THE CAPE COD AQUIFER
MANAGEMENT PROJECT (CCAMP)
A MASS-BALANCE NITRATE MODEL FOR
PREDICTING THE EFFECTS OF LAND USE
ON GROUNDWATER QUALITY IN
MUNICIPAL WELLHEAD PROTECTION AREAS
Eastham
CCAMP WAS UNDERTAKEN BY:
U.S. ENVIRONMENTAL PROTECTION AGENCY, REGION I
U.S. GEOLOGICAL SURVEY, MASSACHUSETTS DISTRICT OFFICE
MASSACHUSETTS DEPT. OF ENVIRONMENTAL QUALITY ENGINEERING
CAPE COD PLANNING AND ECONOMIC DEVELOPMENT COMMISSION
IN COOPERATION WITH:
THE TOWN OF BARNSTABLE AND THE TOWN OF EASTHAM
IDLY 1988
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9O1388OO7
A Mass-Balance Nitrate Model For
Predicting The Effects Of Land Use On
Groundwater Quality In Municipal
Wellhead Protection Areas
By
Michael H. Frimpter
U.S. Geological Survey
Water Resources Division
John J. Donohue, IV
Massachusetts Department of Environmental Quality Engineering
Division of Water Supply
Michael V. Rapacz
Massachusetts Department of Environmental Quality Engineering
Division of Water Pollution Control
July 1988
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TABLE OF CONTENTS
Section Page
Table of contents i
List of figures ii
List of tables iii
Abstract 1
Introduction 2
Hydrogeologic setting 3
Previous Nitrate Loading Approaches: 6
Relation Between Nitrate Loading and
Housing Density in the Zone of Contribution
Proposed Approach: Accounting for Nitrate 8
from All Sources Within Municipal Wellhead
Protection Areas
Applications
Example No. 1 13
Example No. 2 15
Example No. 3 16
Example No. 4 18
Assumptions and Qualifications 20
Conclusion 22
References Cited 23
General References 24
Appendix A: Nitrate Concentrations Associated A-l
With Varying Land Uses (pp. A1-A8)
Appendix B: Directions for the Preparation of a B-l
Computerized Spread Sheet for the Nitrate Loading
Calculations (pp. B1-B4)
Appendix C: List of Acronyms, Chemical Formulas C
and Mathematical Symbols Used
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LIST OF FIGURES
Figure Title
Hydrogeologic section of a pumped
well in a valley fill aquifer
Block diagram of house lot showing
inflow of nitrate diluted with
recharge from precipitation
Block diagram of municipal wellhead
protection area (Zone II) to a public
supply well
Sources of nitrate and zones of con- 10
tribution to a municipal supply well
pumped at 1 million gallons and 0.5
million gallons per day
Map view of glacial valley aquifer 19
showing the zones and stream that con-
tribute water to a public supply well
ii
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LIST OF TABLES
Table No. Title
Summary of nitrate loads from sep- 13
tic systems for average one day
period - one million gallon per
day well (in liters and milligrams
per day)
Summary of solid nitrate loads 14
- in milligrams per day
Increase in nitrate load due to 15
proposed hospital development - one
million gallon per day public supply
well
Summary of nitrate loads from septic 17
systems for average one day period
• 0.5 million gallon per day public
supply well (in liters and milligrams
per day)
Summary of solid nitrate loads - 0.5 17
million gallon per day well
iii
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A MASS-BALANCE NITRATE MODEL FOR PREDICTING THE EFFECTS
OF LAND USE ON GROUNDWATER QUALITY IN WELLHEAD PROTECTION AREAS
by '" '
Michael H. Frimpter, U. S. Geological Survey, Water Resources Division
John J. Donohue, IV, Massachusetts Department of Environmental Quality
Engineering, Division of Water Supply
Michael V. Rapacz, Massachusetts Department of Environmental Quality
Engineering, Division of Water Pollution Control
ABSTRACT
A mass-balance accounting model can be used to guide the management of
septic systems and fertilizers to control the degradation of groundwater
quality in zones of an aquifer that contribute water to public supply
wells. . The nitrate nitrogen concentration of the mixture in the well can
be predicted for steady-state conditions, by calculating the concentration
that results from the total weight of nitrogen and total volume of water
entering the zone of contribution to the well. These calculations will
allow water quality managers to predict the nitrate concentrations that
would be produced by different types and levels of development, and to
plan development accordingly. Computations for different development
•schemes provide a technical basis for planners and managers to compare
water quality effects and to select alternatives that limit nitrate
concentration in wells.
Appendix A contains tables of nitrate loads and water volumes from common
sources for use with the accounting model. Appendix B describes the pre-
paration of a spreadsheet for the nitrate loading calculations with a
software package generally available for desktop computers.
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Introduction
Protection of groundwater quality for public water supply use has
become a priority environmental issue. In recent years, one ubiquitous
cause of degradation of groundwater quality has been nitrate contributed
by subsurface wastewater disposal systems and agricultural activities. In
New England, where shallow, unconsoli'dated aquifer systems provide large
quantities of public drinking water and also receive large quantities of
wastewater, the potential for water quality degradation is a primary con-
cern. In order for these two potentially conflicting activities to co-
exist within acceptable limits, the interrelation between withdrawal for
water supply and wastewater discharge needs to be accurately defined.
This definition requires a characterization of the aquifer system and quan-
tification of the contribution of nitrate to groundwater from land use.
The purpose of this paper is to provide an approach for evaluating the
cumulative effects of nitrogen contributing land uses on water quality in
public supply wells. The procedure involves the summation of all nitrate
sources within a municipal wellhead protection area (Zone II) of a public
supply well to predict resultant steady-state nitrate concentrations at
the well head.
Specifically, the paper presents a mass-balance accounting equation,
tables of nitrate nitrogen concentrations and flow volumes (Appendix A),
general model examples and directions for the preparation of a comput-
erized spreadsheet for the mass-balance accounting model (Appendix B).
The proposed approach departs from previous nitrate loading approaches
used in Massachusetts, by comprehensively accounting for nitrate inputs to
a subset subdivision of the aquifer system the Municipal Wellhead Protec-
tion Area (Zone II). Properly applied, this approach will provide the nec-
essary scientific foundation for planning development through land use man-
agement, to keep nitrate concentrations at the well head below a chosen
threshold value. Anyone intending to apply this approach needs a thorough
understanding of the Applications and Qualifications section of this
paper.
Nitrate was chosen as the contaminant of concern for several reasons:
Nitrate acts as a conservative chemical species in groundwater; it is not
sorbed by aquifer materials nor does it enter into most chemical reac-
tions. Although nitrogen may be introduced to groundwater in several dis-
solved forms, the proposed approach assumes that all nitrogen in ground-
water is converted to nitrate before reaching a public supply well. The
principal mechanism by which nitrate is attenuated is by dilution. Sec-
ondly, two health hazards are related to the consumption of water con-
taining large concentrations of nitrate (or nitrite); induction of methe-
moglobinemia, particularly in infants, and potential formation of carcino-
genic nitrosamines (National Research Council, 1977). Because of these
health related concerns, the U.S. Environmental Protection Agency (1975)
has established a maximum contaminant level for nitrate as nitrogen in
drinking water at 10 mg/L (milligrams per liter). Nitrate, as used
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hereafter in this report, refers to nitrate as nitrogen. In addition, the
results of a study in Australia suggest that the consumption of drinking
water containing elevated concentrations of nitrate during pregnancy is
associated with a significantly increased risk of malformations in off-
spring (Dorsch, 1984). Although nitrate may not be the cause of malforma-
tions, it is associated with their presence. It has been demonstrated
that nitrate is a geochemical indicator for other more toxic contaminants
associated with wastewater (Dorsch, 1984, Dewalle, 1985 and LeBlanc,
1984).
Acknowledgments
The authors express their appreciation to the Cape Cod Aquifer Manage-
ment Project (CCAMP) project for providing the impetus and forum to re-
search and develop this document. The CCAMP was initiated in 1985 for the
purpose of examining the adequacy of groundwater programs at all levels of
government and for developing or recommending modifications of these pro-
grams. Members of the project included the Cape Cod Planning and Economic
Development Commission, the Massachusetts Department of Environmental
Quality Engineering, the U. S. Environmental Protection Agency, Region I,
and the U. S. Geological Survey. This report is one of several products
of the CCAMP intergovernmental collaboration. The authors also greatly
appreciate the assistance of Ms. H. Gile Beye in preparing Appendix B, a
user's guide to simplify data handling.
Hydrogeologic Setting
Glacial outwash and ice contact deposits of sand and gravel form the
most productive aquifers in Massachusetts and New England. These water
table aquifers are most commonly less than 25 feet below land surface and
less than 100 .feet thick. They are typically located either on broad
plains or in low valley areas adjacent to the streams of the region.
Because these aquifers are recharged from the land immediately overlying
them, groundwater quality is highly dependent on local land uses. Massa-
chusetts has developed an approach to managing groundwater quality which
focuses management efforts on the land which recharges that part of
aquifers which contribute water to wells. " "
The delineation of the land area that provides'recharge to a pumping
well is a prerequisite for the application of the methodology set forth in
this paper. In Massachusetts, the land surface that contributes recharge
to a public supply well is referred to as Zones II and III by the Depart-
ment of Environmental Quality Engineering.' Zone II and Zone III are
defined in 310 CMR 24.00 (the Massachusetts Aquifer Land Acquisition
Program Regulations, 1983) and shown in Figure 1.
Zone II (the Municipal Wellhead Protection Area) is defined in 310 CMR
24.00 as "The area of an aquifer that recharges a well [the land surface
which overlays that part of the aquifer that recharges a well] under the
most severe recharge and pumping conditions that can be realistically
anticipated. It is bounded by the groundwater divides that result from
pumping the well and by the contact of the edge of the aquifer with less
permeable materials such as till and bedrock."
