a
very real boundary situation where the horizontal extent of the aquifer
varies from only 200 to 1,200 ft (60 to 365 m).

         In  the second assumption the aquifer is  not homogeneous,
isotropic, or uniform in thickness.

        As  for the final assumption, the potentiometric surface slopes
steeply at  the rate of 50 to 70 ft/mile (10 to 13 m/km) within the
alluvium.

        Aquifers in the Recharge Area.   There are a number of aquifers
in the alluvium, some of which are shown in Figures 18 and 20.   They
are not necessarily connected horizontally, and  isolated sand and gravel
lenses are not uncommon.  Precise knowledge of the strata can only come
from additional deep borings;  the more borings the better will  be the
knowledge of the area.   However based on borings and well  logs  avail-
able, information on recharge rates and  water levels, observations in
the field, and engineering judgment; certain tentative conclusions can
be made as to the nature of the water-bearing strata in the vicinity
of the recharge area.   These conclusions are discussed in the following
paragraphs.

        There are one and possibly two main aquifers that transmit the
major portion of the groundwater in the  upper aquifers through  the
recharge area.  The theorized location of these  aquifers is shown orr
Figure 34.  The field permeability (Kf)  value in the most porous section
of the main aquifer is  in the range of 3,000 to  7,000 gpd/sq ft (122 to
                                  100

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                                    PUBLIC SAFETY
                                    HEADQUARTERS
                              G G-S-oWxr-f" CHECK DAMS
                                                   GUT
            GGL-3B
               6*3-4
                                                          SECONDARY
                                                          FLOW
                                                                                  (15CM)\
                                                                                 R LINE >
                                                                                 .V.I.
                                                                                 V
NEGRO BAY:  MAIN FLOW
RAIN GAGE
SPREADING BASINS
                                                                                             FAIR PLAINS
                                                                                             WELL FIELD
                              100,000 GAL
                               (38ฐ CU M)
                                    TANK
   NEGRO BAY
RECHARGE AREA
                                                         6 IN. (15 CM) FORCE
                                                JFfp    MAIN TO CONVEY
                                                      RENOVATED WASTEWATER
                                                        TO RECHARGE AREA
   SPRAY

1000
         Scale Feet
        0     500
        0   1O"0 200  300
        Scale \n Meters
                                                                                         BMW-1

                                                                                   PRIMARY  WASTEWATEFfN
                                                              MB-5 _  __===>, *  TREATMENT PLANT
                         Figure 34. Hypothesized flow of groundwater in the upper aquifer in Golden Grove.

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285 cu m/day/sq m).  This was determined by approximating the system
during recharging as a constant head parameter.  The resulting Kf
value checks with the range of K values for aquifers with sands and
gravels given by Todd (1959, p. 53) and Davis and DeWiest (1966,
p. 164).  The average temperature of groundwater on St. Croix is
about 27ฐ C which decreases viscosity and increases the K by
approximately 33 percent (Todd, 1959, p. 51).

        It is believed that a portion of the main aquifer was partially
exposed during the excavation of the new stream channel recently
constructed just south of the adult correctional facility.  Based on
the recharge operations, it is estimated that the major aquifer below
the basins has a main transmitting area of approximately 600 sq ft
(55 sq m).  This aquifer traces the course of an old streambed across
the area.

        Basins 1, 4, 5, and 6 are located wholly, or in part, over the
probable location of the main channel.   Basin 2 is interconnected to it
by a thinner sand lens.  The nature of the interconnection of basin 3
is not clearly understood due to its limited period of recharging.  None
of the project wells are located within the main channel in Golden Grove
since its presence was not suspected until after the wells were con-
structed.  Wells PW-7 and PW-8 are apparently isolated from the main
aquifer while wells PW-5 and PW-6 are connected to it via sand lenses.
Wells PW-1 and PW-4 are located on either side of the main aquifer but
are probably connected to it by a thin transverse aquifer which continues
north underneath the stream.

        Water Level Response to Recharging.  An examination of the water
levels in the various wells in the area compared with the rainfall and
periods of artificial recharge reveals many points of interest.

        In Figure 35, the general water levels during 1973 dropped due
to the lack of sufficient natural recharge from rainfall.  Both wells
GG-3 and GG-5 are upstream of the recharge area.  GG-3 was selected as
the control well since activity in the recharge area did not appear to
affect it.  After recharging began in 1974, GG-5 was almost immediately
affected, as can be seen in Figure 35.   The flattening of the slope of
this well beginning in March was due to the hindrance of the normal  flow
in the upper aquifers due to the recharge water added to the same
aquifer.

        Figure 36 compares the immediate boundary wells on the approaches
to the recharge area with a well, PW-8, within the. area.  GG-13 is 1,500
ft (425 m) north of the area.  A-18 is 3,700 ft (1,130 m) northwest of
the recharge area at the upper end of the aquifer which flows under the
basins.  GG-3 is in the same general aquifer system as A-18 and 1,300 ft
(400 m) upstream of the basins.  The lack of activity in these boundary
wells indicates that outside influences such as rainfall are not
                                   102

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ELEVATION
42.4
GOLDEN GROVE
1973
               EAST RECHARGE BASINS (5 and 6)

               WEST RECHARGE BASINS (1, 2, 3, and 4)
GOLDEN GROVE
1974
 JAN  I  FEB
       XfamS&SS & ซ S3              n*fKvarf*rsf*xx .V^^^^.Y^V^WB.VV.
       APRI  1 MAY r JUN I  JUL  I AUG I  SEP  '  OCT '  NOV

                       TIME

Figure 35.  Comparison of wells GG 3 and GG-5,1973-1974.
                                     103

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               EAST RECHARGE BASINS (5 and 6)
               WEST RECHARGE BASINS (1, 2, 3, and 4)
GOLDEN GROVE
1974
                                                          OCT I  NOV I  DEC
                       JUN  I  JUL
                         TIME

Figure 36. Comparison of wells A-18, GG-3, GG-13, and PW-8,1974.

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disturbing the groundwater system.   Hence the reaction of PW-8  is,  in
fact, caused by the artificial  recharge operations  taking place within
the localized area of Golden Grove.

        Figure 37 is significant in  two ways.  First it shows the  extent
of water level alterations caused by recharging,  as measured  in wells in
the vicinity of the basins during 1974.  Well PW-6  is plotted along with
control well GG-3.  During 1975, when no recharging took place, the
rainfall during the first 7 months was very similiar to that  of the
previous year.  Again PW-6 and  GG-3  are plotted and it should be noted
that they move almost in unison. The inference is  that this  is the
pattern that the water levels would  have taken during 1974, had arti-
ficial recharge not taken place.

        The second manner in which  Figure 37 is significant is  in  the
response that PW-6 exhibits when recharging is switched from  the eastern
to the western basins during the first week in April, 1974.   Whereas PW-6
responded almost immediately to recharge in the eastern basins, there
was a delay of approximately 15 days before it responded to the operation
of basin 4.  This delay is attributed to the initial slaking  of the soil
and filling of the pore space combined with the hydraulic travel time
from the basin to the monitor well.   This response  pattern is repeated
in the latter part of August with a  similiar switch from an eastern to
western basin.

        The response of PW-8 to recharging (see Figure 38) is indicative
of a well which is located within a  sand lens that  is not interconnected
to the aquifer carrying the major portion of flow from the basins.   The
lens is, however, adjacent to the eastern basins.

        The response of PW-6 to recharging appears  to demonstrate  that
it is in a sandy lens which is  interconnected to the lower part of the
main aquifer area.  The interconnection is hydraulic and does not
consist of water flowing rapidly through the lens.

        PW-7 is isolated from the basins and main aquifer area. Its
water level variations are damped out considerably  and they depend on
seepage through a less porous soil.

        Recharged water entering the upper aquifer  system from  the
basins moves laterally through  the  aquifers in a general east-south-
easterly direction.  As the water moves along the aquifer it  satisfies
the storage demand of any of the unsaturated soil in the vicinity.   The
main lateral velocity is believed to be in the range of 15 to 25 ft/day
(4.6 to 7.6 m/day) in the vicinity  of the recharge  area while under
the direct influence of basin loading.  When the groundwater  mounding
under the basin subsides, and/or if  the aquifer dimensions increase
substantially, the velocity decreases considerably.
                                    105

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              EAST RECHARGE BASINS (5 and 6)

              WEST RECHARGE BASINS (1,2, 3, and 4)
ELEVATION
21.6
GOLDEN GROVE
1974
              '
 JAN   FEB   MAR   APR   MAY  JUN    JUL   AUG   SEP  ' OCT  ' NOV ' DEC
 ELEVATION
 46.7
ELEVATION
33.8
GOLDEN GROVE
1975
 JAN   FEB   MAR   APR   MAY   JUN  ' JUL  ' AUG '  SEP '  OCT ' NOV  ' DEC
                                 TIME
            Figure 37. Comparison of wells GG-3 and PW-6, 1974-1975.
                                   106

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              EAST RECHARGE BASINS (5 and 6)

              WEST RECHARGE BASINS (1,2, 3, and 4]
                   ELEVATION
                   35.6
ELEVATION
34.7
ELEVATION
22.7
GOLDEN GROVE
1974
                                    TIME

             Figure 38. Comparison of wells GG 3, PW-8, and PW-9,1974.

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        A generalized view of the changing potentiometric surface in the
Golden Grove area during the entire period of the project can be seen in
Figures 39 and 40.

Groundwater Augmentation by Artificial Recharge

        By comparing two identical sections of the groundwater system,
one without and the other with artificial  recharging, an approximate
idea of the net effect of recharging can be ascertained.  Only the imme-
diate area containing, and adjacent to, the spreading basins is considered
in this analysis.  Once the artificially recharged water has entered the
groundwater aquifers and starts its horizontal flow, it is considered as
normal groundwater, subject to the same losses that existed without the
project.

        Figure 41 shows two typical vertical sections of the Golden
Grove valley.  Each section has the important water inputs and outputs,
one section with and the other without a recharge operation taking
place.  By comparison, the major changes will be in the addition of
recharge water and the subsequent increase in flow in the aquifer.
Increased consumptive losses will be the added evaporation from the
shallow water-filled basin.  It can also be expected that evapotrans-
piration will be increased to some degree in the immediate area
due to the additional water available for this either in the aquifer
or in the percolating water forming the mound underneath the basin.
Percolation between aquifers is believed to be minimal, based upon
drilling observations, but might increase with the increased hydraulic
head available beneath the inundated basins.  However, since extraction
of groundwater will take place from all the aquifers in the alluvium,
the transfer of water between them will not change the ultimate amount
of product.

        Thus the major new loss to the recharged system is in the added
evapotranspiration due to the available moisture in the pond and soil.
Meyer (1952) reported that the average annual evaporation from an open
pan in the Anna's Hope area, in central St. Croix, over a 10-year
period was 70.2 in./yr (177.8 mm/yr), which averages about 0.19 in./day
(4.87 mm/day).  This is probably high for the basins due to the rapid
turnover of water and consequently its lower temperature.  This also
neglects the evapotranspiration that no longer occurs from the soil
covered by the water in the basin.

        Increased evapotranspiration for the sections shown in Figure
41 may be approximated by the difference between Bowden's (1968) highest
and lowest monthly evapotranspiration estimates for the Kingshill area
adjacent to Golden Grove, which come to 0.12 in./day (3 mm/day).  This
represents the possible rise in evapotranspiration due to the increased
availability of water in the area which, according to Meyer, is a prime
factor to be considered.
                                    108

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          OCT 20,1973
               FEB20, 1974
             (1 WEEK BEFORE
           RECHARGING BEGAN)
                                                             OCT 20,1972
                                                         I ARTIFICIAL  I
                                                           RECHARGE
                                                              AREA
UJ
                                                                                                       WELL FP-9
                  1,000
2,000
3,000         4,000          5,000
HORIZONTAL DISTANCE (ft)
6,000
7,000
                         Figure 39. Potentiometric groundwater levels in Estate Golden Grove, 1972-1974.

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                \
LU
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UJ
LU
GO
LU

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LU
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LU
    70
    60
    50
40
30
    20
    10
                                   GROUND SURFACE
                                                                     ,       MAY 20,1974
                                                                          (11 WEEKS AFTER
                                                                     |  RECHARGING STARTED)
                                       FEB 20,1974  X
                                     (1 WEEK BEFORE
                                   RECHARGING BEGAN) |
                                                WEEKS AFTER
                                              MAJOR FLOOD)
                                                                                                        WELL FP-9
                                                       |  ARTIFICIAL  I
                                                          RECHARGE
                                                       r-ซ-  AREA
                                  _E
                                            ฑ
               _h
                   1,000
                             2,000
3,000         4,000         5,000
HORIZONTAL DISTANCE (ft)
6,000
7,000
                          Figure 40. Potentio metric ground water levels in Estate Golden Grove, 1974-1975.

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 NORMAL
 GROUNDWATER
 CONDITION
                                     EVAPOTRANSPI RATION
                                     FROM TREES
                    EVAPOTRANSPI RATION
                    FROM SOI LAND GRASS
 AQUIFER
 FLOW IN
LEAKAGE BETWEEN^
 MAJOR AQUIFERS
              EVAPOTRANSPIRATION
              FROM SOIL AND GRASS
 ARTIFICIAL
 RECHARGING
 OF THE
 GROUNDWATER
AQUIFER
FLOW IN
                                                                AQUIFER
                                                                FLOW OUT
                                                   POSSIBILITY OF INCREASED
                                                   EVAPOTRANSPIRATION
                                                   DUE TO MORE AVAILABLE
                                                   GROUNDWATER
             DIRECT
             EVAPORATION
1 INCREASED LEAKAGE 1
      QCT\A/CCM
               f   AQUIFERS AND    t
                    INTO MARLS
                                                                INCREASED
                                                                AQUIFER
                                                                FLOW OUT
         Figure 41. Water balance in Golden Grove with and without artificial recharging.
                                    Ill

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         For  the  largest  basin,  basin  4,  this means  a  possible total
 added  evapotranspiration loss of  about 1,500 gpd  (5.5 cu m/day) which
 may  be compared  to  the average  daily  infiltration for this basin of
 approximately  125,000 gpd (473  cu m/day).  This represents a loss of
 about  1.2  percent of the influent to  the basin after  initial slaking
 of the soil  has  taken place  at  the  beginning of every inundation.
 Other  losses do  occur, but these  are  common to both naturally and
 artificially recharged water in the aquifers.  Probably the largest
 loss of this sort in Golden  Grove is  that due to the  evapotranspiration
 involved with  the large  deep-rooted trees adjacent  to River Gut.
 These  trees  are  protected by Virgin Islands law; and  although they
 supply shade,  a  windbreak, and  soil stabilization along the stream
 bank,  they do  extract an undetermined quantity of water from the soil.

         Attempts of quantifying the amount has not been overly
 successful.  One recent  researcher, Rex  Meyer (1952,  pp. 23-26),
 discussed  transpiration  of length in a Department of  the Interior
 report and finally commented that "the difference in  plant species
 and climatic conditions  on the  island of St. Croix makes it imprac-
 ticable to apply transpiration  ratios determined elsewhere on similiar
 plants  to  the  vegetation on  the island."  He concluded his section on
 transpiration  by saying  that "it is not  possible with the available data
 to make a  reliable estimate  of  transpiration in any part of St.  Croix."
 This investigation could  not improve on  this statement but strongly
 recommends that local research  efforts be made in this direction in
 the future.  It is possible  that increased soil  moisture caused by
 recharging would increase  consumptive use by these trees.

         Groundwater extraction  efficiency will  play a large part in the
 ultimate economies of the water reuse system.   Fortunately the ground-
 water  geology  of Golden  Grove as portrayed in Figure 18 keeps the
 groundwater  flow within  defined bounds where it is relatively easy to
 tap and  withdraw with a  minimum of loss.   However, the aquifer is thin
 and in  some  areas in Golden Grove it is  limited in its transmissibility.
 The entrance losses from these  thin alluvial aquifers into the well
 casing  generally would limit the extraction by individual  well
 to about 20  to 30 gpm (1.3 to 1.9 I/sec).

         Based  on operating results and engineering judgment,  the best
mode of  operation of the  recharge facility in the future is to plan to
 extract  85 percent of the recharged water in the immediate area  of the
 spreading basins.  The remainder should  be permitted to flow down the
aquifer  to be  used to protect the Fair Plains  well  field from further
 saline degradation.   The pumping at the  Fair Plains  well  field can then
 be adjusted  to a rate that will  efficiently remove the groundwater
without  permitting a decrease in overall  water quality in  the area.
                                   112

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 WATER QUALITY CHANGES DUE TO RECHARGING

 Negro Bay

         The operations in Negro Bay did not affect  the  underlying
 groundwater to any detectable degree.   The two  reasons  for  this  are
 first, little, if any, recharged water reached  the  marl-limestone
 interface that was located 15 ft (4.6  m)  below  the  area.  This was
 due to the low rate of infiltration and percolation combined with the
 high rate of evapotranspiration.   Second,  even  if water did arrive at
 this interface,  it would  need to penetrate approximately 60 ft (18 m)
 of horizontally  layered limestone which is above a  confined aquifer.

         The early termination of operations in  Negro Bay combined with
 the physical  difficulties  mentioned above  essentially preclude the
 possibility that recharged water reached  the aquifer.

 Golden Grove

         The water artificially recharged  into the Golden Grove area
 had only a minor effect on the groundwater quality  in that basin.  In
 order  for the monitoring  to be valid,  only continuously pumped wells
 were considered  in the final  evaluation of the  project's effects.

         Monitor  Wells.  Due to their location the key wells considered
 for monitoring the recharge operations  were GG-8 and FP-8, downstream
 of the recharge  area, .plus  PW-1  and PW-4 immediately upstream of the
 basins.   The  changing  chloride content  of  these wells was judged to be
 significant as chloride in groundwater is  essentially a refractory
 substance.  As such  it is  not  likely to undergo changes due to bio-
 logical  or physiochemical   effects  such  as  phosphates, nitrates, ammonia,
 and  degradable organics can, which  is why  chlorides are often used as
 a  tracer.

         A  change  of  chloride content is possible in the wells if water
 with a  different  chloride concentration joins or replaces the existing
 water  source.  This would be the case in the pumping wells being
 monitored  when the artificially recharged water, with a different
 chloride content, moves through the aquifer and encounters them.   A
 graph of the  chloride content  for  these wells and the recharged water
 is shown in Figure 42.

        Well A-16.  Figure  42  compares the chloride levels with the
 rainfall and  the quantities of recharged water used during 1974.   Well
A-16 is a  control well and  is  located above the recharge area  at  the
 head of the alluvial valley at Adventure.   The location of this well
 is such that  it cannot be  affected by the recharging.  The changes  in
 chloride content shown for A-16 are those normally  experienced  by wells
 in the area.
                                   113

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  MOV  I   DEC


     1973
                                                                                                    /**•









                                                                                EAST RECHARGE BASINS (5 and 61





                                                                                 EST RECHARGE BASINS II. 2, 3. and 4
                      JAN
                             FEE
                                      JUN  I  JUL 1 AUG     SEP     OCT

                                         1974

                                         TIME


               Figure 42. Chloride content of monitor wells in the study area.
                                                                                           NOV
JAN    FEB  |  MAR


       1975
                                                                                                                      700
                                                                                                                      600
                                                                                                                      500
                                                                                                                      400
                                                                                                                      300
                                                                                                                      200
                                                                                                                      100
                                                                                                                                 -


                                                                                                                                 C/]
                                                                                                                                 _
                                                                                                                                 G

                                                                                                                                 a.
                                                                                                                                 ~

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        Well PW-1.  Well PW-1 is located about 200 ft (61  m)  upstream
of the edge of basin 1.  By examination of Figure 42 it is apparent
that the recharging affected the chloride content in both  June, to a
slight degree, and again in September and October.  Both of these times
were periods when either basins 1 or 2 were in operation.   We can expect
that the rapid increase during September and October could have been
higher had the water added to the aquifer by heavy rainfall in August
not occurred.  An apparent rise in nitrates from 5.4 mg/1  to  6.7 mg/1
also occurred at this time but it cannot be substantiated  as  there is
insufficient background data on this well.  A pump was not installed
on PW-1 until January, 1974, so the data available are limited.

        Well PW-4.  Well PW-4 also showed some indications of a chloride
rise but it was minor.  Although this well is only 300 ft  (91 m) from
basin 1, it is believed that the intervening aquifer structure is
connected only in an indirect manner.  The water from this well was
reduced in chloride concentration during November due to the  heavy
rains and flooding which naturally recharged the soil over the entire
area.

        Well GG-8.  Well GG-8 is located about 1,500 ft (460  m) downstream
of basin 6.  The water from this well generally has a chloride content
higher than the artificially recharged water.  However, this  well, like
many others on St. Croix, derives its water from more then one aquifer.
The method of well drilling on the island is such that it  is  not possible
to separately test the aquifers encountered for water quality.^ However
from field observations and tests made while drilling, indications are
that the water in the different aquifers is often of sharply  varying
chemical character.  Thus changes in chemical characteristics in a well
water are often caused simply by a variation in the contribution to a
well that each aquifer makes.  Indications are that the recharge water
is probably increasing the chloride content in an aquifer  which normally
acts as a source of dilution water for well GG-8.  The reaction to the
early recharging operations is delayed in time due to the  rate of flow
of the recharged water from the basins to the well itself. The effect
of the later periods of recharge are obscured by the heavy rains that
occurred in the fall.  This well water has had a trend toward increasing
chloride content since sampling began in 1971.  The mean chloride values
for 1971, 1972, and 1973 are 426, 453, and 507 mg/1, respectively.  The
variation in the other parameters for water from that well fell within
a standard deviation of past performance and cannot be considered
significant.

        Well FP-8.  Well FP-8 is located approximately 3,300  ft (1,000 m)
downstream of basin 6 when measured along the assumed course  of the main
aquifer.  It is likely that FP-8 receives water from both  the River Gut
and the Bethlehem Gut drainage basins.  FP-8 is probably well 45a
referred to by Cederstrom (1950, p. 68).  This well was drilled to a
                                   115

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depth of 225 ft  (68.6 m) through the alluvium and marl and 17 ft (5.2 m)
into the Jealousy formation.

        Cederstrom reports  (1950, p. 84) that the chloride content in
1940 was 510 mg/1.  In 1971, 1972, and 1973 the mean chloride content
was 640, 649, and 670 mg/1, respectively.

        Inspection of Figure 42 shows some indication of increasing
chlorides in FP-8 during the latter part of 1974.  Although it could
be due to the recharged water it cannot, with certainty, be said that
this is the cause for the increased chloride content.  The water in the
Fair Plains well field has  been undergoing a general increase in chlorides
over the past few years.  During 1974, 3 out of the 9 wells in Fair Plains
were abandoned due to excess IDS.  The water in the adjacent well, FP-7,
showed a continuous increase in chlorides from 1973 up to September, 1974.
This may have had an influence on FP-8.

        The other chemical and biological parameters monitored in the
water from the wells did not show significant changes during this
period.  Had the recharging operations continued longer and/or the
floods not occurred, then it is possible that additional changes in
the groundwater might have occurred.

        With many of the parameters measured it is likely that the
concentration of the substance in question underwent changes during
the recharging operations.  A basic discussion of changes which can
occur appears in several reports concerning land disposal of waste-
water (McGauhey and Krone, 1967; Drivers et al., 1972).  In the
following paragraphs several of the most important parameters are
discussed with relation to their possible fate in the soil  system.
This discussion is only a summary and the references cited can be
consulted for greater detail.

