dEPA
United States
Environmental Protection
Agency
Office of Water
4304
EPA 822-B-00-007
December 2000
Ambient Water Quality
Criteria Recommendations
Information Supporting the Development
of State and Tribal Nutrient Criteria
Lakes and Reservoirs in
Nutrient Ecoregion II
-------
EPA-822-B-00-007
AMBIENT WATER QUALITY CRITERIA RECOMMENDATIONS
INFORMATION SUPPORTING THE DEVELOPMENT OF STATE AND TRIBAL
NUTRIENT CRITERIA
FOR
LAKES AND RESERVOIRS IN NUTRIENT ECOREGION II
Western Forested Mountains
including parts of the States of:
Washington, Oregon, California, Idaho, Montana, Wyoming, Utah, Colorado, South Dakota,
New Mexico, Arizona, Texas
and the authorized Tribes within the Ecoregion
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF WATER
OFFICE OF SCIENCE AND TECHNOLOGY
HEALTH AND ECOLOGICAL CRITERIA DIVISION
WASHINGTON, D.C.
DECEMBER 2000
-------
FOREWORD
This document presents EPA's nutrient criteria for Lakes and Reservoirs in Nutrient
Ecoregion II. These criteria provide EPA's recommendations to States and authorized Tribes for
use in establishing their water quality standards consistent with section 303(c) of CWA. Under
section 303(c) of the CWA, States and authorized Tribes have the primary responsibility for
adopting water quality standards as State or Tribal law or regulation. The standards must contain
scientifically defensible water quality criteria that are protective of designated uses. EPA's
recommended section 304(a) criteria are not laws or regulations - they are guidance that States
and Tribes may use as a starting point for the criteria for their water quality standards.
The term "water quality criteria" is used in two sections of the Clean Water Act, Section
304(a)(l) and Section 303(c)(2). The term has a different impact in each section. In Section 304,
the term represents a scientific assessment of ecological and human health effects that EPA
recommends to States and authorized Tribes for establishing water quality standards that
ultimately provide a basis for controlling discharges or releases of pollutants or related
parameters. Ambient water quality criteria associated with specific waterbody uses when
adopted as State or Tribal water quality standards under Section 303 define the level of a
pollutant (or, in the case of nutrients, a condition) necessary to protect designated uses in ambient
waters. Quantified water quality criteria contained within State or Tribal water quality standards
are essential to a water quality-based approach to pollution control. Whether expressed as
numeric criteria or quantified translations of narrative criteria within State or Tribal water quality
standards, quantified criteria serve as a critical basis for assessing attainment of designated uses
and measuring progress toward meeting the water quality goals of the Clean Water Act.
EPA is developing section 304(a) water quality criteria for nutrients because States and
Tribes consistently identify excessive levels of nutrients as a major reason why as much as half of
the surface waters surveyed in this country do not meet water quality objectives, such as full
support of aquatic life. EPA expects to develop nutrient criteria that cover four major types of
waterbodies - lakes and reservoirs, rivers and streams, estuarine and coastal areas, and wetlands -
across fourteen major ecoregions of the United States. EPA's section 304(a) criteria are
intended to provide for the protection and propagation of aquatic life and recreation. To support
the development of nutrient criteria, EPA is publishing Technical Guidance Manuals that describe
a process for assessing nutrient conditions in the four waterbody types.
EPA's section 304(a) water quality criteria for nutrients provide numeric water quality
criteria, as well as procedures by which to translate narrative criteria within State or Tribal water
quality standards. In the case of nutrients, EPA section 304(a) criteria establish values for causal
variables (e.g., total nitrogen and total phosphorus) and response variables (e.g., turbidity and
chlorophyll a). EPA believes that State and Tribal water quality standards need to include
quantified endpoints for causal and response variables to provide sufficient protection of uses and
to maintain downstream uses. These quantified endpoints will most often be expressed as
numeric water quality criteria or as procedures to translate a State or Tribal narrative criterion
into a quantified endpoint.
-------
EPA will work with States and authorized Tribes as they adopt water quality
criteria for nutrients into their water quality standards. EPA recognizes that States and authorized
Tribes require flexibility in adopting numeric nutrient criteria into State and Tribal water quality
standards. States and authorized Tribes have several options available to them. EPA
recommends the following approaches, in order of preference:
(1) Wherever possible, develop nutrient criteria that fully reflect localized conditions and
protect specific designated uses using the process described in EPA's Technical Guidance
Manuals for nutrient criteria development. Such criteria may be expressed either as
numeric criteria or as procedures to translate a State or Tribal narrative criterion into a
quantified endpoint in State or Tribal water quality standards.
(2) Adopt EPA's section 304(a) water quality criteria for nutrients, either as numeric
criteria or as procedures to translate a State or Tribal narrative nutrient criterion into a
quantified endpoint.
(3) Develop nutrient criteria protective of designated uses using other scientifically
defensible methods and appropriate water quality data.
Geoffrey H. Grubbs, Director
Office of Science and Technology
in
-------
DISCLAIMER
This document provides technical guidance and recommendations to States, authorized
Tribes, and other authorized jurisdictions to develop water quality criteria and water quality
standards under the Clean Water Act (CWA) to protect against the adverse effects of nutrient
overenrichment. Under the CWA, States and authorized Tribes are to establish water quality
criteria to protect designated uses. State and Tribal decision-makers retain the discretion to adopt
approaches on a case-by-case basis that differ from this guidance when appropriate and
scientifically defensible. While this document contains EPA's scientific recommendations
regarding ambient concentrations of nutrients that protect aquatic resource quality, it does not
substitute for the CWA or EPA regulations; nor is it a regulation itself. Thus it cannot impose
legally binding requirements on EPA, States, authorized Tribes, or the regulated community, and
it might not apply to a particular situation or circumstance. EPA may change this guidance in the
future.
IV
-------
EXECUTIVE SUMMARY
Nutrient Program Goals
EPA developed the National Strategy for the Development of Regional Nutrient Criteria
(National Strategy) in June 1998. The strategy presents EPA=s intentions to develop technical
guidance manuals for four types of waters (lakes and reservoirs, rivers and streams, estuaries and
coastal waters, and wetlands) and produce section 304(a) criteria for specific nutrient ecoregions
by the end of 2000. In addition, the Agency formed Regional Technical Assistance Groups
(RTAGs) which include State and Tribal representatives working to develop more refined and
more localized nutrient criteria based on approaches described in the waterbody guidance
manuals. This document presents EPA=s current recommended criteria for total phosphorus, total
nitrogen, chlorophyll a, and turbidity for lakes and reservoirs in Nutrient Ecoregion II (Western
Forested Mountains) which were derived using the procedures described in the Lakes and
Reservoirs Nutrient Criteria Technical Guidance Manual (U.S. EPA, 2000a).
EPA's ecoregional nutrient criteria are intended to address cultural eutrophication— the
adverse effects of excess nutrient inputs. The criteria are empirically derived to represent
conditions of surface waters that are minimally impacted by human activities and protective of
aquatic life and recreational uses. The information contained in this document represent starting
points for States and Tribes to develop (with assistance from EPA) more refined nutrient criteria.
In developing these criteria recommendations, EPA followed a process which included, to
the extent they were readily available, the following elements critical to criterion derivation:
! Historical and recent nutrient data in Nutrient Ecoregion II
Data sets from Legacy STORET and EPA Region 10 were used to assess nutrient
conditions from 1990 to 1998. This ecoregion has a highly heterogeneous coverage with
regard to nutrient data. At least 8 Sub-Ecoregions (level 3) contain fewer than 15
stations. This makes it difficult to generalize at the aggregate level. In the northwest area
increased logging has likely increased sedimentation which is often associated with
nutrient leaching and run-off to lakes and streams. Urbanization around large
metropolitan areas has likely contributed to nutrient additions to streams and directly to
some lakes. Grazing is another activity that may have played a role in increased nutrient
loading. Wildfires likely cause considerable yearly variation in nutrient loading.
! Reference sites/reference conditions in Nutrient Ecoregion II
Reference sites/reference conditions in Nutrient Ecoregion II were based on the lake
population distribution approach using a representative sample of all lakes within the
Ecoregion (see Nutrient Criteria Technical Guidance Manual-Lakes and Reservoirs, April
2000, EPA-822-BOO-001). States and Tribes are urged to determine their own reference
sites for lakes and reservoirs within the ecoregion at different geographic scales and to
compare them to EPA's reference conditions.
v
-------
! Models employed for prediction or validation
EPA did not identify any specific models used in the ecoregion to develop nutrient
criteria. States and Tribes are encouraged to identify and apply appropriate models to
support nutrient criteria development.
! RTAG expert review and consensus
EPA recommends that when States and Tribes prepare their nutrient criteria, they obtain
the expert review and consent of the RTAG.
! Downstream effects of criteria
EPA encourages the RTAG to assess the potential effects of the proposed criteria on
downstream water quality and uses.
In addition, EPA followed specific QA/QC procedures during data collection and
analysis: All data were reviewed for duplications. All data are from ambient waters that were not
located directly outside a permitted discharger. The following States indicated that their data
were sampled and analyzed using either Standard methods or EPA approved methods:
Idaho, Oregon, and Washington
The following tables contain a summary of Aggregate and level III ecoregion values for
TN, TP, water column chl a, and turbidity:
BASED ON 25th PERCENTILES ONLY
Nutrient Parameters
Total phosphorus (|ig/L)
Total nitrogen (mg/L)
Chlorophyll a (|ig/L) (Fluorometric method)
Secchi depth (meters)
Aggregate Nutrient Ecoregion II Reference
Conditions
8.8
0.1
1.9
4.5
For subecoregions 1, 2, 4 15, 19, 21, and 23 the ranges of nutrient parameter reference conditions
are: (Note: Ecoregions 5, 9, 11, 16, 17, 41, 77, and 78 each have fewer than 15 stations sampled
over the reference period of 1990-98, so their data were excluded from the table.)
VI
-------
BASED ON 25th PERCENTILE ONLY
Nutrient Parameters
Total phosphorus (|ig/L)
Total nitrogen (mg/L)
Chlorophyll a (|ig/L) (Fluorometric method)
Secchi depth (meters)
Range of Level III Subecoregions
Reference Conditions
5.3-21.5
0.1-0.8
0.9-6.1
1.8-5.6
Vll
-------
NOTICE OF DOCUMENT AVAILABILITY
This document is available electronically to the public through the INTERNET at:
(http://www.epa.gov/OST/standards/nutrient.html). Requests for hard copies of the document
should be made to EPA's National Service Center for Environmental Publications (NSCEP),
11029 Kenwood Road, Cincinnati, OH 45242 or (513) 489-8190 or toll free (800) 490-9198.
Please refer to EPA document number EPA-822-B-00-007.
Vlll
-------
ACKNOWLEDGMENTS
The authors thankfully acknowledge the contributions of the following State and Federal
reviewers: EPA Regions 8, 9, and 10; the States of California, Washington, Oregon, Idaho, Utah,
Colorado, Montana, Arizona, New Mexico, Wyoming, and South Dakota; the Tribes within the
Ecoregion; EPA Headquarters personnel from the Office of Wetlands, Oceans and Watersheds,
Office of Wastewater Management, Office of General Counsel, Office of Research and
Development, and the Office of Science and Technology. EPA also acknowledges the external
peer review efforts of Eugene Welch (University of Washington), Robert Carlson (Kent State
University), Steve Heiskary (Minnesota Pollution Control Agency), Greg Denton and Sherry
Wang (Tennessee Department of Environment and Conservation), and Gerhard Kuhn (U.S.
Geological Survey).