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DRAINAGE DIVIDE
ZONE I - 400 FOOT RADIUS ABOUT PUBLIC SUPPLY WELL
ZONE II - LAND SURFACE OVERLAYING THE PART OF THE
AQUIFER THAT CONTRIBUTES WATER TO THE WELL
ZONE III - LAND SURFACE THROUGH AND OVER WHICH WATER
DRAINS INTO ZONE II
-.._..- DRAINAGE DIVIDE
*** DIRECTION OF WATER FLOW
FIGURE 1: Hydrogeologic section of a pumped well in a valley-
fill aquifer
Zone III is defined as "That land area beyond the area of Zone II from
which surface water and groundwater drain into Zone II. The surface drain-
age area as determined by topography is commonly coincident with the
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groundwater drainage area [groundwater divides in the upland materials]
and will be utilized to delineate Zone III. In some locations, where sur-
face water and groundwater drainage are not coincident, Zone III shall con-
sist of both the surface drainage area and the groundwater drainage area."
Zone II and . Zone III are two-dimensional map projections of a
three-dimensional subsurface volume. As such, the proper delineation of
Zone II and Zone III should account for significant aspects of the surface
water and groundwater hydrogeology: when a well is pumped, the resulting
Zone II and associated Zone III represent a state of physical equilibrium.
This state of physical equilibrium is reached (after days, weeks, or
months), and maintained when the withdrawal from the aquifer because of
pumping is balanced by various recharge mechanisms. These mechanisms
include: areal recharge from precipitation; recharge from induced infil-
tration of surface water; recharge from subsurface wastewater disposal
systems; and recharge from overland runoff and groundwater that drain from
Zone III into Zone II. An accurate delineation of Zone II and Zone III
would account for these various recharge mechanisms in their relative
proportions. For a more detailed treatment of the determination of Zone
II and Zone III see (Massachusetts Department of Environmental Quality
Engineering, 1986 and Donohue, 1986).
Within Zone II, all groundwater flow is toward and converges at the
well. This results in a complete mixing effect of the water (and associ-
ated contaminants) at the well as it is withdrawn from the aquifer.
The mass-balance accounting model presented in this paper is used to
predict nitrate concentrations at the municipal wellhead. The concen-
trations predicted represent steady-state conditions at the wellhead.
In the field, steady-state conditions are reached when physical and
dilution equilibrium are attained. Physical equilibrium is attained when
the volume of water contributed by the various recharge mechanisms matches
the amount of water withdrawn. Dilution equilibrium is attained at the
wellhead when the concentration of nitrate nitrogen in the various re-
charge mechanisms stabilizes, and that recharge (water and associated
nitrate nitrogen) has had sufficient time to move from the most distant
regions of the Zone II to the wellhead. Steady-state conditions may take
tens of years or more to achieve, after nitrate loads to the Zone II have
stabilized. The amount of time necessary to achieve steady-state depends
on the rate of movement of groundwater in the Zone II being considered.
In summary, the delineations of Zone II and Zone III are important be-
cause water of impaired quality recharging the groundwater system within
these areas ultimately will affect the quality of water at the wellhead.
When steady-state conditions have been reached, the water quality observed
at the wellhead represents the sum of the constituents (ratio of nitrate
to the volume of water pumped) entering the Zone II. Accordingly, the
management of nitrate loading within the Zone II and Zone III areas is an
effective approach to prevent contamination of municipal supply wells by
nitrate.
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Previous Nitrate Loading Approaches: The Relationship Between
Nitrate Loading and Housing Density
Previous work on calculating nitrogen loading to ground water for
Massachusetts has focused on the determination of the minimum house lot
size (Figure 4) that could be allowed on an aquifer recharge area without
violating the nitrate limit (10 mg/L nitrate as nitrogen) for drinking
water (Cape Cod Planning and Economic Development Commission, 1978). This
approach was based on a mass-balance mixture equation described as
follows. The average nitrate load and water volume from a septic system
were estimated and the average nitrate load from a lawn was estimated
using information available in the literature (see Appendix A). To deter-
mine the quantity of recharge required to dilute the nitrate to the limit
of 10 mg/L, these estimates of water volume and nitrate load were substi-
tuted in a mixture equation similar to the one shown below. All nitrogen
from the septic system and fertilizer is assumed to be oxidized to nitrate
after traveling through the aquifer to the public supply well. Although
the nitrate limit for drinking water is 10 mg/L, a planning goal of 5 mg/L
was adopted by the Cape Cod Planning and Economic Development Commission
to ensure that the health standard would be rarely exceeded (Cape Cod
Planning and Economic Development Commission, 1978). The mixture equation
could be written as:
LOAD OF NITRATE
CONCENTRATION -
VOLUME OF WATER
or,
LOAD FROM RECHARGE + LOAD FROM SOURCES
CONCENTRATION -
TOTAL VOLUME OF WATER
Where load from recharge equals recharge volume times nitrate concentra-
tion in recharge (0.05 mg/L nitrate as nitrogen) for Cape Cod, Mass.).
The house lot nitrate loads used were 5 pounds per person per year and
9 pounds per year per lawn, or 1090 x 10 rag (milligrams) for a 3-person
household. The volume of wastewater return flow was 65 gallons per person
for 3 persons for 365 days, or 7 x 10 gallons (27 x 10 liters) per
household per day. Solving the equation for recharge volume (in cubic
feet), then dividing by the annual recharge rate (1.33 feet per year), a
lot size of 59,250 ft (square feet) (Figure 2) was calculated as being
required to capture sufficient recharge to dilute the mixture to the
5 mg/L nitrate planning goal.
For the Cape Cod 208 Water Quality Management Plan, this value was
adjusted to 43,560 square feet, or 1 acre, for areas zoned for single
family housing (Cape Cod Planning and Economic Development Commission,
1979) "after allowing for standard percentages of roads and open space
associated with residential development." Land use data for housing and
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GROUND WATER FLOW
TO PUBLIC SUPPLY WELL
NOT TO SCALE
FIGURE 2: Block diagram of house lot showing inflow of nitrate
diluted with recharge from precipitation
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open space supporting this adjustment were not provided (Cape Cod Planning
and Economic Development Commission,1979). With use of the nitrate
accounting model described in the next section of this report, the need to
provide open space data to justify the adjustment to 1 acre lots is
eliminated.
The conclusion that a housing density of one house per acre would meet
the planning goal of 5 mg/L nitrate translated into a general planning
guideline to protect groundwater quality. This calculation provided an
average limit on housing density where groundwater quality is to be pro-
tected. For the protection of groundwater quality, this housing density
guideline, or some adaptation of it, has been adopted by many towns and
incorporated in their land use zoning ordinances and development plans.
Proposed Approach: Nitrate Loading From All Sources In Municipal Wellhead
Protection Areas
The intent of this guide and the following equation is to offer a com-
prehensive approach to limiting nitrate degradation from all sources in the
zones that contribute water to public supply wells (Zone II, as defined by
the Massachusetts Department of Environmental Quality Engineering, Division
of Water Supply (Fig. 3). Nitrogen from all sources is assumed to be oxi-
dized to nitrate before entering a public supply well. The mass-balance
accounting model described here is for prediction of future conditions. It
is for steady-state conditions in which all of the nitrate and water enter-
ing the Zone II are in equilibrium with and equal to that withdrawn for pub-
lic supply. Currently observed low concentrations of nitrate are not neces-
sarily indicative of future concentrations because many years may be re-
quired to reach steady state conditions. On the basis of slow movement of
groundwater, as determined in the Cape Cod aquifer (LeBlanc, 1984), the
steady-state condition is estimated to take tens of years or more to be
approached in most parts of the Cape Cod aquifer. This method also re-
quires that only a small percentage (less than 25 percent) of the water
withdrawn is discharged to and recharges groundwater within Zone II. If a
large part of the water produced by a public supply well were returned to
the zone that contributes water to the well (Zone II), then recycled ni-
trate would dominate the effects of dilution from precipitation and other
recharge sources, and nitrate would increase and exceed 10 mg/L. Wells so
affected by recycled nitrate will eventually produce water with more than
10 mg/L nitrate. For these wells, the approach described here is ineffec-
tive. For most wells, this approach is effective because most public sup-
ply wells serve areas much larger than their Zone II.
Although there are reasons for ground-water quality protection outside
of the Zone II , this paper is limited to activities within the wellhead
protection area (Zone II) (Fig. 4) that affect nitrate concentration in
water from the public supply well. This approach is an expansion of and
more complete use of the mass-balance dilution equation used previously to
determine a maximum average housing density on Cape Cod. An example of the
equation and its accounting for all sources follows:
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ZONE OF
CONTRIBUTION
PUMPING
WATERi
LEVEL
AQUIFER
NOT TO SCALE
FIGURE 3: Block diagram of a municipal wellhead protection area
(Zone II) to a public supply well showing the zone
that contributes water to the well
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10.
NOT TO SCALE
FIGURE 4: Sources of nitrate and zones of contribution to a public
supply well pumped at 1 million gallons per day (Mgal/d
and 0.5 million gallons per day (Mgal/d)
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Nitrate
concentration
in well water
Cw~
11
Nitrate load from precipitation + nitrate load from sources
Total volume of water
Cr x (Vw -0.9 x (V1+V2+...+Vn)) + < 1^+1.2+... +!<„>
w
where: C,
w
V.
w
c1+c2-K..+cn
nitrate concentration of ground water at the well,
in milligrams per liter;
volume of withdrawal from well in liters (volume
must be converted to liters because concentrations
are calculated in milligrams per liter;
nitrate concentration in recharge from precipitation
in milligrams per liter;
nitrate load in milligrams from individual sources
where L - C x V, when load is calculated from the
volume and nitrate concentration of effluent from
the source;
nitrate concentration in individual sources; and
volume of water used by each source before dis-
charge to septic system, in liters.