        Nitrates.  The average nitrate nitrogen concentration measured
in the recharge water during the period of January through October,
1974, was 12.9 mg/1.  The groundwater in the area of the recharge
basins has a natural concentration that ranges between 3 and 7 mg/1.
Nitrates are not readily absorbed by the soil  and thus tend to move
through the soil in solution.   Reduction in concentration can occur
by plant uptake and denitrification (Murrmann and Koutz, 1972, p.  71).
A report sponsored by the Corps of Engineers (Driver et al., 1972),
mentions that the removal of nitrogen by denitrification is dependent
on the soil  type and length of inundation of infiltration ponds,with
clay soils and long inundation times promoting nitrogen removal.   Based
on plotted data (Driver et al., 1972, p.  93),  a  10-day inundation
period would remove about 35 percent of the applied nitrogen.

        Nitrate uptake by plants will occur most rapidly during the
dry period of the wet-dry cycle when plant growth is the most rapid
                                  116

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in the basins.  Uptake will be limited to the amount of nitrates
available in the soil moisture remaining after recharging has ceased.
During operation of the project the grass in the basins was frequently
mowed and removed from the area.

        It is probable that a combination of these two mechanisms
reduced the nitrate level in the applied recharge water in Golden Grove.
The chief concern with nitrates is to keep the level in water consumed
by the public to below 10 mg/1 as N03-N.  This is to prevent the
occurrence of methemoglobinemia in infants.  Dilution of the water
pumped from municipal wells in the recharge area with other sources
of water contributing to the island's water supply maintains an
acceptable nitrate concentration in the water supply.

        Ammonia.  The average ammonia-nitrogen concentration in the
applied recharge water was about 7 mg/1 during the period of January
through October, 1974.  The normal concentration in the groundwater in
Golden Grove ranges up to about 0.5 mg/1.

        Ammonia at a neutral pH, 6 to 7, is readily adsorbed onto clay
soil particles  (Murrmann and Koutz, 1972).  This will act to hold the
ammonia for use by plants at a generally slower rate of uptake.  The
effluent used in recharging generally had a pH between 6.5 and 7.0.
The rapid growth of vegetation on the basins between inundation periods
followed by mowing and harvesting should continue to remove ammonia
from the system.

        Phosphorus.  The average concentration of all forms of phosphorus
in the applied  recharge water was about 9 mg/1 as P during the period
January to October,  1974.  The normal concentration in the groundwater in
Golden Grove ranges  up to about 0.1 mg/1.

        Phosphorus acts similarly to ammonia and is adsorbed in the soils
especially on clay particles which are  prevalent at the recharge site.
The phosphorus  will  also be utilized by vegetation  in the area and can
be removed from the  system through plant harvesting.

        Coliforms.   The level of standard  coliforms in the applied
effluent was very low due  to  the effective  disinfection process at the
AWWTP.  The effectiveness  of  soils in removing  bacterial  pathogens is
documented and  discussed in detail by McGauhey  and  Krone  (1967, pp.
70-78) and in a recent report  issued by the Corps of Engineers  (Driver
et al., 1972, pp. 49-55).  These reports mention the mechanisms of
mechanical filtration and  adsorption along  with natural dieback of
pathogens  in  the soil.  These  are especially effective in clayey and
silty  soils which predominate  in Golden Grove.

        The  background data on  all of  the  public wells in the  study
area  show  a  substantial  level  of coliforms  in many  of  the wells.  The
                                    117

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operation and sanitation of these wells was not under project control
during this study.  Many public wells on St. Croix were not sealed
properly to prevent surface leakage and contamination until rather
recently.  Disinfection of the wells before, or during, operation is
generally not practiced.  Under these conditions it is not possible to
correlate recharge operations with any change in coliforms in pumping
wells in the area.  Based on the disinfection practices used and the
literature cited, it is highly doubtful that any bacterial contamination
of the pumping wells did, or will, occur due to recharging operations in
Golden Grove.

        BOD, COD, and TOC.  The water applied to the recharge basins had
an average BOD of 11.5 mg/1 and a COD of 30 mg/1.  The ability of a soil
system to reduce this oxygen demand caused by organics is discussed in
many reports (McGauhey and Krone, 1967; Driver et al., 1972; Broadbent,
1973).  The organic loading from the AWWTP effluent on the soil system
was low.  Evidence of increased organic concentrations in the monitored
wells was not apparent and it is likely that the organic content was
diminished due to oxidation.

        In studying the results of the analysis of the monitoring wells
in the study area for BOD and COD, as presented in the Appendix, two
facts must be kept in mind.  The first is that BOD and COD measurements
at a low level of 0 to 20 mg/1 are not very dependable since any minor
contamination, or laboratory error, will dramatically affect the results.
The second problem is that all of the pumping public wells monitored are
equipped with a vertical turbine pump whose shaft bearings are lubricated
by dripping oil down the space between two concentric shafts in the
well. This oil, up to about 0.5 gal/month (2 I/month), accumulates and
floats on the surface of the water inside the well.  Depending on the
level of the water in the well in relation to the-pump, this oil can be
intermixed with the water and pumped out of the well in varying con-
centrations.  This, then, also has noticeable effect on TOC measurements
taken on samples.  Due to the circumstances of pump start-up and
throttling required for the homogenation and entrance of the oil into
the pumped water, it will happen at irregular times without necessarily
a definite pattern being detected.

        Summary of Water Quality Changes.  The previous paragraphs have
reviewed the possible reasons behind the water quality changes observed
in the monitored pumped wells in the study area in the vicinity of the
recharge facilities.

        Other wells closer to the spreading basins were also sampled and
tested for the same parameters during recharge operations.  These were
wells PW-6, PW-7, and PW-8.  The primary purpose of these wells was to
monitor water level information and hence they were not equipped with
pumps.  Samples were obtained by the use of a torpedo sampler.  Although
the sampler was filled several times before taking a sample for labo-
ratory analysis the procedure did not cause much movement of water
within the 8-in. (20 cm) well casing.
                                   118

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        The monthly data for the analysis of the samples appear in the
Appendix.  The data do not show the changes, especially in chloride
concentrations, that could be expected.  This is probably due to two
reasons.  First the wells are believed to be located in sand lenses
which are not directly connected to the main flow path of groundwater
through the area.  Second the wells were not pumped so that a continuous
interchange of water could occur in the wells.  Had continuous pumping
occurred, the location of the wells away from the main path of flow
would probably have been less significant.  As it is, the data are
included only for general background information for future studies.


WATER QUALITY IN FUTURE OPERATIONS

        Once the problem of saltwater flushing in Frederiksted is
resolved the artificial recharge operations can resume.  If, at that
time, the distribution of potable water is planned so as to transfer
the low TDS desalinized water to the western end of the system, then
it will result in the collection of wastewater with a low chloride
concentration.  Judging from the anlysis of wastewater from villages
served wholly by desalinized water (Black, Crow and Eidsness, Inc.,
1973, pp. 3-12), it can be expected that the wastewater will have a
chloride content of about 100 to 150 mg/1.

        The use of processed effluent with a low level of chlorides
for recharge operations in Golden Grove should eliminate the chloride
problems experienced during the project's operations in 1974.  With
proper extraction control, it could lead to partial restoration of the
Fair Plains well field.
AWWTP OPERATIONS

        The operations of the AWWTP was discussed in detail in the
earlier sections.  The data obtained from the operation have been
tabulated and presented in a statistical format in Tables E-l and
E-2 of the Appendix.

        The production of the plant which was used for recharge
purposes is shown in Figure 27 and the average operating parameters
in Tables 4 and 5.

        These data cover the period January through October, 1974.
January marked the beginning of normal operation after the start-up
phase.  The project ceased recharge operations during the last week
of October due to the high TDS wastewater, while at the same time
the heavy rains began to affect the plant performance due to excessive
inflow.  In early November, 1974, the flooding on the island damaged
portions of the interceptors so that much of the influent to the plant
consisted of the streamflow from Bethlehem Gut.  During subsequent
                                   119

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repairs of this interceptor and the one to Frederiksted, which took
place over the following 6 months, flows were interrupted and/or bypassed
so that normal operation of the AWWTP was not possible.  In view of this,
the data presented are limited to the period stated.


COST FACTORS

        Cost factors, based on the operation of the AWWTP and the
recharge facilities, have been projected for the production of
artificially recharged groundwater.  These data are shown in Table 7
and include treatment in the AWWTP, recharge operations, and ground-
water recovery by wells.

        Cost factors are presented for production at the present
design capacity of 0.5 mgd (1,890 cu m/day) and also for expanded
operation at the level of 0.75 mgd (2,840 cu m/day) and 1 mgd
(3,785 cu m/day).

        The information upon which the costs are determined is
presented in the table along with the assumptions used.  If
circumstances, assumptions, or prices change; then the cost factors
can be restructured within the table to arrive at a revised unit
cost.

        A large percentage of the total cost of reclaiming water is
centered around secondary treatment.  At present only primary treat-
ment is used by the government before discharge of wastewater into
the sea.  If secondary treatment were required, then the cost of
this portion of the facility could, in a large part, be allocated
to sanitation instead of reclamation.  Only the additional costs
of tertiary treatment and recharging could be directly attributable
to reclamation.  This would then decrease the unit cost considerably
in an accountant's view, although the government would continue to
pay the total cost.  However with secondary treatment of all waste-
water before reclamation or discharge to the sea, the economies of
scale would begin to reduce the unit cost of production.  This is
especially true in the matter of labor where the difference in
staffing between a 1 mgd (3,785 cu m/day) and a 5 mgd (18,925
cu m/day) plant would not be significant.  This is especially true
if the recommendation to combine the management of the primary and
reclamation plant is followed.
                                   120

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      TABLE 7. PROJ ECTED COSTS FOR THE PRODUCTION AND RECOVERY OF
                RECLAIMED WASTEWATER BY GROUNDWATER RECHARGE

PRODUCTION-ANNUAL COSTS*
1. Depreciation (20 yr straight line)
Initial cost $800,000
Phase 1 improvements t 30,000
Phase 2 improvements t 70,000
Phase 3 improvements f 140,000
Total Depreciation
II. Maintenance and repair
III. Labor
Project director @ $20,000/yr
Plant superintendent @ 15,000/yr
Operator, chief @ 10,000/yr
Operator @ 8,500/yr
Operator, trainee @ 7,000/yr
Chemist @ 12,000/yr
Secretary @ 7,000/yr
Labor Subtotal
15 percent fringe benefits
Total Labor
TOTAL ANNUAL COST
PRODUCTION-UNIT COSTS ($/thousand gal)
The annual cost on a unit basis with 15 percent
downtime
Coagulant-aluminum sulfate
50mg/lat $0.10/lb($0.22/kg)
Chlorine
20 mg/l at $0.25/lb ($O.S5/kg)
Power
Total Production Costs
RECOVERY-UNIT COSTS ($/thousand gal)
If 85 percent of recharged water is recovered by wells
Cost of groundwater recovery^
TOTAL COST-PRODUCTION AND RECOVERY
($/thousand gal)
($/cum)
AWWTP
0.5 mgd
(1,890 cum/day) (2


$ 40,000
1,500
-
^•I^MMHH
41 ,500
36,000

20,000
15,000
10,000
17,000
14,000
12,000
3.500
91 ,500
13.725
$105,225
$182,725


1.18

0.042

0.042
0.30
1.56

1.85
0.30

2.15
0.57
Production Capacity
0.75 mgd 1.0 mgd
,840 cu m/day) (3,785 cu m/day)


$ 40,000
1,500
3,500
^MW^H
45,000
42,000

20,000
15,000
10,000
34,000
14,000
12,000
3.500
108,500
16.275
$124.775
$211,775


0.91

0.063$

0.042
0.30
1.32

1.55
0.30

1.85
0.49


$ 40,000
1,500
3,500
7.000
52,000-
48,000

20,000
15,000
10,000
34,000
21 ,000
12,000
3.500
115,500
17.325
$1 32.825
$232,525


0.75

0.042

0.042
0.30
1.13

1.34
0.30

1.64
0.43
'Includes operation of the recharge facilities.
fSee the section on project facilities for a discussion of the work involved in each phase of plant expansion.
(Dose rate of 75 mg/l.
Includes all costs of drilling and operating the wells.
                                        121

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                              SECTION IX

            MAJOR PROBLEM AREAS ENCOUNTERED IN THE PROJECT
        As In any large undertaking, there have been a considerable
number of problems that have occurred during the course of the
project.  The vast majority of these were solvable as the project
progressed.  Some of them required minor changes in the direction of
the project while others caused considerable delay in the completion
of the project itself.  The following is a discussion of some of the
major problem areas within the project that became apparent as the
work proceeded.
CONCEPTUAL

        The reuse of water cannot be treated as an isolated event in
the water resource plans of an area.  The concept must be integrated
into both the water supply and wastewater treatment systems.  However
this project was, by definition and funding, an experimental facility
built to determine whether the concept was feasible.  Thus major
changes in the existing system and future construction could not
really be expected until the feasibility was proven.

        This meant that the concept of reuse had to be fitted into a
system that was basically designed without that idea in mind.  Since
St. Croix has a variety of water sources, ranging from distilled to
brackish to seawater, that feed into the wastewater system at different
points; it makes it essential to coordinate the entire operation.
Hence certain problems were already built, or designed, into the system
and either had to be compensated for during the project or will require
modification in the future.

        The most notable problem resulting from this conceptual gap is
the high chloride level of the incoming wastewater.  In order for
project operations to proceed at all, a chloride level of up to 500
mg/1 had to be tolerated and used for recharge purposes.  This was the
result of the brackish well water that was being used in the section
of the island whose wastewater supplied the project.

        Even more critical is the use of seawater for fire and
flushing purposes in the towns of Christiansted and Frederiksted.  It
was the connection of the wastewater collection network of
Frederiksted, with its salty wastewater, to the central primary
                                  122

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treatment plant that finally closed the project down in October, 1974.
Although the problem in Frederiksted will be resolved, at least
temporarily, in the fall of 1975, the potential chloride problem posed
by the connection of Christiansted to the system in 1977 lies ahead.
COORDINATED PLANNING

        There are numerous agencies within the territorial government
which have an interest and responsibility for the production,
distribution, and usage of public potable water plus the collection,
treatment, and disposal of the island's wastewater.  This split
responsibility has caused confusion and occasional problems in
fulfilling the project goals.
CHANGING CONDITIONS

        Under actual field conditions on a project of this magnitude
and time span, unwanted changing conditions had to be accepted.   Many
of these changes would not be tolerated in a laboratory operation
where it is desirable to hold conditions the same while varying
selected parameters, preferably one at a time.  There were four  main
areas where these changing conditions caused problems.

Weather

        Several extreme, and unseasonable, variations in the amount of
precipitation occurred during the project.  This resulted in excess
groundwater during the exploratory and design phase.  Then an extreme
deficiency occurred during the recharge operations.  The operations
were finally terminated by record rains and floods that severely
damaged the facilities.  This has been followed by another unusual  and
extended drought period.  These swings have affected the quality of
wastewater received, the well yields, aquifer conditions, and surface-
water activity.

Water Sources

        The changing production levels of the various sources of water
on the island affected the quality of the subsequent wastewater  to  a
large extent.  This is especially true in the western portion of the
island where any reduction in the production of desalinized water from
the Martin Marietta plant meant an immediate increase in the
proportion of brackish well water used.  This had an effect on the
quality of water produced at the reclamation plant due to the change
in the mineral content of wastewater received.
                                  123

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Construction Activity

        This activity occurred both in the drainage areas tributary to
the recharge area and those associated with the wastewater collection
system.  In the immediate area, the construction of a large
penitentiary complex adjacent to the recharge area resulted in the
loss of a large number of piezometers and the use of a portion of the
streambed that had been planned for recharge operations.

        The large amount of public housing constructed during project
development which contributed its wastewater to the interceptor system
changed the expected character of that wastewater.  All during the
project the interceptor system was being expanded.  This  meant that
the volume of wastewater was increasing and changing as areas with
different water sources were sewered.

Groundwater Extraction

        The quantity of groundwater removed from the study area was
varied to meet local demand or to inversely match the output of the
desalinization plants.  The project had no control, besides
suggestive, over the operation of these wells.
PROJECT LOCATION

        It was implicitly assumed that the reclamation plant would be
located adjacent to the newly constructed central  primary treatment
plant on the island.  This latter facility was located on the island
with hydraulic transport and outfall disposal characteristics in mind.
This location, along with the funding limitations  in constructing a
force main, restricted the choice of recharge areas.
DELAYS

        The wide scope of the project made it extremely vulnerable to
delays due to complications in some stage of either this project or
one of the many other activities that affected this project.   The most
significant delays are discussed in the following paragraphs.

        The completion of the interceptor sewers was  delayed  in
schedule, which greatly reduced the amount of wastewater that  the
project had available to process and reuse.  This delay has to be
weighed against the benefit of not completing the Frederiksted pumping
station on time.  It permitted the operation of the recharge phase
without the flow of salt water that accompanied the Frederiksted
wastewater.
                                  124

-------
        The construction of the AWWTP was delayed due to shipment and
procurement problems with some of the proprietary devices, problems
with subcontractors, and construction difficulties.

        The shipment of spare parts for the repair of equipment was
often delayed during plant operation.  The customs status of the
territory and the distance between the mainland United States and the
Virgin Islands caused numerous difficulties in obtaining spare parts
and manufacturers' service.  Airfreighting of shipments was no
guarantee that they would arrive in a reasonable time.  Most spare
parts were unavailable locally.
EQUIPMENT OUTAGES

        Problems were experienced with several pieces of equipment in
the AWWTP.  These were mainly pumps which required numerous repairs.
During the periods when these pumps were out of service, the
production of the AWWTP was reduced, often to no usable output at all.
NATURAL DISASTERS

        Flooding occurred on the island during October and November in
1974, seriously damaging the recharge facility and necessitating
extensive repairs to the basins, roadways, and pipelines.  The floods
also damaged the primary treatment plant and many of the major
wastewater interceptors so that the amount of wastewater supplied to
the AWWTP was severely restricted for several months and that which
was received was difficult to handle due to the high percentage of
clay it contained.
SUMMARY

        Despite all of these problems experienced during the project
and all those that will occur during its future operation, the
economics of the system will make it worthwhile to continue.  The
cost of fresh water is too high on St.  Croix to use it only once and
throw it away.
                                 125

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                              SECTION X

                   OTHER ACTIVITIES ASSOCIATED WITH
                  THE WASTEWATER RECLAMATION PROJECT
        Although the purpose of the project was to determine the
feasibility of artificial groundwater recharge, it did encourage other
uses for reclaimed wastewater.  The purpose of this was two-fold;
first, to explore alternative uses for treated wastewater.  This is
especially important if these alternative uses can replace potable
water, which is both expensive and in short supply on the island.
Secondly, it was a means of encouraging community-wide interest and
support for the idea of wastewater reclamation and water reuse.  If
another organization or agency actually worked with water reuse and
was successful, then it could mean more support for the continuance of
the project once the local government assumed operations.  The project
personnel were successful in encouraging other people to experiment
with the reclaimed water and several of these activities are discussed
below.
IRRIGATION

        One of the biggest hindrances to the development of a sound
agricultural industry on St. Croix, in the area of fruits and
vegetables, is the lack of water.  A large amount of water is needed
in agriculture to counteract the excessive evapotranspiration rate
caused by the high ambient temperature and steady tradewinds.  Only a
week without water can severely damage many vegetable crops on the
island.  Rainfall has traditionally been extremely unreliable in its
time patterns on the island.  The rainfall pattern in the last three
years has been such that a vegetable enterprise without supplemental
irrigation would have faced disaster.  Unfortunately, the potable
water is too expensive, at $1,300/acre-ft ($1.05/cu m), to be used;
the groundwater is limited in quantity; and in many areas the
groundwater's sodium absorption ratio (SAR) and/or chloride content is
too high for prolonged use.

        Reclaimed wastewater with a controlled SAR and chloride level
could be used, in many cases, for agricultural irrigation.  Initial
uncontrolled experiments were carried out in this area by personnel at
the AWWTP in growing ornamental plants and vegetables in a small
nursery.  Chlorinated effluent from the AWWTP was used for the
necessary irrigation.  This was an extremely effective public
                                  126

-------
 relations  feature  for the  project.   If visitors  could  not  fully
 comprehend the workings  of the  biological  and  chemical  treatments
 going  on within the  AWWTP,  they could  easily appreciate the  profusion
 of flowers and vegetables  that  were  grown  with the  finished  product.
 This was especially  true since  the rest of the island  was  parched and
 brown  due  to  one of  the  longest droughts in recent  times.

        This  created sufficient interest that  a  cooperative  venture by
 the V.I. Extension Service and  the V.I.  Experiment  Station financed
 and built  a 3,000-ft (915  m)  spur line that will  permit the  transfer
 of reclaimed  wastewater  directly to  the St. Croix campus of  the
 College of the Virgin Islands.   There  it will  be  used  for  research
 into the uses and  effectiveness of irrigation  under the subtropical
 conditions existing  in the  territory.   This research activity was
 halted due to the  high chloride content in the wastewater  but is
 expected to resume in the  fall  of 1975.
CLAM CULTURE

        Using the nutrients available  in the wastewater effluent from
the AWWTP, a project to culture freshwater clams  (Rangia cuneata) has
been started.  This project is under the direction of the biological
oceanography section of the Lamont-Doherty Geological Observatory of
Columbia University.  It has a facility on St. Croix which has been
conducting research on the use of ocean nutrients for production of
shellfish for the past 6 years.  The clam operation is quite similar
in that it utilizes the nutrients remaining in the wastewater effluent
to grow algae which are fed to clams.  Presently  the clam-raising
facilities, which are actually large chemostats,  have been constructed
on the grounds of the AWWTP and began operations  in August, 1975.  The
first phase consists of stabilizing the algal growth in the
chemostats.  Extensive preliminary tests have already been run at the
Columbia University laboratory in St. Croix to select the algae
strains to be used and to approximate the growth  rate to be expected.

        The ultimate purpose of the clams will be to use them for a
protein source for poultry on the island.  When the clams reach the
desired size, both the meat and shells will be ground up and the
mixture fed to chickens.
PISCICULTURE

        This project also uses the nutrients in the effluent of the
AWWTP to grow algae.  In this case it will be used to grow Talapia
aurea which are a freshwater herbivorous food fish.

        This project is sponsored primarily by the V.I. Agricultural
Experiment Station.  Four ponds have been constructed in the vicinity
                                  127

-------
of the recharge area in Estate Golden Grove and fish are being raised
in one of them.  Each of these ponds has a capacity of about 0.1  mil
gal (380 cu m).  The fish will grow in cages suspended in the water.
The effluent from the ponds will be used for irrigation purposes.  It
is proposed that these fish will be used for human consumption.
INTERRELATIONSHIP

        In addition to these three activities involving water reuse
that have been developed in cooperation with the wastewater
reclamation project, other projects have been suggested by local
groups and citizens interested in utilizing this valuable resource.
Many of these additional suggestions require further definition and
sound financing.  The local government, in cooperation with the Water
Resources Research Center in St.  Thomas, is developing better
guidelines and regulations applicable to wastewater reclamation and
reuse.

        Since water is precious in the territory, all of these
activities help to complete the water resources picture on St. Croix.
Figure 43 shows the interrelationships between the existing water
sources and the reclamation project with all of its various associated
activities.
                                 128

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               STORAGE
                                       IRRIGATION
                                      PISCICULTURE
to
to
                                  WASTEWATER RECLAMATION
                                  PLANT (AWWTP)
            CLAM
            CULTURE
            OCEAN
            DISCHARGE
         PRIMARY
         TREATMENT
1
PRIMARY
TREATMENT
                                                     GROUND-
                                                     WATER
                                                     RECHARGE
                                                                      DESALINIZED AND
                                                                      RAINWATER
                                                        WELL
                                                        WATER
                                                                 DOMESTIC USAGE
                                                                 (FREDERIKSTED)
                                            SALT
                                            WATER
                                                    DOMESTIC USAGE
                                                    (CHRISTIANSTED)
                                                                   LOW CHLORIDE
                                                                   WASTEWATER
                                 HIGH
                               CHLORIDE
                              WASTEWATER
                            Figure 43. Proposed interrelationships between water use and reuse activities on St. Croix.