IX
-------
LISTS OF TABLES AND FIGURES
Figures
Figure 1
Figure 2
Figure 3
Figure 4a
Figure 4b
Tables
Table 1
Table 2
Table 3a-p
Aggregate Ecoregion II
Aggregate Ecoregion II with level III ecoregions shown 12
Sampling locations within each level III ecoregion
Illustration of data reduction process for lake data
14
29
Illustration of reference condition calculation 30
Lake and reservoir records for Aggregate Ecoregion II-Western
Forested Mountains 15
Reference conditions for Aggregate Ecoregion II lakes 18
Reference conditions for level III ecoregion lakes 19
-------
TABLE OF CONTENTS
Foreword ii
Disclaimer iv
Executive Summary v
Notice of Document Availability viii
Acknowledgments ix
List of Tables and Figures x
Table of Contents xi
1.0 Introduction 1
2.0 Best Use of this Information 4
3.0 Area Covered by This Document (waterbody type and ecoregion) 6
3.1 Description of Aggregate Ecoregion II-Western Forested Mountains 6
3.2 Geographical Boundaries of Aggregate Ecoregion II 7
3.3 Level III Ecoregions within Aggregate Ecoregion II 7
4.0 Data Review for Lakes and Reservoirs in Aggregate Ecoregion II 11
4.1 Data Sources 11
4.2 Historical Data from Aggregate Ecoregion II (TP, TN, Chi a, Turbidity) 12
4.3 QA/QC of Data Sources 12
4.4 Data for All Lakes/Reservoirs within Aggregate Ecoregion II 13
4.5 Statistical Analysis of Data 17
4.6 Classification of Lake/Reservoir Type 28
4.7. Summary of Data Reduction Methods 28
5.0 Reference Sites and Conditions in Aggregate Ecoregion II 31
6.0 Models Used to Predict or Verify Response Parameters 31
7.0 Framework for Refining Recommended Nutrient Criteria for Lakes and Reservoirs in
Aggregate Ecoregion II 31
7.1 Example Worksheet for Developing Aggregate Ecoregion and Subecoregion Nutrient
Criteria 32
7.2 Tables of Refined Nutrient Water Quality Criteria for Aggregate Ecoregion II
xi
-------
and Level III Subecoregions 33
7.3 Setting Seasonal Criteria 34
7.4 When Data/Reference Conditions Are Lacking 34
7.5 Site-Specific Criteria Development 35
8.0 Literature Cited 35
9.0 Appendices 36
xn
-------
1.0 INTRODUCTION
Background
Nutrients are essential to the health and diversity of our surface waters. However, in excessive
amounts, nutrients cause hypereutrophication, which results in overgrowth of plant life and decline
of the biological community. Excessive nutrients can also result in potential human health risks,
such as the growth of harmful algal blooms - most recently manifested in the Pfiesteria outbreaks
of the Gulf and East Coasts. Chronic nutrient overenrichment of a waterbody can lead to the
following consequences: low dissolved oxygen, fish kills, algal blooms, overabundance of
macrophytes, likely increased sediment accumulation rates, and species shifts of both flora and
fauna.
Historically, National Water Quality Inventories have repeatedly shown that nutrients are a
major cause of ambient water quality use impairments. EPA's 1996 National Water Quality
Inventory report identifies excessive nutrients as the leading cause of impairment in lakes and the
second leading cause of impairment in rivers (behind siltation). In addition, nutrients were the
second leading cause of impairments reported by the States in their 1998 lists of impaired waters.
Where use impairment is documented, nutrients contribute roughly 25-50% of the impairment
nationally. The Clean Water Act establishes a national goal to achieve, wherever attainable, water
quality which provides for the protection and propagation offish, shellfish, and wildlife and
recreation in and on the water. In adopting water quality standards, States and Tribes designate
uses for their waters in consideration of the Clean Water Act goals, and establish water quality
criteria that contain sufficient parameters to protect those uses. To date, EPA has not published
information and recommendations under section 304(a) for nutrients to assist States and Tribes in
establishing numeric nutrient criteria to protect uses when adopting water quality standards.
In 1995, EPA gathered a set of national experts and asked the experts how to best deal
with the national nutrient problem. The experts recommended that the Agency not develop single
criteria values for phosphorus or nitrogen applicable to all water bodies and regions of the country.
Rather, the experts recommended that EPA put a premium on regionalization, develop guidance
(assessment tools and control measures) for specific waterbodies and ecological regions across the
country, and use reference conditions (conditions that reflect pristine or minimally impacted
waters) as a basis for developing nutrient criteria.
With these suggestions as starting points, EPA developed the National Strategy for the
Development of Regional Nutrient Criteria (National Strategy), published in June 1998. This
strategy presented EPA's intentions to develop technical guidance manuals for four types of waters
(lakes and reservoirs, rivers and streams, estuaries and coastal waters, and wetlands) and,
thereafter, to publish section 304(a) criteria recommendations for specific nutrient ecoregions.
Technical guidance manuals for lakes/reservoirs and rivers/streams were published in April 2000
and July 2000, respectively. The technical guidance manual for estuaries/coastal waters will be
published in spring 2000 and the draft wetlands technical guidance manual will be published by
December 2001. Each manual presents EPA's recommended approach for developing nutrient
criteria values for a specific waterbody type. In addition, EPA is committed to working with
-------
States and Tribes to develop more refined and more localized nutrient criteria based on approaches
described in the waterbody guidance manuals and this document.
Overview of the Nutrient Criteria Development Process
For each Nutrient Ecoregion, EPA developed a set of recommendations for two causal
variables (total nitrogen and total phosphorus) and two early indicator response variables
(chlorophyll a and some measure of turbidity). Other indicators such as dissolved oxygen and
macrophyte growth or speciation, and other fauna and flora changes are also deemed useful.
However, the first four are considered to be the best suited for protecting designated uses.
The technical guidance manuals describe a process for developing nutrient criteria that
involves consideration of five factors. The first of these is the Regional Technical Assistance
Group (RTAG), which is a body of qualified regional specialists able to objectively evaluate all of
the available evidence and select the value(s) appropriate to nutrient control in the water bodies of
concern. These specialists may come from such disciplines as limnology, biology, natural
resources management— especially water resource management, chemistry, and ecology. The
RTAG evaluates and recommends appropriate classification techniques for criteria determination,
usually physical within an ecoregional construct.
The second factor is the historical information available to establish a perspective of the
resource base. This is usually data and anecdotal information available within the past ten-twenty
five years. This information gives evidence about the background and enrichment trend of the
resource.
The third factor is the present reference condition. A selection of reference sites chosen to
represent the least culturally impacted waters of the class existing at the present time. The data
from these sites is combined and a value from the distribution of these observations is selected to
represent the reference condition, or best attainable, most natural condition of the resource base at
this time.
A fourth factor often employed is theoretical or empirical models of the historical and
reference condition data to better understand the condition of the resource.
The RTAG comprehensively evaluates the other three elements to propose a candidate
criterion (initially one each for TP, TN, chl a, and some measure of turbidity).
The last and final element of the criteria development process is the assessment by the
RTAG of the likely downstream effects of the criterion. Will there be a negative, positive, or
neutral effect on the downstream waterbody? If the RTAG judges that a negative effect is likely,
then the proposed State/Tribal water quality criteria should be revised to ameliorate the potential
for any adverse downstream effects.
-------
While States and authorized Tribes would not necessarily need to incorporate all five
elements into their water quality criteria setting process (e.g., modeling may be significant in only
some instances), the best assurance of a representative and effective criterion for nutrient
management decision making is the balanced incorporation of all five elements, or at least all
elements except modeling.
Because some parts of the country have naturally higher soil and parent material
enrichment, and different precipitation regimes, the application of the criterion development
process has to be adjusted by region. Therefore, an ecoregional approach was chosen to develop
nutrient criteria appropriate to each of the different geographical and climatological areas of the
country. Initially, the continental U.S. was divided into 14 separate ecoregions of similar
geographical characteristics. Ecoregions are defined as regions of relative homogeneity in
ecological systems; they depict areas within which the mosaic of ecosystem components (biotic
and abiotic as well as terrestrial and aquatic) is different than adjacent areas in a holistic sense.
Geographic phenomena such as soils, vegetation, climate, geology, land cover, and physiology that
are associated with spatial differences in the quantity and quality of ecosystem components are
relatively similar within each ecoregion.
The Nutrient ecoregions are aggregates of U.S. EPA=s hierarchal level III ecoregions. As
such, they are more generalized and less defined than level III ecoregions. EPA determined that
setting ecoregional criteria for the large scale aggregates is not without its drawbacks - variability
is high due to the lumping of many waterbody classes, seasons, and years worth of multipurpose
data over a large geographic area. For these reasons, the Agency recommends that States and
Tribes develop nutrient criteria at the level III ecoregional scale and at the waterbody class scale
where those data are readily available. Data analyses and recommendations on both the large
aggregate ecoregion scale as well as more refined scales (level III ecoregions and waterbody
classes), where data were available to make such assessments, are presented for comparison
purposes and completeness of analysis.
Relationship of Nutrient Criteria to Biological Criteria
Biological criteria are quantitative expressions of the desired condition of the aquatic
community. Such criteria can be based on an aggregation of data from sites that represent the
least-impacted and attainable condition for a particular waterbody type in an ecoregion,
subecoregion, or watershed. EPA's nutrient criteria recommendations and biological criteria
recommendations have many similarities in the basic approach to their development and data
requirements. Both are empirically derived from statistical analysis of field collected data and
expert evaluation of current reference conditions and historical information. Both utilize direct
measurements from the environment to integrate the effects of complex processes that vary
according to type and location of waterbody. The resulting criteria recommendations, in both
cases, are efficient and holistic indicators of water quality necessary to protect uses.
States and authorized Tribes can develop and apply nutrient criteria and biological criteria
in tandem, with each providing important and useful information to interpret both the nutrient
enrichment levels and the biological condition of sampled waterbodies. For example, using the
-------
same reference sites for both types of criteria can lead to efficiencies in both sample design and
data analysis. In one effort, environmental managers can obtain information to support assessment
of biological and nutrient condition, either through evaluating existing data sets or through
designing and conducting a common sampling program. The traditional biological criteria
variables of benthic invertebrate and fish sampling can be readily incorporated to supplement a
nutrient assessment. To demonstrate the effectiveness of this tandem approach, EPA has initiated
pilot projects in both freshwater and marine environments to investigate the relationship between
nutrient overenrichment and apparent declines in diversity indices of benthic invertebrates and fish.
2.0 BEST USE OF THIS INFORMATION
EPA recommendations published under section 304(a) of the CWA serve several purposes,
including providing guidance to States and Tribes in adopting water quality standards for nutrients
that ultimately provide a basis for controlling discharges or releases of pollutants. The
recommendations also provide guidance to EPA when promulgating Federal water quality
standards under section 303(c) when such action is necessary. Other uses include identification of
overenrichment problems, management planning, project evaluation, and determination of status
and trends of water resources.
State water quality inventories and listings of impaired waters consistently rank nutrient
overenrichment as a top contributor to use impairments. EPA's water quality standards
regulations at 40 CFR § 131.11 (a) require States and Tribes to adopt criteria that contain sufficient
parameters and constituents to protect the designated uses of their waters. In addition, States and
Tribes need quantifiable targets for nutrients in their standards to assess attainment of uses,
develop water quality-based permit limits and source control plans, and establish targets for total
maximum daily loads (TMDLs).
EPA expects States and Tribes to address nutrient overenrichment in their water quality
standards, and to build on existing State and Tribal initiated efforts where possible. States and
Tribes can address nutrient overenrichment through establishment of numerical criteria or through
use of new or existing narrative criteria statements (e.g., free from excess nutrients that cause or
contribute to undesirable or nuisance aquatic life or produce adverse physiological response in
humans, animals, or plants). In the case of narrative criteria, EPA expects that States and Tribes
establish procedures to quantitatively translate these statements for both assessment and source
control purposes.
The intent of developing ecoregional nutrient criteria is to represent conditions of surface
waters that are minimally impacted by human activities and thus protect against the adverse effects
of nutrient overenrichment from cultural eutrophi cation. EPA's recommended process for
developing such criteria includes physical classification of waterbodies, determination of current
reference conditions, evaluation of historical data and other information (such as published
literature), use of models to simulate physical and ecological processes or determine empirical
relationships among causal and response variables (if necessary), expert judgement, and evaluation
of downstream effects. To the extent allowed by the information available, EPA has used elements
of this process to produce the information contained in this document. The values for both causal
-------
(total nitrogen, total phosphorus) and biological and physical response (chlorophyll a, turbidity)
variables represent a set of starting points for States and Tribes to use in establishing their own
criteria in standards to protect uses.
In its water quality standards regulations, EPA recommends that States and Tribes establish
numerical criteria based on section 304(a) guidance, section 304(a) guidance modified to reflect
site-specific conditions, or other scientifically defensible methods. For many pollutants, such as
toxic chemicals, EPA expects that section 304(a) guidance will provide an appropriate level of
protection without further modification in most cases. EPA has also published methods for
modifying 304(a) criteria on a site-specific basis, such as the water effect ratio, where site-specific
conditions warrant modification to achieve the intended level of protection. For nutrients,
however, EPA expects that, in most cases, it will be necessary for States and authorized Tribes to
identify with greater precision the nutrient levels that protect aquatic life and recreational uses.
This can be achieved through development of criteria modified to reflect conditions at a smaller
geographic scale than an ecoregion such as a subecoregion, the State or Tribe level, or specific
class of waterbodies. Criteria refinement can occur by grouping data or performing data analyses
at these smaller geographic scales. Refinement can also occur through further consideration of
other elements of criteria development, such as published literature or models.