The load of nitrate in recharge from precipitation is the product of ni-
trate concentration in recharge (C ) times the volume of recharge de-
rived from precipitation after adjustment for water from other recharge
sources (V..-0.9 x (Vi+V2+...+V )). Nitrate concentration in
Cape Cod (C ) was estimated
groundwater recharge from precipitation on
as 0.05 mg/L on the basis of an analysis of the frequency'distribution of
nitrate concentration in groundwater. Thirty percent of about 5,000
groundwater samples from Cape Cod had nitrate concentrations of 0.05 mg/L
or less.
a summation
zone. The
of the loads of nitrate from
term 0.9 x (V1+Vo+...+Vn)
The term (L^+ L2+...+1^) is
all sources within the ... __ , L / n-
represents the quantity of water returned to the aquifer by the septic
systems and other return flows and is subtracted from the withdrawal rate
to obtain the quantity of recharge from precipitation that will reach the
well. The value of the term Vj+V2+..-+V would have been determined
for delineation of the zone of contribution (Zone II) and therefore would
be available for substitution in the mass-balance nitrate calculation.
The sum of the volumes of waste water are multiplied by 0.9 to adjust for
a 10 percent loss by evapotransporation as estimated in the previous work
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12
by CCPEDC. Nitrogen 15 be introduced to the ground in the reduced state
(ammonium) but is oxidized to nitrate nitrogen in the well water. For
liquid .sources, C^ and V^ are the concentration of nitrogen in nitrate
nitrogen equivalents and volume of water contributed by the first source,
respectively,; . C^> and.-.. A^ .the second source, and Cn and Vn are the
last (nth) source.These data are compiled, summed and substituted in the
equation to calculate an estimate of the nitrate nitrogen concentration
for ground water at the well (C ). It is repognizedthatvthis calcula-
tion is an estimate that approximates the concentration of nitrate at a
public supply well under several simplifying conditions, none of which are
expected to be fully met in an actual situation. The process of denitri-
fication of groundwater has not yet been described in sufficient detail to
allow its inclusion in these calculations and is omitted. The resulting
influence of this omission on the calculation is expected to be small
because of the low .rate of the denitrification in groundwater, but the
calculation should result .itira slightly higher estimate than would actu-
ally occur. Other inaccuracies of the calculated concentration may be
introduced by the imprecision with which the individual loads are esti-
mated, the imprecision of the mapping of the municipal wellhead protection
area (Zone II), and the areal variation of recharge from precipitation
over the Zone. The nitrate concentrations calculated by this approach are
intended to be a guide for broad decisions on limiting land uses that
increase nitrate nitrogen in water supply wells. The significance of
nitrate as a contaminant and an indicator of contamination for public
health in drinking water is described in the introduction to this report.
Applications
The prediction of nitrate concentration at a well by the dilution
accounting approach can be used to evaluate the potential for exceeding
nitrate concentration health limits or planning goals. Dilution account-
ing calculations also can be used to assess the relative effects of vari-
ous specific land uses or levels of development on water quality. In
these applications, nitrate dilution accounting is a water quality plan-
ning and management tool that can be used to guide decisions. To calcu-
.late nitrate concentrations in milligrams per liter, the water volumes and
nitrate weights given in many references and in Appendix A of this report
must be converted to the metric units. Some examples of calculations and
discussion of their potential use for planning and management of ground-
water quality follow.
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Example No. 1: Effects of existing and proposed land uses on the nitrate
concentration for a well
Dumped at 1 million gallons per dav (Fi
e. 4)
Table No. 1 - Summary of nitrate loads from septic systems for average one day period
for a well pumped at 1 million gallons per day (in liters and milligrams per day)
SOURCE F10W
(eallons/d)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
1/2 acre housing
High school
65/person
20/student
Fast food 150/seat
Restaurant (table seat) <
Fast Food 350/seat
Restaurant (counter seat)
One acre housing
Condominium
Shopping center
Office building
Gas station
Church
Motel A
Motel B
13. Hospital
Totals (VJ+V9+...+V,,;
65/person
65/person
60/employee
15/employee
500/island
3/seat
75/person
75/person
200/bed
)
• UNITS VOLUME CONCENTRATION** LOAD
(•variable) QitersAD (me/L} (me./d)
400 people
1,000 students
70 seats
10 seats
200 people
120 people
50 employees
25 employees
2 islands
200 seats
40 people
160 people
60 beds
98,410
75,700
39,740
13,250
49,210
29,520
11,360
1,420
3.785
2,270
11,355
45,420
45,420
426,860 (L,
40
40
40
35
40
40
40
40
40
40
35
35
35
+LO+ . . . +LI •
3,936,400
3,028.000
1,589,700
463,750
1,968,400
1,180,800
454,400
56,800
151,400
90,800
397,425
1,589,700
1,589,700
,) 16,497,275
Note: Values are selected from Appendix A, nitrate concentrations in effluent were
increased by 5 mg/L based on the assumption that public water supply would not
exceed the 5 mg/L planning goal, the 453,592 milligram per pound conversion was
rounded to 454,000 milligrams per pound, and a conversion factor of 3.785 liters
per gallon was used. Volume was rounded to nearest 5 liters.
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14
Table No. 2 - Summary of solid nitrate loads in milligrams per day
14.
15.
SOURCE
Lawns (5,000 ft2)
Horses @ 1,200 Ib
UNITS
100 lawns
6 horses
NITRATE
(pounds/d)
0.025*
0.027/100
MILLIGRAMS/POUND
454,000
Ib 454,000
LOAD
fmpAn
1,135,000
882.580
each of animal
Total (L14+L15> 2,017,580
Note: Based on 9 Ibs/yr of nitrate leaching into the groundwater >system from 5,000
ft of lawn (Cape Cod Planning and Economic Development Commission, 1979)
(Vl + V2 +...+V13) = 426,860 liters
(Lx + L2 +...+L15) = 2,017,580 + 16,497,275 = 18,514,855
By substituting the calculated total volume and total load in the mixture equation
described above, the concentration' of nitrate at the pumped well can be calculated
as follows:
Calculation No. 1
Cr x
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15
Example No.2: Prediction of the effect of a proposed forty bed addition
to the hospital in Example No.l.
The predicted 4.94 mg/L concentration is close to the planning goal of
5 mg/L. The advisability of permitting a proposed 40-bed addition to the
hospital (fig. 6, table 3) in the zone of contribution can be determined
by predicting its effect on nitrate concentration in the well. To
calculate the nitrate concentration that would result with the hospital
addition, the estimated additional water volume and additional nitrate
load can be added to the previously determined totals and the new totals
substituted in the equation.
Table No. 3 - Increase in nitrate load due to proposed hospital addition
SOURCE FLOW UNITS VOLUME CONCENTRATION LOAD
(gal/d) (variable) Qiters/d) (mg/L) (me/d)
16. Hospital
addition 200/bed 40 beds 30,280 35 1,059,800
Calculation No. 2
(Vj+V2+...+V14) + V16 = 457,140 liters
(L1+L2+...+L16) - 19,574,655 milligrams
Cr x (Vw-0.9 x (7^2+...+V)) + (1^+1^+.
-Cw
Vw
0.05x(3,785,000-0.9x(457,140)) + 19,574,655
Cw
3,785,000
Cw - 5.22 mg/L (nitrate)
Calculation No. 2 includes the water volume and nitrate load that
would be caused by the hospital addition, and exceeds the planning goal of
5 mg/L. If the planning goal is to be upheld, then the conclusion must be
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16
to deny approval of the hospital addition as proposed. In this way, the
nitrate accounting equation becomes a decision-making tool for limiting
the amount of nitrate discharged to the wellhead protection area. It can
also be used to compare various potential development plans and to select
future development alternatives. For example, the effect of sewering
could be predicted by subtracting the load of nitrate that would be
sewered rather than discharged within the Zone II.
Example No. 3: Effects of existing land uses in Example No.l on nitrate
for the same well with pumping reduced to 0.5 million gallons per day
This example considers a nonuniform distribution of nitrate sources
and a reduced pumping rate. Because a well may-not be pumped at the same
rate every year and because there is no guarantee that the sources of
nitrate will be uniformly distributed within the zone of contribution,
additional calculations are advisable. If a lower pumping rate is
assumed, then the predicted zone of contribution to the well will be
correspondingly smaller and closer to the well. See Figure 4 which shows
the zone of contribution for a well pumped at 1 million gallons per day
and a smaller zone of contribution for the same well when pumped at 0.5
million gallons per day. By summing the water volume and nitrate load
produced by the sources within the smaller zone and solving the equation
to predict the nitrate concentration at the well, it is possible to
determine whether the 5 mg/L planning goal would be exceeded at a lower
pumping rate. Comparison of the two nitrate concentration predictions
under different pumping rates would also indicate whether the sources of
nitrate are uniformly distributed within the larger wellhead protection
area, or whether they are concentrated close to or far from the well.
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17
Table No. 4 - Summary of nitrate loads from septic systems for average
one day period - 0.5 million gallon per day public supply well
SOURCE FLOW
( gallons /d)
1.
2.
3.
4.
5.
6.
7.
1/2 acre housing
High school
Condos
Shopping center
Office building
Gas station
Motel B
Totals
65/person
20/student
65/person
60/employee
15/employee
500/island
75/person
(L! + L2+.