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                           REFERENCES
Black, Crow and Eidsness, Inc., 1972.   "Wastewater reclamation at St.
        Croix, U.S. Virgin Islands—An interim progress report for
        April 1971 to May 1972."  Gainesville, Florida:  Black, Crow
        and Eidsness, Inc.

Black, Crow and Eidsness, Inc., 1973.   "Wastewater reclamation at St.
        Croix, U.S. Virgin Islands—The second interim progress report
        covering the period from June 1972 to September 1973."
        Gainesville, Florida:  Black,  Crow and Eidsness, Inc.

Bowden, M. J., 1968.  Water Balance of a Dry Island.   Hanover, New
        Hampshire:  Dartmouth College.

Broadbent, F. E., 1973.   "Organics" .In.:  Proceedings  on the Joint
        Conference on Recycling Municipal Sludges and Effluent on Land,
        Washington, D.C.:  National Association of State Universities
        and Land Grant Colleges.

Busch, A. W., 1971.  Aerobic Biological Treatment of Waste Waters.
        Houston:  Oliodynamic Press.

Camp, Dresser and McKee, Inc., 1966.  "Report on sewerage and sewage
        treatment.  CDM-389-1.  U.S. Virgin Islands."  Boston:  Camp,
        Dresser and McKee, Inc.

Cederstrom, D. J., 1941.  "Notes of the physiography of St. Croix,
        Virgin Islands."  Amer. J. Sci. Vol. 239, No. 8, August
        1941, 553-576.

Cederstrom, D. J., 1950.  "Geology and ground-water resources of
        St. Croix Virgin Islands."  USGS Water Supply Paper 1067.

Gulp, R. L. and Culp, G. L., 1971.  Advanced Wastewater Treatment.
        New York:  Van Nostrand Reinhold Company.

Davis, S. N. and DeWiest, R. J., 1966.  Hydrogeology.  New York:
        John Wiley & Sons, Inc.

Driver, C. H., Hrutfiord, B. F., et al., 1972.  "Assessment of the
        effectiveness and effects of land disposal methodologies of
        wastewater management."  Wastewater Management Report 72-1.
        Corps of Engineers.  Department of the Army.
                                  130

-------
Engineering Science, Inc., 1966.  "Water reclamation for the U.S.
        Virgin Islands."  Arcadia, California:  Engineering Science, Inc.

English, J. N., Linstedt, K. D., and Bennett, E. R., 1975.   "Research
        required to establish confidence in the potable reuse of waste-
        water."  A paper presented at WPCF 48th Annual Conference.
        Miami Beach.  October 5-9, 1975.

Environmental Protection Agency, 1975.  "Environmental Protection
        Agency—Interim primary drinking water standards."  Federal
        Register, Vol. 40, No.  51, March 14, 1975, 11990-11998.

FWPCA, 1970.  Application for Class II Demonstration grant entitled
        "Wastewater Reclamation at St. Croix, U.S. Virgin Islands."
        Federal Water Pollution Control Administration, Atlanta,
        Georgia.

Grigg, D. I., Shatrosky, E. L., and Van Eepoel, R. P, 1971.  "Operating
        efficiencies of package sewage plants on St. Thomas, V.I.,
        August-December, 1970."  Government of the Virgin Islands
        Water Pollution Report No. 12.  St. Thomas:  Caribbean Research
        Institute.

Jordan, D. G., 1973.  "A survey of the water resources of St. Croix,
        Virgin Islands."  USGS Caribbean District open-file report,
        San Juan.

Koenig, L., 1966.  "Studies related to market projections for advanced
        waste treatment."  FWPCA Publication No. WP-20 AWTR-17.
        Cincinnati:  FWPCA.

Kruseman, G. P. and DeRidder, N. A., 1970.   Analysis and Evaluation
        of Pumping Test Data.  Wageningen,  The Netherlands:
        International Institute for Land Reclamation and Improvement.

McKinzie, W. E., Scott, B. F., Rivera, L. H., 1965.  Soils and their
        Interpretations for Various Uses, St. Croix, American Virgin
        Islands.  Spartanburg, South Carolina:  Soil Conservation
        Service.

McGauhey, P. H. and Krone, R. B., 1967.  "Soil mantle as a wastewater
        treatment system."  SERL Report No. 67-11.  Berkeley:  University
        of California.

Meyer, R. R., 1952.  "Geology and hydrology of dam sites on the Island
        of St. Croix, Virgin Islands."  USGS and the Office of
        Territories, Department of the Interior.
                                   131

-------
Murrmann, R. P. and Koutz, F. R., 1972.  "Role of soil chemical processes
        in reclamation of wastewater applied to land."  In:  "Wastewater
        management by disposal on the land."  Cold Regions Research and
        Engineering Laboratory Special Report 171.  Hanover, New
        Hampshire:  Corps of Engineers, U.S. Army.

Rivera, L. H., Fredrick, W. D., et al., 1970.  Soil Survey. Virgin
        Islands of the United States.  Washington:  Soil Conservation
        Service.

Robison, T. M., 1972.  "Ground water in central St. Croix, U.S. Virgin
        Islands."  USGS Caribbean District open-file report, San Juan.

Sawyer, C. N. and McCarty, P. L., 1967.  Chemistry for Sanitary Engineers,
        New York:  McGraw-Hill Book Company.

Stolz, S. B., 1975.  "Water quality management, new Golden Grove well
        field St. Croix."  Letter to K. Euros (Black, Crow and Eidsness,
        Inc.) July 7, 1975.  Christiansted:  Government of the V.I.,
        Division of Natural Resources Management.

Todd, D. K., 1959.  Ground Water Hydrology.  New York:  John Wiley &
        Sons, Inc.

Whetten, J. T., 1962.  Geology of St. Croix, Virgin Islands.  Princeton
        University Ph.D. dissertation.  Ann Arbor:  University Microfilms.
                                    132

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                                APPENDIX


Part                                                                Page

 A      LOGS OF PROJECT WELLS                                       135

        Part A contains the drilling logs of the nine wells
        which were constructed as part of the project.  The
        locations of these wells are shown in Figure 16.

 B      PRIMARY WELLS-ANALYTICAL DATA                              144

        Part B contains monthly data on the analysis of water
        samples taken from the primary wells monitored during the
        project.  Data for the period April through September,
        1975, are furnished through the courtesy of the Caribbean
        Research Institute of the College of the Virgin Islands.
        The locations of these wells are shown in Figure 16.

 C      SECONDARY WELLS—ANALYTICAL DATA                            178

        Part C contains monthly data of the analysis of water
        samples taken from the secondary wells monitored during
        the project.  .Data for the period April  through September,
        1975, are furnished through the courtesy of the Caribbean
        Research Institute of the College of the Virgin Islands.
        The locations of these wells are shown in Figure 16.

 D      STREAM SAMPLES--ANALYTICAL DATA                             2ฐ0

        Part D contains monthly data of the analysis of surface
        water samples taken from the stream referred to as River
        Gut.  Data for the period April through September, 1975,
        are furnished through the courtesy of the Caribbean
        Research Institute of the College of the Virgin Islands.
        The locations of the sampling points are shown in
        Figure 16.

 E      AWWTP OPERATIONAL DATA                                      206

        Part E contains a statistical presentation of the
        operational  data from the AWWTP for the period January
        through October, 1974.
                                   133

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                          APPENDIX (CONTINUED).


Part                                                                Page

 F      SOIL BORING INFORMATION                                     208

        Part F contains a figure showing the driller's logs of
        the soil  borings taken in the Golden Grove area.

 G      WATER LEVELS IN PROJECT WELLS                               210

        Part G contains graphs of the water levels in various
        wells in  relation to the amount of rainfall.   The
        locations' of these wells are shown in Figure  16.

 H      ENGLISH-TO-METRIC CONVERSION                                244

        In recognition of the advance of the United States to
        the metric system, the text of this report is written
        with metric equivalents following the English units of
        measurement.  To avoid confusion and space problems some
        of the tables and illustrations do not have these
        equivalents.  The following table is a list of English
        units used and their metric equivalents to assist in
        making individual conversions.   The standard  abbrevi-
        ations for the respective units are used.
                                  134

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                            APPENDIX  -  PART A
                 TABLE A-l.  LOG FOR PROJECT WELL NO. 1 (PW-1)
          Description
                  Thickness
                  of strata
                      ft
Depth of
strata*
   ft
     Elevation
     of stratat
         ft
Alluvium
  Topsoil                                     2
  Silty clay                                 13
  Clayey sand trace gravel and silt,
   water encountered at elevation 33 ft       9
  Sandy silty clay trace gravel               3
  Clayey silty gravel (water bearing)         4
  Silty clay                                  4
  Clayey sand with gravel (water bearing)     3
  Silty clay trace sand & gravel             10
  Sandy gravel trace clay (water bearing)     4
  Clayey silty gravel (water bearing)         2
  Silty clay                                  6
  Clay trace silt                             7
Kingshi 11 marl
  White limestone, seashells                  9
                                 2
                                15

                                24
                                27
                                31
                                35
                                38
                                48
                                52
                                54
                                60
                                67

                                76
             51
             38

             29
             26
             22
             18
             15
              5
              1
             -1
             -7
            -14

            -23
Casing perforations:
3 slots/ft
3 slots/ft
3 slots/ft
3 slots/ft
3 slots/ft
15
28
35
48
68
25
32
40
55
74
Well location:  Golden Grove
Casing used:  8 in. steel - 78 ft
First encountered water at elevation:
               33 ft
                         Date drilled:   July 1972
                         Ground elevation:   53 ft
Test pumping of aquifer located at elevation -1 ft yielded 13 gpm in
August 1972.  The combined aquifers were pumped at 45 gpm.

Static water level in August 1972 was at elevation 41 ft.

                                                   Feet x  0.3048 = meters
*Depth to bottom of strata.
tElevation of the bottom of the strata.
                                  135

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              TABLE A-2.  LOG FOR PROJECT WELL NO. 2 (PW-2)
             Description
Thickness  Depth of  Elevation
of strata  strata*   of stratat
   ft         ft         ft
Kirighill marl
Topsoil
White stratified limestone (dry)
White limestone, very hard layer
Encountered water just below hard
layer
White limestone stratified
Casing perforations: 1 1/2 slots/ft
3 1/2 slots/ft

2
77


1
20



2
79


80
100
30 - 65
65 - 95

74
-3


-4
-24


Well location:  Negro Bay
Casing used:  8 in. steel - 103 ft
First encountered water at elevation:   -4 ft
       Date drilled:   July 1972
       Ground elevation:   76 ft
In August 1972, the well was test pumped at 60 gpm (limit of the  pump).

The static water level in August 1972, was at elevation 14 ft.

                                                   Feet x 0.3048  -  meters
*Depth to bottom of strata.
tElevation of the bottom of the strata.
                                   136

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              TABLE A-3.  LOG FOR PROJECT WELL NO. 3 (PW-3)
             Description
Thickness  Depth of  Elevation
of strata  strata*   of stratat
    ft        ft         ft
Kingshill marl
Topsoil
White stratified limestone
White limestone, very hard layer
Encountered water just below hard
layer
White limestone soft
Jealousy Formation
Blue clay
2
77
1
72
3
2
79
80
152
155
76
-2
-3
-75
-78
Casing - only an 8 ft piece of casing at the top of the well.   Supported
by angle iron at the surface.
Well location:  Negro Bay
Casing used:  8 in. steel - 8 ft
First encountered water at elevation:  -3 ft
       Date drilled:   July  1972
       Ground elevation:  77  ft
In August 1972, the well was test pumped at 2 gpm when 100 ft deep and
again at 2 gpm when 155 ft deep.

The static water level in August 1972 was at elevation 33 ft.

                                                   Feet x 0.3048 = meters
*Depth to bottom of strata.
tElevation of the bottom of the strata.
                                   137

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              TABLE A-4.   LOG FOR PROJECT WELL NO.  4 (PW-4)
             Description
Thickness
of strata
   ft
Depth of
strata*
   ft
Elevation
of stratat
    ft
Alluvium
  Silty clay                                  5
  Silty clay with angular gravel               5
  Sandy clayey gravel                         4
  Gravel, encountered water                   1
  Sandy gravel                                3
  Clay with some gravel                       4
  Clay, very hard layer at depth
   27-28 ft                                   6
  Sandy clay with a trickle of water          7
  Sandy gravel trace clay (water  bearing)     2
  Clay trace gravel                          13
  Clay, hard layer                            5
Kingshill marl
  white soft marl                            21
  White stratified limestone                  4
  White soft marl                            30
               5
              10
              14
              15
              18
              22

              28
              35
              37
              50
              55

              76
              80
             no
             45
             40
             36
             35
             32
             28

             22
             15
             13
              0
             -5

            -26
            -30
            -60
Casing - only the top 62 ft of the well
is cased.  Perforations are as follows:
                    7 slots/ft
                    7 slots/ft
                    7 slots/ft
           13 - 18
           33 - 43
           56 - 61
Well location:  Golden Grove
Casing used:  8 in. steel - 65 ft
First encountered water at elevation:  36 ft
       Date drilled:  July 1972
       Ground elevation:  50ft
In August 1972 the well was test pumped at 25 gpm when 65 ft deep and  at
27 gpm when 110 ft deep.

The static water level in August 1972 was at elevation 39 ft.

                                                   Feet x 0.3048 = meters
*Depth to bottom of strata.
tElevation of the bottom of the strata.
                                   138

-------
              TABLE A-5.  LOG FOR PROJECT WELL NO.  5 (PW-5)

Description

Thickness
of strata
ft
Depth of
strata*
ft
Elevation
of stratat
ft
Alluvium
  Silty clay
  Silty clay trace sand
  Silty clay trace gravel
  Clayey sandy silt trace  gravel
  Sandy clayey gravel, trickle of water
   at elevation 30 ft
  Clayey gravel
  Sandy silty clay trace gravel,  sticky
  Sandy clay trace gravel, hard layer
  Sandy clay trace gravel
                       8
                       4
                       6
                       2

                       7
                       3
                       2
                       6
                       2
    8
   12
   18
   20

   27
   30
   32
   38
   40
47
43
37
35

28
25
23
17
15
Casing perforations:
7 slots/ft
7 slots/ft
20 - 27
33 - 40
Well location:  Golden Grove
Casing used:  6 in. PVC - 42 ft
First encountered water at elevation:   30 ft
                        Date drilled:   August  1972
                        Ground elevation:   55  ft
In August 1972 the well  was test pumped at less than 5 gpm.

The static water level in August 1972 was elevation  34 ft.

                                                   Feet x 0.3048  = meters
*Depth to bottom of strata.
tElevation of the bottom of the strata.
                                   139

-------
              TABLE A-6.   LOG FOR PROJECT  WELL  NO.  6  (PW-6)
             Description
Thickness
of strata
   ft
Depth of
strata*
   ft
                                                               Elevation
                                                               of  stratat
                                                                   ft
Alluvium
  Clay
  Sandy clay trace gravel
  Clay, very sticky
  Sandy clay trace gravel
  Clay, very fine smooth
  Sandy clay trace gravel
  Sandy clay trace gravel, trickle of
   water at elevation 17 ft
  Sandy gravelly clay
  Clay, sticky
                                              5
                                              5
                                              2
                                              8
                                              7
                                              3

                                              4
                                              1
                                              4
               5
              10
              12
              20
              27
              30

              34
              35
              39
             43
             38
             36
             28
             21
             18

             14
             13
              9
Casing perforations:   7 slots/ft
           21 - 39
Well location:  Golden Grove
Casing used:  8 in. steel - 42 ft
First encountered water at elevation:   17 ft
     Date drilled:  August 1973
     Ground elevation:  48 ft
The well was moist but had no water in August 1973.

The static water level in May 1975 was at elevation  25 ft.

Elevation to top of casing is 51  ft.   The casing was buried  to  the  top
edge during construction of the fish  ponds in 1973.

                                                   Feet x 0.3048 =  meters
*Depth to bottom of strata.
tElevation of the bottom of the strata.
                                   140

-------
              TABLE A-7.  LOG FOR PROJECT WELL NO.  7 (PW-7)
                                          Thickness  Depth of  Elevation
             Description                  of strata  strata*   of stratat
                                             ft         ft         ft
Alluvium
Clay
Clayey sand
Sandy clay
Gravelly clayey sand
Sandy clay, sticky
Sandy silty clay, sticky
3
2
7
2
1
5
3
5
12
14
15
20
44
42
35
33
32
28
Casing perforations:   7 slots/ft                     1  - 20


Well location:  Golden Grove                   Date drilled:  August 1973
Casing used:  8 in. steel  - 21 ft              Ground elevation:   47 ft
First encountered water at elevation:  None encountered

The well was moist but had no water in August 1973.

The static water level in February 1975 was elevation 31  ft.

                                                   Feet  x 0.3048  = meters
*Depth to bottom of strata.
tElevation of the bottom of the strata.
                                   141

-------
              TABLE A-8.  LOG FOR PROJECT WELL NO.  8 (PW-8)

Description

Thickness
of strata
ft
Depth of
strata*
ft
Elevation
of stratat
ft
Alluvium
  Clay trace sand
  Sandy clay trace gravel
  Sandy gravelly clay
  Sandy clay
  Clay trace sand
  Clayey gravel
  Clayey sand, trickle of water at
   elevation 24 ft
  Clay
                       5
                       5
                       2
                       2
                       5
                       3

                       6
                       2
    5
   10
   12
   14
   19
   22

   28
   30
42
37
35
33
28
25

19
17
Casing perforations:
7 slots/ft
7 slots/ft
 8-12
19 - 29
Well location:  Golden Grove
Casing used:  8 in. steel  - 33 ft
First encountered water at elevation:   24 ft
                        Date drilled:   August  1973
                        Ground elevation:   47  ft
The well had no water in August 1973.

The static water level in January 1975 was at elevation  35  ft.

                                                   Feet  x 0.3048  = meters
*Depth to bottom of strata.
tElevation of the bottom of  the strata.
                                   142

-------
              TABLE A-9.  LOG FOR PROJECT WELL NO. 9 (PW-9)
             Description
Thickness
of strata
   ft
Depth of
strata*
   ft
Elevation
of stratat
    ft
Alluvium
  Clay trace sand
  Clayey sand trace gravel
  Clayey sand
  Sandy clay
    8
    7
    2
    3
    8
   15
   17
   20
   41
   34
   32
   29
Casing - The elevation 29 to 41, an 8 in. steel casing is used.  This is
slotted 10 shots/ft in its upper 6 ft.  Above this is a 2 in.  galvanized
pipe which goes to the surface.  At the connection of the two  is a con-
crete seal.  The purpose of the well was to test the feasibility of an
injection well.
Well location:  Golden Grove                   Date drilled:  August 1973
Casing used:  See above                        Ground elevation:   49 ft
First encountered water at elevation:  No flow encountered

The well was moist but had no water in August 1973.

The static water level in February 1975 was at elevation 33 ft.

                                                   Feet x 0.3048  = meters
*Depth to bottom of strata.
tElevation of the bottom of the strata.
                                   143

-------
TABLE B-1. ANALYSIS OF SAMPLES TAKEN FROM WELL A-16
Date
1971 Jul
Aug
Sep
Oct
Nov
Dec
Mean
StdDev

1972 Jan
Feb
Mar
Apr

May
Jun
July
Aug
Sep
Oct
Nov
Dec
Mean
StdDev
1973 Jan
Feb
Mar
Apr
May
Jun
Chlorides
mg/l

145
170
160
_ .
145
153
10

200
160
150
150

150
120
120
150
180
180
170
150
163
24
150
145
150
160
180
180
Conductivity
JUmhos/cm2
at 25ฐ C
1,500
1,420
1,400
1,480
_
1,500
1,441
40

1,300
1,430
1,450
1,450

,400
,400
,400
,400
,400
,400
,400
,400
1,320
324
1,300
1,400
1,400
1,400
1,400
1,300
Total
Hardness
mg/l as
CaCOj
—
254
272
252
_
272
262
10

260
280
280
288

268
276
280
272
272
272
268
268
274
10
284
262
260
284
280
272
Ca
mg/l as
CaCOj
mm
78
100
108
-
112
103
12

112
100
120
108

112
88
88
92
92
100
100
100
100
9
104
88
104
116
112
108
Mg
mg/l as
CaCO,

176
172
144
-
160
159
12

148
180
160
180

156
188
192
180
180
172
168
168
174
12
180
174
156
168
168
164
COj
mg/l as
CaCOj
0
0
0
0
0
0
0
0

0
0
0
0

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCO,
mg/l as
CaCOj

523
530
575
576
568
554
26

576
584
568
576

572
568
564
568
564
568
560
564
569
7
560
600
536
516
527
536
NO.VN NO2-N
mg/l mg/l
_ __
-
-
- -
— _
- -
- _
-

-
-
-
-

- _
-
<1
<1
<1
- <1
4.1 <1
3.8 <1
4.0
0.2
3.9 <1
-
-
2.8 0.010
3.1 0.004
2.7
NH,-N
mg/l

-
-
-
_
-
_
-

-
-
-
-

-
-
0.36
0.37
0.34
0.40
0.39
0.40
0.38
0.02
0.42
-
0.81
-
0.46
0.47
Total
P
mg/l

_
_
-
M
-
_
_

_
_
-
-

-
-
0.027
0.037
0.033
0.035
0.025
0.040
0.03
0.01
0.035
-
0.029
0.035
0.060
0.134
COD BOD TOC
mg/l mg/l mg/l
mm mm
_ _ _
_ — _
_
I ~ ~
-
__
— — —

_ _ _
_ — —
_ — ..
_

_ — —
— — —
_ _ -
_ 30
2.6
- _ -
— _ —
-
16.3
19.4
8
-
16
-
- <5 12
- <5
Standard
Coliforms
Colonies/
100ml
M
_
_
-
~
0

_

10
—
6
9

_
_
-
-
_
-
-
-
_
—
-
-
0
0
0
1







J,
T3
m
z
o
>— *
X
1
-o

— 1
CO














-------
                                              TABLE B-1 (CONTINUED).
cn
Date
1973



Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std
1974











1975








Dev
Jan
Feb
Mar
Apr
May
Jun
July
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
July
Aug
Sep
Chlorides
mg/l
200
170
170
170
150
170
170
33
180
160
160
-
130
170
170
170
170
180
-
170
170
170
210
—
190
190
175
180
180
Conductivity
fAnhos/cm2
at 25ฐ C
1,400
1,500
1,500
1,400
1,300
1,400
1,385
61
1,350
1,400
1,300
-
1,400
1,400
1300
1,200
1,200
1,300
-
1,300
1,300
1,300
1,350
-
1,300
1,400
1,300
1,300
1,300
Total
Hardness
mg/l as
CaC03
280
304
288
260
260
276
13
300
256
272
-
260
256
248
248
260
260
-
-
_
260
-
—
_
272
-
345
-
Ca
mg/l as
CaCOj
120
112
126
104
100
108
10
112
68
100
-
96
80
104
100
92
96
-
-
_
108
-
—
_
97
-
76
-
Mg
mg/l as
CaCOj
140
192
142
156
160
166
15
188
188
172
-
164
176
144
148
168
164
-
-
_
152
-
—
_
175
-
269
-
CO.,
mg/l as
CaCOj
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-
-
_
0
-
-
_
0
-
0
-
HCO.,
mg/l as
CaC03
556
520
524
512
504
536
27
528
496
532
-
530
536
416
516
516
508
-
-
_
524
-
—
_
524
-
513
-
NOj-N
mg/l
3.6
3.3
3.2
-
2.9
3.8
3.2
0.4
3.4
3.2
3.0
-
3.5
3.6
3.4
3.3
3.3
-
-
3.3
3.6
-
3.2
-
3.8
-
3.2
3.7
3.4
NOj-N
mg/l
100
- 0
-
<5

-------
TABLE B-2. ANALYSIS OF SAMPLES TAKEN FROM WELL BMW-3
Date
1972
1973



Oct
Feb
Mar
Apr
May
Jun
July
Aug
Sep
Oct
Nov
Dec
Mean
Std
1974











1975

Dev
Jan
Feb
Mar
Apr
May
Jun
July
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Chlorides
mg/l
520
510
530
570
600
580
600
490
470
550
560
550
546
43
600
580
610
—
590
580
590
610
570
560
- '
530
590
600
Conductivity
ฃlmh os/cm2
at 25ฐ C
2,800
2,800
3,000
2,800
3,000
2,800
2,800
2,600
2^00
3,000
2,600
2,800
2,818
140
2,800
2,800
2,800
—
3,000
3,000
2,700
2,600
2,200
2,400
-
2,400
2,600
2,600
Total
Hardness
mg/l as
CaC03
260
254
264
256
288
280
284
268
280
288
300
275
17
296
308
304
—
276
280
272
-
296
272
-
-
308
308
Ca
mg/l as
CaC03
100
120
124
140
144
140
128
128
132
132
132
132
8
156
140
152
—
132
132
136
-
140
136
-
-
140
140
Mg
mg/l as
CaCOj
160
134
130
116
144
140
156
140
148
156
168
143
15
140
168
252
—
144
148
136
-
156
136
—
-
168
168
CO.,
mg/l as
CaCO.!
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-
0
0
-
-
0
0
HCO3
mg/l as
CaCO.,
640
696
616
596
588
620
620
596
616
600
592
614
31
624
624
624
-
612-
608
616
-
596
586
-
-
608
624
N03-N
mg/l
4.2
5.4
5.1
4.1
4.7
5.3
5.0
5.3
4.9
0.5
4.6
4.4
4.9
—
4.4
5.2
5.1
5.4
5.2
4.4
~
3.4
4.8
5.2
NOrN
mg/l
0.004
0.003
0.001
_

-------
                                                TABLE B-2 (CONTINUED).