The values presented in this document generally represent nutrient levels that protect
against the adverse effects of nutrient overenrichment and are based on information available to the
Agency at the time of this publication. However, States and Tribes should critically evaluate this
information in light of the specific designated uses that need to be protected. For example, more
sensitive uses may require more stringent values as criteria to ensure adequate protection. On the
other hand, overly stringent levels of protection against the adverse effects of cultural
eutrophication may actually fall below levels that represent the natural load of nutrients for certain
waterbodies. In cases such as these, the level of nutrients specified may not be sufficient to
support a productive fishery. In the criteria derivation process, it is important to distinguish
between the natural load associated with a specific waterbody and current reference conditions,
using historical data and expert judgement. These elements of the nutrient criteria derivation
process are best addressed by States and Tribes with access to information and local expertise.
Therefore, EPA strongly encourages States and Tribes to use the information contained in this
document and to develop more refined criteria according to the methods described in EPA's
technical guidance manuals for specific waterbody types.
To assist in the process of further refinement of nutrient criteria, EPA has established ten
Regional Technical Advisory Groups (experts from EPA Regional Offices and States/Tribes). In
the process of refining criteria, States and authorized Tribes need to provide documentation of
data and analyses, along with a defensible rationale, for any new or revised nutrient criteria they
submit to EPA for review and approval. As part of EPA's review of State and Tribal standards,
EPA intends to seek assurance from the RTAG that proposed criteria are sufficient to protect uses.
In the process of using the information and recommendations contained in this document,
as well as additional information, to develop numerical criteria or procedures to translate narrative
criteria, EPA encourages States and Tribes to:
-------
• Address both chemical causal variables and early indicator response variables. Causal
variables are necessary to provide sufficient protection of uses before impairment occurs
and to maintain downstream uses. Early response variables are necessary to provide
warning signs of possible impairment and to integrate the effects of variable and potentially
unmeasured nutrient loads.
• Include variables that can be measured to determine if standards are met, and variables that
can be related to the ultimate sources of excess nutrients.
• Identify appropriate periods of duration (i.e., how long) and frequency (i.e., how often) of
occurrence in addition to magnitude (i.e., how much). EPA does not recommend
identifying nutrient concentrations that must be met at all times, rather a seasonal or annual
averaging period (e.g., based on weekly measurements) is considered appropriate.
However, these seasonal or annual central tendency measures should apply each season or
each year, except under the most extraordinary of conditions (e.g., a 100 year flood).
3.0 AREA COVERED BY THIS DOCUMENT
The following sections provide a general description of the aggregate ecoregion and its
geographical boundaries. Descriptions of the level III ecoregions contained within the
aggregate ecoregion are also provided.
3.1 Description of Aggregate Ecoregion II - Western Forested Mountains
Region II includes most of the great mountain ranges that are located west of the Great
Plains. This large, disjunct region is characterized by forests, high relief terrain, steep slopes,
perennial streams, and a general lack of cropland agriculture. The highest mountains are wetter
and colder than lower elevations and are often snow-covered during the winter months; they can
be glacially modified and lake-studded. Overall, Region II receives far more precipitation than the
lower nutrient regions that surround it. However, within Region II, rainshadow influences are
common and precipitation varies with elevation and latitude. Alpine vegetation grows in the
highest areas, coniferous forests dominate the high areas, mixed deciduous and coniferous stands
with a grass understory are found at the lower elevations, and shrubs and grasses are common at
the lowest elevations.
Dominant land uses in the Western Forested Mountains (II) are logging, recreation,
grazing, and mining. Logging can increase erosion and contribute large amounts of sediment to
streams. Grazing can contribute significant amounts of nitrogen, phosphorus, and sediment to
surface waters. Locally, mining activities have contributed suspended sediments, acidic drainage,
and toxic trace elements such as arsenic, cadmium, copper, lead, manganese, and zinc to surface
waters. Cropland agriculture is uncommon except within some mountain valleys and a part of the
Puget Lowland.
The forests of Region II are characterized by much lower anthropogenic inputs of nitrogen
and phosphorus from artificial fertilizers than neighboring, more agricultural, nutrient regions.
-------
3.2 Geographical Boundaries of Aggregate Ecoregion II
Ecoregion II is a large, discontinuous region covering the mountainous areas of the
western Unites States. In total, 11 states are included in this ecoregion. The region includes the
western 1/3 of Washington and Oregon and the northern border between Oregon and California.
The region continues southwards as a narrow strip running down the eastern side of California;
where California's border bends eastward, the region continues to stretch southward into the
center of the state terminating in the southwestern part of the state.
Another segment of the region begins in north central Washington. This region runs along
the U.S.-Canada border across Washington, Idaho and 1/3 of Montana. The region extends south
to include northeastern Oregon, the northern 2/3rds of Idaho, the western 1/3rd of Montana and
the northwest corner of Wyoming.
The remaining segments of the ecoregion are discrete areas of varying size. One of the
larger segments runs through central Colorado, extending into southern Wyoming and northern
New Mexico. A narrow segment of the region runs through central Utah. Similarly, an area of
central Arizona extending into New Mexico is included in this ecoregion. Five small pockets of
New Mexico are encompasses in the region. Finally, a small area that straddles the border between
South Dakota and Wyoming is designated as part of this ecoregion.
3.3 Level III Ecoregions within Aggregate Ecoregion II
1. Coast Range
Highly productive, rain-drenched coniferous forests cover the low mountains of the Coast Range.
Sitka spruce and coastal redwood forests originally dominated the fog-shrouded coast, while a
mosaic of western red cedar, western hemlock, and serai Douglas-fir blanketed inland areas.
Today Douglas-fir plantations are prevalent on the intensively logged and managed landscape.
2. Puget Lowlands
This broad rolling lowland is characterized by a mild maritime climate and flanks the intricately cut
coastline of Puget Sound. It occupies a continental glacial trough and has many islands,
peninsulas, and bays. Coniferous forest originally grew on the ecoregion's ground moraines.
outwash plains, floodplains, and terraces. The distribution of forest species is affected by the
rainshadow from the Olympic Mountains.
-------
Aggregate Nutrient Ecoregion 2
Figure 1. Aggregate Ecoregion II.
4. Cascades
This mountainous ecoregion is underlain by Cenozoic volcanics and has been affected by alpine
glaciations. It is characterized by broad, easterly trending valleys, steep ridges in the west, a high
plateau in the east, and both active and dormant volcanoes. Elevations range upwards to 4,390
meters. Its moist, temperate climate supports an extensive and highly productive coniferous forest.
Subalpine meadows occur at high elevations.
5. Sierra Nevada
The Sierra Nevada is a deeply dissected block fault that rises sharply from the arid basin and range
ecoregions on the east and slopes gently toward the Central California Valley to the west. The
eastern portion has been strongly glaciated and generally contains higher mountains than are found
in the Klamath Mountains to the northwest. Much of the central and southern parts of the region
is underlain by granite as compared to the mostly sedimentary formations of the Klamath
Mountains and volcanic rocks of the Cascades. The higher elevations of this region are largely
federally owned and include several national parks. The vegetation grades from mostly ponderosa
pine at the lower elevations on the west side and lodgepole pine on the east side, to fir and spruce
at the higher elevations. Alpine conditions exist at the highest elevations.
8. Southern California Mountains
Like the other ecoregions in central and southern California, the Southern California Mountains
has a Mediterranean climate of hot dry summers and moist cool winters. Although Mediterranean
types of vegetation such as chaparral and oak woodlands predominate, the elevations are
-------
considerably higher in this region, the summers are slightly cooler, and precipitation amounts are
greater, causing the landscape to be more densely vegetated and stands of ponderosa pine to be
larger and more numerous than in the adjacent regions. Severe erosion problems are common
where the vegetation cover has been destroyed by fire or overgrazing.
9. Eastern Cascades Slopes and Foothills
The Eastern Cascade Slopes and Foothills is in the rainshadow of the Cascade Mountains. Its
climate exhibits greater temperature extremes and less precipitation than ecoregions to the west.
Open forests of ponderosa pine and some lodgepole pine distinguish this region from the higher
ecoregions to the west where spruce fir forests are common, and the lower dryer ecoregions to the
east where shrubs and grasslands are predominant. The vegetation is adapted to the prevailing dry
continental climate and is highly susceptible to wildfire. Volcanic cones and buttes are common in
much of the region.
11. Blue Mountains
This ecoregion is distinguished from the neighboring Cascades and Northern Rockies ecoregions
because the Blue Mountains are generally not as high and are considerably more open. Like the
Cascades, but unlike the Northern Rockies, the region is mostly volcanic in origin. Only the few
higher ranges, particularly the Wallowa and Elkhorn Mountains, consist of intrusive rocks that rise
above the dissected lava surface of the region. Unlike the bulk of the Cascades and Northern
Rockies, much of this ecoregion is grazed by cattle.
15. Northern Rockies
The Northern Rockies is an ecoregion of high, rugged mountains. Although alpine characteristics,
including numerous glacial lakes, are found in the higher elevations, the region is not as high nor as
snow and ice covered as the Canadian Rockies. The mosaic of vegetation that presently and
originally covered the region is different than that of the Middle Rockies. Although Douglas fir,
subalpine fir, Englemann spruce, and ponderosa pine are characteristic of both regions, western
white pine, western red cedar, and grand fir were and are common in the Northern Rockies, but
not the Middle Rockies. Mining activities have caused stream water quality problems in portions
of the region.
16. Montana Valley and Foothill Prairies
The Montana Valley and Foothill Prairies is a region characterized by shortgrass prairie but is
unlike other grassland-type ecoregions in the Great Plains because of the close proximity to nearby
high forested mountains which feed the region with many perennial streams, resulting in a different
mosaic of terrestrial and aquatic fauna. Most of the region is farmed and many parts of the valleys
have been irrigated. Grazing of beef cattle and sheep is prevalent in the region, even in the
forested parts of the foothills.
17. Middle Rockies
Like the Northern Rockies, this region is composed of steep-crested high mountains that are
largely covered by coniferous forests. However, the mix of tree species is somewhat different in
the two regions. Lodgepole pine is more common in the Middle Rockies, and white pine, grand
fir, and cedar, which are prevalent in the Northern Rockies, are not in this region. Soils in the
region are mainly Alfisols, whereas Inceptisols are the major soil order in the Northern Rockies.
-------
Also, a greater portion of the Middle Rockies is used for summer grazing of livestock. Recreation
and lumbering are major land use activities.
19. Wasatch and UintaMountains
This ecoregion is composed of a core area of high, precipitous mountains with narrow crests and
valleys flanked in some areas by dissected plateaus and open high mountains. The elevational
banding pattern of vegetation is similar to that of the Southern Rockies except that aspen,
chaparral, and juniper-piny on and oak are more common at middle elevations. This characteristic,
along with a far lesser extent of lodgepole pine and greater use of the region for grazing livestock
in the summer months, distinguish the Wasatch and Uinta Mountains ecoregion from the more
northerly Middle Rockies.
21. Southern Rockies
The Southern Rockies are composed of high elevation, steep rugged mountains. Although
coniferous forests cover much of the region, as in most of the mountainous regions in the western
United States, vegetation, as well as soil and land use, follows a pattern of elevational banding.
The lowest elevations are generally grass or shrub covered and heavily grazed. Low to middle
elevations are also grazed and covered by a variety of vegetation types including Douglas fir,
ponderosa pine, aspen, and juniper oak woodlands. Middle to high elevations are largely covered
by coniferous forests and have little grazing activity. The highest elevations have alpine
characteristics.
23. Arizona/New Mexico Mountains
The Arizona/New Mexico Mountains are distinguished from neighboring mountainous ecoregions
by their lower elevations and an associated vegetation indicative of drier, warmer environments,
which is also due in part to the region's more southerly location. Forests of spruce, fir, and
Douglas fir, that are common in the Southern Rockies and the Uinta and Wasatch Mountains, are
only found in a few high elevation parts of this region. Chaparral is common on the lower
elevations, pinyon-juniper and oak woodlands are found on lower and middle elevations, and the
higher elevations are mostly covered with open to dense ponderosa pine forests.
41. Canadian Rockies
As its name indicates, most of this region is located in Canada. It straddles the border between
Alberta and British Columbia in Canada and extends southeastward into northwestern Montana.
The region is generally higher and more ice-covered than the Northern Rockies. Vegetation is
mostly Douglas fir, spruce, and lodgepole pine at lower elevations and alpine fir at middle
elevations. The higher elevations are treeless alpine. A large part of the region is in national parks
where tourism is the major land use. Forestry and mining occur on the nonpark lands.
77. Northern Cascades
The terrain of the North Cascades is composed of high, rugged mountains. It contains the greatest
concentration of active alpine glaciers in the conterminous United States and has a variety of
climatic zones. A dry continental climate occurs in the east and mild, maritime, rainforest
conditions are found in the west. It is underlain by sedimentary and metamorphic rock in contrast
to the adjoining Cascades which are composed of volcanics.