UNITS
(variable)
300 persons
1,000 students
120 persons
50 employee
25 employee
2 island
160 persons
. .+L7)
VOLUME
(liters/d)
73,807
75,700
29,523
11,355
1,419
3,785
45.420
241,009 (V
CONCENTRATION
(me/L)
40
40
40
40
40
40
35
i + v2+...+v7)
LOAD
(mg/d)
2,952,300
3,028,000
1,180,920
545,200
56,760
151,400
1.589.700
9,504,280
Table No. 5 Summary of solid nitrate loads for average one day
period - 0.5 million gallon per day public supply well
8.
SOURCE
Lawns
(5,000 ft2)
UNITS
(variable)
50
NITRATE
(pounds /d)
0.025
MILLIGRAMS/POUND
CONVERSION
454,000
LOAD
(me/d)
567,500
Calculation No. 3
(Vj+V2+...+V7) - 241,010 liters
(L1+L2+...+Lg) = 10,071,780 milligrams
Cr x (Vw-0.9x(V1+V2+...+Vn))
Cw -
Cw -
*w
.05 x (1,892,500-0.9 x (241,010)) + 10,071,780
1,892,500
Cw •= 5.37 mg/L nitrate
-------
18
In this example, because the loading sources were more heavily concen-
trated close to the well, the nitrate concentration predicted for the
smaller zone of contribution is higher than that calculated for the larger
zone, violating the 5 mg/L planning goal. Similarly, calculations of load
can be expanded to account for larger areas of contribution if additional
pumping is planned.
Example No. 4: Application to glacial-valley aquifers
Most public supply wells in New England are in glacial-valley aquifers
bounded by less permeable till and bedrock uplands and by streams. To
account for nitrate loading in these aquifers, some additional components
must be added to the dilution accounting equation. Where a well derives
part of its yield from induced infiltration from a stream (figs. 1 and 5),
the quantity of water (Vg) and nitrate concentration (Cg) of the
stream water must be entered into the accounting. Similarly, where water
drains from beyond the aquifer into the zone that contributes water to the
well (Figs. 1 and 5), the volume of that water (Vjjj) and the nitrate
concentration of that water C^jj must be entered in the accounting.
These considerations result in the following expansion of the dilution
accounting equation:
Concentration precipitation load + source load + stream load + Zone III load
at public = '•
supply well total volume of water pumped
or,
Cr x (Vw~Vs~VIII"^'^ x (vl+ V2+1 ' >+Vn^+^Ll+L2+'''+I^^+^Vs x Cs^+^VIII x CIII^
Vw
Where the new terms are:
V_ = Volume of induced infiltration from streams, in liters:
o
volume of drainage from Zone III into Zone II, in liters;
Cs = nitrate concentration in induced infiltration, in milligrams per
liter; and
nitrate concentration of drainage from Zone III to Zone II, in
milligrams per liter.
The volume of water from streams and the volume of water from Zone III
are essential ingredients for the determination of the zone of contribu-
tion to a well (Donohue, 1986 and Morrissey, 1987) and, therefore, must be
available wherever the zone of contribution (Zone II) has been determined.
-------
19
ZONE 1-400 foot radius about public supply well
NOT TO SCALE
ZONE Ih-Land surface overlaying the part of the aquifer that contributes
water to the well
ZONE Ill-Land surface through and over which water drains into Zone II
DRAINAGE DIVIDE
FIGURE 5: Idealized map view of glacial-valley aquifer showing the zones
and stream which contribute water ,to a public supply well
-------
20
In Massachusetts , nitrate concentration data for streams may be available
from the Division of Water Pollution Control or samples may have to be
collected for chemical analysis. Estimates of the nitrate concentration
of water draining from Zone III could be made from a dilution accounting
calculation for that zone, or chemical analysis of representative water
samples might be used.
Appendix B is a computer spreadsheet for applying this accounting
approach to a public supply well in the most complicated case where there
are contributions from surface water and from Zone (III) outside of the
aquifer. If no water is contributed from these sources, as on Cape Cod,
then zeros are entered for Vs, C , V-r-r-r, and
From inspection and comparison of the calculated nitrate loads from
various sources , a relative ranking of the importance of the sources can
be developed. Once the nitrate loading data are entered into an automatic
spreadsheet, such as shown in Appendix B of this report, only minor
modifications are necessary to make sensitivity analyses to test for the
consequences of different development levels or scenarios . Assessment and
comparison of the potential effects of all sources through the nitrate
accounting process described here assists in the recognition of greatest
threats to water quality and corresponding selection of priorities and
scale of groundwater quality management efforts.
ASSUMPTIONS AND QUALIFICATIONS
1. The nitrate accounting approach described here provides the necessary
information for land use decisions that will limit groundwater contam-
inants in the wellhead protection area of wells completed in water
table aquifers. The approach is appropriate for contaminants that
are attenuated predominantly by dilution and that may be tolerated in
the 1-to 500-mg/L range of concentration, such as nitrate, chloride,
and total dissolved solids. The approach should not be used to manage
or evaluate threats from other types of contaminantion, such as sol-
vents and fuels. The nitrate predictions that result are approxima-
tions of long-term average concentrations, which are imprecise in that
actual concentrations may be expected to be above and below the
average. For this reason, a planning standard, or goal, of 5 mg/L,
which is lower than the 10 mg/L health standard, has been advocated by
the Cape Cod Planning and Economic Development Commission and is used
in the examples in this guide .
2. The approach assumes that, under steady-state withdrawal conditions,
all of the water and nitrate withdrawn from the well are derived from
the zone of contribution for the well, and that only some of the water
withdrawn is returned to the zone of contribution as return flow. In
those situations where a well derives some of its yield from induced
infiltration from streams or other surface water bodies, the quantity
and quality of induced infiltration need to be entered in the account-
ing. The quantity of water derived from induced infiltration would
-------
21
have been computed in order to delineate the zone of contribution and,
therefore, would be available for nitrate calculations. In those
situations where a well derives some of its yield from an area of till
upland beyond the boundary of the aquifer from which ground and
surface water drain (Zone III), the quantity and quality of such
drainage need to be entered in the accounting.
3. The formula predicts concentration at the well under steady-state
conditions where all of the water from the zone of contribution is
mixed. Individual plumes with elevated concentrations of contaminants
would be expected to emanate from septic systems and other sources
within the zone of contribution. Therefore, the prediction should not
be used to determine contaminant concentration at other points within
the aquifer, or to determine the concentration in any smaller (private
domestic supply) wells within the zone of contribution.
4. The contaminant (nitrate) is considered to act conservatively. It is
not absorbed or adsorbed by aquifer materials. Attenuation is assumed
to occur only through the process of dilution. Some diminishment of
nitrate through other processes is known to occur, but the quantities
affected are not large enough to be considered in these gross
calculations.
5. The zone of contribution to the well is assumed to remain constant in
size and shape for application of the nitrate accounting approach
described here. Actually, the size of the zone is expected to become
smaller as more return flow from septic systems recharges the zone of
contribution, but additional recalculations of the zone of contribu-
tion would most likely be expensive and have an unacceptably high cost
to benefit ratio. Therefore, this assumption results in protection in
a zone slightly larger than may actually contribute water to the well
and is therefore considered conservative if sources are uniformly dis-
tributed. Recharge to the aquifer is assumed to be uniform over the
zone of contribution. Where variations of aquifer properties or sur-
face drainage characteristics cause irregular distribution of re-
charge, both the delineation of the zone of contribution and the cal-
culation of contaminant concentration would have to take those varia-
tions into account. Under such conditions, the predictive approach
described in this guide may not be accurate.
6. For the examples shown here, return flow of public supply water is
estimated to be 10 percent less than the quantity of water supplied
because of evaporation and transpiration from outdoor uses and from
septic system leach fields. Future research may indicate that the
return flow from septic systems is somewhat different. The 10 percent
value is based on the findings of Cape Cod Planning and Economic
Development Commission and estimates for Long Island, New York. Soil
conditions over other aquifers will most likely allow different rates
of evaporation and transpiration.
-------
22
7. On the basis of nitrate analyses of about 5,000 water samples from
shallow wells on Cape Cod, the nitrate concentration of groundwater
recharge was estimated to be 0.05 mg/L for the examples in this
guide. The concentration of nitrate in recharge may vary considerably
from region to region primarily because of differences in quality of
precipitation, soils, and geology. Application of the nitrate account-
ing approach described here needs to take these local geochemical and
hydrologic conditions into consideration.
8. It is necessary to demonstrate that the sources of nitrate are rela-
tively uniformly distributed within the zone of contribution by using
the technique for predicting nitrate concentrations at the well for
lower withdrawal rates. Without application of the prediction for
lower withdrawal rates, it would be possible for land uses to be
concentrated about a well in such a pattern that although the nitrate
planning goal is not exceeded at the maximum withdrawal rate, it might
be exceeded at some lower withdrawal rate. This is a significant
consideration, because withdrawal rates from an individual well are
commonly changed from time to time.
CONCLUSION:
This nitrate accounting approach can be used to predict nitrate
concentrations in public supply wells. These predictions will allow
planners and managers to recognize what level of incremental development
will cause violations of nitrate planning goals thereby signaling the need
to cease further development of nitrate loading activities within the zone
of contribution. Alternatively, predictions may be used to indicate the
level of development at which sewering within the zone of contribution
would be needed to limit nitrate contamination of a public supply well.
Most importantly, this nitrate accounting approach provides a technical
basis for evaluating future alternative development plans and for compar-
ing tradeoffs between various land uses and development proposals in
groundwater quality protection areas.
-------
23
REFERENCES CITED
1. Bear, Jacob, 1979, Hydraulics of Groundwater: New York, N.Y.,
McGraw-Hill, Inc., 569 p.