Date
1975






Mar
Apr
May
Jun
July
Aug
Sep

Chlorides

mg/l
600
580
600
600
588
538
540

Conductivity
//mhos/cm
at 25ฐ C
2,600
2,600
2,600
2,800
2,800
2,800
2,600
Total
Hardness
mg/l as
CaC03
_
310
306
314
-
-
-

Ca
mg/l as
CaCOj
_
124
136
148
-
-
-

Mg
mg/l as
CaCO,
•*
186
170
166
-
-
-

CO,
mg/l as
CaC03
0
0
0
0
_
-
-

HCO,
mg/l as
CaCO,
_,_
604
588
596
_
-
-

NO3-N

mg/l
5.1
-
5.0
-
5.0
4.2
1.3

NO2-N

mg/l
—
-
0.001
0.003
0.002
0.002
-

NH.,-N

mg/l
0.13
-
0.14
0.13
0.12
0.09
0.09
Total Standard
P* COD BOD TOC Coliforms
Colonies/
mg/l mg/l mg/l mg/l 100ml
<5
_ o
_ - - - _
- 0
_ - -
_ - - - _
-
*Not measured since phosphates are added to water at the well by the owner.

-------
                             TABLE B-3. ANALYSIS OF SAMPLES TAKEN FROM WELL BMW-4
00
Date
1972 jut
Oct
1973 Mar
Apr
May
Jun
Jul
Aug
Mean
Std Oev
Total
Chlorides Conductivity Hardness
/Anhos/cm2 mg/l as
mg/l at25ฐC CaCOj
250
230
280
420
440
440
440
—
404
70
WELL INOPERATIVE
1974 May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
1975 Jan
Feb
Mar
Apr
May
Jun
410
440
360
410
340
430
-
400
400
390
400
340
390
380
1,700
1,700
1,900
2,200
2,400
2,300
2,400
—
2,240
207
SEPT 1973- APRIL
2,400
2,600
2,000
2,000
1,700
2,200
-
2,000
2,200
2,100
2,200
2,200
2,200
2,200
236
240
204
208
-
192
196
200
200
6
1974
180
192
188
188
212
208
-
-
188
192
-
217
196
202
Ca
mg/l as
CaCO,
112
132
92
96
-
92
92
96
94
2

84
88
96
76
80
84
-
-
76
96
-
85
90
85
Mg
mg/l as
CaCO;,
124
108
112
102
-
100
104
104
104
5

96
104
92
112
132
124
-
-
112
96
-
132
106
117
CO,
mg/l as
CaCO.,
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
-
-
0
0
-
0
0
0
HCOj
mg/l as
CaCO.,
536
548
556
592
-
620
600
612
596
25

620
628
592
616
576
612
-
-
616
620
-
580
596
600
NO.,-N
mg/l
-
_
3.1
4.4
-
4.8
-
4.1
0.9

3.4
4.6
4.4
4.5
,_
4.3
-
3.7
3.8
4.2
3.9
-
4.0
-
NO2-N
mg/l
-
_

-------
                  TABLE B-4. ANALYSIS OF SAMPLES TAKEN FROM WELL BMW-5
Chlorides Conductivity
/lmhos/cm2
Date mg/l at 25ฐ C
1973



Mean
Jul
Aug
Sep
Oct
Nov
Dec

Std Dev
1974











1975







Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
340
330
290
320
350
326
23
360
340
360
-
390
400
410
420
350
460
190
-
320
330
_
350
360
380
396
420
2,500
2,600
2,600
2,400
2,400
2,500
100
2,400
2,200
2,200
-
2.400
2,600
2,200
2,200
2,000
2,200
1,600
-
2,200
2,100
_
2,200
2,200
;2,200,
2,400
2,400
Total
Hardness
mg/l as
CaC03
320
384
396
392
373
36
412
352
328
-
324
328
332
344
336
348
-
-
380
380
_
365
388
377
. -
373
Ca
mg/l as
CaC03
104
176
184
176
160
38
172
172
160
-
158
148
160
168
140
160
-
-
132
142
_
140
167
175
-
159
Mg CO3
mg/l as mg/l as
CaCO3 CaCO3
216
208
212
216
213
4
240
180
148
-
166
180
172
176
166
188
-
-
248
238
_
225
221
202
-
214
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCO3
mg/l as
CaCO3
720
804
784
748
764
37
780
692
676
-
688
708
688
680
692
696
-
-
760
736
_
696
716
708
-
680
NO3-N
mgfl
0.9
1.2
3.0
2.8
2.5
2.1
.1
2.0
1.9
0.9
-
_
-
1.2
1.4
__
6.0
-
5.4
5.0
5.0
4.3
-
3.5
-
4.2
2.6
NO2-N NH3-N
mg/l mg/l
0.016
-
0.002
0.004
_
-
0.004
0.001
0.002
-
0.002
0.002
0.002
0.005
0.003
0.002
-
-
0.003
0.003
_
-
0.005
0.021
0.128
0.024
0.18
0.47
-
0.19
0.11
0.24
0.16
0.04
0.04
-
<0.01
0.23
0.17
0.19
0.19
0.24
0.30
-
-
0.38
0.45
0.18
-
0.16
0.19
0.12
0.14
Total
P
mg/l
0.098
0.128
0.136
0.114
0.122
0.120
0.010
0.095
0.120
0.116
-
_
-
0.145
0.160
0.144
0.168
-
0.150
0.160
0.144
0.125
-
0.118
0.122
0.125
0.118
COD
mg/l
-
-
<5
<5
_.
-
5
100
>100
>100
5
0
_
-
0
0
0
-
0
0
0
0
10
0
-
-
4
1
_
51
-
10
-
0
Sep
2.7
0.002
                                                                  0.08  0.117

-------
TABLE B-5. ANALYSIS OF SAMPLES TAKEN FROM WELL FP-5
Date
1971 Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1972










Jan
Feb
Mar
Apr
May
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std
1973





Dev
Jan
Feb
Mar
Apr
May
Jun
Chlorides
mg/l
1,035
940
1,090
1,060
1,070
1,039
59
1,090
1,120
1,050
1,100
1,100
1,150
1,130
1,160
1,120
800
980
1,073
103
980
995
1,090
1,230
1,360
1,460
Conductivity
jLOnh os/cm2
at25ฐC
4,100
4,200
3,900
4,200
3,700
4,100
4,033
197
4,000
4,100
4,000
3,900
4,200
4,000
3,000
4,000
4,000
3,000
3,500
3,791
428
3,500
4,000
4,000
4,000
4,250
4,500
Total
Hardness
mg/l as
CaC03
675
580
856
680
704
699
100
700
692
-
704
740
740
760
748
769
464
672
699
88
684
714
780
836
976
1,036
Ca
mg/l as
CaC03
336
308
372
372
356
348
27
364
376
-
368
372
368
364
380
384
248
300
352
44
272
368
408
456
504
528
Mg C03
mg/l as mg/l as
CaC03 CaC03
339
272
484
308
348
350
81
336
316
-
336
368
372
396
368
385
216
372
347
52
412
346
372
380
472
508
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCO3
mg/l as
CaC03
488
508
545
516
528
517
21
524
524
-
540
520
528
528
532
520
544
540
530
9
540
556
504
480
488
496
NO3-N NO2-N NH3-N
mg/l mg/l mg/l
-.
_ _
_
_
_
_ _ _
<1 0.49
<1 0.47
<1 0.49
<1 0.52
<1 0.49
4.7 <1 0.43
0.48
0.03
4.8 <1 0.48
_
3.1 - 0.80
4.1 <0.01 0.22
3.8 0.004 0.67
3.4 - 0.22
Total
P COD
mg/l mg/l
_
_
-
-
-
_
0.020
0.047
0.047
0.041
0.033
0.047
0.040
0.010
0.055
-
0.042
0.018
0.064
0.082
BOD TOC
mg/l mg/l
_
_ _
_
-
_
_
17
-
28
_
9.2
5.5
15
10
21
_
_
-
<5 IS
<3
Standard
Conforms
Colonies/
100ml
20
0
>100
-
6
>100
_
-
-
—
_
-
-
_
-
-
-
>100
>100
0
>100

-------
                                         TABLE B-5 (CONTINUED).
Date
Jul
Aug
Sep
Oct
Nov
Mean
Std Dev
1974 Jan
Feb
Mar
Apr
May
Jun
Chlorides
mg/l
1,460
1,540
1,530
1,600
1,710
1,350
261
1,610
1,780
1,850
-
2,040
1,920
PUMP INOPERATIVE
1975 Jul
Aug
Sep
1^70
1,880
1,900
Conductivity
pbnhos/cm
at25ฐC
5,000
5,000
5,000
5,000
5,000
4,477
553
5,000
5,500
6,000
-
7,000
7,000
DUE TO BRUSH
5,500
5,000
5,500
Total
Hardness
mg/l as
CaC03
1,032
1,160
_
1,220
1.304
974
216
1,168
1,372
1,490
-
1,500
—
FIRE JUL
_
1,400
—
Ca
mg/l as
CaCOj
516
596
_
616
652
492
118
604
668
700
-
790
—
1974-JUN
_
722
—
Mg C03
mg/l as mg/l as
CaCO3 CaCO3
516
564
_
604
652
483
105
564
704
790
-
710
—
1975
_
678
~
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
HC03
mg/l as
CaC03
484
468
_
464
468
494
32
472
460
430
-
460
—

_
458
~
NO3-N
mg/l
4.0
5.8
3.7
4.0
-
4.1
0.8
_
3.8
4.0
-
3.4
3.8

_
4.1
0.4
NOj-N
mg/l
0.003
<0.001
_
-
0.002
_
-
_
0.003
0.004
-
0.022
—

0.011
0.008
0.006
NH3-N
mg/l
0.23
0.46
0.49
0.18
0.33
0.41
0.21
0.32
0.10
-
<0.01
0.19
—

_
0.11
0.08
Total
P COD
mg/l mg/l
0.038
0.040
0.068
0.048
<5
0.050
0.020
— —
0.055 < 5
0.052 <5
- -
0.041 7
0.062

_ _
_
— —
BOD TOC
mg/l mg/l
8
<5 2
_ —
<5
<5 11
11
7
<5
<5 3.5
<5
-
<5
_ —

_ _
-
— —
Standard
Coliforms
Colonies/
100ml
0
7
>100
c*
c
_
-
0
c
-
-
27
—

_
>100
—
*Confluent colonies.

-------
TABLE B-6. ANALYSIS OF SAMPLES TAKEN FROM WELL FP-6
Date
1971 Jun
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1972 Jan
Feb
Mar
Apr
May
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1973 Jan
Feb
Mar
Apr
May
Jun
Chlorides
mg/l
620
600
660
660
640
636
26
620
610
590
520
580
650
680
610
620
570
570
602
43
570
560
600
700
700
980
Conductivity
/Km h os/cm
at25ฐC
3,300
3,200
3,000
3,000
3,100
3,100
3,050
3,107
110
2,800
3,000
3,000
2,800
2,900
2,900
3,000
2,900
3,000
2,900
2,900
2,918
75
2,600
2,800
3,000
2,900
3,100
3^00
Total
Hardness
mg/l as
CaC03
527
500
536
532
524
524
14
524
484
496
488
484
480
488
492
500
392
400
475
41
500
470
508
532
580
756
Ca
mg/l as
CaC03
232
236
248
236
248
240
8
252
232
224
216
216
160
228
208
224
180
180
211
27
208
218
232
252
272
328
Mg C03
mg/l as mg/l as
CaCO3 CaCOj
295
264
288
296
276
284
14
272
252
272
272
268
320
260
284
276
212
220
264
29
292
252
276
280
308
428
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/l as
CaCO3
532
532
575
548
572
552
21
588
568
552
564
560
560
568
564
556
520
560
560
16
560
588
532
512
520
504
NO3-N
mg/l
~
-
-
_
-
_
-
-
-
_
-
-
-
_
4.2
4.1
4.2
0.1
4.6
-
3.5
4.0
4.0
3.1
NO2-N NH3-N
mg/l mg/l
-
- -
_
_ —
-
__ _
_ _
-
-
_ _
<3 0.34
<1 0.33
<1 0.38
<1 0.38
<1 0.87
<1 0.44
0.49
0.21
<1 0.42
- -
0.63
<0.010 0.09
0.004 0.72
0.41
Total
P
mg/l
"**
-
-
_
-
—
-
-
-
_
0.069
0.090
0.085
0.083
0.035
0.066
0.070
0.020
0.083
_
0.090
0.085
0.094
0.096
COD BOD TOC
mg/l mg/l mg/l
_
_
_
_ .. _
-
— — __
_ _ -
_
- - -
— _ _
- - 27
_ _ _
39
7.6
_
6
20
16
— _ —
_ _ _
11
_
<5 14
<5 7
Standard
Coliforms
Colonies/
100ml
0
_
0
_
-
0
0
-
0
	
-
-
-
—
_
-
_
-
_
-
0
0
„
>100

-------
                                                      TABLE B-6 (CONTINUED).
en
GO
Date
1973 Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1974 Jan
Feb
Mar
Apr
Chlorides Conductivity
Jttihos/cm2
mg/l at25ฐC
1,260
1,540
1,590
1,660
1,800
-
1,087
492
1,680
1,960
2,250
-
4,000
5,000
5,500
5,500
5,500
-
3,945
1,199
5,000
6,000
7,000
-
Total
Hardness
mg/l as
CaC03
964
1,220
_
1,652
1,532
-
871
450
1,372
1,620
1,950
-
Ca
mg/l as
CaC03
448
560
_
620
708
-
385
186
624
748
865
-
Mg C03
mg/l as mg/l as
CaC03 CaCO3
516
660
_
1,032
824
-
487
270
748
872
1,085
-
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/l as
CaCO3
488
460
_
472
408
-
505
51
456
436
400
—
N03-N
mg/l
4.1
3.6
3.5
4.1
3.6
-
3.8
0.4
_
3.6
3.5
-
NO2-N
mg/l

-------
                           TABLE B-7. ANALYSIS OF SAMPLES TAKEN FROM WELL FP-8
cn
Date
1971 Jun
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1972 Jan
Feb







May
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std
1973







Dev
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Chlorides
mg/l
660
600
650
630
660
640
26
660
700
660
690
640
680
690
620
500
649
62
460
650
650
700
800
700
700
670
Conductivity
/Jmh os/cm
at 25ฐ C
3,500
3,200
3,400
3,000
3,200
3,050
3,050
3,200
189
3,000
3,200
3,200
3,000
3,000
3,000
3,000
3,000
3,000
3,044
88
2,400
3,000
3,000
2,900
3,100
3,000
3,000
3,000
Total
Hardness
mg/l as
CaC03
442
412
440
460
440
439
17
428
424
432
456
432
416
436
408
372
423
23
408
440
472
452
484
456
440
448
Ca
mg/l as
CaCO3
210
204
240
224
232
222
15
220
224
220
176
192
188
196
200
188
200
17
180
220
252
220
248
224
216
216
Mg C03
mg/l as mg/l as
CaCO3 CaCO3
232
208
200
236
208
217
16
208
200
212
280
240
228
240
208
184
222
28
328
220
220
232
236
232
224
232
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCOj
mg/l as
CaC03
545
572
605
608
568
580
27
596
580
580
510
580
576
560
592
612
576-
29
616
608
588
540
568
548
560
548
N03-N
mg/l
-
-
-
_
-
-
4.9
4.3
4.6
0.4
4.2
-
-
4.0
3.9
3.4
3.6
5.7
N02-N NH3-N
mg/l mg/l
•~ •"
-
<1 0.49
<1 0.44
<1 0.46
<1
<1 0.50
<1 0.25
0.43
0.10
<1 0.46
_
0.49
0.010 0.06
0.004 0.36
0.49
0.014 0.18
0.47
Total
P
mg/l
-
-
0.069
0.081
0.070
0.059
0.071
0.047
0.070
0.010
0.060
-
0.051
0.098
0.096
0.084
0.068
0.076
COD BOD
mg/l mg/l
™" *™
_
- -
_
-
_
—
_
_
- -
_
-
_
<5
- <5
<5
-
- <5
Standard
TOC Coliforms
Colonies/
mg/l 100ml
-
-
20
-
15
-
6.6
6.0
12
7
24
-
-
12
_
7
-
<0.1
"~
-
—
_
-
-
—
0
_
-
0
-
0
4
21
0
0
4

-------
                                            TABLE B-7 (CONTINUED).
en
en
Date
1973 Sep
Oct
Nov
WELL NOT
Mean
Std Dev
1974 Jan
Feb
Mar
Apr
May
jun
Jul
Aug
Sep
Oct
Nov
Chlorides Conductivity
pmhos/cm2
mg/1 at25ฐC
680
690
670
OPERATING
670
81
700
680
680
-
690
700
680
680
720
720
-
PUMP TURNED OFF NOV
1975 Jan
Feb
Mar
May
Jun
Jul
Aug
Sep
730
750
750
680
750
692
700
700
3,000
3,000
2,800

2,927
190
3,000
3,000
3,000
-
3,000
3,000
2,800
2,600
2,400
2,800
-
1974-JAN
2,800
2,800
2,800
2,800
3,000
2,800
2,800
3,000
Total
Hardness
mg/l as
CaCO3

432
480

451
23
492
488
452
-
440
408
416
416
460
444
-
I975
_
464
-
-
458
-
441
—
Ca
mg/l as
CaC03
_
212
220

221
19
224
216
232
-
212
204
212
204
216
204
-

_
228
-
-
217
-
217
—
Mg C03
mg/l as mg/l as
CaCO3 CaCO3
.
220
260

240
33
268
272
220
-
228
204
204
212
244
240
-

_
236
-
-
241
-
224
—
0
0
0

0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
HC03
mg/l as
CaCO3
_
552
540

567
28
536
540
548
-
548
544
536
536
540
532
-

_
544
-
-
540
-
542
—
NO3-N
mg/l
3.9
4.9
4.4

4.2
0.7
_
4.1
4.4
—
3.9
4.2
4.3
4.2
_
-
-

4.3
4.8
4.2
5.8
-
4.4
4.1
3.6
N02-N
mg/l
_
0.004
-

-
-
0.002
<0.001
0.004
—
0.014
0.005
0.002
0.005
0.003
0.004
0.003

0.007
0.004
<0.001
0.002
0.008
0.006
0.005
0.006
NH3-N
mg/l
0.37
0.20
0.15

0.32
0.16
0.10
0.08
-
0.02
0.22
0.17
0.34
0.30
<0.01
-
0.15

-
0.27
0.16
—
0.10
0.16
0.11
0.23
Total
P
mg/l
0.116
0.081
0.076

0.080
0.020
_
0.092
0.070
—
0.060
0.073
0.101
0.063
0.076
-
-

0.077
0.066
0.059
0.070
0.083
0.082
0.064
0.062
Standard
COO BOO TOC Coliforms
Colonies/
mg/l mg/l mg/l 100ml
_ 	 __
<5
<5 <5

14
— — 9
<5 <5
<5 <5 3.5
<5 <5
— — -ป
<5 <5
7 <5
<5 <5 16
8 — —
<5
<5
<5 - -

<5
•J __ _
<5
— — —
_
-
_
™ "" "™
1
0
0

-
—
0
0
0
—
4
0
2
0
49
1
—

-
0
-
—
0
-
0
"

-------
                           TABLE B-8. ANALYSIS OF SAMPLES TAKEN FROM WELL GG-1
en
Date
1971 Sep
Oct
Nov
Dec
Mean
Std Dev
1972 Jan
Feb
Mar
Apr
May
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1973 Jan
Feb
Mar
Apr
May
Jun
Chlorides Conductivity
pmh os/cm2
mg/l at25ฐC
200
200
190
200
196
5
210
210
210
230
185
210
230
240
240
210
210
217
17
220
210
_
260
280
260
WELL DISMANTLED
Aug
Sep
—
-
1,675
1,800
1,630
1^00
1 ,726
87
1,650
1,770
1,750
1,650
1,800
1,800
1,700
1,700
1,700
1,700
1,500
1,703
84
1,700
1,600
_
1,700
1,700
1,650
Total
Hardness
mg/l as
CaC03
368
292
300
306
317
35
296
300
304
312
296
320
297
320
304
320
360
312
19
320
352
_
352
336
340
Ca
mg/l as
CaC03
316
204-
140
116
194
89
140
120
128
116
120
104
108
128
128
128
152
125
14
144
128
-
156
140
156
Mg C03
mg/l as mg/l as
CaCO3 CaCO3
52
88
160
190
123
64
156
180
176
196
176
216
189
292
176
292
208
205
46
176
224
_
196
196
184
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCO3 NO3-N
mg/l as
CaCO3 mg/l
636
675
660
640
653
18
660
636
640
652
644
642
648
640
624
640
632
643
8
640
664
2.9
572 2.5
592 2.3
600 2.6
NO2-N NHj-N
mg/l mg/l
_ _
-
-
— —
_
<1 0.42
<1 0.41
<1 0.40
<1 0.46
<1 0.49
<1 0.46
0.44
0.04
<1 0.44
-
0.76
0.010 0.12
0.004 0.41
0.56
Total Standard
P COD BOD TOC Conforms
Colonies/
mg/l mg/l mg/l mg/l 100ml
_
-
-
—
-
0.056
0.065
0.058
0.059
0.057
0.051
0.060
0.001
0.060
-
0.073
0.085
0.096
0.084
_ _ _
_
-
— — —
_
25
_ _ -
44
5
-
14.3
22
- - 17
_ _ _
7
12
— - -
- <5 17
- <5
44
225
17
-
45
93
-
-
-
—
-
-
—
-
—
-
-
5
10
40
55
FOR DISINFECTION
_
-
_
-
_
-
_
-
0
0
_
-
0.49
0.35
-
-
_
- - -
8
0

-------
                                           TABLE B-8 (CONTINUED).
en
Date
1973