10
-------
IR.Klamath Mountains
The ecoregion is physically and biologically diverse. Highly dissected, folded mountains, foothills,
terraces, and floodplains occur and are underlain by igneous, sedimentary, and some metamorphic
rock. The mild, subhumid climate of the Klamath Mountains is characterized by a lengthy summer
drought. It supports a vegetal mix of northern Californian and Pacific Northwest conifers.
4.0 DATA REVIEW FOR LAKES AND RESERVOIRS IN AGGREGATE
ECOREGION II
The following section describes the nutrient data EPA has collected and analyzed for this
Ecoregion, including an assessment of data quantity and quality. The data tables present the data
for each causal parameter— total phosphorus and total nitrogen (both reported and calculated from
TKN and nitrite/nitrate), and the primary response variables- some measure of turbidity and
chlorophyll a. These are the parameters which EPA considers essential to nutrient assessment
because the first two are the main causative agents of enrichment and the two response variables
are the early indicators of system enrichment for most of the surface waters
(See Chapter 5 of the Lakes and Reservoirs Nutrient Criteria Guidance Manual (U.S. EPA, 2000a)
for a complete discussion on choosing causal and response variables.)
Suggested Ecoregional subdivisions or adjustments.
EPA recommends that the RTAG evaluate the adequacy of EPA nutrient ecoregional and
subecoregional boundaries and refine them as needed to reflect local conditions.
4.1 Data Sources
Data sets from Legacy STORET, and EPA RegionlO were used to assess nutrient
conditions from 1990 to 1999. EPA recommends that the RTAGs identify additional data sources
that can be used to supplement the data sets listed above. In addition, the RTAGs may utilize
published literature values to support quantitative and qualitative analyses.
11
-------
Aggregate Nutrient Ecoregion 2
Ecoregion ID
D 1
D 2
D 8
D
Figure 2. Aggregate Ecoregion II with level III ecoregions shown
4.2 Historical Data from Aggregate Ecoregion II (TP, TN, Chlor a and Secchi Depth)
This ecoregion has a highly heterogeneous coverage in the above data as shown by Fig. 3.
At least 8 Sub-Ecoregions contain fewer than 15 stations. This makes it difficult to generalize at
the aggregate level. In the northwest area increased logging has likely increased sedimentation
which is often associated with nutrient leaching and run-off to lakes and streams. Urbanization
around large metropolitan areas has likely contributed to nutrient additions to streams and directly
to some lakes. Grazing is another activity that may have played a role in increased nutrient
loading. Variability in "wildfires" likely causes considerable year to year variation in nutrient
loading. EPA recommends that States/Tribes assess long-term trends observed over the past 50
years. This information may be obtained from scientific literature or documentation of historical
trends. To gain additional perspective on more recent trends, it is recommended that States and
Tribes assess nutrient trends over the last 10 years (e.g., what do seasonal trends indicate?)
4.3 QA/QC of Data Sources
An initial quality screen of data was conducted using the rules presented in Appendix C.
Data remaining after screening for duplications and other QA measures (e.g., poor or unreported
analytical records, sampling errors or omissions, stations associated with outfalls, storm water
sewers, hazardous waste sites) were the data used in the statistical analyses.
States within Ecoregion II were contacted regarding the quality of their data. The
following States provided information on the methods used to sample and analyze their waters:
Idaho, Oregon, and Washington. In all cases, States indicated a Standard method or an
12
-------
approved EPA method was used. California, Nevada, Utah, Colorado, Arizona, New Mexico,
Texas, Wyoming, and Montana, South Dakota did not provide information prior to the publication
of this document.
4.4 Data for all Lakes/Reservoirs within Aggregate Ecoregion II
The map in Figure 3 shows the location of the sampling stations within each sub ecoregion.
Table 1 presents all data records for all parameters for Aggregate Ecoregion II and subecoregions
within the Aggregate Ecoregion. Most of the data were derived from sub-ecoregions from the
Oregon, Washington, Colorado and Utah.
13
-------
Nutrient 2
Lake and Reservoir Stations
Level lil Ecoregions
4|
Stations
9
11
15
16
23
100 0 100 200
US
n
^y"" '
Figure 3. Sampling locations within each level III ecoregion.
14
-------
Table 1. Lake records for Aggregate Ecoregion II - Western Forested Mountains
# of Lakes/Reservoirs
# of Lake Stations
Key Nutrient Parameters
(listed below)
- # of records for Secchi
depth
- # of records for
Chlorophyll a (all methods)
- # of records for Total
Kjeldahl Nitrogen (TKN)
- # of records for Nitrate +
Nitrite (NO2 + NO3)
- # of records for Total
Nitrogen (TN)
- # of records for Total
Phosphorus (TP)
Total # of records for key
nutrient parameters
Aggregate
Ecoregion
II
441
725
4144
3931
3099
2681
1951
7894
23,700
Sub
ecoR 1
24
53
903
173
63
5
72
276
1492
Sub
ecoR2
19
32
506
411
0
72
614
1074
2677
Sub
ecoR4
161
213
584
1158
45
1326
977
1290
5380
Sub
ecoRS
2
2
0
0
11
0
14
32
57
Sub
ecoR9
13
29
50
241
423
419
0
429
1562
Sub
ecoR 11
6
6
7
7
10
1
0
14
39
Sub
ecoR 15
38
69
122
25
499
395
0
410
1451
15
-------
Table 1 (continued). Lake records for Aggregate Ecoregion II - Western Forested Mountains
# of Lakes/Reservoirs
# of Lake Stations
Key Nutrient Parameters
(listed below)
- # of records for Secchi
depth
- # of records for
Chlorophyll a (all methods)
- # of records for Total
Kjeldahl Nitrogen (TKN)
- # of records for Nitrate +
Nitrite (NO2 + NO3)
- # of records for Total
Nitrogen (TN)
- # of records for Total
Phosphorus (TP)
Total # of records for key
nutrient parameters
Sub
ecoR 16
6
11
0
37
0
13
132
124
292
Sub
ecoR 17
18
35
54
29*
108
29
0
165
385
Sub
ecoR 19
93
152
1216
1328
992
42
0
2946
6566
Sub
ecoR 21
51
86
593
388
826
265
32
960
3064
Sub
ecoR 23
13
26
62
108
106
106
58
102
542
Sub
ecoR 41
2
6
0
20
8
8
52
59
145
Sub
ecoR 77
1
1
1
2
0
0
0
4
7
Sub
ecoR 78
4
4
46
4
8
0
0
9
67
* Summer only
16
-------
Definitions used to complete Table 1:
1. # of records refers to the total count of observations for
that parameter over the entire decade (1990-1999) for that
particular aggregate or subecoregion. These are counts for
all seasons over that decade.
2. # of lake stations refers to the total number of lake and
reservoir stations within the aggregate or subecoregion from
which nutrient data were collected. Since lakes and
reservoirs can cross ecoregional boundaries, it is important to
note that only those portions of a lake or reservoir (and data
associated with those stations) that exist within the ecoregion
are included within this table.
4.5 Statistical Analysis of Data
EPA's Technical Guidance Manual for Developing Nutrient Criteria for Lakes and
Reservoirs describes two ways of establishing a reference condition. One method is to choose the
upper 25th percentile (75th percentile) of a reference population of lakes. This is the preferred
method to establish a reference condition. The 75th percentile was chosen by EPA since it is likely
associated with minimally impacted conditions, will be protective of designated uses, and provides
management flexibility. When reference lakes are not identified, the second method is to determine
the lower 25th percentile of the population of all lakes within a region. The 25th percentile of the
entire population was chosen by EPA to represent a surrogate for an actual reference population.
Data analyses to date indicate that the lower 25th percentile from an entire population roughly
approximates the 75th percentile for a reference population (see case studies for Minnesota lakes in
the Lakes and Reservoirs Nutrient Criteria Technical Guidance Document [U.S. EPA, 2000a], the
case study for Tennessee streams in the Rivers and Streams Nutrient Criteria Technical Guidance
Document [U.S. EPA, 2000b], and the letter from Tennessee Department of Environment and
Conservation to Geoffrey Grubbs [TNDEC, 2000]). New York State has also presented evidence
that the 25th percentile and the 75th percentile compare well based on user perceptions of water
resources (NYSDEC, 2000).
The following tables 2 and 3a-p, present the potential reference conditions for both the
aggregate ecoregion and the subecoregions using both methods. However, the reference lake
column is left blank because EPA does not have observed reference data and anticipates that States
will provide information on reference lakes. Appendix A provides a complete presentation of all
descriptive statistics for both the aggregate ecoregion and the level III subecoregion.
Table 2.Reference conditions for aggregate ecoregion II lakes.
17
-------
Parameter
TKN (mg/L)
NO2 + NO3 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
162
144
NA
45
296
302
130
100
41
Reported values
Min
0.01
0.00
0.01
0.00
0.00
0.00
0.3
0.5
0.8
Max
3.52
0.92
4.44
3.07
507.5
10.5
44.3
33.4
f
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.16
0.02
0.18
0.10
8.75
4.5
1.9
1.9
2.8
Reference Lakes * *
P75 all seasons
P25:
P75:
**
F
S
T
NA
25th percentile of all data
75th percentile of all data
as determined by the Regional Technical Assistance Groups (RTAGs)
Median for all seasons' 25th percentiles. E.g. this value was calculated from four seasons'
25th percentiles. If the seasonal 25th percentile (P25) TP values are - spring lOwg/L,
summer 15wg/L, fall 12wg/L, and winter 5wg/L, the median value of all seasons P25 will be
llwg/L.
N = largest value reported for a decade / Season.
TN calculated is based on the sum of TKN + NO2+NO3
TN reported is actual TN value reported in the database for one sample.
Chlorophyll a measured by Fluorometric method with acid correction.
Chlorophyll a measured by Spectrophotometric method with acid correction.
Chlorophyll a b c measured by Trichromatic method.
Not Applicable
Table(s) 3a.- p present the potential reference conditions for lakes and reservoirs in the Level III
subecoregions within the Aggregate Ecoregion. The footnotes for Table 2 apply to tables 3a-p.
18
-------
Table Sa.Reference conditions for level III ecoregion 1 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
4
2z
NA
Iz
14
19
11
-
-
Reported values
Min
0.11
0.02
0.13
0.19
5.0
1.0
1.8
-
-
Max
0.26
0.88
1.14
0.19
35.4
6.8
7.6
-
-
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.11
0.02 zz
0.13
0.19
7.10
5.1
2.3
-
-
Reference Lakes * *
P75 all seasons
Table Sb.Reference conditions for level III ecoregion 2 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
-
3z
NA
14
18
15
15
Reported values
Min
-
0.33
-
0.28
10.5
1.1
2.1
Max
-
0.79
-
1.23
124.8
5.6
29.2
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
-
0.33
-
0.41
21.5
3.5
3.2
Reference Lakes * * II
P75 all seasons
19
-------
Table Sc.Reference conditions for level III ecoregion 4 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
8
85
NA
15
74
97
78
-
7
Reported values
Min
0.12
0.00
0.12
0.00
1.5
0.0
0.3
-
Chla #'s
Max
0..28
0.07
0.35
0.34
98.0
10.5
41.4
-
being
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.12
0.001
0.12
0.00
6.25
5.6
0.9
-
checked
Reference Lakes * *
P75 all seasons
Table Sd.Reference conditions for level III ecoregion 5 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
lz
-
NA
lz
lz
-
-
-
-
Reported values
Min
0.24
-
-
0.25
15.00
-
-
-
-
Max
0.24
-
-
0.25
100.00
-
-
-
-
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.24
-
-
0.25
15.00
-
-
-
-
Reference Lakes * * II
P75 all seasons
20
-------
Table Se.Reference conditions for level III ecoregion 8 lakes.
Note: No Lakes in this Sub-Ecoregion
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
NA
Reported values
Min
Max
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
Reference Lakes * *
P75 all seasons
Table Sf.Reference conditions for level III ecoregion 9 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
'Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
5
3z
NA
-
6
9
3z
-
3S
Reported values
Min
1.15
0.01
1.16
-
65
3.5
4.7
-
1.4
Max
2.09
0.06
2.15
-
191.2
6.1
44.5
-
9.5
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
1.15
0.01
1.16
-
68.80
4.4
4.7
-
1.4
Reference Lakes * * II
P75 all seasons
*No winter data
S = Summer data only
21
-------
Table Sg.Reference conditions for level III ecoregion 11 lakes.