2. Cape Cod Planning and Economic Development Commission (CCPEDC) 1978,
Environmental Impact Statement and 208 Water Quality Management Plan
for Cape Cod, Vol. 1 and Vol. 2, 340 p.
3. Cape Cod Planning and Economic Development Commission (CCPEDC) 1979,
Water Supply Protection Project - Final Report: ..Barnstable, Bourne,
Brewster, Dennis, Yarmouth, 20 p.
4. Dewalle, F.B. Kalman, D.A., Norman, 6., Plews, 6., 1985, Determination
of toxic chemicals in effluent from household septic tanks: U.S.
Environmental Protection Agency, Water Engineering Research Laboratory
EPA/600/S2-85/050, 9 p.
5. Donohue, J. J. IV, 1986, "Zone II Determination: A Case Study of Two
Hydrogeological Investigations," Proceedings of the Third Annual
Eastern Regional Ground Water Conference, National Water Well Associa-
tion, Dublin/Ohio, pp. 54-63.
6. Dorsch, M.M., 1984, "Congenital Malformations and Maternal Drinking
Water Supply in Reval, South Australia, American Journal of Epidemio-
logy, Vol. 119, No. 4, pp. 473-486.
7. LeBlanc, D.R., 19B4, "Sewage Plume in a Sand and Gravel Aquifer, Cape
Cod, Massachusetts," U.S. Geological Survey Water Supply Paper 2218:
Washington,D.C., Government Printing Office, 28 p. /
8. LeBlanc, D.R., Guswa, J.H., Frimpter, M.H. and Londquist, C.J. 1987,
"Ground-Water Resources of Cape Cod, Massachusetts," U.S. Geological
Survey Hydrologic Atlas 692, Washington, D.C., U.S. Government
Printing Office, 4 pis., scale 1:48,000.
9. Massachusetts Aquifer Land Acquisition Program Regulations (310 CMR
25.00), 1983, Massachusetts Department of Environmental Quality Engi-
neering, Division of Water Supply, Boston, Massachusetts, 4 p.
10. Massachusetts Department of Environmental Quality Engineering, Divi-'
sion of Water Supply, 1986, Hydrogeologic Study Requirements for the
Delineation of Zone II and Zone III for New Source Approvals, Boston,
MA, 11 p. (
^
11. National Research Council, 1977, "Drinking Water and Health", Washing-
ton, National Academy of Sciences, 939 p.
12. U. S. Environmental Protection Agency, 1975, Water programs, national
, ' interim primary drinking water regulations, V. 40, No. 248, Wednesday,
December 24, 1975, Part IV, p. 59566-59587. ' ^
-------
24
GENERAL REFERENCE LIST
1. Anderson - Nichols and Co., Inc., 1985, Edgartown Water Resource
Protection Program - Final Report
2. Bear, Jacob, 1979, Hydraulics of Groundwater: New York, N.Y.,
McGraw-Hill, Inc.
3. Belfit, G., 1986, Personal communication concerning fertilizer appli-
cation rates to golf courses on Cape Cod: Cape Cod Planning and
Economic Development Commission (CCPEDC).
4. Bennett, E.R., Leach, L.E., Enfield, C.G. and Walters, D.M., 1985,
Optimization of nitrogen removal by rapid infiltration: U.S. Environ-
mental Protection Agency, EPA/600/S2-85/016.
5. Cape Cod Planning and Economic Development Commission (CCPEDC), 1979,
Water Supply Protection Project - Final Report: Barnstable, Bourne,
Brewster, Dennis, Yarmouth.
6. Cape Cod Planning and Economic Development Commission (CCPEDC),
1978, Environmental Impact Statement and 208 Water Quality Management
Plan for Cape Cod, Vol. 1 and Vol. 2.
7. Clark, B., 1986, Communication concerning fertilizer application
rates, leaching rates and grass types on Cape Cod: Barnstable County
Extension Service - personal communication.
8. Cooper, R., 1986, Communication concerning fertilizer components,
application rates, potential for leachability or uptake, and
fertilization rates: UMASS, Amherst, MA, Dept. of Plant and Soil
Sciences.
9. Cornell University, 1974, Nitrogen utilization by crops: Cornell
Field Crops Handbook.
10. Deubert, K.H., 1986, Communications concerning nitrogen loading in
the form of fertilizers for cranberry bogs: Wareham, MA. Cranberry
Experiment Station - personal communication.
11. Dewalle, F.B., Kalman, D.A., Norman, G., Plews, G., 1985, Determina-
tion of toxic chemicals in effluent from household septic tanks: U.S.
Environmental Protection Agency, Water Engineering Research
Laboratory, EPA/600/S2-85/050.
12. Dickey, E.G. and Vanderholm, D.E., 1981, Vegetative filter treatment
of livestock feedlot runoff: J. Environ. Quality., Vol. 10, No. 3.
13. Douglas, D.F. 1986, Literature Review of the Cumulative Impact of
On-Site Sewage Disposal Systems on Nitrate - Nitrogen Concentrations
in Ground Water: Ground Water Management Section. Department of
Water Resources and Environmental Engineering, State of Vermont.
-------
25
14. Dorsch, M.M., 1984, "Congenital Malformations and Maternal Drinking
Water Supply in Rural South Australia: A Case-Control Study,"
American Journal of Epidemiology, the John Hopkins University of
Hygiene and Public Health.
15. Eckenfelder, W.W. Jr., 1970, Water quality engineering for practicing
engineers: Boston, MA, Cahner Books International, Inc.
16. Edwards, W.M., Chister, F.W. and Harrold, L.L., 1971, Management of
barnlot runoff to improve downstream water quality: International
Symposium on Livestock Wastes pp. 48-50, 1971.
17. Gerhart, J.M., 1986, Ground-water recharge and its effects on nitrate
concentrations beneath a manured field site in Pennsylvania: Ground-
water, Vol. 24, No. 4, July-August.
18. Harper, J., 1983, Turf and garden fertilizer handbook: Washington,
D.C., The Fertilizer Institute.
19. Hem, J.D., 1970, "Study and Interpretation of Chemical Characteristics
of Natural Water," U.S. Geological Survey Water Supply Paper 2218:
Washington, United States Government Printing Office.
20. Heufelder, G., 1986, Barnstable County Board of Health, Personal
communication.
21. Hinisk, W.W., 1978, Forty questions and answers on manure: Penn-
sylvania State University, College of Agriculture, Leaflet No. 213.
22. Holyoke, V., 1981, Manure is not an evil: New England Farmer.
October 1979.
23. LeBlanc, D.R., 1984, "Sewage Plume in a Sand and Gravel Aquifer, Cape
Cod Massachusetts," U.S. Geological Survey Water Supply Paper 2218:
Washington, United States Government Printing Office.
24. Litchfield, J.H., Meat, fish, and poultry processing wastes: Water
Pollution Control Federation, Volume 56, Number 6.
25. Livestock waste facilities handbook.
26. MacQueen, M., 1986, Pilgrim Resource Conservation and Development
Council, Middleboro, MA, personal communication.
27. Metcalf & Eddy, Inc. 1972, Wastewater: collection, treatment, dis-
posal: New York, McGraw Hill.
28. National Research Council, 1977, "Drinking Water and Health," Washing-
ton, National Academy of Sciences.
-------
26
29. North Carolina State University, 1978, Best management practices for
. agricultural nonpoint source control: Biological and agricultural en-
gineering department, North Carolina State University, Raleigh, N.C..
30. Tchobanoglous, G., rev., 1979, Wastewater engineering: treatment dis-
posal, reuse: New York, McGraw-Hill.
31. Tchobanoglous, G., Theisen, H., and Eliasses, R., 1977, Solid wastes:
engineering principles and management issues: New York, McGraw-Hill
Book Company.
32. U.S. Environmental Protection Agency, 1977, Process design manual for
land treatment of municipal wastewater: U.S. Environmental Protection
., Agency, Office of Water Program Operations, EPA 625/-77-008 (COE
EM1110-1-501).
33. U.S. Environmental Protection Agency, 1984, Handbook for septage treat-
ment and disposal: U.S. Environmental Protection Agency, Environ-
mental Research Laboratory, Ohio, EPA 625/6-84-009.
34. U.S. Environmental Protection Agency, U.S. Army Corps of Engineers,
U.S. Department of Interior, U.S. Department of Agriculture,, 1981, Pro-
cess design manual for land treatment of municipal wastewater: U.S.
Environmental Protection Agency, Center for Environmental Research
Information, EPA/625/1-81-013 (COE EM1110-1-501).
5. U.S. Environmental Protection Agency, 1977, Alternatives for small
wastewater treatment systems, EPA/625/4-77-011.
36. U.S. Environmental Protection Agency, October 1975, Process design
manual for nitrogen control: U.S. Environmental Protection Agency,
Office of Technology Transfer, Washington, D.C.
37. U.S. Department of Agriculture, U.S. Environmental Protection Agency,
1979, Animal waste utilization on cropland and pastureland: USDA
Utilization research report No. 6, EPA - 600-2-79-069.
38. United States Geological, Survey, 1986, Personal communication con-
cerning water quality analysis for public water supply wells on Cape
Cod; Water Resources Division - Boston, MA.
39. Wehrmann, A.E., 1983, Potential nitrate contamination of groundwater
in the Roscoe area, Winnebage County, Illinois: Champaign, Illinois:
Illinois State Water Survey.
40. Wells, R.G., 1986, Communications concerning the .appropriate appli-
cation rates for fertilizers: Washington, D.C., The Fertilizer
Institute.
41. Young, R.A., Huntrods, T. and Anderson, W., 1980, Effectiveness of
Vegetated buffer strips in controlling pollution from feedlot runoff:
Journal of Environmental Quality, Vol. 9, No. 3, 1980.