Mean
Oct
Nov
Dec

Std Dev
1974











1975








Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Chlorides
tng/1
380
370
400
298
75
490
520
520
-
540
530
550
590
600
620
_
260
280
260
270
270
270
270
264
300
300
Conductivity
/^mhos/cm
at25ฐC
2,000
2,000
2,200
1319
217
2,400
2,400
2,600
-
2,800
2,600
2,200
2,400
2,400
2,400
_
1,600
1,600
1,600
1,600
1,700
1,800
1,700
1,700
1,800
1,700
Total
Hardness
mg/l as
CaC03
456
440
424
378
53
412
404
444
-
424
416
400
416
_
428
_
-
464
452
-
438
450
446
-
418
-
Ca
mg/l as
CaCO3
196
192
160
159
24
160
140
176
-
164
172
160
160
_
164
-
-
182
192
-
166
182
179
-
175
-
Mg CO3 HCO3
mg/l as mg/l as mg/l as
CaCO3 CaC03 CaCO3
260
248
264
219
35
252
264
268
-
260
244
240
256
_
264
-
-
282
260
-
272
268
265
-
243
-
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
556
554
536
589
44
542
500
548
-
540
520
536
528
_
526
-
-
604
600
-
592
584
572
1 -
588
-
N03-N
mg/l

-
1.9
2.4
0.4
2.5
1.6
1.2
-
1.2
0.9
1.5
0.8
_
1.0
-
1.0
1.9
1.8
1.3
—
1.3
-
1.3
1.3
1.4
NO2-N NH3-N
mg/l mg/l
_
0.001
0.001
0.370
0.200
0.100
0.001
0.002
-
0.002
0.001
0.001
0.002
-
0.002
0.003
-
0.002
0.002
-
—
0.002
0.003
0.002
0.001
0.002
0.09
0.30
0.22
0.08
0.01
0.01
0.01
-
0.12
0.31
0.23
0.29
0.24
0.30
0.32
-
—
0.27
0.38
0.17
—
0.41
0.16
0.07
~
0.85
Total Standard
P COD BOD TOC Coliforms
Colonies/
mg/l mg/l mg/l mg/l 100ml
__
-
0.084
-
—
0.066
-
0.052
—
0.046
0.040
0.088
0.055
0.027
0.048
-
0.086
0.090
0.088
0.079
—
0.076
0.074
0.088
0.075
0.067.
_
<5
<5
-
—
9
<5
23
—
<5
<5
<5
<5
8
<5
5
—
11
<5
<5
•~
~
—
-
~
-
<5
<5 12
7
11
4
<5
<5 3.5
<5
— —
<5
6
<5 12
— —
-
- -
- -
— "•
-
<5
— —
~~ ~~
-
— —
— —
~~ ~~
-
28
38
10
-
—
54
400
10
—
0
20
0
4
-
128
-
—
192
8
—
131
305
—
—
0
-

-------
                           TABLE B-9. ANALYSIS OF SAMPLES TAKEN FROM WELL GG-8
cn
oo
Date
1971 Jun
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Oev
1972 Jan
Feb
Mar
Apr
May
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1973 Jan
Feb
Mar
Apr
May
Jun
Chlorides
mg/l
445
410
420
430
426
14
440
400
450
-
450
445
460
480
500
450
450
453
26
450
-
450
470
500
500
Conductivity
/Umhos/cm
at25ฐC
2,650
2,500
2,650
2,400
2,400
2,500
2,500
122
2,450
2,250
2,500.
-
2,600
2,400
2,400
2,400
2,200
2,400
2,200
2,380
130
2,200
2,400
2,600
2,400
2,800
2,500
Total
Hardness
mg/l as
CaCO3
273
284
288
272
279
8
284
272
284
-
272
272
264
280
292
260
292
111
11
292
-
264
260
284
228
Ca
mg/l as
CaC03
111
128
124
112
119
9
124
132
88
-
120
98
104
108
128
108
120
113
14
108
-
112
116
132
132
Mg C03
mg/l as mg/l as
CaCO3 CaC03
162
154
164
160
160
4
160
140
196
-
152
174
160
172
164
152
172
164
16
184
-
152
144
152
96
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCO3
mg/l as
CaC03
571
564
592
592
580
14
608
580
564
-
584
590
600
600
568
592
612
580
16
612
-
580
572
580
588
NO3-N NO]-N NH3-N
mg/l mg/l mg/l
_
_
- — -
_
— — —
_ _ _
_
_
— - -
_ _ _
<1 0.50
<1 0.43
<1 0.48
<1 0.44
_
- - -
0.46
0.03
6.3 <1 0.64
_
4.2 - 0.78
5.2 <0.01 0.09
5.4 0.004 0.64
4.6 - 0.58
Total
P COD BOD TOC
mg/l mg/l mg/l mg/l
_
_
- — — -
_ _ _ _
— — — —
_ _ _ _
_
_
- - - -
_ _ _
0.066 - -- 2.3
0.092 -
0.070 - - 4.1
0.075 -
- 4.5
0.068 -
0.070 4
0.010 - - 1
0.070 - - 5.5
- - -
0.070 -
0.082 -
0.090 - <5 14
0.084 - <5
Standard
Coliforms
Colonies/
100ml
1
-
26
—
—
0
-
0
3
-
-
-
—
-
-
—
_
-
~
-
0
0
0
5

-------
TABLE B-9 (CONTINUED).
Date
1973





Mean
Jul
Aug
Sep
Oct
Nov
Dec

Std Dev
1974











1975








Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Chlorides
mg/I
540
530
530
530
530
550
507
36
550
550
560
—
550
570
550
520
560
580
_
500
530
540
540
530
530
540
528
560
-
Conductivity
/^mhos/cm2
at 25ฐ C
2,600
2,700
2,800
2,800
2,600
2,800
2,600
195
2,700
2,700
3,000
-
3,000
3,000
2,600
2,400
2,200
2,500
-
2,200
2,400
2,400
2,400
2,400
2,400
2,600
2,400
2,600
-
Total
Hardness
mg/I as
CaC03
296
296
-
292
284
308
280
24
292
264
304
-
288
280
284
-
320
308
-
-
300
312
-
295
_
307
-
293
-
Ca
mg/I as
CaCO3
124
148
_
140
128
104
132
22
156
92
136
-
128
132
124
-
128
128
-
-
136
144
-
121
_
124
-
126
-
Mg
mg/I as
CaCO3
172
148
_
152
156
204
156
28
136
172
168
-
160
148
160
-
192
180
-
-
164
168
-
174
_
183
-
167
-
C03
mg/I as
CaCO3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/I as
CaCO3
580
572
-
588
. 580
576
583
12
580
560
600
-
596
612
588
-
580
582
-
-
584
588
-
584
-
600
-
580
-
NO3-N
mg/I
5.6
2.0
4.9
6.1
5.8
5.7
5.2
1.0
5.3
6.3
1.3
-
4.7
5.7
3.3
5.5
_
5.0
-
4.7
4.8
5.7
5.7
5.6
5.7
-
5.1
5.4
5.4
NOj-N
mg/I
0.001
<0.001
_
_
0.001
<0.001
_
-
0.001
0.001
0.001
-
0.001
<0.001
0.001
<0.001
0.002
0.002
0.001
-
0.002
0.005
-
-
0.004
-
0.001
0.002
-
NH3-N
mg/I
0.15
0.39
0.39
0.02
0.39
0.24
0.39
0.25
<0.01
0.04
-
0.02
0.20
0.37
0.38
0.47
0.21
0.24
-
-
0.11
0.23
0.13
-
_
0.12
0.11
-
-
Total
P
mg/I
0.060
0.068
0.114
0.087
0.060
0.076
0.080
.0.020
0.081
0.073
0.075
-
0.068
0.065
0.094
0.066
_
0.093
-
0.072
0.077
0.070
0.065
-
0.067
0.077
0.064
-
0.028
COD
mg/I

-
_
-
<5
<5
_
-
6
<5
12
—
<5
7
<5
<5
<5
<5
<5
-
5
<5
<5
-
..
-
-
' -
_
Standard
BOD TOC Conforms
Colonies/
mg/I mg/I 100ml
<5 2
<5
<5
<5
11
<5 9
8
— 5
<5
<5 4
<5
- -
<5 5.25
5
<5 6
-
_
- -
-
-
<5
-
_
-
_ _
-
-
-
_
0
1
0
1
2
0
_
-
1
0
0
-
0
1
10
-
0
0
-
--
0
-
-
0
„
0
-
0
-

-------
                         TABLE B-10. ANALYSIS OF SAMPLES TAKEN FROM WELL GG-9
Date
1971 Jun
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
& 1972 Jan
0 Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
Chlorides
mg/l
_
-
200
210
220
220
250
220
19
240
260
240
-
_
200
250
230
240
250
220
230
236
17
Conductivity
/^mhos/cm
at 25ฐ C
1,625
1,600
1,600
1,550
1,675
1,650
1,700
1,628
51
1,600
1,600
1,600
-
_
1,600
1,600
1,500
1,500
1,500
1,500
1,500
1,550
53
Total
Hardness
mg/l as
CaC03

-
378
372
372
380
392
379
8
380
376
-
-
_
380
308
380
388
400
400
384
377
27
Ca
mg/l as
CaCO3

-
152
170
172
172
172
168
9
172
172
-
-
_
168
168
140
164
168
168
168
165
10
Mg
mg/l as
CaC03

-
226
202
200
208
220
211
11
208
104
-
-
_
212
140
240
224
232
232
216
201
47
C03
mg/l as
CaCO3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCOj NO3-N
mg/l as
CaCO3 mg/l

-
483
476
520
532
556
513
34
528
504
-
- -
_ _
504
508
508
504
492
508 2.6
500 2.9
506 2.8
10 0.2
NOj-N NHj-N
mg/l mg/l

_
-
-
_ _
-
- -
_ _.
-
_ 	
-
-
-
_ _
_
<1 0.27
<1 0.38
<1 0.40
<1 0.48
<1 0.62
<1
0.43
0.13
Total
P COD BOD
mg/l mg/l mg/l

..
_
_
_ _ _
_
- - -
ซ —
- -
— _
_
„
- - -
_ _
_
0.076
0.081
0.080
0.083
0.083
0.085
0.080
_
TOC
mg/l

-
--
-
_
-
-
„.
-
__
-
-
-
_
-
17
-
12
4.0
5.2
4.5
9
6
Standard
Conforms
Colonies/
100ml

-
--
-
21
-
-
_
-
2
-
0
0
49
-
12
52
>100
25
-
-
_
-
 PUMP BEING REPAIRED
1973
Apr
May
260
260
1.500
1,500
                            600
200   400
0
0
468
1.7
1.6
0.004  0.43   0.094
<5
<5
                                                           14

-------
                                               TABLE B-10 (CONTINUED).



Date
1973 Jun
Jul
Aug
PUMP NOT
Oct
Nov
Dec
Mean
Std Dev

Chlorides

mg/l

300
250
RUNNING
330
270
260
276
29

Conductivity
p&tih os/cm2
at25ฐC

1,500
1,600

1,900
1,600
1,600
1,600
141
Total
Hardness
mg/l as
CaCO3

420
440

540
500
456
493
68

Ca
mg/l as
CaCOj

196
196

232
216
192
205
16

Mg
mg/l as
CaC03

224
244

308
284
264
287
63

C03
mg/l as
CaCO3
0
0
0

0
0
0
0
0

HCO3
mg/l as
CaCO3

480
460

_
460
456
465
10

NO3-N

mg/l
4.8
5.7
1.1

— .
0.4
1.2
2.4
2.0

NOj-N

mg/l

0.002
<0.001

_
0.002
<0.001
_
-

NH3-N

mg/l
0.59
0.14
0.42

0.19
0.06
0.07
0.27
0.21
Total
P

mg/l
0.092
0.100
0.082

„
0.056
0.084
0.080
0.020

COD

mg/l

-
-

_
<5
<5
-
-

BOD

mg/l

-
<5

<5
<5
<5
_
-

TOC

mg/l
8
-
1

_
10
4
7
5
Standard
Conforms
Colonies/
100ml

-
-

_
7
4
-
-
a>
       DENIED ACCESS TO PUMP BY OWNER - SAMPLING DISCONTINUED

-------
                           TABLE B-1 1. ANALYSIS OF SAMPLES TAKEN FROM WELL MB-1
OS
to
Date
1971 Jul
Aug
Sep
Nov
Dec
Mean
Std Dev
1972 Jan
Feb
Mar
Apr
May
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1973 Jan
Feb
Mar
Apr
May
Jun
Chlorides
mg/l
_
1,775
1,810
1,810
1,800
1,799
17
1,790
1,820
1,860
1,650
1,670
1,830
1,860
1,890
1,900
1,840
1,700
1,800
88
1,680
1,680
1,670
1,870
1,800
1,860
Conductivity
^mhos/cm2
at2SฐC
7,000
6,800
6,800
6,000
6,500
6,620
390
6,000
6,100
6,000
6,100
6,500
6,000
6,000
6,000
6,000
6,000
6,000
6,064
151
6,000
6,000
6,000
6400
6,000
6,000
Total
Hardness
mg/l as
CaC03
_
362
453
-
456
424
53
440
444
388
468
456
460
460
464
448
448
436
447
22
508
436
436
440
__
472
Ca
mg/l as
CaCO3
_
216
244
244
232
234
13
236
224
168
248
248
204
164
220
240
224
216
218
29
248
280
232
240
^_
252
Mg
mg/l as
CaCO3
_
146
209
-
224
193
41
204
220
220
220
208
256
296
244
208
224
220
229
27
260
156
204
200
_
220
C03
mg/l as
CaCO3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCO3
mg/l as
CaC03
_
425
444
-
452
440
14
468
472
392
464
460
468
464
472
456
460
480
460
23
484
188
452
440
_
456
N03-N
mg/l
_
-
-
-
-
_
-
_
-
-
-
_
-
-
-
_
6.3
5.3
5.8
0.7
5.8
-
4.2
4.3
5.0
4.5
NO2-N NH3-N
mg/l mg/l
_ m.
~
..
— —
-
-
- -
_ _
-
_
— -
_ _
<1
<1 0.39
<1 0.38
<1 0.43
<1 0.33
<1 0.30
0.37
0.05
1 0.35
-
0.73
<0.01 0.20
0.34
0.35
Total
P COD BOD
mg/l mg/l mg/l
_~ _ ป
..
..
— — —
_
_ _ _
— — —
_ _
_
_
— -
— — —
0.015
0.047
0.042
0.015
0.023
0.012
0.026
0.015
0.01 5
_
0.01 6 ~
0.01 0 -
0.021 - <5
0.032 - <5
TOC
mg/l
_
-
-
—
-
-
-
_
-
-
-
-
7
--
15
7
~
—
10
5
-
6.5
15
—
..
12
Standard
Coliforms
Colonies/
100ml
_
-
-
—
0
-
-
>100
-
2
20
-
-
-
-
_
-
—
_
—
-
2
69
—
9
8

-------
                                         TABLE B-11 (CONTINUED).
Date
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
,_, 1974 Jan
O> Feb
CO
Chlorides
mg/l
1,880
1,810
1,830
1,810
1,820
1,800
1,793
75
1,810
1,810

WELL INOPERATIVE
Conductivity
pmh os/cm2
ซ25ฐC
6,000
6,000
7,000
6,000
6,000
6,000
6,125
311
6,000
6,000

FEB 1974-
Total
Hardness
mg/l as
CaC03
492
464
464
500
444
460
465
26
480
-


Ca
mg/l as
CaCO3
256
240
240
252
232
240
247
14
232
-


Mg
mg/l as
CaCO3
236
224
224
248
212
220
219
27
248
-


C03
mg/l as
CaC03
0
0
0
0
0
0
0
0
0
0


HC03
mg/l as
CaC03
464
448
_
452
424
436
424
85
444
-


N03-N
mg/l
5.7
5.4
5.1
5.6
5.1
5.6
5.1
0.6
4.4
5.1


NO2-N
mg/l
0.027
0.001
..
-
<0.001
-
_
-
0.01
-


NH3-N
mg/l
0.05
0.48
0.34
0.17
0.21
0.02
0.29
0.20
<0.01
-


Total
P
mg/l
0.012
0.016
0.072
0.030
0.024
0.017
0.024
0.017
0.010
0.026


COD BOD
mg/l mg/l
<5
<5
<5
<5
5 <5
<5
- -
— —
<5 12
- -


TOC
mg/l

4
_
-
12
—
10
5
-
-


Standard
Coliforms
Colonies/
100ml
0
>100
2
C*
2
0
-
—
4
-


*Confluent colonies.

-------
TABLE B-12. ANALYSIS OF SAMPLES TAKEN FROM WELL MB-2
Date
1971 Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1972 Jan
Feb
Mar
Apr
May
Jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1973 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Chlorides
mg/l
270
280
270
270
290
276
9
280
270
270
-
250
255
290
330
280
260
-
276
24
H
240
280
260
280
300
300
270
Conductivity
/jtmhos/cm2
at2SฐC
1,950
1,840
1,900
1,900
1,950
1,908
46
1,750
1,900
1,900
-
1,900
1,800
1^00
1,800
1,800
1,800
-
1,828
57
_
1,800
1,800
1,710
1,750
1,700
1,500
1,800
Total
Hardness
mg/l as
CaCO3
248
252
256
276
248
256
12
268
252
236
-
248
250
264
252
264
256
-
255
10
_
252
248
264
268
260
276
264
Ca
mg/l as
CaCO3
104
104
104
112
104
106
4
112
112
100
—
100
106
104
104
112
100
-
106
5
_
107
120
112
112
116
124
112
Mg C03
mg/l as mg/l as
CaC03 CaC03
144
148
152
164
144
150
8
156
140
136
—
148
144
160
148
152 •
156
-
149
8
_
145
128
152
156
144
152
152
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCO3
mg/l as
CaC03
564
552
600
600
584
580
22
564
592
576
—
584
576
456
580
456
580
-
552
55
-
616
572
540
548
560
572
540
NO3-N NO2-N NH3-N
mg/l mg/1 mg/l
_ _ —
_
_
— — —
_
_ _ -
- - -
_ _ -
_
_
— — —
_ _
_
<1 0.41
<1 0.49
<1 0.50
<1 0.40
5.2 <1 0.40
0.44
0.05
5.7 <1 0.46
_
3.9 - 0.54
2.6 <0.01 0.05
4.5 0.004 0.55
4.2 - 0.57
5.1 0.005 0.16
<0.001
Total
P
mg/l
..
-
-
—
-
-
-
_
-
-
—
-
-
0.042
0.042
0.041
0.047
0.043
0.043
0.002
0.045
-
0.055
0.046
0.050
0.060
0.032
-
Standard
COD BOD TOC Coliforms
Colonies/
mg/l mg/l mg/l 1 00 ml
_ _ _
_
_
— — —
_
_
— — —
_ _ _
_
„
— — —
_
20
„
16
— — 5
6.4
5.0
10
— — 7
_
15
_
- -- -
<5 18
<5
<5
<5 < 0.1
..
-
-
—
0
-
••
0
-
-
0
-
-
-
—
-
-
-
_
—
-
-
1
0
0
3
0
5

-------
                                           TABLE B-12 (CONTINUED).
05
01
Date
1973



Sep
Oct
Nov
Dec
Mean
Std
1974











1975








Dev
Jan
Feb
Mar
Apr
May
Jun
jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Chlorides
mg/1
280
290
280
290
279
18
290
290
290
-
290
290
280
290
29P
300
_
300
300
310
__
320
340
320
345
360
340
Conductivity
/Arch os/cm
at25ฐC
1,800
1,900
1,700
1,800
1,751
102
1,800
1,800
1,900
-
1,900
1,800
1,700
1,600
1,500
1,600
_
1,600
1,700
1,700
_.
1,800
1,800
1^00
1,800
1,800
1,900
Total
Hardness
mg/l as
CaC03
_
280
268
280
266
11
312
288
284
-
272
260
256
248
288
280
-
-
288
284
_
295
295
272
_
304
-
Ca
mg/l as
CaC03
_
124
148
128
120
12
128
112
120
-
112
—
112
96
108
92
-
-
112
120
_
121
132
101
-
129
-
Mg
mg/l as
CaC03
—
156
120
152
146
12
184
176
164
-
160
-
144
152
180
188
-
-
176
164
_
174
163
171
-
175
-
C03
mg/l as
CaCO3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/l as
CaC03
_
556
540
-
560
25
548
540
572
-
560
-
-
548
540
546
-
—
572
564
-
552
544
548
-
550
-
N03-N
mg/l
4.0
5.1
4.1
4.1
4.3
0.9
4.4
4.2
-
-
_
4.7
4.7
4.6
_
3.8
3.4
—
4.2
4.4
-
-
-
-
4.4
4.3
4.0
N02-N
mg/l
„
-
<0.001
<0.001
-
—
_
<0.001
0.001
-
<0.001
<0.001
<0.001
0.002
0.001
0.001
0.002
—
-
-
-
—
0.003
0.003
0.002
0.002
0.008
NHj-N
mg/l
0.06
0.26
0.09
0.05
0.28
0.23
<0.01
-
-
0.08
0.20
0.24
0.36
0.42
0.18
0.29
-
—
0.29
0.44
0.16
—
0.18
0.14
0.15
0.18
0.06
Total
P
mg/l
0.062
0.076
0.045
0.058
0.053
0.012
0.037
0.050
-
—
-
0.051
0.088
0.043
0.073
0.070
-
0.058
0.056
0.055
-
—
-
0.052
0.058
0.051
0.052
COD
mg/l
_
-
<5
<5
-
—
-
<5
<5
—
<5
6
<5
<5
<5
<5
10
~
-
-
—
—
-
—
—
~
-
Standard
BOD TOC Coliforms
Colonies/
mg/l mg/l 1 00 ml
<5
<5
<5 10
<5 4
- -
— _
<5
<15 3
<5
"~ **
<5 4.8
<5
<5 6
— —
-
-
— —
*~ •*•
<5
—
— —
ซ ซ
_
" —
— —
"™ ™"
-
0
0
0
0
--
—
0
0
0
"~
0
1
2
0
0
—
—
~*
0
6
—
0
-
0
—
0
-

-------
TABLE B-13. ANALYSIS OF SAMPLES TAKEN FROM WELL NB-3

Date
1975 Feb
S Mar
0> Apr
May
Jun
Ju!
Aug

Chlorides
mg/l
290
320
300
320
330
325
335

Conductivity
Jllmh os/cm2
at2SฐC
1,650
1,700
1,700
1,700
1,800
1,800
1,900
Total
Hardness
mg/l as
CaC03
280
279
287
_
-
—

Ca
mg/l as
CaCO3
108
117
116
_
-
—

Mg
mg/l as
CaCO3
172
162
171
_
-
—

C03
mg/l as
CaCO3
0
0
0
0
0
0
0

HCO3
mg/l as
CaC03
568
552
—
_
-
-?