Parameter
TKN (mg/L)
*NO2 + NO3 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP («g/L)
Secchl (meters)
"Chlorophyll « («g/L) - F
Chlorophyll « («g/L) - S
'"Chlorophyll a («g/L) - T
No. of
Lakes
N++
3z
Iz
NA
-
5
5
2z
-
3z
Reported values
Min
0.18
0.00
0.18
-
12.00
2.2
2.0
-
1.6
Max
1.62
0.00
1.62
-
247.0
3.2
8.2
-
90.7
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.18zz
0.00 zz
0.18
-
85.8
2.8
2.0 zz
-
1.6
Reference Lakes * *
P75 all seasons
*Fall data only
** Summer & fall data only
*"Summer data only
Table Sh.Reference conditions for level III ecoregion 15 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
"Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
"Chlorophyll a («g/L) - T
No. of
Lakes
N++
11
12
NA
-
25
22
16
-
2z
Reported values
Min
0.03
0.002
0.03
-
4
2.7
1.2
-
2.4
Max
0.56
0.14
0.70
-
116.5
5.6
11.8
-
0.0
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.05
0.02
0.07
-
6.25
5.55
2.1 zz
-
0.0
Reference Lakes * *
P75 all seasons
* summer only data
22
-------
Table Si.Reference conditions for level III ecoregion 16 lakes.
Parameter
TKN (mg/L)
*N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
-
3z
NA
Iz
Iz
-
Iz
-
Reported values
Min
-
0.003
-
0.10
5.8
-
1.17
-
Max
-
0.003
-
0.10
6.0
-
1.17
-
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
-
0.003 zz
-
0.10zz
5.8
-
1.17
-
Reference Lakes * *
P75 all seasons
*Summer data only
Table 3j.Reference conditions for level III ecoregion 17 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
'Chlorophyll a («g/L) - F
'Chlorophyll a («g/L) - S
'Chlorophyll a («g/L) - T
No. of
Lakes
N++
11
6
NA
-
17
16
5
4
3z
Reported values
Min
0.06
0.025
0.08
-
11.3
1.2
1.6
1.3
0.9
Max
0.84
0.01
0.95
-
116.3
6.7
13.9
11.2
1.3
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.14
0.025
0.16
-
17.5
6.0
4.3 zz
1.4 zz
0.4
Reference Lakes * * II
P75 all seasons
* summer data only
23
-------
Table 3k.Reference conditions for level III ecoregion 19 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
77
9
NA
-
85
79
-
82
-
Reported values
Min
0.02
0.003
0.023
-
2.5
0.5
-
0.7
-
Max
1.15
0.23
1.38
-
187.5
6.1
-
31.7
-
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.20
0.005
0.21
-
5.3
3.8
-
0.7
-
Reference Lakes * *
P75 all seasons
Table Sl.Reference conditions for level III ecoregion 21 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
33
16
NA
7
38
30
-
7
15
Reported values
Min
0.05
0.01
0.06
0.44
4.38
0.5
-
0.9
1.0
Max
3.30
0.10
3.40
3.07
202.5
4.5
-
7.5
10.6
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.17
0.01
0.18
0.88
14.8
4.2
-
1.7
2.7
Reference Lakes * * II
P75 all seasons
24
-------
Table Sm.Reference conditions for level III ecoregion 23 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
6
6
NA
5
6
6
-
5
9
Reported values
Min
0.23
0.01
0.24
0.44
9.06
0.4
-
2.4
3.2
Max
3.01
0.07
3.08
3.07
107.5
1.9
-
21.5
24.2
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.39
0.01
0.40
0.88
12.5
1.8
-
6.1
6.9
Reference Lakes * *
P75 all seasons
Table Sn.Reference conditions for level III ecoregion 41 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
lz
Iz
NA
lz
2z
-
-
lz
-
Reported values
Min
0.20
0.06
0.26
0.11
6.75
-
-
1.0
-
Max
0.20
0.06
0.26
0.11
9.25
-
-
1.0
-
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.20 zz
0.06 zz
0.26
0.11
6.75
-
-
1.0
-
Reference Lakes * * II
P75 all seasons
25
-------
Table So.Reference conditions for level III ecoregion 77 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
Chlorophyll a («g/L) - T
No. of
Lakes
N++
-
-
NA
-
-
Iz
Iz
Reported values
Min
-
-
-
-
-
7.0
0.4
Max
-
-
-
-
-
7.0
0.4
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
-
-
-
-
-
7.0 zz
0.4 zz
Reference Lakes * *
P75 all seasons
Table Sp.Reference conditions for level III ecoregion 78 lakes.
Parameter
TKN (mg/L)
N02 + N03 (mg/L)
TN (mg/L) - calculated
TN (mg/L) - reported
TP (Kg/L)
Secchl (meters)
Chlorophyll a («g/L) - F
Chlorophyll a («g/L) - S
"Chlorophyll « («g/L) - T
No. of
Lakes
N++
2z
-
NA
-
3z
3z
-
-
2z
Reported values
Min
0.20
-
-
-
40.0
2.0
-
-
1.6
Max
0.30
-
-
-
160.0
2.2
-
-
4.2
25th Percentiles based on all
seasons data for the Decade
P25* all seasons +
0.20 zz
-
-
-
40.0 zz
2.2
-
-
1.6 zz
Reference Lakes * * II
P75 all seasons
*Summer data only
26
-------
Definitions used in filling Tables 2 and 3 - Reference Condition tables
1. Number of Lakes in Table 2 refers to the largest number of lakes and reservoirs for
which data existed for a given season within an aggregate nutrient ecoregion.
2. Number of Lakes in Table 3 refers to the number of lakes and reservoirs for which
data existed for the summer months since summer is generally when the greatest amount
of nutrient sampling is conducted. If another season greatly predominates, notification is
made (s=spring, f=fall, w=winter).
3. Medians. All values (min, max, and 25th percentiles) included in the table are based
on waterbody medians. All data for a particular parameter within a lake for the decade
were reduced to one median for that lake. This prevents over-representation of
individual waterbodies with a great deal of data versus those with fewer data points
within the statistical analysis.
4. 25th percentile for all seasons is calculated by taking the median of the 4 seasonal 25th
percentiles. If a season is missing, the median was calculated with 3 seasons of data. If
less than 3 seasons were used to derive the median, the entry is flagged (z).
5. A 25th percentile for a season is best derived with data from a minimum of 4
lakes/season. However, this table provides 25th percentiles that were derived with less
than 4 lakes/season in order to retain all information for all seasons. In calculating the
25th percentile for a season with less than 4 lake medians, the statistical program
automatically used the minimum value within the less-than-4 population. If less than 4
lakes were used in developing a seasonal quartile and or all-seasons median, the entry is
flagged (zz).
Preferred Data Choices and Recommendations When Data Are Missing
1. Where data are missing or are very low in total records for a given parameter, use 25th
percentiles for parameters within an adjacent, similar subecoregion within the same aggregate
nutrient ecoregion or when a similar subecoregion can not be determined, use the the 25th
percentile for the Aggregate ecoregion or consider the lowest 25th percentile from a subecoregion
(level III) within the aggregate nutrient ecoregion. The rationale being that without data, one may
assume that the subecoregion in question may be as sensitive as the most sensitive subecoregion
within the aggregate.
2. TN calculated: When reported Total Nitrogen (TN) median values are lacking or very low in
comparison to TKN and Nitrate/Nitrite-N values, the medians for TKN and nitrite/nitrate-N were
added, resulting in a calculated TN value. The number of samples (N) for calculated TN is not
filled in since it is represented by two subsamples of data: TKN and nitrite/nitrate-N. Therefore,
N/A is placed in this box.
27
-------
3. TN reported: This is the median based on reported values for TN from the database.
4. Chlorophyll a: Medians based on all methods are reported, however, the acid corrected medians
are preferred to the uncorrected medians. In developing a reference condition from a particular
method, it is recommended that the method with the most observations be used. Fluorometric and
Spectrophotometric are preferred over all other methods. However, when no
data exist for Fluorometric and Spectrophotometric methods, Trichromatic values may be used.
Data from the variance techniques are not interchangeable.
5. Periphyton: Where periphyton data exist, record them separately For periphyton-dominated
streams, a measure of periphyton chlorophyll is a more appropriate response variable than
planktonic chlorophyll a. See Table 4, p. 101 of the Rivers and Streams Nutrient Technical
Guidance Manual (U. S. EPA, 2000b) for values of periphyton and planktonic chlorophyll a
related to eutrophy in streams.
6. Secchi depth: The 75th percentile is reported for Secchi depth since this is the only variable for
which the value of the parameter increases with greater clarity. (For lakes and reservoirs only.)
7. Turbidity units: All turbidity units from all methods are reported. FTUs and NTUs are
preferred over JCUs. If FTUs and NTUs do not exist, use JCUs. These units are not
interchangeable. Turbidity is chosen as a response variable in streams since it can be an indicator
of increasing algal biomass due to nutrient enrichment. See pages 32 -33 of the Rivers and
Streams Nutrient Technical Guidance Manual for a discussion of turbidity and correlations with
algal growth.
8. Lack of data: A dash (-) represents missing, inadequate, or inconclusive data. A zero (0) is
reported if the reported median for a parameter is 0 or if the component value is below detection.
4.6. Classification of Lake/Reservoir Type
It is anticipated that assessing the data by lake type will further reduce the variability in the
data analysis. There were no readily available classification data in the National datasets used to
develop these criteria. States and Tribes are strongly encouraged to classify their lakes before
developing a final criterion.
4.7. Summary of Data Reduction Methods
All descriptive statistics were calculated using the medians for each lake within ecoregion
II, for which data existed. For example, if one lake had 300 observations for phosphorus over the
decade or one year's time, one median resulted. Each median from each lake was then used in
calculating the percentiles for phosphorus for the aggregate nutrient ecoregion/subecoregion (level
III ecoregion) by season and year (Figure 4a & b).
28
-------
Observations for All Lakes/Reservoirs
Ecoregion
Winter
Spring
Data Reduced
to
Median Value
for each
Lake/Reservoir
by
Season
Summer
Rainy Lake Median
Fish Reservoir Median
Swan Lake Median
Moon Lake ...
Timber...
Rainy Lake Median
Fish Reservoir Median
Swan Lake Median
Moon Lake ...
Timber...
Rainy Lake Median
Fish Reservoir Median
Swan Lake Median
Moon Lake ...
Timber...
Fall
Rainy Lake Median
Fish Reservoir Median
Swan Lake Median
Moon Lake ...
Timber...
Figure 4a. Illustration of data reduction process for lake data.
29
-------
Select 25th Percentile
from Distribution
of Median
Values
25th
Winter
25
-------
5.0 REFERENCE SITES AND CONDITIONS IN AGGREGATE ECOREGION II
Reference conditions represent the natural, least impacted conditions or what is considered
to be the most attainable conditions. This section compares the different reference conditions
determined from the two methods and establishes which reference condition is most appropriate.
A priori determination of reference sites. The preferred method for establishing reference
condition is to choose the upper percentile of an a priori population of reference lakes. States and
Tribes are encouraged to identify reference conditions based on this method.
Statistical determination of reference conditions (25th percentile of entire database.) See Tables 2
and 3a-p in section 4.0.
RTAG discussion and rationale for selection of reference sites and conditions in Ecoregion II.
The RTAG should compare the results derived from the two methods described above and present
a rationale for the final selection of reference sites.
6.0 MODELS USED TO PREDICT OR VERIFY RESPONSE PARAMETERS
The RTAG is encouraged to identify and apply relevant models to support nutrient criteria
development. The following are three scenarios under which models may be used to derive criteria
or support criteria development.
• Models for predicting correlations between causal and response variables
• Models used to verify reference conditions based on percentiles
• Regression models used to predict reference conditions in impacted areas
7.0 FRAMEWORK FOR REFINING RECOMMENDED NUTRIENT CRITERIA FOR
LAKES AND RESERVOIRS IN AGGREGATE ECOREGION II
Information on each of the following six weight of evidence factors is important to refine
the criteria presented in this document. All elements should be addressed in developing criteria, as
is expressed in our nutrient criteria technical guidance manuals. It is our expectation that EPA
Regions, States, and Tribes (as RTAGs) will consider these elements as States/Tribes develop their
criteria. This section should be viewed as a work sheet (sections are left blank for this purpose) to
assist in the refinement of nutrient criteria. If many of these elements are ultimately unaddressed,
EPA may rely on the proposed reference conditions presented in Tables 3a-o and other literature
and information readily available to the HQ nutrient team to develop nutrient water quality
recommendations for this ecoregion.