-------
APPENDIX A
NITROGEN CONCENTRATIONS ASSOCIATED WITH DIFFERENT LAND USES
Page Section Title
A-1 1 Sewage Flow Volumes and Nutrient Concentrations
A-4 2 Animal Feedlot Nitrogen Production
A-5 3 Nutrient Utilization by Crops, Trees and Ground Cover
A-6 4 Uastewater Treatment Facilities
A-7 5 Septage Pits and Lagoons
A-7 6 Cranberry Bogs and their Fertilization
A-7 7 Fertilizers and Lawns
A-9 8 Nutrient Input from Lawn Fertilizers
A-10 9 Nitrogen Leachability
A-12 10 Golf Courses
A-13 11 Precipitation .
TABLES
Page Table Title
A-1 • 1A Sewage flow volumes and nitrate concentrations
A-4 2A Feedlot Wastes
A-4 2B Influence of Time and Wind Speed on Nitrogen Losses
A-5 3A Nutrient Utilization by crops, trees and commonly occurring ground cover
A-6 4A Nitrogen removal variations
A-8 7A Common Grass Types
A-11 9A Nitrogen Leachability
-------
Section 1.
Sewage Flow Volumes and Nutrient Concentration
The following Table 1A is a list of sewage flew volumes commonly discharged from commercial, recreational and domestic land uses.
The nitrate nitrogen figure presented is the concentration of nitrate nitrogen expected to be generated, assuming ammonia nitro-
gen has been bacterially oxidized and is in the nitrate form.
Table 1A - Sewage Flow Volumes and Nitrate Concentrations
Land Use
Unit
Flow-GPD/
Person or Unit
Concentration
of NOj-N mg/l
Ibs. NCyN/
1000 gallons of Wastewater
Cone.
in mg/l Ibs. NC-N.
1) Restaurants
'A. food service-lounge tavern
B. thruway service area
thruway service area
C. short order
0. bars, cocktail lounge
E. average type
average type
F. cafeteria
G. mess hall
H. coffee shop
2) Schools
A. day/cafeteria
B. day/cafeteria showers
C. day
D. high school
E. elementary
F. boarding
seat
table seat
counter 'seat
person
person
seat
meal
seat
person
person
person
person
person
person
person
person
35
150
350
4
2-20
35
7
150
15
250
10-15
20
10
20
10
75
35-40
35-40
30-35
35-40
35-40
35-40
35-40
30-35
30-35
30-35
35-40
30-35
35-40
30-35
35-40
30-35
10
30
35
40
45
50
100
0.08
0.25
0.29
0.33
0.38
0.42
0.83
A-1
-------
Table 1A • Sewage Flow Volumes and Nitrogen Concentrations - continued
Table 1A • Sewage Flow Volunes and Nitrate Concentrations
Land Use
3) Parks/Campgrounds
A. developed campground
B. camp/mess hall
C. day camp/no meals
D. luxury camp/private bath
E. traitor/toilet/bath
F. trailer village
G. trailer dump station
H. lodge/cabin
I. picnic parks/toilets
J. park/shower/toilet
K. swimming pool/beaches
4) Hospitals
A. hospital
B. hospital
C. prison
5) Recreation
A. fairgrounds/daily
B. assembly halls
C. theatre/auditoriun/inside
D. theatre/outside/food stand
E. gymnasium
F. country club-resident type
G. country club-transient/meals
H. church
I. bowling alley
J. skating rink (3000 gpd+)
Units
person
person
person
person
2 1/2 persons
person
per site
person
person
person
person
bed
person
person
person
person
person
car
person
person
person
seat
alley
seat
Flow-GPO/
Person or Unit
25
15
10
75-100
125-150
35
50
50
5-10
10
10-15
200
125-200
175
1
2
3-5
3-5
3-25
20-100
17-30
3
100-200
5
Potential
Concentration
of NOj-N mg/l
35-40
35-40
35-40
30-35
30-35
35-40
35-40
35-40
35-40
35-40
35-40
30-35
30-35
30-35
35-40
35-40
35-40
35-40
30-35
30-35
35-40
35-40
35-40
30-35
A-2
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Table 1A • Sewage Flow Votunes and Nitrate Concentrations - continued
Land Use
6) Commercial.
A. gas stations
B. gas stations
C. office building
D. office building
E. barber shop/beauty parlor
f. dry good store
G. stores -
H. stores
I. shopping center
Units
island
vehicle
person
1000 ft.2
seat
100 ft. 2
1st 25 ft. of frontage
additional 25 ft.
employee
Flow-GPO/
Person or Unit
300-500
10
10-15
75
100
5
450
400
60
Potential
Concentration
of NOj-N rag/I
35-40
35-40
35-40
35-40
30^35
35-40
35-40
35-40
35-40
7) Dwellings
A. private - pub/priv. water supply
B. apartments/private wells
C. single/multiple
D. general
E. hotels
F. motels
G. boarding house1
H. mobile home park
I. co I leges,: boardi ng • schoo I s
J. residence 'homes/apartments
K. dormitory, bunkhouse
L. construction camp
M. private dwellings
person
person
per bedroom
person
person
person
•person
site
person
person
person
person
110 gal
50-70
75-100
110
55
50-100
50-75
50-75
200
50-65
75
50
50
10-15,000 ft2
30-35
.30-35
30-35
30-35
35?40
30-35
30-35
35-40
,35-40
35-40
35-40
35-40
30-35
Some of the flow/unit values appearing in the above, table have been taken from "310 CMR 15.00" The State Environmental Code-Title
5 Minimum requirements for the subsurface disposal of sanitary sewage." -Title 5 provides flow estimates • for varying land uses.
These values are to be used when sizing a leaching area as part of a subsurface wastewater disposal system.
The potential concentration of NO,-N mg/1 values have been taken from planning documents and sampling date collected by the
Massachusetts Department of Environmental 'Quality' Engineering. The -values : wilt vary depending on water use practices. For
example, a business that employs strict water conservation techniques and hardware will have a higher concentration of NOj-N
when measured as milligrams per liter.
A-3
-------
Section 2 - Animal Feedlot Nitrogen Production
Table 2A presents the nitrogen production potential common to animal feedlot waste products:
TABLE ZA - FEEDLOT WASTES
Ibs/day of nitrogen per
Animal 100 Ibs of animal
without loss
Dairy Cattle . 0.040
Beef Cattle 0.034
Finishing pig 0.045
Sow and litter 0.060
Sheep 0.045
Horses 0.027
Chickens 0.087
Ducks 0.142
Generally one ton (2000 Ibs) of manure is composed of 1380 Ibs. solid and 620 Ibs. of liquid. The liquid portion of manure is
immediately available for plant uptake. Only a small percentage of the solid portion is available the first year, prior to bacte-
riological breakdown of solids in the soils. The potency of manure is greatly decreased because of failure to utilize the liquid
portion and excessive nitrogen loss from solids by ammonia volatilization, due to volatilization and evaporation.
TABLE 2B • INFLUENCE OF TINE AND WIND SPEED ON NITROGEN LOSS
Percent Total nitrogen lost
Manure spread Ho wind 8 1/2 moh wind
12 hrs. 3 68°F 7.7 percent 25 percent
36 hrs. a 68°F 23 percent 31 percent
7 days a 68°F 36 percent 37 percent
Manure that is not collected and applied promptly and properly has very limited value. Ten tons of potent manure (20,000 Ibs) is
comparable in nutrient value to 500 pounds of a 10-6-10 (nitrogen-phosphorous-potash) commercially available fertilizer.
A-4
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Section 3 - Nutrient Utilization by Crops. Trees, and Ground Cover
Uhen considering the amount of nitrogen available to leach throughout vegetated top soils and surficial deposits, the nitrogen uptake poten-
tial of the ground cover must be considered. Table 3A presents values from the literature describing the nitrogen uptake potential for sev-
eral crops and ground covers.
TABLE 3A - NITROGEN UTILIZATION BY CROPS AND COMMONLY-OCCURRING GROUND COVER *
pounds of nitrogen
Vegetative Type per acre per year
corn 250
grass-legume hay 300
oats 60
sunnier annuals 200
pines (trees) 27-62
mixed coniferous 36-71
deciduous (trees) 44-88
alfalfa 450
bromegrass 165
coastal bermuda grass 500
reed canary grass
rye grass 210
sweet clover 157
tall fescue 118
barley 62
cotton 66
milomaize 81
soybeans 94
kentucky bluegrass 178-240
quackgrass 210-250
orchardgrass 225-310
grain sorghum 120
potatoes 205
wheat 143
* Values used are approximations from current literature. The values presented include the nitrogen fixed from the air as N and nitrate
nitrogen in soils. To achieve these values the plant must be harvested.
A-5
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Section 4 - Wastewater Treatment Facilities
Different levels of sanitary wastewater treatment provide varying levels of nitrogen compound removal. Nitrogen remaining after treatment
will presumably be converted to the nitrate form some distance from the subsurface discharge point. Water quality analysis conducted for
municipal wells on Cape Cod supports this presumption. Host samples collected contain nitrate but very limited nitrogen in the ammonia
form.
The Massachusetts regulatory agencies consider primary treatment of effluent to be removal of at least 25% of the five day Biological Oxy-
gen Demand (BOO,) 55X of the suspended solids and 85X of the floating solids and solids that settle out. Secondary treatment is con-
sidered to be removal of at least 85X 800, and suspended solids and removal of all settleable and floating solids. Advanced treatment
is considered any treatment form exceeding secondary treatment. Examples of advanced treatment would be the addition of a nitrification/de-
nitrification stage for nitrogen removal or carbon filtration or an air stripper for the elimination of volatile organic chemicals.