NO3-N
mg/l
2.9
3.8
_
2.8
—

NO2-N
mg/l
0.004
0.004
0.002
0.002
0.002

NH3-N
mg/l
0.19
0.46
0.46
0.13
—
Total
P
mg/l
0.042
0.042
0.046
0.050
0.039

COD BOD
mg/l mg/l
9
<5
— —
_
-
—
Standard
TOC Conforms
Colonies/
mg/l 100ml
8
0
— —
_
-
.,

-------
TABLE B-14. ANALYSIS OF SAMPLES TAKEN FROM WELL NB-4



Date
OS 1975 Feb
-* Mar
Apr
May
)un
Jul

Chlorides

mg/l
290
310
310
330
330
—

Conductivity
^mhos/cm2
at25ฐC
1,600
1,700
1,700
1,700
1^00
—
Total
Hardness
mg/l as
CaC03
296
-
322
330
330
~

Ca
mg/l as
CaCO3
124
-
109
136
136
—

Mg
mg/l as
CaCO3
172
-
213
194
194
~

C03
mg/l as
CaC03
0
0
0
0
0
0

HC03
mg/l as
CaCO3
560
-
540
540
540
~~

NO3-N

mg/l

4.1
-
5.3
-
™~

NO2-N

mg/l
0.005
-
-
0.001
0.003
~~

NH3-N

mg/l
.
0.14
-
0.35
-
0.08
Total
P

mg/l
_
0.039
-
0.036
0.063
~"

COD BOD TOC

mg/l mg/l mg/l
9
<5
-
— — —
_
~ "
Standard
Coliforms
Colonies/
100ml
0
-
1
—
-
"

-------
TABLE B-15. ANALYSIS OF SAMPLES TAKEN FROM WELL NB-5

Hi
0
QO


Date
1975 Feb
Mar
Jul
Aug

Chlorides
mg/I
350
380
426
440

Conductivity
ftmb os/cm2
at25ฐC
MOO
2,220
2,200
Total
Hardness
mg/I as
CaC03
372
384

Ca
mg/I as
CaC03
172
145

Mg
mg/I as
CaC03
200
239

C03
mg/I as
CaC03
0
0
0
0

HCO3
mg/I as
CaC03
528
533

NO3-N
mg/I
7.3
7.8

NO2-N
mg/I
0.001
0.002
0.003

NH3-N
mg/I
0.17
0.08
Total
P
mg/I
0.650
0.067

COD BOD
mg/1 mg/I
7 —
_
Standard
TOC Conforms
Colonies/
mg/I 1 00 ml
0
0

-------
TABLE B-16. ANALYSIS OF SAMPLES TAKEN FROM WELL P-1
Date
1971 Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1972 Jan
Feb
Mar
jul
Aug
Sep
Oct
Nov
Dec
Mean
Std Dev
1973 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Chlorides
mg/l
1,240
1,130
1,050
1,160
1,140
1,144
68
1300
1,300
1,250
1,340
1,290
1,250
1,300
1,200
1,300
1,281
41
1,280
1,350
1,300
1,410
1,400
1,400
1,400
1,440
Conductivity
fJmh os/cm
at25ฐC
5,100
5,000
4,550
5,000
5,000
4,930
215
5,100
5,200
5,000
5,000
5,000
5,000
5,000
5,000
5,000
5,033
71
6,000
5,500
5,500
5,000
5,000
5,000
5,000
5,500
Total
Hardness
mg/l as
CaC03
372
332
260
368
320
330
45
420
396
-
424
380
384
440
380
400
403
23
452
478
432
436
436
440
468
488
Ca
mg/l as
CaC03
228
200
164
220
180
198
27
248
232
-
240
180
188
200
180
180
206
29
224
288
268
268
256
260
280
292
Mg C03
mg/l as mg/l as
CaCO3 CaCO3
144
132
96
148
140
132
21
212
164
-
184
200
196
240
200
220
202
23
228
290
164
168
180
180
188
196
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Total Standard
HCO3 NO3-N NO2-N NHj-N P COD BOD TOC Conforms
mg/1 as Colonies/
CaCO3 mg/l mg/l mg/l mg/l mg/l mg/l mg/l 100ml
648 - - _____
632 - _____
700 - _..___
668 - _____
652 - _____
660 - -
26- - _____
692 - _____
672 - ~ _____
678 - _____
680 - _____
668 - _____
660 - _____
664 - _____
654 - - __..__
_____
671 - - _____
12 - ___.._
672 - - _____
741
f*f| — — rrr .* — —••
652 - - 0.55 0.029 -
616 1.7 <0.010 0.04 0.028 -
640 0.8 0.004 0.84 0.060 - <5 39
632 3.1 - 0.42 0.046 - <5
652 1.8 0.002 0.18 0.012 - - 14
636 2.2 <0.001 0.42 0.026 <5 3
_
-
-
-
-
_
-
3
-
-
—
_
-
_
—
-
_
-
_
_
0
0
0
0
0
0

-------
                                         TABLE B-16 (CONTINUED).
Date
1973



Sep
Oct
Nov
Dec
Mean
Std
1974











1975








Dev
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Chlorides
mg/l
1,460
1,460
1,450
1,320
1,383
63
1,520
1,490
f,420
-
1,360
1,400
1,410
1,260
1,420
1,520
*.
1,390
1,350
1,320
_
1,310
1,320
1,340
1350
1,500
-
Conductivity
/Ltmh os/cm
at 25ฐ C
5,500
5,500
5,500
5,500
5,375
311
6,000
5,500
6,000
-
6,000
5,500
5,000
4,000
4,500
5,000
_
5,000
5,000
4,500
_
4,500
4,500
5,000
5,000
5,000
-
Total
Hardness
mg/l as
CaCO3

520
460
424
458
29
544
432
488
-
404
352
444
368
452
480
_
-
400
376
_
384
400
396
_
411
-
Ca
mg/l as
CaC03

196
264
248
259
28
304
220
288
-
232
180
264
220
256
224
—
-
212
232
_
214
225
225
-
186
-
Mg
mg/l as
CaC03
„
324
196
176
208
52
240
212
200
-
172
172
180
148
196
256
_
-"
188
144
_
170
175
171
-
225
-
C03
mg/l as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/l as
CaC03
_
644
604
716
655
41
652
576
644
-
652
580
632
628
632
584
-
-
_
632
-
628
636
632
-
525
-
NO3-N
mg/l
1.4
2.4
3.3
2.1
2,1
0.8
2.0
2.3
2.4
-
2.8
2.9
2.8
2.9
0.9
-
-
3.9
5.8
5.5
4.6
_
4.9
-
4.1
4.9
-
N02-N
mg/l
__
-
<0.001
<0.001
_
-
<0.001
<0.001
<0.001
-
<0.001
<0.001
0.002
0.002
0.001
-
0.051
-
0.002
0.004
-
-
0.002
0.003
0.001
0.001
0.002
NH3-N
mg/l
0.26
0.17
0.32
0.08
0.33
0.24
0.06
0.12
-
0.03
0.34
0.22
0.40
0.59
<0.01
-
--
-
0.19
0.29
0.14
-
0.16
0.15
0.11
0.11
0.08
Total
P
mg/l
0.047
0.032
0.022
0.080
0.040
0.020
0.006
0.034
0.023
—
0.019
0.027
0.056
0.250
0.052
-
-
0.032
0.035
0.032
0.022
-
0.021
0.036
0.035
0.024
-
COD
mg/l
_
-
6
5
6
1
8
<5
<5
™
<5
6
-
6
9
—
11
—
17
7
8
—
-
-
•-
—
-
Standard
BOD TOC Coliforms
Colonies/
mg/l mg/l 1 00 ml
_
<5
<5 27
<5 3
17
16
<5
<5 4.5
<5
—
<5
5
<5
~ ~"
-.
— —
-
— ~
<5
- -
-
— —
-
— —
-
— —
-
1
0
0
0
-
—
0
11
0
~"
75
C*
0
0
0
1
-
--
44
11
—
0
-
0
—
—
-
^Confluent colonies.

-------
TABLE B-17. ANALYSIS OF SAMPLES TAKEN FROM WELL PW-1
Chlorides Conductivity
pmhos/cm2
Date mg/1 at 25ฐ C
1972 Jul
1974 Jan
Feb
May
Jim
lul
Aug
Sep
Oct
Nov
Dec
1975 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
210
310
300
300
320
280
270
310
460
._
270
290
300
310
310
320
330
304
310
300
1,500
1,800
1,700
1,700
1,900
1,600
1,500
1,600
1,800
_
1,400
1,500
1,500
1,600
1,700
1,650
1,700
1,800
1,700
1,700
Total
Hardness
mg/I as
CaC03
388
520
516
468
384
372
368
-
268
_
-
396
416
-
415
_
415
-
411
-
Ca
mg/I as
CaCOj
180
240
232
192
168
172
164
-
120
_
-
148
184
-
179
_
186
-
183
-
Mg C03
mg/I as mg/I as
CaCOj CaCO3
208
280
284
276
216
200
204
-
148
„
-
248
232
-
236
_
229
-
228
-
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HCO3
mg/I as
CaC03
500
512
524
468
456
500
500
-
276
_
-
440
464
-
480
-
484
-
492
-
N03-N
mg/I
;
-
5.8
2.8
-
5.4
_
4.4
7.8
5.5
4.7
-
4.7
-
4.5
3.7
3.4
NO2-N NH3-N
mg/I mg/I
;
-
0.004
0.029
0.008
0.002
0.002
-
0.002
0.002
-
-
_
0.003
0.002
0.005
0.002
;
-
0.16
0.11
0.20
0.33
_
-
0.15
0.29
0.18
—
0.35
-
0.13
0.11
0.08
Total
P
mg/I
;
-
0.075
0.030
.0.075
0.065
_
0.069
0.083
0.066
0.048
—
0.044
0.052
0.048
0.045
0.020
Standard
COD BOD TOC Coliforms
Colonies/
mg/I mg/I mg/I 100ml
; ; ;
- - -
5 <5 12
<5
<5
<5
<5
- — -
6 <5 -
5 — —
<5
— — —
_
_
- - -
— — —
_
;
-
_
1
-
-
_
-
0
0
-
1
-
1
-
87
-

-------
                           TABLE B-18. ANALYSIS OF SAMPLES TAKEN FROM WELL PW-2
-a
to
Date
1972 jul
1973 May
jun
Jul
A tig
Sep
Oct
Nov
Mean
Std Dev
1974 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
1975 Jan
Feb
Mar
Apr
Chlorides
mg/l
230
240
340
240
230
220
230
250
45
230
240
240
-
250
240
240
240
260
310
-
240
270
260
260
250
Conductivity
/Jmhos/cm2
at25ฐC
1,700
1,700
1,500
1,700
1,700
1,700
1,600
1,650
84
1,600
1,600
1,700
-
1,700
1,700
1,600
1^00
1,500
1,700
-
1,500
1,600
1,550
1,600
1,600
Total
Hardness
mg/l as
CaC03
216
224
224
216
236
244
229
11
268
220
260
-
224
204
224
256
_
272
-
-
248
240
-
245
Ca
mg/l as
CaCO3
40
92
104
104
104
116
104
8
112
72
104
-
100
84
100
96
_
108
-
-
84
100
-
93
Mg COj
mg/l as mg/l as
CaC03 CaC03
176
132
120
112
132
128
125
9
156
148
156
-
124
120
124
160
_
164
-
-
164
140
„
152
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/l as
CaC03
620
576
530
564
568
564
560
18
568
500
564
-
560
540
552
552
.
560
-
-
584
584
-
568
NOj-N
mg/l
-
-
2.7
-
-
-
..
2.7
2.6
0.3
_
2.8
-
1.5
2.6
2.8
2.7
-
NOVN
mg/l
< 0.001
< 0.001
-
< 0.001
0.002
0.002
-
0.002
0.006
0.007
0.004
0.001
0.002
0.001
-
0.004
0.003
-
0.001
NH3-N
mg/l
0.30
0.34
0.32
0.03
0.07
0.04
-
<0.01
0.26
0.17
0.37
0.53
0.28
0.18
-
-
0.12
0.26
0.16
-
Total
P
mg/l
-
-
_
0.043
-
-
_
0.035
0.078
-
0.063
0.062
-
0.037
0.037
0.032
0.033
-
COD
mg/l
8
-
7
<5
<5
-
<5
<5
<5
<5
<5
<5
<5
-

-------
                                                TABLE B-18 (CONTINUED).


Date
1975




May
jun
Jut
Aug
Sep

Chlorides
mg/1
250
240
254
250
260

Conductivity
Jim h os/cm2
at25ฐC
1,600
1,700
1,650
1,600
1,700
Total
Hardness
mg/l as
CaCO3
248
268
-
243
-

Ca
mg/l as
CaC03
97
101
-
103
-

Mg
mg/l as
CaC03
151
167
-
140
-

C03
mg/l as
CaCO3
0
0
0
0
0

HCO3
mg/l as
CaC03
528
580
-
572
-

NO3-N
mg/l
2.6
-
2.3
2.3
2.4

N02-N
mg/l
0.005
0.003
0.001
0.002
0.002

NH3-N
mg/1
0.19
0.13
0.13
0.12
0.19
Total
P COD BOD
mg/l mg/l mg/l
0.030
0.039
0.042
0.035
0.028
Standard
TOC Coliforms
Colonies/
mg/1 1 00 ml
_
0
-
1
-
        'Confluent colonies.
CO

-------
TABLE B-19. ANALYSIS OF SAMPLES TAKEN FROM WELL PW-4
Date
1972 Jul
Aug
Mean
Std Dev
1973 Jul
Aug
Sep
Mean
Std Oev
^j
r^
-q
•*- 1974 Jan
Feb
Chlorides Conductivity
(tmh os/cm
mg/l at 25ฐ C
230
290
260
42
290
280
285
7

290
290
NOT IN OPERATION MAR
jun
Jul
Aug
Sep
Oct
Nov
Dec
1975 Jan
Feb
Mar
Apr
May
Jun
300
280
300
310
320
—
240
320
310
330
300
330
310
1,850
1300
1,900
1,850
71

1,800
1,800
1974-MAY
1,900
1,700
1,600
1,500
1,650
-
1,500
1,700
1,700
1,700
1,900
1,700
1,800
Total
Hardness
mg/l as
CaCO3
216
368
292
107
376

396
388
1974
348
356
372
-
448
-
-
396
396
-
385
392
385
Ca
mg/l as
CaCO3
40
140
90
71
164

180
176

160
168
156
-
180
-
-
156
168
-
171
172
171
Mg
mg/l as
CaCO3
176
228
202
37
212

216
212

188
188 '
216
-
268
-
-
240
228
-
214
220
214
C03
mg/l as
CaCO3
0
0
0
0
0
0
0
0
0

0
0

0
0
0
0
0
0
0
0
0
0
0
0
0
HCO3
mg/l as
CaC03
620
564
592
40
548

548
556

552
540
536
-
536
-
-
536
544
-
528
528
532
NO3-N
mg/l
-

-
2.5

__
2.7
2.4
-
2.8
-
2.0
3.7
3.7
3.6
-
_
-
NO2-N
mg/l
<0:001

0.001
<0.001

—
0.001
0.002
0.001
0.002
0.001
-
0.002
0.003
-
—
0.002
0.003
NH3-N
mg/l
0.45

0.09
0.08

0.19
0.28
0.26
0.14
0.11
-
-
0.33
0.40
0.09
-
0.22
0.07
Tout
P
mg/l
-

-
0.065

_
0.078
0.059
0.093
0.090
-
0.058
0.063
0.070
0.045
-
_
0.063
COD BOD TOC
mg/l mg/l mg/l
_

6 <5
<5 <5 4

_ ,, 	
<5 <5 6.8
<5 - -
<5
<5
<5
_
<5 <5
<5
<5
--
_ _
_
Standard
Coliforms
Colonies/
100ml
1
0
0

0
3

0
3
0
-
2
-
-
0
1
~
5
_
15

-------
                                                             TABLE B-19 (CONTINUED).
            Date
                        Total                                                           Total
Chlorides   Conductivity  Hardness     Ca     Mg      CO3   HCO3   NO3-N  NOj-N   NH3-N     P    COD  BOD
          /Anhos/cm     mg/l as   mg/l as   mg/l as   mg/l as   mg/l as
  mg/l      at 25ฐ C     CaCO3   CaCO3   CaCO3   CaCO3   CaCO3    mg/l    mg/l     mg/l    mg/l   mg/l  mg/l
                                                                        Standard
                                                                  TOC   Conforms
                                                                        Colonies/
                                                                  mg/l    100ml
1975 Jul
     Aug
     Sep
304
300
310
1,700
1,700
1,700
                                            380
                                 171
209
0
0
0
                                                         534
0.002
0.001
0.002
0.16
0.06
0.08
0.050
0.058
0.040
en

-------
                         TABLE B-20. ANALYSIS OF SAMPLES TAKEN FROM WELL PW-6*



Date
1974 Aug
Sep
Oct
Nov
Dec
1975 Jan
Jul
Aug
Sep

Chlorides

mg/l
350
370
330
-
60
_,
345
330
340

Conductivity
A/mhos/cm
at25ฐC
1,500
1,600
1,500
-
650
..
1,600
1,600
1,600
Total
Hardness
mg/l as
CaCO3
468
-
412
-
-
_
-
441
*-

Ca
mg/l as
CaC03
172
-
180
-
-
_
-
190
—

Mg
mg/l as
CaC03
296
-
232
-
-
_
-
' 251
—

C03
mg/l as
CaCO3
0
0
0
0
0
0
0
0
0

HCO3
mg/l as
CaCO3
424
-
436
-
-
_
-
336
—

NO3-N

mg/l
0.3
-
0.7
-
0.4
_
-
0.4
3.7

NO2-N

mg/l
0.068
0.034
0.002
0.029
-
..
0.072
0.019
0.032

NH3-N

mg/l
1.11
0.24
1.06
-
-
0.38
0.26
-
0.26
Total
P

mg/l
0.220
0.036
0.068
-
0.026
_
-
0.092
0.035

COD BOD

mg/l mg/l
5
<5
<5
<5
--
—
_
-
— _
Standard
TOC Coliforms
Colonies/
mg/l tOO ml

_
_ _
-
-
ซ•
..
_
— ~
^Samples obtained from a nonpumped well with a torpedo sampler.

-------
                         TABLE B-21. ANALYSIS OF SAMPLES TAKEN FROM WELL PW-8*




Date
1974




197S



Aug
Sep
Oct
Nov
Dec
Jan
Jul
Aug
Sep

Chlorides
mg/l
250
280
290
-
340
_
335
330
330

Conductivity
JJmh os/cm2
at2SฐC
1,400
1,500
1,500
-
1,600
_
1,800
1,800
1,600
Total
Hardness
mg/l as
CaC03
340
-
346
-
-
_
-
342
™

Ca
mg/l as
CaC03
152
-
116
-
-
_
-
95
—

Mg
mg/l as
CaC03
188
-
230
-
-
_
-
247
—

C03
mg/l as
CaCO3
0
0
0
0
0
0
0
0
0

HC03
mg/l as
CaC03
540
-
526
-
-
_
-
496
—

NO3-N
mg/l
<0.1
-
0.5
-
0.4
_
-
0.6
0.5

NO2-N
mg/l
0.088
0.022
0.026
0.366
-
_
0.022
0.018
0.016

NH3-N
mg/l
0.24
0.07
0.73
-
-
0.71
0.10
-
0.11
Total
P
mg/l
0.028
0.075
0.070
-
0.035
_
-
0.029
0.023

COD BOD
mg/l mg/l
<5
6
<5
8
-
_. _
_ _
-
— —
Standard
TOC Coliforms
Colonies/
mg/l 100ml

_ _
- -
-
-
_•
.. _
_
- -
* Samples obtained from a nonpumped well with a torpedo sampler.

-------
                                TABLE C-l.  ANALYSIS OF SAMPLES TAKEN FROM WELL BMW-1
-q
00
Date
1971 Jul
Aug
Sep
Oct

Nov
Dec

1972 Jan
Feb
Mar
Jun

Jul
Aug
Sep
Oct
Chlorides
mg/l

1,600
1,600
1,610

1,660
1,670

168
1,720
1,650
1,780

1,810
1,810
1,570
1,720
Conductivity
umhos/cm2
at 25ฐ C
5,600
5,600
5,600
5,900

6,000
6,000

6,000
5,900
5,600
6,000

6,000
6,000
6,000
6,000
Total
hardness
mg/l as
CaC03
„
888
892
856

—
876

912
940
—
968

836
880
868
908
Ca
mg/l as
CaC03
mf —
396
396
336

392
400

400
408
—
416

368
208
336
388
Mg
mg/l as
CaC03
ซ
492
496
520

--
476

512
532
--
552

468
672
532
520
CO 3
mg/l as
CaC03
0
0
0
0

0
0

0
0
0
0

0
0
0
0
HC03
mg/l as
CaC03
._
484
472
520

532
492

524
484
—
492

500
496
472
492
Standard
col i forms
Colonies/
100 ml
__
—
--

T3
m
0
X
0 ,
-o
?0
__ — H
o
—
—
—
—
              Nov
1,400
6,000
680
260
0
460
         PUMP INOPERATIVE

-------
TABLE C-2.  ANALYSIS OF SAMPLES TAKEN FROM WELL  BMW-2
Date
1972 Jan
Feb
Mar
Jim
Jul
Aug
Sep
Oct
Nov
Dec
1973 Jan
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Chlorides
mg/l
1,750
1,480
1,980
1,850
1,840
1,810
1,740
1,970
1,850
1,800
1,370
1,660
2,000
2,000
1,860
1,800
2,400
1,440
2,050
2,020
2,060
Conductivity
vimhos/cm2
at 25ฐ C
5,900
5,100
6,200
6,100
6,000
6,000
6,000
6,000
6,000
6,000
6,000
6,000
6,000
6,000
5,500
6,000
6,000
5,000
6,000
6,000
6,500
Total
hardness
mg/l as
CaC03
948
752
—
1,004
988
880
960
1,152
1,000
1,020
908
928
1,128
1,070
1,060
1,000
1,200
750
1,190
1,130
1,136
Ca
mg/l as
CaC03
448
368
—
492
408
208
448
520
440
312
376
444
508
480
490
460
572
380
590
530
544
Mg
mg/l as
CaC03
500
384
—
512
580
672
512
632
560
708
532
484
620
590
570
540
628
370
600
600
592
CO 3
mg/l as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/l as
CaC03
492
492
--
480
476
496
476
468
460
480
476
456
452
450
460
480
436
470
430
450
430
Standard
col i forms
Colonies/
100 ml
0
—
0
—
__
—
—
—
__
—
__
—
—
--
—
--
--
—
_
__
—

-------
                                                TABLE C-2  (CONTINUED).
00
o
Date
1974 Jan
Feb
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
1975 Jan
Feb
Mar
May
Jun
Jul
Chlorides
mg/1
2,260
1,920
1,890
2,070
1,960
1,380
1,990
1,840
2,082
1,480
1,460
1,940
1,940
1,770
1,990
1,785
Conductivity
ymhos/cm2
at 25ฐ C
7,000
6,000
6,000
7,000
6,000
4,500
5,000
5,000
5,500
5,000
4,500
5,500
5,500
5,000
5,500
5,000
Total
hardness
mg/1 as
CaC03
1,400
1,048
964
1,080
1,044
650
1,032
944
1,040
740
760
• 984
920
846
982
854
Ca
mg/1 as
CaC03
600
530
456
520
452
310
484
436
468
368
212
408
420
392
458
400
Mg
mg/T as
CaC03
800
518
408
560
592
340
548
508
572
372
548
576
500
454
524
454
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
430
460
440
440
424
460
436
436
436
448
440
404
440
432
428
416
Standard
col i forms
Colonies/
100 ml
._
—
—
—
__
—
—
—
__
—
__
—
—
—
__
—

-------
                                   TABLE C-3.   ANALYSIS OF SAMPLES TAKEN FROM FP-1
CD
Date
1971 Jul
Aim
••— j
Sep
** r
Oct
Nov
Dec
1972 Jan
Feb
Mar
Jun
SAMPLING
Oct
PUMP NOT
Dec
1973 Jan
Feb
Mar
Apr
Chlorides
mg/1

795
870
910
930
960
1,020
1,100
1,140
1,240
TAP REMOVED
1,440
RUNNING
1,350
1,350
1,380
1,380
1,540
Conductivity
umhos/cm2
at 25ฐ C
3,450
3,500
3,600
3,800
3,500
3,800
3,800
4,000
4,000
4,500

6,000

4,500
4,000
5,000
5,000
5,500
Total
hardness
mg/1 as
CaC03
„.
469
496
512
536
560
640
616
—
728

888

860
908
904
908
1,056
Ca
mg/1 as
CaC03
ซ •
240
276
284
288
316
336
336
—
400

--

464
472
482
508
536
Mg
mg/1 as
CaC03
• •—
229
220
228
248
244
304
280
—
328

—

396
432
422
400
520
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0

0

0

0
0
0
0
0
HC03
mg/1 as
CaC03
__
468
464
510
504
512
492
488
— -
468

—

464
452
498
444
416
Standard
coli forms
Colonies/
100 ml
—
—
—
3
—
0
2


""

—

—
—
-•—
— —
_*_

-------
                                                TABLE C-3 (CONTINUED).
00
to
Chlorides
Date mg/1
1973






1974


PUMP

PUMP
May
Jun
Jul
Aug
Sep
Oct
Nov
Jan
Feb
Mar
1
1
1

1
1
1

1

,600
,600
,620
—
,670
,700
,660
__
,220
—
Conductivity
umhos/cm2
at 25ฐ C
5
5
5

5
5
5

4

,000
,000
,000
—
,500
,500
,500
__
,500
—
Total
hardness
mg/1 as
CaC03
1,050
1,080
1,080
—
1,120
1,130
1,130
— —
520
--
Ca
mg/1 as
CaC03
540
590
560
—
600
600
580
_ _
230
—
Mg
mg/1 as
CaC03
510
490
520
—
520
530
550
__
290
—
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
430
500
450
--
--
470
430
__
330
--
Standard
coliforms
Colonies/
100 ml
.. _
—
0
48
1
5
C*
0
0
17
NOT RUNNING
May
REMOVED
1

,230

4

,000

396

140

256

0

260

—

       *Confluent colonies.