-------
7.1 Example Worksheet for Developing Aggregate Ecoregion and Subecoregion Nutrient
Criteria
• Literature sources
Historical data and trends
Reference condition
Models
RTAG expert review and consensus
Downstream effects
32
-------
7.2 Tables of Refined Nutrient Water Quality Criteria for Aggregate Ecoregion II and Level
III Subecoregions for TP, TN, Chi a, Turbidity (where sufficient data exist)
Aggregate Ecoregion II- Western Forested
Mountains
Total Phosphorus (|ig/L)
Total Nitrogen (mg/L)
Chlorophyll a (|ig/L or mg/m2)
Secchi depth (meters)
Other (Index; other parameter such as DO)
Proposed Criterion
Literature sources
Historical data and trends
Reference condition
Models
33
-------
RTAG expert review and consensus
Downstream effects
Ecoregion #5-Sierra Nevada
Total Phosphorus (|ig/L)
Total Nitrogen (mg/L)
Chlorophyll a (|ig/L or mg/m2)
Secchi depth (meters)
Other (Index; other parameter such as DO)
Proposed Criterion
7.3 Setting Seasonal Criteria
The criteria presented in this document are based in part on medians of all the 25th
percentile seasonal data (decadal), and as such are reflective of all seasons and not one particular
season or year. It is recommended that States and Tribes monitor in all seasons to best assess
compliance with the resulting criterion. States/Tribes may choose to develop criteria which reflect
each particular season or a given year when there is significant variability between seasons/years
or designated uses that are specifically tied to one or more seasons of the year (e.g., recreation,
fishing). Using the tables in Appendix A and B, one can set reference conditions based on a
particular season or year and then develop a criterion based on each individual season. Obviously,
this option is season-specific and would also require increased monitoring within each season to
assess compliance.
7.4 When Data/Reference Conditions Are Lacking
When data are unavailable to develop a reference condition for a particular parameter(s)
within a subecoregion, EPA recommends one of three options: 1. Use data from a similar
neighboring subecoregion. E.g., If data are few or nonexistent for the northern cascades, consider
using the data and reference condition developed for the cascades; or 2. Use the 25th perecentiles
34
-------
for the Aggregate ecoregion or 3. Consider using the lowest of the yearly medians for that
parameter calculated for all the subecoregions within the Aggregate Ecoregion.
7.5 Site-specific Criteria Development
Criteria may be refined in a number of ways. The best way to refine criteria is to follow the
critical elements of criteria development as well as to refer to the Lakes and Reservoirs technical
guidance manual (U. S. EPA, 2000a).
The Lakes and Reservoirs Nutrient Criteria Technical Guidance Manual presents sections
on each of the following factors to consider in setting criteria
- refinements to ecoregions (Chapter 3)
- classification of waterbodies (Chapter 3)
- setting seasonal criteria to reflect major seasonal climate differences (Chapter 7)
accounting for significant or cyclical rainfall events - high flow/low flow conditions (Chapter 7)
setting criteria for reservoirs only (The technical guidance manual recommends that data be
separated for lakes and reservoirs and treated independently if possible because of differing
physical conditions that occur in lakes and reservoirs. In this document all data from both
reservoirs and lakes were considered together since STORET does not allow for the
differentiation of data except by waterbody name.)
8.0 LITERATURE CITED
NYSDEC (New York State Department of Environment and Conservation). 2000.
Memorandum from Scott Kishbaugh to Jay Bloomfield, September 26, 2000, regarding
reference lakes for nutrient criteria.
TNDEC (Tennessee Department of Environment and Conservation). 2000. Letter to
Geoff Grubbs, October 5, 2000, containing comments on draft nutrient criteria
recommendations.
U.S. EPA. 2000a. Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs,
U.S. Environmental Protection Agency, Washington, DC. EPA-822-BOO-001.
U.S. EPA. 2000b. Nutrient Criteria Technical Guidance Manual: Rivers and Streams,
U.S. Environmental Protection Agency, Washington, DC. EPA-822-BOO-002.
35
-------
9.0 APPENDICES
A. Descriptive Statistics Data Tables for Aggregate Ecoregion
B. Descriptive Statistics Data Tables for Level III Subecoregions within Aggregate Ecoregion
C. Quality Control/Quality Assurance Rules
36
-------
APPENDIX A
Descriptive Statistics Data Tables for Aggregate Ecoregion
-------
Aggregate Nutrient Ecoregion: II
SEASON
FALL
SPRING
SUMMER
WINTER
SEASON
FALL
SPRING
SUMMER
WINTER
SEASON
FALL
SPRING
N
71
3b
1DD
1
EE
ES
41
ID
ES
14
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla_Fluo_ug_L_Median
SEASON
FALL
SPRING
SUMMER
WINTER
N
fll
E7
13D
a
MEAN
fl.31
ID- 5
b-bl
4-33
MIN
• E1S
• 3DD
• DDD
• 1DD
MAX
5LSD
4L 3D
47- 3D
14- 4D
STDDEV
IE- 3
1 • 11
L33
4- El
STDERR
L37
L11
D-flE
L41
CV
147
14
14D
17
P5
D-4D
Lib
D-3D
D-1D
PES
LID
E • ID
L3D
E-4b
MEDIAN
E-4D
7-E5
3-E3
3- ED
P7S
ID- 5
17-4
fl.7D
4-D3
PIS
3fl-D
ELD
E4-D
14-4
MEAN
b-DS
5-bS
5.ID
5-17
MEAN
13D
113
55-1
7E-D
MEAN
11.5
fl.54
MIN
• 54D
LID
• DDD
b.flS
MIN
• DDD
• DDD
Aggregate Nutrient Ecoregion: n
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla_Phyto_Spec_A_ug_L_Median
MIN
• 3E5
• SbD
• 45D
• 7flD
MAX
5L EE
Ifl.flD
4fl-DD
LSD
STDDEV
LDD
4-Sfl
7- 3D
3-D3
STDERR
LD7
D-7b
D-73
LD1
CV
141
fll
143
51
PS
D-5D
D-1D
D-7D
D-7fl
PES
L7fl
E • Dfl
L4D
3-5D
Aggregate Nutrient Ecoregion: n
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla_Tric_U_ug_L_Median
MAX
14DD-DD
143E-SD
IDflD-DD
37S-DD
STDDEV
31S
37E
E14
13E
STDERR
fl4-3
74-4
33-4
4L7
CV
3DS
3E1
3flE
Ifl3
PS
D-lfl
L37
D-43
b.flS
Aggregate Nutrient Ecoregion: n
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter DIP_ug_L_Median
MAX
114.DD
33-DD
STDDEV
E3-fl
l.fll
STDERR
4-7b
E-b4
CV
ED7
lib
PS
D.DD
D.DD
PES
3-31
L4D
7-ID
PES
E-DD
D.DD
MEDIAN
3-DS
4-43
E-flS
S-7fl
MEDIAN
3-17
S-lfl
4-3S
11.1
MEDIAN
4-DD
7-ES
P7S
b-73
fl. tD
S-fll
b-17
P7S
1E-E
b-7b
LSD
17-7
P7S
1D-D
11.S
PIS
1LD
IS-4
Ifl.b
LSD
PIS
13DD
lEbD
ID-7
37S
PIS
SD-D
33-D
-------
SUMMER
WINTER
1D.1
• DDD
• DDD
11.DD
ED.DD
15.1
11. 5
.IE
ISfl
173
D.DD
D.DD
E.DD
D.DD
b-SD
D.DD
1D-D
ED-D
4E-D
ED-D
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter DO_mg_L_Median
SEASON
FALL
SPRING
SUMMER
WINTER
N
Ibl
tfl
ESb
El
MEAN
7-74
7.fl1
7-47
1 • IE
MIN
• 3DD
• 3DD
• 3DD
b-ED
MAX
13. ID
IE- 77
IE. ID
lb-7D
STDDEV
E.11
E-71
Lflb
E-3S
STDERR
D-17
D-33
D-IE
D-44
CV
Efl
34
ES
E4
PS
3-flD
LSD
4- ED
b-3D
PES
b-7S
t • t4
t. tt
7-7D
MEDIAN
7-15
fl.SS
7-S7
ID- 7
P7S
fl.TD
T-73
fl. tfl
11. E
PTS
11. E
11. 1
1D-D
13-3
SEASON
FALL
SPRING
SUMMER
WINTER
N
US
57
144
14
MEAN
D-D4
D-D7
D-D3
D.ED
MIN
• DDD
• DDD
• DDD
• DID
Aggregate Nutrient Ecoregion: n
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter NOE_N03_mg_L_Median
MAX
D.1E
D.1E
D-bD
1-3D
STDDEV
D-14
D-14
D.DT
D-3S
STDERR
D-Dl
D.DE
D.DI
cv
311
EDI
EflE
173
PS
D.DD
D.DD
D.DD
D.DI
PES
D.DD
D.DI
D.DD
D-D3
MEDIAN
D.DI
D-D3
D.DD
D.DS
P7S
D-D3
D.Dt
D.DE
D-37
PTS
D-E3
D-43
D-14
1-3D
SEASON
FALL
SPRING
SUMMER
WINTER
MEAN
D.DD
D.DD
D.DD
E7SD
MIN
• DDD
• DDD
• DDD
EDDD
Aggregate Nutrient Ecoregion: n
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter P_T_Rea_ug_L_Median
MAX
D.DD
D.DD
D.DD
3SDD-DD
STDDEV
D.DD
D.DD
D.DD
IDbl
STDERR
D.DD
D.DD
D.DD
7SD
cv
PS
D.DD
D.DD
D.DD
EDDD
PES
D.DD
D.DD
D.DD
EDDD
MEDIAN
D.DD
D.DD
D.DD
E7SD
P7S
D.DD
D.DD
D.DD
3SDD
PIS
D.DD
D.DD
D.DD
3SDD
-------
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter SECCHI m Median
SEASON
FALL
SPRING
SUMMER
WINTER
SEASON
FALL
SPRING
SUMMER
WINTER
SEASON
FALL
SPRING
SUMMER
WINTER
SEASON
FALL
SPRING
N
113
fit
3DE
El
N
fl3
tfl
lt,E
Et,
45
31
45
13
EDfl
111
MEAN
3-45
E-73
3-5D
3-34
MEAN
D-5E
D. t,4
D-43
D-7D
MEAN
D-51
D-74
D-43
D-51
MEAN
3fl-3
51-4
MIN
• ODD
• DDD
• DDD
LID
MIN
.DDD
• DID
.DDD
• DSD
MIN
.DDD
.DDD
.DDD
.DDD
MIN
.DDD
.DDD
MAX
13-ED
7-flD
Ib-SD
t,.D5
STDDEV
E-E1
1-74
E-E1
LSt,
STDERR
D-17
D.11
D-13
D-E1
CV
tt
t,4
t,s
47
P5
D. t,5
D-3D
I.DD
l.lfl
Aggregate Nutrient Ecoregion: n
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter TKN_mg_L_Median
MAX
3-15
3-fll
3-DE
4-3D
STDDEV
D. t,7
D-7b
D-4t,
D-17
STDERR
D-D7
D-D1
D-D4
D.11
CV
1E1
111
1D1
13fl
P5
D-D5
D-D5
D-D5
D-D5
Aggregate Nutrient Ecoregion: n
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter TN_mg_L_Median
MAX
3-Dfl
3-17
3-Dt,
E-fl3
STDDEV
D. t,4
D-fl3
D-5E
D-77
STDERR
D-ID
D-13
D-Dfl
D-El
CV
1E5
113
1E1
13D
P5
D.DD
D.DD
D.DD
D.DD
Aggregate Nutrient Ecoregion: n
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter TP_ug_L_Median
MAX
5E5-DD
IflD-DD
STDDEV
IDb
STDERR
4-b7
ID-l
CV
EDb
P5
E-5D
E-5D
PE5
L.flD
L-5fl
L-lfl
MEDIAN
P75
1-7D
PE5
D-13
D.ED
D-lfl
D.ID
PE5
D-11
D.ED
D-Dfl
D.ID
PE5
7-DD
1D-D
DD
El
Dl
3-45
MEDIAN
D-Efl
D-3b
D-3D
D-31
MEDIAN
D-31
D-44
D-33
D-4D
MEDIAN
It. t
ED-D
tD
5D
4-5D
P75
D- bl
D-flE
D-5D
D.ID
P75
D. tt
Lit
D-Sfl
D-fl7
P75
31-5
53-D
P15
7-E5
5-t,4
P15
E-D3
Lb7
L15
E-7fl
P15
L-5D
3-DE
L.ED
E-fl3
P15
IflD
IflD
-------
SUMMER
WINTER
SEASON
FALL
SPRING
SUMMER
WINTER
4fl
N
7fl
El
113
ID
35-4
flD.D
MEAN
14
E3
ED
• DDD
E.5D
7-lfl
MIN
S.ED
b • bO
S.SD
b.flD
41D-DD
45D-DD
54-E
1E3
3-IS
17-7
153
153
E.5D
4-DD
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter pH_Median
MAX
fl.flD
7-flD
fl.TD
7-S3
STDDEV
D-5b
D-3S
D-7D
D-EE
STDERR
D-Db
D-Dfl
D-D7
D-D7
CV
fl
5
ID
3
PS
5.ID
b-71
t.lD
t.flD
fl.DD
T-SD
PES
7-DD
b-TD
b-7D
7-DD
ED-D
3D-4
MEDIAN
ED
IS
ED
4D-D
73-fl
7-lfl
P7S
7-SD
7-31
41D
PIS
7-fl3
7-73
fl.SD
7-S3
-------
APPENDIX B
Descriptive Statistics Data Tables for Level III Subecoregions within Aggregate Ecoregion
-------
Eco_
Level_
III
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla Fluo ug L Median
MIN
STDDEV
STDERR
MEDIAN
1
1
1
1
2
2
2
2
4
4
4
4
5
5
5
5
9
9
9
9
1
1
5
5
5
5
6
6
6
6
•-j
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
2
2
11
1
15
14
15
6
60
9
78
1
0
0
0
0
-^
2
-^
0
1
2
0
0
16
0
0
0
0
0
0
1.15
1.15
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla Fluo ug L Median
11.8
SPRING
SUMMER
WINTER
FALL
MIN
STDDEV
STDERR
71
P5
MEDIAN
P75
-------
19
19
19
21
21
21
21
41
41
41
41
Eco_
Level_
III
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla_Phyto_Spec_A_ug_L_Median
MIN
STDDEV
STDERR
P5
MEDIAN
P75
11
11
15
15
15
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
-------
Eco_
Level_
III
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla_Phyto_Spec_A_ug_L_Median
MIN
STDDEV
STDERR
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
41
41
41
41
Eco_
Level_
III
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla Trie U ug L Median
MIN
STDDEV
STDERR
P5
MEDIAN
P75
P95
FALL
SPRING
SUMMER
WINTER
FALL
-------
Eco_
Level_
III
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter Chla Trie U ug L Median
MIN
STDDEV
STDERR
P5
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
41
41
41
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
-------
41
Eco_
Level_
III
WINTER
SUMMER
FALL
SPRING
SUMMER
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter DIP ug L Median
MIN
STDDEV
STDERR
1
1
1
1
2
2
2
2
4
4
4
4
5
5
5
5
9
9
9
9
1
1
5
5
5
5
6
6
6
6
•-j
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
0
0
0
0
0
0
0
0
23
13
54
-^
0
0
0
0
0
0
0
0
0
0
2
1
2
0
0
0
0
0
0
.000
.000
.000
.000
.000
.000
.000
141
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter DIP ug L Median
-------
Ill
MIN
STDDEV
STDERR
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
41
41
41
41
Eco_
Level_
III
1
1
1
1
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
88
0
0
0
0
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter DO mg L Median
MIN
STDERR
0.59
11.5
MEDIAN
-------
Eco_
Level_
III
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
15
14
4
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter DO mg L Median
10
MIN
STDDEV
STDERR
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
23
23
23
23
41
41
41
41
7 7
78
78
78
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
2
11
2
53
27
81
~-/
21
14
2 4
6
2
1
1
1
0
0
0
0
1
0
0
2
Eco_
Level_
III
47
18
17
14
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter NO2 NO3 mg L Median
.15
11
MIN
STDDEV
STDERR
MEDIAN
-------
Eco_
Level_
III
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
0.39
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter NO2 NO3 mg L Median
0.39
0.39
12
MIN
STDDEV
STDERR
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
-------
23
23
23
41
41
41
41
7 7
78
78
78
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
11
6
2
0
1
1
0
0
0
0
0
Eco_
Level_
III
.010
.010
.010
0.