TABLE 4A - NITROGEN REMOVAL VARIATIONS
Treatment
Process
primary
secondary
advanced
(denitrification)
Nitrogen Removal
Potential X
no removal 0-10X
none-slight 0-30%
70-95X
Total
Nitrogen Concentration
of Untreated Effluent
ma/1
40
40
40
Total
POST Treatment
Nitrogen Concentration
mg/l
35-40
25-40
6-10
In the Commonwealth of Massachusetts treatment plant discharges to ground-waters are required to discharge at or below the drinking
water standard for nitrates or total nitrogen (10 mg/l) if they are an industrial discharger, discharge over 150,000 gallons per day of
sanitary wastewater or are considered by the regulatory agency to be in an environmentally sensitive area. The use of treatment plants is
required for all industrial discharges and sanitary wastewater discharges over 15,000 gallons per day. It is highly unlikely that the
State of Massachusetts would permit the construction of a municipal scale wastewater treatment plant within the delineated Zone II of a
public supply well. Location of commercial and large scale residential wastewater treatment plants is evaluated on a case by case basis
with drinking water supplies being considered the most important potentially impacted resource.
A-6
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Section 5 - Septage Pits and Sanitary Lagoons
Although great effort has been made by regulatory authorities to phase out "septage pits" as a disposal option, several municipal and
private pits/lagoons exist throughout the Commonwealth. Because of the less-dilute nature of septage the nitrogen levels (organic nitrogen
and ammonia-nitrogen) available for conversion to nitrate greatly exceed sanitary wastewater. The ammonia nitrogen levels commonly
observed in septage exceed 100 mg/l. EPA documents reviewed suggested that 150 mg/l would be an appropriate design figure although total
nitrogen concentrations observed in septage samples often approach 400 mg/l. One thousand gallons of septage has the potential to generate
between 0.83 and 1.25 pounds of nitrate nitrogen.
Section 6 - Cranberry Bogs and Their Fertilization
Massachusetts is this countries highest bulk producer of cranberries. This requires the use of thousands of acres of land for
cultivation and the use of tons of fertilizer to stimulate plant growth. Between ten and forty pounds of nitrogen/acre/year are applied to
cranberry bogs. Thirty Ibs/acre/year is assuned to be the average application rate. Nitrate applications are monitored carefully because
the plants will sprout leaves rather than berries if excessive quantities of nitrogen are applied. It is therefore probable that a large
percentage of the nitrogen applied to the bogs is utilized by the plant. Since the plant is harvested, very little plant decay matter is
available for bacteriological breakdown. Very acidic, low pH environments associated with bogs do not stimulate bacteriological activity
necessary for the conversion to nitrate. Surface water runoff via drainage ditches, flood channels or tributary streams associated with
bogs sometimes have elevated nitrate nitrogen concentrations.
Section 7 - Fertilizer and Lawns
Fertilizers are applied to ground covers and crops to stimulate growth and productivity. The following table describes the lawn
fertilizer application rates suggested by the National Fertilizer Institute in their publication "Turf and Garden Fertilization Handbook".
The rates of application suggested should stimulate maximum plant growth under most circumstances. The grasses listed are common ground
covers found throughout Massachusetts and the fertilizers are readily available commercial products.
A-7
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Table 7A
Common Grass Types - Reconroended Fertilizer Application
Grass Type
Kentucky Blue
Kentucky Blue
Rye
Rye
Tall Fescue
Tall Fescue
Leafy Fescue
Leafy Fescue
Fertilizer
regular
slow release
regular
slow release
regular
slow release
regular
slow release
Ibs/ni trogen
1000 ft2/vear
2-3
3-4
3-5
4-6
3
3-4
2
4
Recommended
Nunber of
Applications
3
2
3
2
2
2
2
2
Most cultivated lawns include these grass types in varying percentages. For example, an attractive, durable, well-maintained lawn may
include 40X Kentucky Blue grass, 30X fescue and 30X rye grass.
Section 8 - Nutrient Input from Lawn Fertilizers
The Long Island Cooperative Extension Service presented in a 1978 planning stud/, fertilizer application rates thought to be typical for
lawns on Long Island. It was assumed that:
o 3 IDS of nitrogen are applied per 1000 ft /yr of lawn
o most lawns are 5000 ft
o 1000 ft2 x 5 x 3 Ibs nitrogen = 15 IDS nitrogen/5000 ft2/yr
o 60% of nitrogen applied (15 Ibs) leached into groundwater
o 60% x 15 Ibs = 9 Ibs
o nitrogen converted to nitrate form
o 9 Ibs nitrate nitrogen /5000 ft lawn/yr leaches to groundwater
A-8
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Many factors play a part in determining the quantity of nitrogen that teaches into groundwater. When considering lawns the following fac-
tors appear to be of primary importance:
o fertilizer application rate
o type of fertilizer
o soil type
o precipitation/rates
o type of plant/uptake potential
o stage of plant growth
o frequency of harvesting - cut and remove
o nitrate in precipitation
o conversion from nitrogen to nitrate
o depth to water table
Conversations with several life long residents of Cape Cod suggest that the 3 lbs/1000 ft /yr figure utilized in the Long Island 208
study might be excessive when discussing the average lawn on Cape Cod. Golf courses on Cape Cod, meticulously maintained apparently apply
on the average between 3 and 4 pounds of nitrogen per 1000 ft per year. It is highly unlikely that the average lawn on Cape Cod is
maintained to such rigorous standards. For arguments sake we'll assume that'the average lawn of Cape Cod receives more than half the
fertilizer per unit area than that of a professionally maintained golf course. In this case a volume of 2 lbs/1000 ft /yr could be used
as an average, stretching the application rate to 3 Ibs for green lawn enthusiasts.
Section 9 - Nitrate teachability
Following a literature review and consultation with-people working in the agricultural disciplines, it appears that there is a probable
range of values representing the percent of-nitrate leaching into groundwater through vegetative cover and soils. Nitrogen applied to the
lard surface from various fertilizers is presumed to be converted to nitrate and from 10-60% of the volume initially applied will reach
the groundwater as nitrate. This large range of leaching nitrate is dependent on the factors listed above. Values in the neighborhood of
45-50% might be most representative of the Cape Cod environment. For the sake of argument several scenarios concerning fertilizer applica-
tions are presented below:
A-9
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Table 9A
Nitrogen Leachability
Application Rate
(lbs/1000 ft2/yr>
Average Lawn Size
(ft2)
Nitrogen leaching
(X)
Nitrate nitrogen volume
available to
groundwater (Ib/yr)
2
3
2
3
2
3
6
6
6
6000
6000
6000
6000
5000
5000
5000
5000
5000
10
10
45
45
60
60
10
45
60
1.0
1.5
4.5
6.75
6.0
9.0
3.0
13.50
18.00
Assuming average lawn sizes to be approximately 5000 ft (CCPEDC, 1979) these are the probable ranges of nitrogen likely to leach
into groundwater. The application rate of 6 lbs/1000 ft /yr was used to demonstrate volumes that are generated by over-zealous or in-
correct applications of lawn fertilizer. As was mentioned earlier, grasses are most productive when a specific quantity of fertilizer
is applied (per Table 7A). Over fertilization may be harmful to the plants and results in excess nitrogen available to leach into
groundwater. In this case, more is definitely not better.
Lawn sizes and fertilizer application rates vary greatly from region to region and from home to home. Local conditions should be
evaluated to accurately predict the effects of lawns on groundwater quality.
A-10
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Section 10 - Golf Courses
Fertilization rates for two golf course settings were available for review. Both courses are situated on Cape Cod.
Fertilization Rates For Two Golf Courses on Cape Cod
Application Rate
Area Ibs nitrogen/1000ft2/yr
fairways 3.1-4.0
greens 4.3-6.0
tees 3.8
rough 0-2.0
Since fairways generally constitute close to 90% of a golf course's total land area, the fertilizer application rates assigned to
fairways can be used to represent an overall application volume:
Ibs of nitrogen/acre/yr =
3.1-4.0 lbs/1000 ft2 X 43560 ft2/acre = between 135-17-lbs/acre/yr
Section 11 - Recharge from precipitation
Thirty percent of about 5,000 groundwater samples from Cape Cod had nitrate notrogen concentrations of 0.05 mg/L or less. These ni-
trate concentrations are interpreted to result from recharge of precipitation in undeveloped areas without anthropogenic sources in the
recharge area. Therefore, a recharge concentration, Cp, of 0.05 was used to calculate the nitrate load derived from'precipitation
for Cape Cod. This value is significantly lower than the 2 year nitrate nitrogen average concentration of 0.26 mg/L measured in pre-
cipitation at Truro on Cape Cod. The reduction of nitrogen concentration between precipitation and groundwater is apparently caused by
biological activity in the soil zone and at land surface. Nitrogen loads in precipitation, soil, and vegetative conditions vary
greatly from place to place and nitrate concentrations values for recharge need to be developed from emperical data representative of
the region for which the mass balance nitrate calculations are being made.
A-11
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APPENDIX B
Directions for the Preparation of a Computerized Spreadsheet
for Automated Calculation of Nitrogen Loads
by H. Gile Beye
A spreadsheet to calculate nitrogen loads can easily be set up with
Lotus 1-2-3 or similar software packages. A working knowledge of the
software, package is prerequisite to use of the spreadsheet. The example,
shown on p. B2 and described below, uses Lotus 1-2-3. The spreadsheet is
set up in seven parts. Each part generates values to ultimately be used to
solve the nitrate-loading mass-balance equation.