-------
                               TABLE C-4.   ANALYSIS OF SAMPLES TAKEN FROM WELL FP-3
oo
CO
Date
1971 Jul
Aug
Sep
Total
Chlorides Conductivity hardness
ymhos/cm2 mg/1 as
mg/1 at 25ฐ C CaC03
_.
1,950
1,350
PUMPING DISCONTINUED OCT
Dec
1972 Jan
Feb
Mar
Jun
Aug
Sep
2,180
2,120
2,160
2,240
2,295
2,590
2,480
6,000
6,200
5,000
1971 -DEC 1971
6,700
6,200
6,800
6,800
7,000
8,000
8,000
„
1,240
920

1,440
1,410
1,460
—
1,630
1,844
1,980
Ca
mg/1 as
CaC03
„.
580
440

780
720
730
—
820
856
942
Mg
mg/1 as
CaC03
..
660
480

660
690
730
—
810
988
1,038
C03
mg/1 as
CaC03
0
0
0

0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
„
415
472

424
448
436
—
440
436
420
Standard
col i forms
Colonies/
100 ml

—
--

38
9
—
0
--
__
—
          PUMPING DISCONTINUED  OCT 1972 DUE TO HIGH CHLORIDES-PUMP  REMOVED

-------
                               TABLE C-5.  ANALYSIS OF SAMPLES TAKEN FROM WELL FP-4
00
Date
1971 Jul
Aug
Sep
Oct
Nov
Dec
1972 Jan
Feb
Mar
Jun
Jul
Aug
Sep
Oct
Dec
1973 Jan
Feb
Mar
Apr
Chlorides
mg/1
„
985
650
— •
1,260
1,250
970
940
860
980
1,220
1,220
1,170
1,300
780
1,270
1,640
1,860
2,280
Conductivity
ymhos/cm2
at 25ฐ C
3; 800
4,000
3,050
—
4,500
4,600
3,700
3,700
3,500
3,800
5,000
5,000
4,000
5,000
3,500
3,500
5,500
6,000
6,100
Total
hardness
mg/1 as
CaC03
_.
672
480
—
880
920
684
660
—
700
876
' 856
864
1,024
532
972
1,258
1,532
1,868
Ca
mg/1 as
CaC03
„
316
240
--
480
448
332
312
--
340
372
360
377
480
232
464
610
748
864
Mg
mg/1 as
CaC03
M •ป
356
240
--
400
472
352
348
—
360
504
496
487
544
300
508
648
784
1,004
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
mm mm
490
528
—
512
520
520
520
—
516
500
512
500
492
—
__
524
452
444
Standard
col i forms
Colonies/
100 ml
mM —
—
—
0
*ป.
0
2
—
1
--
--
—
—
--
—
__
—
—
—
        PUMP BEING REPAIRED, APR 1973-MAY 1974

-------
                                               TABLE C-5  (CONTINUED).
CO
01






Date
1974




1975


Jun
Jul
Aug
Sep
Oct
Jan
Feb
Mar

Chlorides

mg/1
3,740
3,720
3,420
3,225
--
2,270
2,340
2,560

Conductivity
pmhos/cm2
at 25ฐ C
10,000
10,000
10,000
8,000
—
6,000
6,000
6,000
Total
hardness
mg/1 as
CaC03
3,130
3,080
3,090
2,700
—
1,932
1,916
1,936

Ca
mg/1 as
CaC03
1,528
1,480
1,515
1,352
—
712
912
936

Mg
mg/1 as
CaC03
1,602
1 ,600
1,575
1,648
—
1,220
1,004
1,000

CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0

HC03
mg/1 as
CaC03
410
400
390
390
--
436
456
440
Standard
col i forms
Colonies/
100 ml
__
1
0
~ ~
0
__
0
--
         PUMPING DISCONTINUED APR 1975 DUE TO HIGH CHLORIDES

-------
                                TABLE C-6.  ANALYSIS OF SAMPLES TAKEN FROM WELL FP-7
00
01
Date
1971 Jim
Jul
Aug
Sep
Oct
Nov
Dec
1972 Jan
Feb
Mar
Jun
Jul
Aug
Sep
Oct
Dec
1973 Jan
Feb
Mar
Apr
Chlorides
mg/1
*• ซ•
—
470
460
480
480
470
480
470
380
470
500
530
510
520
460
350
480
450
500
Conductivity
ymhos/cm2
at 25ฐ C
2,700
2,700
2,650
2,600
2,700
2,600
2,600
2,550
2,600
2,400
2,600
2,500
2,600
2,600
2,600
2,600
2,000
2,600
2,600
2,600
Total
hardness
mg/1 as
CaC03
__
__
362
348
348
364
360
352
344
—
360
396
372
388
388
368
408
388
936
404
Ca
mg/1 as
CaC03
__
--
164
164
196
164
168
172
188
—
172
168
168
156
164
164
184
176
192
204
Mg
mg/1 as
CaC03
__
—
198
184
152
200
192
180
156
—
188
228
204
232
224
204
224
212
744
200
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
— —
—
563
568
620
620
612
620
636
—
612
620
614
616
612
624
632
700
596
624
Standard
col i forms
Colonies/
100 ml
— _
—
--
-—
1
--
0
1
—
21
--
—
--
—
—
—
--
--
--
--

-------
                                                TABLE  C-6 (CONTINUED).
00
-3
Date
1973 May
Jun
Jul
Aug
Sep
Oct
Nov
1974 Jan
Feb
May
Jun
Jul
Aug
Sep
Oct
1975 Jan
Feb
Mar
Jun
Chlorides
mg/1
500
500
540
480
490
490
480
510
540
550
580
560
590
710
—
620
600
610
608
Conductivity
ytnhos/cm2
at 25ฐ C
2,600
2,400
2,400
2,600
2,800
2,600
2,440
2,440
2,800
2,800
2,600
2,700
2,600
2,400
—
2,600
2,600
2,500
2,600
Total
hardness
mg/1 as
CaC03
420
400
430
430
380
420
392
416
416
448
418
416
—
500
—
488
476
440
481
Ca
mg/1 as
CaC03
230
200
190
190
200
200
200
192
196
212
194
200
--
200
--
240
216
192
229
Mg
mg/1 as
CaC03
190
200
240
240
180
220
192
224
220
236
224
216
--
300
—
248
260
248
252
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
600
590
600
580
580
590
580
580
580
572
578
572
--
578
—
572
596
604
580
Standard
col i forms
Colonies/
100 ml
_ _
—
0
0
4
0
2
0
0
1
2
54
2
--
6
__
5
—
—
              Jul
0

-------
                                TABLE C-7.  ANALYSIS  OF  SAMPLES TAKEN  FROM WELL FP-9
00
00
Date
1971 Jul
Aug
Sep
Oct
Nov
Dec
1972 Jan
Feb
Mar
Jun
Jul
Aug
Sep
Oct
Dec
1973 Jan
Feb
Mar
Apr
May
Jun
Chlorides
mg/1
• •ป
305
270
360
290
340
330
330
305
310
300
330
350
320
370
340
330
330
380
360
360
Conductivity
ymhos/cm2
at 25ฐ C
2,200
2,150
1,800
2,350
1,950
2,050
1,920
2,100
1,900
2,000
1,900
2,000
2,000
2,000
2,200
2,000
2,200
2,200
2,100
2,200
2,000
Total
hardness
mg/1 as
CaC03
• ซ•
420
340
484
400
384
400
400
--
368
372
388
.400
420
452
492
440
432
460
460
460
Ca
mg/1 as
CaC03
— —
170
160
232
188
168
180
204
—
168
176
168
120
160
196
188
206
200
208
220
260
Mg
mg/1 as
CaC03
ซi ••
250
180
252
212
216
220
196
-_
200
196
220
280
260
256
304
234
232
252
240
200
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
..
586
520
710
628
612
620
604
—
616
612
628
636
640
692
__
810
652
672
630
650
Standard
coli forms
Colonies/
100 ml

--
—
—
__
—
_.
—
--
—
• •
—
—
—
0
0
—
2
—
__
—

-------
                                      TABLE C-7 (CONTINUED).
Chlorides
Date mg/1
1973



Jul
Aug
Sep
Oct
PIPELINE BEING
1974







Jan
Feb
Mar
May
Jun
Jul
Aug
Sep
340
370
370
—
Conductivity
ymhos/cm2
at 25ฐ C
2,000
2,200
2,200
--
Total
hardness
mg/1 as
CaC03
420
480
470
—
Ca
mg/1 as
CaC03
230
220
240
—
Mg
mg/1 as
CaC03
190
260
230
—
CO 3
mg/1 as
CaC03
0
0
0
0
HC03
mg/1 as
CaC03
610
640
650
--
Standard
coli forms
Colonies/
100 ml
77
0
0
6
REPAIRED-PUMP OFF
300
300
—
310
310
300
330
340
1,800
1,900
--
2,000
1,900
2,000
1,900
1,900
408
392
—
372
358
324
408
388
168
172
—
180
162
160
180
180
240
220
—
192
196
164
228
208
0
0
0
0
0
0
0
0
576
568
--
—
560
556
584
596
0
0
0
0
0
0
7
—
      Oct

 PUMPING DISCONTINUED OCT 1974-JAN  1975
                                                                                       0
1975
Jan
Feb
Mar
300
310
330
1,700
1,900
1,800
368
380
376
180
172
172
188
208
204
0
0
0
496
544
568
0
0

-------
                                TABLE  C-8.  ANALYSIS OF SAMPLES TAKEN FROM WELL F-l
to
o
Date
1971 Jul
Aug
Sep
Oct
Nov
Dec
1972 Jan
Feb
Jul
Aug
Sep
Oct
Nov
Dec
1973 Jan
Feb
Mar
Chlorides
mg/1
._
99
110
110
110
130
130
130
100
110
100
100
120
100
100
no
100
Conductivity
ymhos/cm2
at 25ฐ C
730
900
900
950
920
1,000
920
1,000
800
800
800
900
800
750
650
850
850
Total
hardness
mg/1 as
CaC03
..
371
388
384
400
400
420
434
372
368
364
340
368
400
376
364
368
Ca
mg/1 as
CaC03
„
168
208
212
218
220
216
224
184
184
192
184
152
188
184
190
192
Mg
mg/1 as
CaC03
„.
203
180
172
182
180
204
210
188
184
172
156
216
212
192
174
174
C03
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
„.
328
338
--
364
364
368
384
348
352
348
—
--
—
H_
358
316
Standard
coliforms
Colonies/
100 ml
„
—
—
--
_ _
—
__
—
—
—
—
—
—
—
__
--
—
        SAMPLING TAP REMOVED APR 1973

-------
                               TABLE  C-9.   ANALYSIS OF SAMPLES  TAKEN FROM WELL F-2
CO
Date
1972 Feb
Jul
Aug
Sep
Oct
Nov
Dec
1973 Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
1974 Jan
Feb
Chlorides
mg/1
105
no
130
100
110
120
no
140
90
no
180
120
100
100
no
no
no
100
no
no
100
Conductivity
ymhos/cm2
at 25ฐ C
850
850
850
900
800
900
900
850
950
900
900
900
850
875
950
1,000
950
1,000
1,000
900
950
Total
hardness
mg/1 as
CaC03
312
308
320
332
368
340
344
380
312
320
332
340
344
352
344
356
356
376
288
320
336
Ca
mg/1 as
CaC03
164
160
168
172
180
132
208
204
190
118
196
208
200
196
208
212
220
228
228
204
204
Mg
mg/1 as
CaC03
148
148
152
160
188
208
136
176
122
202
136
132
144
156
136
144
136
148
60
116
132
CO 3
mg/1 as
CaC03
0
0
0
0
20
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0 •
HC03
mg/1 as
CaC03
368
364
372
384
348
400
382
388
414
352
364
356
368
460
364
368
368
380
384
384
364
Standard
col i forms
Colonies/
100 ml
_.
—
--
—
—
—
—
__
—
—
—
—
—
—
—
—
—
—
—
__
—

-------
                                               TABLE  C-9  (CONTINUED).
to
10
Date
1974






1975





May
Jun
Jul
Aug
Sep
Oct
Nov
Jan
Feb
Mar
May
Jun
Jul
Chlorides
mg/1
90
90
100
no
105
116
140
230
170
160
150
160
152
Conductivity
ymhos/cm2
at 25ฐ C
900
900
950
950
1,000
900
1,000
1,050
1,050
1,000
1,050
1,000
950
Total
hardness
mg/1 as
CaC03
352,
318
320
424
356
372
452
456
412
376
376
396
396
Ca
mg/1 as
CaC03
244
152
204
196
200
220
224
256
200
220
229
232
229
Mg
mg/1 as
CaC03
208
166
116
228
156
152
228
200
212
156
147
164
167
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
368
380
368
372
372
388
420
376
388
372
360
372
374
Standard
coli forms
Colonies/
100 ml
_ _
--
__
—
—
--
—
__
—
—
—
__
—

-------
                              TABLE C-10.  ANALYSIS  OF  SAMPLES TAKEN  FROM WELL  GG-6
CO
CO
Date
1971 Jul
Aug
Sep
Oct
Nov
Dec
1972 Jan
Feb
Jun
Jul
Aug
Sep
Oct
Nov
Dec
1973 Jan
Apr
May
Chlorides
mg/1
„
290
260
310
320
330
330
310
330
300
300
310
330
310
300
330
400
400
Conductivity
^mhos/cm2
at 25ฐ C
2,200
2,200
1,750
2,200
2,200
2,200
2,100
1,800
2,100
2,000
2,000
2,000
2,000
2,000
2,000
2,000
2,200
2,200
Total
hardness
mg/1 as
CaC03
„
402
324
396
404
400
400
388
432
404
408
404
392
392
380
332
468
480
Ca
mg/1 as
CaC03
._
198
164
192
208
192
192
176
196
172
173
160
164
156
80
160
200
220
Mg
mg/1 as
CaC03
„
204
160
204
196
208
208
212
236
232
235
244
228
236
300
172
268
260
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
..
596
480
685
652
692
688
660
644
648
644
648
620
612
640
632
660
670
Standard
coli forms
Colonies/
100 ml

—
--
—
__
—
__
—
--
—
__
—
--
—
--
__
—
—
        WELL DRY, JUN 1973-DEC 1974

-------
                                              TABLE C-10 (CONTINUED).






Date
1975


Jan
Feb
Mar

Chlorides

mg/1
700
650
570

Conductivity
ymhos/cm2
at 25ฐ C
3,000
3,000
2,000
Total
hardness
mg/1 as
CaC03
992
920
692

Ca
rng/1 as
CaC03
360
384
248

Mg
mg/1 as
CaC03
632
536
444

CO 3
mg/1 as
CaC03
0
0
0

HC03
mg/1 as
CaC03
464
476
512
Standard
col i forms
Colonies/
100 ml
ซ V
—
—
        ENTRANCE TO WELL SEALED UP, SAMPLING IMPOSSIBLE
to
*>.

-------
TABLE C-ll.  ANALYSIS OF SAMPLES TAKEN FROM WELL MB-4
Date
1971 June
Aug
Sep
Nov
Dec
1972 Jan
Feb
Mar
Jun
Jul
Aug
Sep
Oct
1973 Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Chlorides
mg/1
__
640
1,040
670
670
1,050
1,060
920
680
920
680
770
730
710
750
1,140
1,440
1,200
1,240
1,540
1,270
Conductivity
umhos/cm2
at 25ฐ C
3,400
3,050
4,500
3,200
3,200
4,200
4,200
3,900
3,300
4,000
3,000
3,500
3,000
3,500
3,500
4,900
5,000
4,250
5,000
5,500
5,000
Total
hardness
mg/T as
CaC03
._
356
514
372
368
560
516
—
364
472
360
396
396
420
432
600
700
610
640
776
650
Ca
mg/1 as
CaC03
„
168
228
180
168
228
220
--
172
196
160
156
160
198
200
276
290
300
280
336
340
Mg
mg/1 as
CaC03
„
188
186
182
200
332
296
—
192
276
200
240
236
222
232
324
410
310
360
440
310
CO 3
mg/1 as
CaC03
0
0
0
0
0
12
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
„
524
524
548
528
548
540
—
552
552
544
540
544
610
524
528
510
530
530
508
510
Standard
col i forms
Colonies/
100 ml
„
—
—
--
—
__
—
—
--
—
--
--
—
—
—
—
— —
_-
0
1
>100

-------
                                              TABLE C-ll (CONTINUED).
to
o>
Date
1973


1974









1975







Oct
Nov
Dec
Jan
Feb
Mar
May
Jun
Jul
Aug*
Sep
Oct
Nov
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Chlorides
mg/1
1,330
1,500
1,350
990
1,200
—
1,450
1,120
1,220
600
670
1,410
1,020
1,340
1,240
1,400
—
1,310
1,280
1,005
•. •_
Conductivity
vimhos/cm2
at 25ฐ C
5,000
5,500
5,500
4,000
.5,000
—
6,000
4,000
4,500
2,800
2,600
4,500
4,000
4,500
4,500
4,500
—
4,500
4,500
3,750
™*~
Total
hardness
mg/1 as
CaC03
690
748
680
524
650
—
700
578
610
404
452
708
532
664
584
600
--
621
621
513
— ซ•
Ca
mg/1 as
CaC03
280
324
288
240
280
--
304
224
250
172
168
296
228
260
256
284
—
256
261
217
~~
Mg
mg/1 as
CaC03
410
424
392
284
370
—
396
354
360
232
284
412
304
404
328
352
—
365
360
296
*~ ~
C03
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
510
500
516
524
520
—
500
522
520
528
516
514
448
500
516
520
--
432
512
517
~ ~
Standard
col i forms
Colonies/
100 ml
0
4
0
1
9
0
1
0
0
0
0
0
--
--
—
8
0
—
0
—
0
       *Water contaminated with some type of petroleum product that smells like kerosene, Aug 1974-Jul 1975,

-------
TABLE C-12.  ANALYSIS OF SAMPLES TAKEN FROM WELL MB-5
Date
1971 Nov
Dec
1972 Jan
Feb
Mar
PUMP BROKEN
1974 May
Jun
Jul
Aug
Sep
Oct
Nov
1975 Mar
May
Jun
Jul
Chlorides Conductivity
ymhos/cm2
mg/1 at 25ฐ C
710
710
710
710
740
APR 1972-APR
690
690
700
680
610
748
730
760
760
--
742
3,200
3,400
3,400
3,200
3,400
1974
3,500
3,000
3,000
2,800
2,800
2,800
3,000
2,800
2,800
—
3,000
Total
hardness
mg/1 as
CaC03
340
328
340
348
—

364
320
328
346
292
372
376
340
361
—
384
Ca
mg/1 as
CaC03
168
156
168
164
—

172
152
164
144
168
164
196
168
166
--
186
Mg
mg/1 as
CaC03
172
172
172
184
—

192
168
164
202
124
208
180
172
195
__
198
C03
mg/1 as
CaC03
0
0
0
0
0

0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
560
530
552
528
—

524
550
524
516
510
520
524
540
508
• —
513
Standard
col i forms
Colonies/
100 ml

—
__
--
—

0
--
0
—
0
—
--
—
—
21
—

-------
                                TABLE C-13.  ANALYSIS OF SAMPLES  TAKEN FROM WELL MB-29
CO
00
Date
1971




1972







1973







Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Jun
Jul
Oct
Nov
Dec
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Chlorides
mg/1
920
890
960
930
970
1,000
1,080
1,000
940
980
890
1,130
980
950
990
1,060
1,040
1,040
1,060
1,020
1,450
Conductivity
ytnhos/cm2
at 25ฐ C
4,000
4,000
4,000
4,000
3,700
4,000
4,500
4,000
4,000
4,000
4,000
4,000
4,000
4,000
4,000
4,000
4,000
3,750
4,000
4,000
4,500
Total
hardness
mg/1 as
CaC03
372
376
384
384
388
400
432
—
356
400
368
436
408
396
400
428
430
430
440
440
440
Ca
mg/1 as
CaC03
164
164
176
172
168
192
172
--
164
152
140
160
148
180
180
184
190
210
230
192
210
Mg
mg/1 as
CaC03
208
212
208
212
220
208
260
—
192
248
228
276
260
216
220
244
240
220
210
248
230
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
532
532
570
564
560
542
568
--
536
568
580
572
568
—
528
544
530
540
540
524
520
Standard
col i forms
Colonies/
100 ml
__
--
--
--
--
__
--
--
--
__
--
—
—
—
--
—
--
__
0
4
--

-------
                                                 TABLE C-13 (CONTINUED).
CO
co


Date
1973


1974




Oct
Nov
Dec
Jan
Feb
May
Jun
Jul
Chlorides
mg/1
1,030
1,060
1,090
1,080
1,060
1,090
1,100
__
Conductivity
iamhos/cm2
at 25ฐ C
4,000
4,000
5,000
4,000
4,500
4,500
4,000
__
Total
hardness
mg/1 as
CaC03
440
450
448
500
412
404
366
• __
Ca
mg/1 as
CaC03
230
240
208
220
188
188
140
__
Mg
mg/1 as
CaC03
210
210
240
280
224
216
226
__
CO 3
mg/1 as
' CaC03
0
0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
540
540
532
550
512
536
494
_ _
Standard
col i forms
Colonies/
100 ml
90
0
0
3
1
—
>100
>100

-------
TABLE D-l.  ANALYSIS OF STREAM SAMPLES TAKEN FROM RIVER GUT-CENTERLINE ROAD STATION
Date
1971 Jul
Aug
Sep
Oct

Nov
to Dec
0
o
1972 Jan
Feb
Mar
Jul
Aug
NO NATURAL FLOW
1974 Nov
1975 Jan
Feb
Chlorides Conductivity
ymhos/cm2
mg/1 at 25ฐ C

145
80
90

100
140


150
170
120
160
180
IN RIVER
100
200
180
1
1




1


1
1

1
1
,250
,300
700
680

930
,100


,090
,150
980
,300
,300
GUT AT THIS STATION

1
1
580
,300
,300
Total
hardness Ca
mg/1 as mg/1 as
CaC03 CaC03
_.
386
236
224

272
312


320
316
—
360
356
SEPT 1972-OCT
248
484
440
ซ •
156
112
112

140
140


152
142
—
152
140
1974
172
236
232
Mg
mg/1 as
CaC03
— —
230
124
112

132
172


168
174
—
208
216

76
248
208
C03
mg/1 as
CaC03
0
0
0
0

0
0


0
0
0
0
0

0
0
0
HC03
mg/1 as
CaC03
ซ •>
558
244
270

384
424


448
444
__
516
532

188
484
520


ja
•o
-o
m
0
ป— *
X
i

5
5
o







-------
                   TABLE  D-2.   ANALYSIS OF  STREAM  SAMPLES TAKEN  FROM  RIVER  GUT-FOUNTAIN  STATION
to
Date
1971