0.
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter P T Rea ug L Median
MIN
STDDEV
STDERR
P5
0.
MEDIAN
0.
0.
1
1
1
1
2
2
2
2
4
4
4
4
5
5
5
5
9
9
9
9
1
1
5
5
5
5
6
6
6
6
•-j
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
0
0
0
0
0
0
0
0
2
2
2
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.000
.000
.000
2000
Aggregate Nutrient Ecoregion: II
14
-------
Eco_
Level_
III
MIN
STDDEV
STDERR
P5
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
41
41
41
41
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter SECCHI m Median
15
Eco_
Level_
III
MIN
STDDEV
STDERR
MEDIAN
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
-------
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
16
Eco_
Level_
III
MIN
STDDEV
STDERR
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
41
41
41
41
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
1.44
1.44
-------
Eco_
Level_
III
MIN
STDDEV
STDERR
MEDIAN
Eco_
Level_
III
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
0.
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter TKN mg L Median
18
MIN
STDDEV
STDERR
MEDIAN
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
11
18
-------
19
21
21
21
21
41
41
41
41
Eco_
Level_
III
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
1.49
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter TN mg L Median
.00
19
MIN
STDDEV
STDERR
MEDIAN
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
1
1
1
1
14
13
14
2
15
6
15
•^
1
1
1
2
0
0
0
0
0
0
0
0
0
0
1
-------
Eco_
Level_
III
SPRING
SUMMER
WINTER
FALL
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter TN mg L Median
MIN
STDDEV
STDERR
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
41
41
41
41
Eco_
Level_
III
1
1
1
1
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
10
5
1
1
1
1
1
0
0
0
0
.15
.15
1.11
.15
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter TP ug L Median
MIN
STDDEV
STDERR
.15
.15
MEDIAN
.15
.15
-------
Eco_
Level_
III
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
194
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter TP ug L Median
31.0
14.0
10.5
18.5
5.00
10.0
95.0
20.0
205
193
149
42.5
135
4.00
190
6.50
7.50
12.0
9.50
20.0
6.00
6.00
5.50
70.0
MIN
STDDEV
STDERR
MEDIAN
17
17
17
19
19
19
19
21
21
21
21
41
41
41
41
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
-------
Eco_
Level_
III
FALL
SPRING
SUMMER
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter pH_Median
MIN
STDDEV
STDERR
MEDIAN
Eco_
Level_
III
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SUMMER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
1
1
1
1
16
13
15
6
58
6
71
2
0
0
0
0
1
0
1
0
1
^
1
1
18
0
0
0
0
0
0
Aggregate Nutrient Ecoregion: II
Lakes and Reservoirs
Descriptive Statistics by Decade and Season
Parameter pH_Median
MIN
STDDEV
STDERR
P5
MEDIAN
-------
17
17
17
19
19
19
19
21
21
21
21
23
23
23
23
41
41
41
41
7 7
78
78
78
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
FALL
SPRING
SUMMER
WINTER
SUMMER
FALL
SPRING
SUMMER
0
5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-------
APPENDIX C
Quality Control/Quality Assurance Rules
-------
Support for the Compilation and Analysis of National Nutrient Data
15 Nutrient Ecoregion/Waterbody Type Summary Chapters
Prepared for:
Robert Cantilli
Environmental Protection Agency
OW/OST/HECD
Prepared by:
INDUS Corporation
1953 Gallows Road
Vienna, Virginia 22182
Contract Number: 68-C-99-226
Task Number: 04
Subtask Number: 4
August 8, 2000
-------
CONTENTS
1.0 BACKGROUND 1
1.1 Purpose 1
1.2 References 1
2.0 QA/QC PROCEDURES 2
2.1 National Data Sets 3
2.2 State Data 3
2.3 Laboratory Methods 4
2.4 Waterbody Name 4
2.5 Ecoregion Data 5
3.0 STATISTICAL ANALYSIS REPORTS 5
3.1 Data Source Reports 6
3.2 Remark Code Reports 7
3.3 Median of Each Waterbody 7
3.4 Descriptive Statistic Reports 7
3.5 Regression Models 8
4.0 TIME PERIOD 8
5.0 DATA SOURCES AND PARAMETERS FOR THE AGGREGATE NUTRIENT
ECOREGIONS 9
5.1 Lakes and Reservoirs 9
5.1.1 Aggregate Nutrient Ecoregion 2 9
5.1.2 Aggregate Nutrient Ecoregion 6 10
5.1.3 Aggregate Nutrient Ecoregion 7 10
5.1.4 Aggregate Nutrient Ecoregion 8 11
5.1.5 Aggregate Nutrient Ecoregion 9 12
5.1.6 Aggregate Nutrient Ecoregion 11 12
5.1.7 Aggregate Nutrient Ecoregion 12 13
5.1.8 Aggregate Nutrient Ecoregion 13 13
5.2 Rivers and Streams 14
5.2.1 Aggregate Nutrient Ecoregion 2 14
5.2.2 Aggregate Nutrient Ecoregion 3 15
5.2.3 Aggregate Nutrient Ecoregion 6 16
5.2.4 Aggregate Nutrient Ecoregion 7 16
5.2.5 Aggregate Nutrient Ecoregion 9 17
5.2.6 Aggregate Nutrient Ecoregion 11 18
5.2.7 Aggregate Nutrient Ecoregion 12 19
5.2.8 Aggregate Nutrient Ecoregion 14 20
-------
APPENDIX A Process Used to QA/QA the Legacy STORE! Nutrient Data Set
APPENDIX B Process for Adding Aggregate Nutrient Ecoregions and Level III
Ecoregions
APPENDIX C Glossary
in
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
1.0 BACKGROUND
The Nutrient Criteria Program has initiated development of a national Nutrient Criteria Database
application that will be used to store and analyze nutrient data. The ultimate use of these data will
be to derive ecoregion- and waterbody-specific nutrient criteria ranges. EPA converted STOrage
and RETrieval (STORET) legacy data, National Stream Quality Accounting Network
(NASQAN) data, National Water-Quality Assessment (NAWQA) data, and other relevant
nutrient data from universities and States/Tribes into the database. The data imported into the
Nutrient Criteria Database will be used to develop national nutrient criteria ranges.
1.1 Purpose
The purpose of this deliverable is to provide EPA with information regarding the data used to
create the statistical reports which will be used to derive ecoregion- and waterbody-specific
nutrient criteria ranges for Level III ecoregions. There are fourteen aggregate nutrient
ecoregions. Each aggregate nutrient ecoregion is divided into smaller ecoregions referred to as
Level III ecoregions. EPA will determine criteria ranges for the waterbody types and Level III
ecoregions within the following aggregate nutrient ecoregions:
Lakes and Reservoirs
Aggregate Nutrient ecoregions: 2, 6, 7, 8, 9, 11, 12, 13
• Rivers and Streams
Aggregate Nutrient ecoregions: 2, 3, 6, 7, 9, 11, 12, 14
1.2 References
This section lists documents that contain baselines, standards, guidelines, policies, and references
that apply to the data analysis. Listed editions were valid at the time of publication. All
documents are subject to revision, but these specific editions govern the concepts described in this
document.
Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs (Draft). EPA, Office of
Water, EPA 822-D-99-001, April 1999.
Nutrient Criteria Technical Guidance Manual: Rivers and Streams (Draft). EPA, Office of
Water, EPA 822-D-99-003, September 1999.
Guidance for Data Quality Assessment: Practical Methods for Data Analysis. EPA, Office of
Research and Development, EPA QA/G-9, January 1998.
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
2.0 QA/QC PROCEDURES
In order to develop nutrient criteria, EPA needed to obtain nutrient data from the states. EPA
requested nutrient data from the states and forwarded the data sets to INDUS via e-mail and/or
US mail. In addition, EPA tasked INDUS to convert data from three national data sets. EPA
provided INDUS with a Legacy STORET extraction to convert into the database. The United
States Geologic Survey (USGS) sent INDUS a CD-ROM with NASQAN data to convert.
INDUS downloaded NAWQA files from the USGS Web site to convert the data. In total,
INDUS converted and imported the following national and state data sets into the Nutrient
Criteria Database:
Legacy STORET
NAWQA
NASQAN
• Region 1
• Region 2 - Lake Champlain Monitoring Project
• Region 2 - NYSDEC Finger Lakes Monitoring Program
• Region 2 - NY Citizens Lake Assessment Program
• Region 2 - Lake Classification and Inventory Survey
Region 2 - NYCDEP (1990-1998)
Region 2 - NYCDEP (Storm Event data)
Region 2 - New Jersey Nutrient Data ( Tidal Waters)
• Region 5
• Region 3
• Region 3 - Nitrite Data
• Region 3 - Choptank River files
• Region 4 - Tennessee Valley Authority
• Region 7 - Central Plains Center for BioAssessment (CPCB)
Region 7 - REMAP
• Region 2 - Delaware River Basin Commission (1990-1998)
• Region 3 - PA Lake Data
• Region 3 - University of Delaware
• Region 10
• University of Auburn
As part of the conversion process, INDUS performed a number of Quality Assurance/Quality
Control (QA/QC) steps to ensure that the data was properly converted into the Nutrient Criteria
Database. Section 2 explains the steps performed by INDUS to convert the data.
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
2.1 National Data Sets
INDUS converted three national data sets into the Nutrient Criteria Database: Legacy STORET
data, NASQAN data, and NAWQA data. A previous EPA contractor performed the extraction of
Legacy STORET data and documented the QA/QC procedures used on the data. This
documentation is included in Appendix A. INDUS performed minimal QA/QC on the Legacy
STORET data set because the previous contractor completed the steps outlined in Appendix A.