The first part of the spreadsheet, summary of liquid nitrate loads,
contains data necessary to calculate the sum of liquid nitrate load from
different land uses and also to calculate the total volume of water con-
tributed by the sources (VI + V2+...+Vn). The spreadsheet software package
does not accommodate subscripts, so the terms in the formula are modified
from those presented in the text. The calculations are based on long-term
averages for an arbitrary period of 1 day. The first column in part 1 of
the spreadsheet is labeled SOURCE. Listed in this column is the land use
source of nitrate. The next column is labeled FLOW. The flow is the
discharge from the source in gallons per day per person, seat, employee, or
other unit. The next column is labeled UNITS; it lists the number of units
in each land use category. The names of the units can be included to
clarify the FLOW and UNITS columns, as shown in the example. To do this,
set up a separate column for the names (Lotus does not allow letters to be
listed in the same column as numbers that will be used for calculations).
The next column is labeled VOLUME; the volume is calculated by multiplying
FLOW, UNITS and a conversion factor of 3.7853 (liters per gallon). To set
up this equation, type an opening (left) parenthesis, the cell address of
the first value in the FLOW column, an asterisk (*), the cell address of
the first value in the UNITS column, another asterisk, 3.7853, and the
closing (right) parenthesis. The resultant value appears in the first cell
of the VOLUME column. It represents the volume of discharge per land use,
in liters per day. Copy the formula into the other cells in the VOLUME
column (use the copy procedure in the Lotus menu). If data are missing
from the FLOW and UNITS column, a zero will appear in the VOLUME column.
This will be automatically replaced by a value when the data are entered in
those columns. The next column is labeled CONCENTRA TION. It is the
concentration of nitrate for each land use listed. The final column is
labeled LOAD. It is the total nitrate load per land use per day. This is
the product of the VOLUME and the CONCENTRATION columns. To compute the
load, type an opening (left) parenthesis, the cell address of the first
value in the VOLUME column, an asterisk, the cell address of the first
value in the CONCENTRATION column, and then a closing (right) parenthesis.
Copy this formula into each cell of the LOAD column. Then, total the
VOLUME column by typing at the bottom "@SUM (cell address of first value in
column..cell address of last value in column)." Type only the information
Use of product or trade names does not consitute endorsement by
the authors or their agencies.
-------
within the quotation marks, for example @SUM(G9..G22). This will give the
value for (VI + V2+...+Vn) in the final nitrate loading .mass balance
equation. To total the LOAD column, follow the same procedure.
The second part of the spreadsheet, summary of solid nitrate loads,
solves an equation which computes the load of solid nitrate, in milligrams
per day. The procedure for setting up this equation is the same as that
used for the liquid nitrate equation, except there will not be a FLOW
column. When the LOAD values have been calculated,•total the column using
the @sum procedure. The total solid nitrate load is added to the total
liquid nitrate load for a total load (LI + L2 +...+ Ln). Set this up as an
equation on a separate line in the spreadsheet. The equation is "(cell
address of total liquid nitrate load + cell address of total solid nitrate
load)".
The third part of the spreadsheet is the nitrate concentration in
recharge from precipitation (Cr). This varies from case to case. Enter on
this line the value to be used for the current case.
The fourth part of the spreadsheet converts the volume of pumpage from
well (Vw) from English (inch, pound) to Metric units (meter, gram). Set up
the equation with gallons per day in one column and the conversion factor
(3.7853) to change gallons to liters in the next column. In the third
column, type "(cell address of the gallons per day value * cell address of
the conversion factor). The resultant value, pumpage in liters per day,
will appear in the cell.
Part five of the spreadsheet, nitrate load of induced infiltration from
streams, is the product of the volume of induced infiltration from streams
(Vs) and the nitrate concentration of the induced infiltration (Cs).
Part six of the spreadsheet, nitrate load of drainage from Zone III to
Zone II, is the product of the volume of drainage from Zone II'I to -Zone II
(VIII) and the nitrate concentration of the drainage (CIII).
Part seven of the spreadsheet, concentration at well, is the final
equation. The equation using the variables defined in this spreadsheet
looks like this:
Cw = [Cr * [Vw-Vs-VIII -(0.9 * (VI + V2+...+Vn))] + [(LI + L2
+ ...+Ln) + (Vs * Cs) + (VIII * GUI)] /Vw.
Set this up by typing an opening (left) parenthesis, the cell addresses of
the values that correspond to the variables in the equation, and a closing
(right) parenthesis. In Lotus syntax it looks like this:
"C39*(F46-(0.9*122)) + (I35+C53+C60)/F46." The result is the concentration
of nitrate in mg/L at the well.
B2
-------
The advantage in using a spreadsheet to solve this equation is that
the effects of additional or different land uses can be easily
evaluated. If additions are anticipated at the time of spreadsheet
generation, set up extra rows for them. When changes are made, test to
be sure that accuracy in the solution of the equations is preserved.
The software package Lotus 1-2-3 was used for this example. How-
ever, a similar spreadsheet can be designed with any software package
that has the capability to perform mathematical functions. This
appendix describes a general format for structuring data to solve equa-
tions by means of a spreadsheet. The format can be modified to meet
the requirements of other spreadsheet software.
B3
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SUMHAHY OF UATEW VOLUMES ANII NlTKATt LOADS CALCULATED PEN DAY IN THE ZONE OF CONTRIBUTION
1) Suiiart) of liquid nitrate loads tig/day)
SOURCE
(Land use!
1/3 Acre housing
High School
Fast Food table seats
Fast Food counter seats
1 Acre housing
Condoiiniuis
Shopping Center
Office Building
Gas Station
Church
Hotel
Hotel
Hospital
FLOW
( gallons/ day 1
65
SO.
150
350.
65
65
60
15
500
3
75
75.
200
.00
00
.00
00
.00
.00
.00
.00
.00
00
.00
00
.00
•
UNITS
' - VOLUME - CONCENTRATION -
• (varies)
/people
/people
/seat
/seat
/people
/people
/eiployee -
/eiployee -
/island -
/seat
/people
/people
/bed
400
1000
70
10
200
120
50
25
2
200
40
160
60
people
people
•seats
seats
people
people '•' -
employees -
employees -
islands -
scats
people
people
beds
(liters)
98117
75706.
39745
13248.
49208
29525
11355
1419
3785
2271.
11355
15123
45423
.80 ..-
00 .-
.65 -
55 -
.90 -
.34 -
.10 -
49 -
.30 -
18 -
.90 -
60 -
.60 -
dg/L)
40
40.
40
35.
40
40.
40
40
40
40.
35
35.
35
.00 -
00 -
.00 -
00 -
00 -
.00 -
.00 -
00 -
.00 -
00 -
.00 -
00 -
.00 -
LOAD
lig)
3936718
3028240
1599826
463699
1968356
1181013
454E36
56779
151412
90847
397456
1589826
1589826
.00
00
.'00
.25
.00
60
.00
.50
.00
.20
.50
00
.00
Total VOLUME (VI + V2 +...Vn) = 426887.21 Total liquid LOAD= 16498230.05
2) Smeary of solid nitrate loads tig/day)
SOURCE
Lawns 5000 sq. ft.
Horses P 1200 Ib each
UNITS
(varies)
100 launs
6 horses
NITRATE
libs)
- 0.025 /lawn
- 0.027 /100 Ibs
of aniial
CONVERSION
(•g/lb)
454000
454000
Total Nitrate LOAD, liquid and solid coibined (LI + L2 f...Ln) =
31 (Crl- Nitrate concentration in recharge frot precipitation.
0.05 ig/L
4) (Vwl- Voluie of puaipage froi well
Total solid LOAD*
17706778.05
LOAD
dg)
1135000.00
73548.00
1208548.00
VOLUME CONVERSION
IGPD) (GPD) x 3.7853
1000000
3.7853
L/day
3785300
5) Nitrate load of induced infiltration concentration froi streais
(Vsl- Voluis of induced infiltration froi streais
ICs)- Nitrate concentration in induced infiltration
IVs * Cs) = 0.00 ig
6) Nitrate load of drainage froi Zonelll to Zonell
(VIII)- Voluie of drainage froi Zonelll into Zonell
(CUD- Nitrate concentration of drainage froi Zonelll to Zonell
(VITI * CIIII - 0.00 ig
71 (Cul- Concentration of nitrate at well
Cu = [ Cr * CV« - Vs - VIII - 10.9 * (VI + V2 +...Vnll ] + (Li + L2 +...Ln)
Cw= 4.72 ig/L
0.00 L
0.00 ig/L
0.00 L
0.00 ig/L
IVs x Csl + (VIII x CIIII / Vu
B-4
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Appendix C
List of Acronyms, Chemical Formulas and Mathematical Symbols Used
ACRONYMS
BOD: 5 day Biological Oxygen Demand
CCPEDDC: Cape Cod Planning Ahd Economic Development Commission
GPD: Gallons Per Day
MGD: Million Gallons Per Day
MG/L: Milligrams Per Liter
USEPA: United States Environmental Protection Agency
WHPA Wellhead Protection Area
Mathematical Symbols
C : Nitrate concentration in individual sources (mg/L)
Cr: Nitrate nitrogen concentration in recharge from precipitation (mg/L)
Cs: Nitrate concentration in induced infiltration (mg/L)
GW: Nitrate nitrogen concentration at well (mg/L)
'"'III' Nitrate concentration of drainage from Zone III to Zone II (mg/L)
L^: Nitrate nitrogen load in milligrams for individual septic systems
V : Volume of water used by each source before discharge to septic system
(liters)
V ': Volume of induced infiltration from streams (liters)
s
Vw: Volume of withdrawal from well (liters)
Volume of drainage from Zone III into Zone II (liters)
Chemical Formulas
N: Nitrogen
N2: Nitrogen (atmospheric)
N2: Nitrite Nitrogen
N03: Nitrate Nitrogen
NHo: Ammonia Nitrogen
NH^: Ammonia Nitrogen (ionized)
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