1972

Jul
Aug
Sep
Oct
Nov
Dec
Jan
Mar
NO NATURAL FLOW
1974
1975



Nov
Jan
Feb
Mar
May
Chlorides
mg/1
„
125
150
130
100
130
55
60
IN RIVER
120
130
140
170
200
Conductivity
ymhos/cm2
at 25ฐ C
980
950
980
900
800
1,000
580
650
GUT AT THIS STATION
650
800
850
950
1,000
Total
hardness Ca
mg/1 as mg/1 as
CaC03 CaC03
„
450
448
400
332
400
276
—
APRIL
272
444
440
424
508
• M
228
280
224
178
220
176
—
1972-OCT 1974
160
248
236
224
283
Mg
mg/1 as
CaC03
.„
222
168
176
154
180
100
—

112
196
204
200
225
C03
mg/1 as
CaC03
0
0
0
0
0
0
0
0

0
0
0
0
0
HC03
mg/1 as
CaC03
.„
428
348
358
352
364
304
--

180
308
304
300
316
                 Jun         210          1,000          523         287        236         0         336

-------
        TABLE D-3.  ANALYSIS OF STREAM SAMPLES TAKEN FROM RIVER GUT-GOLDEN GROVE STATION






to
0
DO







Date
1971 Jul
Sep
Oct
Nov
Dec
1972 Jan
Feb
Mar

Chlorides

mg/1
..
220
95
150
220
230
240
180

Conductivity
pmhos/cm2
at 25ฐ C
1,700
1,450
740
1,220
1,400
1,500
1,600
1,280
Total
hardness
mg/1 as
CaC03

340
232
320
376
380
380
—

Ca
mg/1 as
CaC03

132
112
156
180
176
168
—

Mg
mg/1 as
CaC03

208
120
164
196
204
212
—

CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
-

HC03
mg/1 as
CaC03

472
272
440
544
_-.
544
--
NO FLOW IN RIVER GUT AT THIS STATION FROM APR 1972-OCT 1974

-------
                   TABLE  D-4.   ANALYSIS OF STREAM SAMPLES TAKEN FROM RIVER GUT-HOLY CROSS STATION
to
o
CO
Date
1971




1972


NO
1974
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
NATURAL FLOW
Nov
1975 Jan



Feb
Mar
May
Chlorides Conductivity
vimhos/cm2
mg/1 at 25ฐ C
180
170
95
90
110
150
165
no
IN RIVER
100
170
150
150
200
1
1



1
1

,400
,250
750
900
950
,120
,200
950
GUT AT THIS STATION

1
1
1
1
650
,100
,100
,000
,300
Total
hardness
mg/1 as
CaC03
437
404
248
284
316
356
376
—
FROM APR
268
476
416
392
489
Ca Mg
mg/1 as mg/1 as
CaC03 CaC03
208
208
124
160
156
180
180
—
1972-OCT 1974
136
216
188
188
245
229
196
124
124
160
176
186
—

132
260
228
204
244
C03
mg/1 as
CaC03
0
0
0
0
0
0
0
0

0
0
0
0
0
HC03
mg/1 as
CaC03
597
436
300
364
376
436
444
—

200
404
380
380
508
                 Jun         220          1,400          528         242        286         0         532

-------
                     TABLE D-5.  ANALYSIS OF STREAM SAMPLES TAKEN  FROM  RIVER GUT-RIVER STATION
to

1971





Date
Jul
Aug
Sep
Oct
Nov
Dec
1972 Jan




NO
1974
1975





Feb
Mar
Jul
Aug
NATURAL FLOW
Nov
Jan
Feb
Mar
May
Jun
Jul
Chlorides Conductivity
umhos/cm2
mg/1 at 25ฐ C
• ••
85
90
60
50
70
80
100
75
70
90
IN RIVER
80
190
130
150
150
150
152
980
920
700
500
560
660
750
770
640
500
850
GUT AT THIS STATION
480
800
800
900
1,000
1,100
1,000
Total
hardness
mg/1 as
CaC03
„'
339
272
180
220
236
288
284
-_
312
320
FROM SEPT
212
368
372
384
423
433
442
Ca Mg
mg/1 as mg/1 as
CaC03 CaC03

156
124
92
108
120
152
144
—
144
152
1972-OCT 1974
108
192
180
176
198
221
225

183
148
88
112
116
136
140
—
168
168

104
176
196
208
225
212
217
CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
HC03
mg/1 as
CaC03
..
464
280
198
252
268
332
316
— -
404
408

152
324
316
320
396
420
433

-------
                     TABLE D-6.   ANALYSIS OF STREAM SAMPLES TAKEN FROM RIVER GUT-USGS STATION
to
o
en



Date
1971 Aug
Sep
Oct
Nov
Dec
1972 Jan
Feb
Mar
Apr
Jun
Jul

Chlorides

mg/1
255
140
105
130
210
200
225
170
250
190
310

Conductivity
ymhos/cm2
at 25ฐ C
1,800
960
750
1,100
1,550
1,400
1,500
1,270
1,800
1,600
2,000
Total
hardness
mg/1 as
CaC03
394
284
240
300
376
364
348
—
400
336
400

Ca
mg/1 as
CaC03
172
152
108
152
164
180
160
—
160
152
128

Mg
mg/1 as
CaC03
222
132
132
148
202
184
188
—
240
184
272

CO 3
mg/1 as
CaC03
0
0
0
0
0
0
0
0
0
0
0

HC03
mg/1 as
CaC03
672
300
287
408
516
516
536
—
668
580
648
         NO  NATURAL  FLOW IN  RIVER GUT AT  THIS  STATION  FROM AUG  1972-OCT  1974

-------
                    TABLE E-1. OPERATING DATA FOR THE AWWTP, JANUARY-OCTOBER, 1974
to
o
Time
Period
1974
Jan-Feb



1974
Mar-Apr




1974
May-Jun



1974
Jul-Aug



1974
Sep-Oct



1974
Jan-Oct

Range
Upper
Lower
Mean
StdDev
Range
Upper
Lower
Mean
Std Dev

Range
Upper
Lower
Mean
Std Dev
Range
Upper
Lower
Mean
Std Dev
Range
Upper
Lower
Mean
Std Dev
Mean

BOD
mgft

79
56
68
9

-
-
-
-


184
56
118
49

289
56
140
27

143
19
107
26
113

COD
mg/l

280
102
194
46

203
128
168
27


296
158
219
46

259
96
215
53

370
63
209
76
206

N09-N
mg

0.8
0.2
0.4
0.3

1.4
0.3
0.6
0.5


2.7
0.1
0.6
0.9

0.3
0.1
0.2
0.1

1.0
0.3
0.6
0.4
0.6

NH3-N

25.5
10.5
17.8
5.5

27.5
11.6
19-5
6.5


34.5
15.0
24.9
6.3

30.5
14.0
25.3
9.1

44.5
8.0
22.7
12.4
22.6

Influent Data
Total Chlorides
P

12.0
6.8
10.8
2.8

18.7
9
12.6
4.2


41.0
10.9
19.5
12.1

12.6
7.6
10.3
2.0

11.8
3.0
8.0
3.0
12.3


500
340
409
48

480
420
449
24


680
430
486
67

790
300
480
119

980
301
453
153
456

Conductivity

2,000
1,500
1,763
48

2,000
1,500
1,775
206


2,500
1,400
1,990
355

2,600
1,300
1,817
358

2,800
1,200
1,677
320
1,778

Total
Hardness

274
168
220
35

296
240
261
26


360
180
283
61

416
260
318
59

808
248
348
177
289

Ca

100
56
83
13

112
96
105
8


160
88
120
25

152
100
125
19

232
96
133
41
114

Mg

180
92
137
28

184
132
156
24


208
80
163
42

264
152
193
42

576
116
204
142
172

C03

0
0
0
-

0
0
0
-


0
0
0
--

0
0
0
-

0
0
0
-
0

HC03

428
316
355
37

372
316
344
26


356
264
321
38

356
248
312
39

336
164
274
51
318

pH

--
-
-
—

7.7
7.2
7.4
0.2


8.1
7.2
7.6
0.4

7.6
7.2
7.4
0.1

7.8
6.8
7.3
0.2
7.4








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-------
                 TABLE E-2. OPERATING DATA FOR THE AWWTP, JANUARY-OCTOBER, 1974
Time
Period
1974 Range
Jan-Feb Upper
Lower
Mean
Std Dev
1974 Range
Mar-Apr Upper
Lower
Mean
Std Dev
0 1974 Range
"^ May-Jun Upper
Lower
Mean
Std Dev
1974 Range
Jul-Aug Upper
Lower
Mean
Std Dev
1974 Range
Sep-Oct Upper
Lower
Mean
Std Dev
BOD
mg/l

10
2
5
4

-
-
-
-

11
2
6
4

25
6
14
7

32
11
22
8
COD
mg/ป

43
5
26
11

76
20
39
19

64
7
25
13

53
18
37
10

48
4
31
13
NO3-N
mg/l

24
4.8
12.6
8.5

16.8
1.5
9.0
6.3

19.8
6.5
12.1
4.3

21.6
9.6
16.7
5.0

20.2
0.1
11.8
9.0
NH3-N
mg/l

6.5
2.0
3.6
1.8

6.0
1.5
3.4
1.9

18.0
1.5
9.3
7.0

18.0
3.5
9.6
5.7

16.5
<0.1
6.2
5.3
Effluent Data
Total CO3
P mg/l as
mg/l CaCO3

9.4
0.7
5.2
4.3

12.2
7.9
9.8
1.8

11.0
5.1
8.8
2.3

10 J
4.6
6.7
2.0

6.4
1.1
4.7
1.7

0
0
0
-

0
0
0
-

0
0
0
-

0
0
0
-

0
0
0
_
HC03
mg/l as
CaC03

236
136
199
33

220
152
181
31

140
40
92
33

72
44
53
10

260
40
95
69
PH

7.2
7.2
7.2
7.2

7.3
6.5
6.8
0.2

7.7
6.7
7.0
0.3

6.8
6.4
6.5
0.1

7.2
5.7
6.6
0.4
Turbidity
FTU

5
0.6
1.5
0.9

1.8
0.1
1.3
0.5

3.0
0.4
1.4
0.6

1.5
0.8
1.0
0.3

3.0
1.0
1.4
0.5
Aeration Tank
MLSS SVI
mg/l mg/l

1,980
300
922
482

1,620
545
962
328

4,630
395
1,707
780

3,850
490
1,638
951

2,190
760
1,334
326

404
55
104
68

250
39
84
54

337
31
81
56

96
22
64
15

62
27
46
9
AWWTP
Electric
Power
kwh

27,120




62,1 60




69,720




62,400




60,960



1974
jan-Oct
Mean
12
31
12.9
6.8
9.0
123
6.7
1.3
1,351
75
28,236*
^Average kwh/month.

-------
                   APPENDIX   -  PART  F
QW Well-graded gravels, gravel-sand mixtures,
    little or no fines.

GM Silty gravels, poorly graded gravel • sand
    silt mixtures.

GC Clayey gravels, poorly graded gravel • sand-
    clay mixtures.

SW Well-graded sands, gravelly sands, little or
    no fines.
DESCRIPTION


      SM  Silty sands, poorly graded sand-silt mixtures.

      SC  Clayey sands, poorly graded sand-clay mixtures.

      ML  Inorganic silts and very fine sands, rock flour, silly,
          or clayey fine sands with slight plasticity.

      CL  Inorganic clays of low-to-medium plasticity, gravelly
          clays, sandy clays, silty clays, lean clays.
     Poorly graded sands, gravelly sands, little or
     no fines.
      CH  Inorganic clays of nigh plasticity, fat clays.

      ^  SURVEY MONUMENT
                                                      100    200    300     400     500
  Figure  F-1.  Soil boring locations in Golden Grove.
                              208

-------
^ ,   STRUCK WATER
     DURING BORING
                                UNIFIED SOIL CLASSIFICATION SYSTEM USED
                   Figure F-1. (Extended)
                             209

-------
                        APPENDIX  - PART G
     __ 'L'J  f,'_  _Jfc^nki^~ .—fc-^-J—*-****^^**""*"™^
JAN  I FEB  I MAR I  APR I MAY  I JUN  I  JUL I  AUG I  SEP I  OCT I NOV I  DEC
                Figure G-1.  Water levels in well A 15,1971-1972.
                                  210

-------
            MAR '  APR '  MAY  ' JUN  '  JUL   AUG   SEP  ' OCT '  NOV '  DEC
JAN '  FEB  ' MAR '  APR '  MAY  '  JUN '  JUL '  AUQ
                                 TIME
                Figure G-2. Water levels in well A-15,1973-1974.
                                 211

-------
ง
ฃ
LLJ

73

71

69

67

65

63

61


"
57
                                                                    TOP OF CONCRETE
                                                                    PUMP BASE-EL. 86,4
     JAN  '  FEB   MAR  '  APR    MAY '  JUN  '  JUL '  AUG '   SEP '  OCT '  NOV '  DEC
                                                                                           6
  u.
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3<
  cc
                          Figure G-3. Water levels in well A-15, 1975.
                                          212

-------
z
  62


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258
                                                     TOP OF CONCRETE
                                                     PUMP BASE - EL. 77.2
                     A-18
                     1971
                     Jfe
JAN   FEB    MAR   APR   MAY
JUN   JUL    AUG
                                                              1
                                                          SEP   OCT
                                             1
                                                                      NOV
                                                   DEC
                                                                                   <
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                                             J
      JAN   FEB   MAR   APR   MAY   JUN    JUL   AUG    SEP   OCT   NOV   DEC
                                        TIME

                       Figure G-4.  Water levels in well A-18.1971-1972.
                                                                                    c
                                                                                   • —
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                                                                                   <
                                                                                   a;
                                         213

-------
  62

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                    A-18
                    1973
                                                          TOP OF CONCRETE
                                                          PUMP BASE -EL. 77 2
         1
       JAN
             FEB   MAR   APR  'MAY   JUN   JUL
                                                 AUG
                                                        SEP   OCT
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                                                                          DEC
4_,
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2
      JAN
             FEB '  MAR   APR   MAY  JUN   JUL  ' AUG '  SEP  '  OCT T NOV   DEC
                                       TIME
                      Figure G-5. Water levels in well A-18, 1973-1974.
                                       214

-------
   62
   60
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256
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111
w 52
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                                      p ''"••'—f
       JAN  '  FEB   MAR  ' APR   MAY   JUN   JUL   AUG   SEP   OCT   NOV   DEC
                                          TIME
                          Figure G 6.  Water levels in well A 18, 1975.
                                          215

-------
   88

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                                                             TOP OF CONCRETE
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                  A-19
                  1971
                                      Ufa m -JL
                                                                     ii
       JAN
           FEB   MAR   APR   MAY   JUN    JUL  AUG    SEP   OCT   NOV   DEC
                                      TIME
                       Figure G-7. Water levels in well A-19,1971.
                                        216

-------
  14


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                                                     TOP OF CASING - EL. 30.6
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                                                                             4_T
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                                                                    1
            FEB   MAR   APR   MAY   JUN   JUL
                                                AUG   SEP   OCT   NOV   DEC
FP-2

1972
                                                                             6
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                                                                               LL

                                                                             3|

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      JAN   FEB   MAR   APR   MAY   JUN   JUL   AUG   SEP   OCT   NOV   DEC

                                      TIME
                     Figure G-8. Water levels in well FP-2,1971-1972.
                                       217

-------
   14

   1?
1 8
LLI
uj 4
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oc
LU
5
                                                        TOP OF CASING - EL. 30.6
                  FP-2
                  1973
                                                                               6

       JAN
14

12
I8
$6
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LU 4
LU
_l
cc.
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             FEB
                  MAR   APR   MAY   JUN   JUL
                                                 AUG
                                                                               3
                                                        SEP   OCT
                                                                 NOV
                                                                       DEC
                    FP-2
                    1974
                                JL
                                                                               LJ_
                                                                               z
                                                                            3  <
                                                                               CC
   JAN    FEB   MAR  APR   MAY  JUN    JUL  AUG   SEP   OCT
                                     TIME
                    Figure G-9.  Water levels in well FP-2,1973-1974.
                                                                    NOV
                                                                          DEC
                                        218

-------

14
12
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                TIME
Figure G-10. Water levels in well FP-2, 1975.
                  219

-------
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                                                 J
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      JAN   FEB   MAR   APR   MAY   JUN   JUL   AUG   SEP   OCT   NOV   DEC
                        3<
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                    GG-3
                     1973
                                                                        LJL
      JAN    FEB    MAR   APR   MAY   JUN   JUL   AUG   SEP   OCT   NOV   DEC
                                    TIME
                   Figure G 11.  Water levels in well GG-3, 1972-1973.
                        6
                                                                                LL
                                                                                Z
                                        220

-------
      JAN    FEB   MAR   APR   MAY   JUN   JUL   AUG   SEP    OCT   NOV    DEC
  48


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26
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       JAN
            11
I
FEB  ' MAR '  APR  ' MAY ' JUN  ' JUL    AUGT  SEP   OCT   NOV   DEC

                        TIME

      Figure G-12.  Water levels in well GG-3. 1974-1975.
                                          221

-------
   50


   48


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       JAN '  FEB '  MAR  ' APR    MAY '  JUN   JUL  '  AUG '  SEP '  OCT  ' NOV
                                        TIME
                      Figure G 13. Water levels in well GG-4, 1974-1975.
                                                                            LL
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                                                                     DEC
                                        222

-------
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       JAN
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FEB  ' MAR
                          APR
                                                     AUG   SEP
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                                          TIME
                       Figure G-14. Water levels in well GG-5, 1971-1972.
                                                     OCT  ' NOV '  DEC
                                                                                     3<
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                                          223

-------
   48


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       JAN
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                      Figure G 15. Water levels in well GG-5,1973-1974.
                                        224

-------
   48

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 1975
                                     iU
      JAN  '  FEB ' MAR '  APR '  MAY '  JUN '  JUL '  AUG  ' SEP  ' OCT  ' NOV '
                                       TIME
                        Figure G-16. Water levels in well GG-5,1975.
                                                            Z
                                                           3<
                                       225

-------
  18
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                  1971

                                      p.
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     JAN   FEB   MAR  APR   MAY   JUN   JUL   AUG   SEP   OCT   NOV  DEC
                                   TIME
                   Figure G-17. Water levels in well GG-7,1971-1972.
4<
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32
                                    226

-------
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                                                                              4_J
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       JAN
             FEB   MAR   APR   MAY   JUN   JUL   AUG
                                    SEP   OCT   NOV   DEC
       JAN '  FEB '  MAR'  APR '  MAY  ' JUN  ' JUL   AUG   SEP   OCT   NOV   DEC
                                       TIME
                      Figure G-18  Water levels in well GG-7,1973-1974.
                                        227

-------
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Figure G 19.  Water levels in well GG-7,1975.
                                    228

-------

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JAN
FEB  ' MAR '  APR '  MAY '  JUN '  JUL  ' AUQ '  SEP   OCT   NOV '  DEC
                            TIME
         Figure G-20. Water levels in well GG-13,1973-1974.
                                   229

-------
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       JAN
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                                        TIME

                       Figure G-21. Water levels in well GG-13, 1975.
                                           230

-------
            FEB ' MAR  ' APR   MAY '  JUN '  JUL '  AUG
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    JAN. 1976
                                                                         3<
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                                     EL
JAN I  FEB I  MAR  ' APR ' MAY '  JUN T JUL
                                 TIME
               Figure G 22. Water levels in welt NB-3, 1974-1975.
                                                        SEP  '  OCT '  NOV '  DEC
                                        231

-------
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                                PUMC INSTALLED
                                JUN. 1974.
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    JAN  ' FEB  ' MAR   APR   MAY  ' JUN  '  JUL    AUG   SEP   OCT   NOV '  DEC
                                     TIME
                    Figure G 23. Water levels in well PW-1,1973-1974. .
                                                                             <
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                                      232

-------
38
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           APPENDIX - PART H
TABLE H-l.  ENGLISH-TO-METRIC CONVERSION
English unit
acre
acre-ft
cu ft
ft
gal
gal
gpd/sq ft
gpm
hp
in.
Ib
mgd
mile
sq ft
sq in.
sq miles
Multiplier
0.405
1,233.5
0.028
0.3048
0.003785
3.785
0.0408
0.0631
0.7457
2.54
0.454
3,785
1.61
0.0929
6.452
2.590
Metric unit
ha
cu m
cu m
m
cu m
1
cu m/day/sq m
I/sec
kw
cm
kg
cu m/day
km
sq m
sq cm
sq km
               244

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
 1. REPORT NO.
   EPA-600/2-76-134
                                                           3. RECIPIENT'S ACCESSION-NO.
 4. TITLE AND SUBTITLE
   WASTEWATER RECLAMATION  PROJECT,
   ST. CROIX, U.S. VIRGIN  ISLANDS
                                                           5. REPORT DATE
                                                              June 1976 (Issuing  Date)
               6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)

   Oscar Krisen Buros
               8. PERFORMING ORGANIZATION REPORT NO,

                  540-70-83
 9. PERFORMING ORGANIZATION NAME AND ADDRESS
   Black, Crow and Eidsness,  Inc.
   7201 NW llth Place
   Gainesville, Florida  32602
               1O. PROGRAM ELEMENT NO.
                  WRD/1BC611
               11. CONTRACT/GRANT NO.
                                                             11010 GAK
 12. SPONSORING AGENCY NAME AND ADDRESS
   Municipal  Environmental Research Laboratory
   Office of  Research and Development
   U.S.  Environmental Protection  Agency
   Cincinnati, Ohio  45268
               13. TYPE OF REPORT AND PERIOD COVERED
                  Final
               14. SPONSORING AGENCY CODE
                  EPA-ORD
 15. SUPPLEMENTARY NOTES
 16. ABSTRACT
        St.  Croix is a subtropical  semiarid island in  the  Territory of the U.S. Virgin
   Islands.   The expanding  population and rising standard  of living have resulted  in  a
   level  of potable water consumption above the available  supply of surface and ground-
   water.   Seawater desalinization  plants are currently  being used to produce the
   needed water.  The cost  of  this  desalinized water ranges  up to $7/thousand gal
   ($1.84/cu m).
        Since 1971 work has been  proceeding on a project to  use tertiary-treated waste-
   water effluent for artificial  recharge of the groundwater on St. Croix.  A 0.5  mgd
   (1,890 cu m/day) advanced wastewater treatment plant  and  recharge facilities were
   designed and constructed.   Background data on water quality and quantity in the
   surrounding area were collected  for 2-1/2 years before  recharging began.  Recharge
   operations were carried  out for  8 months during 1974, using both spray irrigation
   and  spreading basins.  The  best  method of recharging  proved to be the use of
   spreading basins in an alluvial  valley.   The cost for the wastewater treatment,
   recharge operations, and recovery of groundwater was  estimated to be about $2.15/
   thousand gal ($0.57/cu m) at 0.5 mgd (1,890 cu m/day) with a reduction in estimated
   costs  to $1.64/thousand  gal  ($0.43/cu m) if the operation is expanded to 1 mgd
   (3,785 cu m/day).
 7.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
  b.lDENTIFIERS/OPEN ENDED TERMS  C.  COSATI Field/Group
  Waste  treatment
  Water  reclamation
  Ground water recharge
   Wastewater  reclamation
   Artificial  groundwater
     recharge
   Water reuse
    13B
 8. DISTRIBUTION STATEMENT
  Release  to  PUblic
  19. SECURITY CLASS (ThisReport)
     Unclassified
21. NO. OF PAGES
    259
                                              20. SECURITY CLASS (Thispage)
                                                 Unclassified
                             22. PRICE
EPA Form 2220-1 (9-73)
245
                                                               4USGPO: 1976 — 657-695/5443 Region 5-11

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