INDUS and EPA also agreed to convert the NAWQA and NASQAN data sets with minimal
QA/QC on the assumption that the source agency, the USGS, QA/QC'd the data.
For each of the three national data sets, INDUS ran queries to determine if 1) samples existed
without results and 2) if stations existed without samples. Per Task Order Project Officer
(TOPO) direction, these records were deleted from the system. For analysis purposes, EPA
determined that there was no need to keep station records with no samples and sample records
with no results. INDUS also confirmed that each data set contained no duplicate records.
In addition, INDUS deleted all composite results from the Legacy STORET data. Per TOPO
direction, it was decided that composite sample results would not be used in the statistical
analysis.
2.2 State Data
Each state data set was delivered in a unique format. Many of the data sets were delivered to
INDUS without corresponding documentation. INDUS analyzed each state data set in order to
determine which parameters should be converted for analysis. INDUS obtained a master
parameter table from EPA and converted the parameters in the state data sets according to those
that were present in the EPA parameter table. INDUS converted all of the data elements in the
state data sets that mapped directly to the Nutrient Criteria Database; data elements that did not
map to the Nutrient Criteria Database were not converted. In some cases, state data elements
that did not directly map into the Oracle database were inserted into a comment field within the
database. Also, INDUS maintained an internal record of which state data elements were inserted
into the comment field.
As part of the data clean-up efforts, INDUS determined whether or not there were any duplicate
records in the state data sets and deleted the duplicate records. INDUS checked the waterbody,
station, and sample entities for duplicate records. In addition, INDUS deleted station records
with no samples and sample records with no results. INDUS also deleted waterbody records that
were not associated with a station. In each case, INDUS maintained an internal record of how
many records were deleted.
If INDUS encountered referential integrity errors, such as samples that referred to stations that
did not exist, or if INDUS was unsure of whether a record was a duplicate, INDUS contacted the
agency directly via e-mail or phone to resolve any issues that arose. INDUS saved an electronic
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
copy of each e-mail correspondence with the states to ensure that a record of the decision was
maintained. INDUS also contacted each agency to determine which laboratory methods were
used for each parameter.
Finally, INDUS examined the remark codes of each result record in the state data sets. INDUS
mapped the remark codes to the STORET remark codes listed in Table 2 of Appendix A. If any
of the state result records were associated with remark codes marked as "Delete" in Table 2 of
Appendix A, the result records were not converted into the database.
2.3 Laboratory Methods
Many of the state data sets did not contain laboratory method information. In addition, laboratory
method information was not available for the three national data sets. In order to determine
missing laboratory method information, EPA tasked another contractor to contact the data
owners to obtain the laboratory method. In some cases, the data owners responded and the
laboratory methods were added to the database.
2.4 Waterbody Name and Class Information
A large percentage of the data did not have waterbody-specific information. The only waterbody
information contained in the three national data sets was the waterbody name, which was
embedded in the station 'location description' field. Most of the state data sets contained
waterbody name information; however, much of the data was duplicated throughout the data sets.
Therefore, the waterbody information was cleaned manually. For the three national data sets, the
'location description' field was extracted from the station table and moved to a temporary table.
The 'location description' field was sorted alphabetically. Unique waterbodies were grouped
together based on name similarity and whether or not the waterbodies fell within the same county,
state, and waterbody type. Finally, the 'location description' field was edited to include only
waterbody name information, not descriptive information. For example, 110 MILE CREEK AT
POMONA DAM OUTFLOW, KS PO-2 was edited to 110 MILE CREEK. Also, if 100 MILE
CREEK was listed ten times in New York, but in four different counties, four 100 MILE CREEK
waterbody records were created.
Similar steps were taken to eliminate duplicate waterbody records in the state data sets. If a
number of records had similar waterbody names and fell within the same state, county, and
waterbody type, the records were grouped to create a unique waterbody record.
Most of the waterbody data did not contain depth, surface area, and volume measurements. EPA
needed this information to classify waterbody types. EPA attempted to obtain waterbody class
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
information from the states. EPA sent waterbody files to the regional coordinators and requested
that certain class information be completed by each state. The state response was poor; therefore,
EPA was not able to perform statistical analysis for the waterbody types by class.
2.5 Ecoregion Data
Aggregate nutrient ecoregions and Level III ecoregions were added to the database using the
station latitude and longitude coordinates. If a station was lacking latitude and longitude
coordinates or county information, the data were not included in the statistical analysis. Appendix
B lists the steps taken to add the two ecoregion types (aggregate and Level III) to the Nutrient
Criteria Database. The ecoregion names were pulled from aggregate nutrient ecoregion and Level
III ecoregion Geographical Information System (GIS) coverages. In summary, the station latitude
and longitude coordinates were used to determine the ecoregion under the following
circumstances:
The latitude and longitude coordinates fell within the county/state listed in the station
table.
The county data was missing.
The county centroid was used to determine the ecoregions under the following circumstances:
The latitude and longitude coordinates were missing, but the state/county information was
available.
The latitude and longitude coordinates fell outside the county/state listed in the station
table. The county information was assumed to be correct; therefore, the county centroid
was used.
If the latitude and longitude coordinates fell outside the continental US county coverage file
(i.e., the point fell in the ocean or Mexico/Canada), the nearest ecoregion was assigned to the
station.
3.0 STATISTICAL ANALYSIS REPORTS
Aggregate nutrient ecoregion tables were created by extracting all observations for a specific
aggregate nutrient ecoregion from the nutrient criteria database. Then, the data were reduced to
create tables containing only the yearly median values. To create these tables, the median value
for each waterbody was calculated using all observations for each waterbody by Level III
ecoregion, year, and season. Tables of decade median values were created from the yearly
median tables by calculating the median for each waterbody by Level III ecoregion by decade and
season.
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
The Data Source and the Remark Code reports were created using all observations (all reported
values). All the other reports were created from either the yearly median tables or the decade
median tables. In other words, the descriptive statistics and regressions were run using the
median values for each waterbody and not the individual reported values.
Statistical analyses were performed under the assumption that this data set is a random sample. If
this assumption cannot be verified, the observations may or may not be valid. Values below the
1st and 99th percentile were removed from the Legacy STORET database prior to the creation of
the national database. Also, data were treated according the Legacy STORET remark codes in
Appendix A.
The following contains a list of each report and the purpose for creating each report:
Data Source Created to provide a count of the amount of data and to identify the
source(s).
Remark Codes Created to provide a description of the data.
• Median of Each Waterbody by Year This was an intermediate step performed to obtain a
median value for each lake to be used in the yearly descriptive statistics reports and the
regression models.
Median of Each Waterbody by Decade This was an intermediate step performed to obtain
a median value for each lake to be used in the decade descriptive statistics.
Descriptive Statistics Created to provide EPA with the desired statistics for setting criteria
levels.
Regression Models Created to examine the relationships between biological and nutrient
variables.
Note: Separate reports were created for each season.
3.1 Data Source Reports
Data source reports were presented in the following formats:
• The number and percentage of data from each data source were summarized in tables for
each aggregate nutrient ecoregion by season and waterbody type.
The number and percentage of data from each data source were summarized in tables for
each Level III ecoregion by season and waterbody type.
The 'Frequency' represents the number of data values from a specific data source for each
parameter by data source. The 'Row Pet' represents the percentage of data from a specific data
source for each parameter.
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
3.2 Remark Code Reports
Remark code reports were presented in the following formats:
• The number and percentage of data associated with a particular remark code for each
parameter were summarized in tables by Level III ecoregion by decade and season.
The number and percentage of data associated with a particular remark code for each
parameter were summarized in tables by Level III ecoregion by year and season.
The 'Frequency' represents the number of data values corresponding to the remark code in the
column. The 'Row Pet' represents the percentage of data that was associated with the remark
code in that row.
In the database, remark codes that were entered by the states were mapped to Legacy STORET
remark codes. Prior to the analysis, the data were treated according to these remark codes. For
example, if the remark code was 'K,' then the reported value was divided by two. Appendix A
contains a complete list of Legacy STORET remark codes.
Note: For the reports, a remark code of'Z' indicates that no remark codes were recorded. It does
not correspond to Legacy STORET code 'Z.'
3.3 Median of Each Waterbody
To reduce the data and to ensure heavily sampled waterbodies or years were not over represented
in the analysis, median value tables (described above) were created. The yearly median tables and
decade median tables were delivered to the EPA in electronic format as csv (comma separated
value or comma delimited) files.
3.4 Descriptive Statistic Reports
The number of waterbodies, median, mean, minimum, maximum, 5th, 25th , 75th , 95th
percentiles, standard deviation, standard error, and coefficient of variation were calculated. The
tables (described above) containing the decade median values for each waterbody for each
parameter were used to create descriptive statistics reports for:
• Level III ecoregions by decade and season
Aggregate nutrient ecoregions by decade and season
In addition, the tables containing the yearly median values for each waterbody for each parameter
were used to create descriptive statistics reports for:
• Level III ecoregions by year and season
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
3.5 Regression Models
Simple linear regressions using the least squares method were performed to examine the
relationships between biological and nutrient variables in lakes and reservoirs, and rivers and
streams. Regressions were performed using the yearly median tables. Chlorophyll(s) in
micrograms per liter (ug/L), secchi in meters (m), dissolved oxygen in milligrams per liter (mg/L),
turbidity, and pH were the biological variables in these models. When there was little or no data
for chlorophyll, then pH or dissolved oxygen was substituted for chlorophyll. Secchi data were
used in the lake and reservoir models, and turbidity data were used in the river and stream models.
The nutrient variables in these models include: total phosphorus in ug/L, total nitrogen in mg/L,
total kjeldahl nitrogen in mg/L, and nitrate and nitrite in mg/L. Regressions were also run for
total nitrogen and total phosphorus for ecoregions where both these variables were measured.
Note: At the time of creation of this document only regressions for aggregate nutrient ecoregion 7
for lakes and reservoirs were delivered to the EPA. Regressions for the remaining aggregate
nutrient ecoregions will be delivered in August 2000.
4.0 TIME PERIOD
Data collected from January 1990 to December 1999 were used in the statistical analysis reports.
To capture seasonal differences, the data were classified as follows:
Aggregate nutrient ecoregions: 6, 7, and 8
Spring: April to May
Summer: June to August
Fall: September to October
Winter: November to March
• Aggregate nutrient ecoregions: 1, 2, 9, 10, 11, 12, and 13
Spring: March to May
Summer: June to August
Fall: September to November
Winter: December to February
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
5.0 DATA SOURCES AND PARAMETERS FOR THE AGGREGATE NUTRIENT
ECOREGIONS
This section provides information for the nutrient aggregate ecoregions that were analyzed by
waterbody type. Each section lists the data sources for the aggregate nutrient ecoregion
including: 1) the data sources, 2) the parameters included in the analysis, and 3) the Level III
ecoregions within the aggregate nutrient ecoregions.
Note: For analysis purposes, the following parameters were combined to form Phosphorous,
Dissolved Inorganic (DIP):
Phosphorus, Dissolved Inorganic (DIP)
Phosphorus, Dissolved (DP)
Phosphorus, Dissolved Reactive (DRP)
Orthophosphate, dissolved, mg/L as P
Orthophosphate (OPO4_PO4)
5.1 Lakes and Reservoirs
5.1.1 Aggregate Nutrient Ecoregion 2
Data Sources:
Legacy STORE!
EPA Region 10
Parameter:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Phosphorus, Total Reactive (ug/L)
SECCHI (m)
pH
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
Level III ecoregions:
1, 2, 4, 5, 9, 11, 15, 16, 17, 19, 21, 23, 41, 77, 78
5.1.2 Aggregate Nutrient Ecoregion 6
Data Sources:
Legacy STORE!
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level III ecoregions:
46, 47, 48, 54, 55, 57
5.1.3 Aggregate Nutrient Ecoregion 7
Data Sources:
LCMPD
Legacy STORET
NYCDEP
EPA Region 1
Parameters:
Chlorophyll A, Fluorometric Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
10
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level III ecoregions:
51, 52, 53, 56,60,61, 83
5.1.4 Aggregate Nutrient Ecoregion 8
Data Sources:
LCMPD
Legacy STORET
NYCDEP
NYCDEC
EPA Region 1
EPA Region 3
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B (ug/L)
Chlorophyll C (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level III ecoregions:
49, 50, 58, 62, 82
11
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
5.1.5 Aggregate Nutrient Ecoregion 9
Data Sources:
Auburn University
Legacy STORE!
EPA Region 4
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Pheophytin (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level III ecoregions:
29, 33, 35, 37, 40, 45, 64, 65, 71, 72, 74
5.1.6 Aggregate Nutrient Ecoregion 11
Data Sources:
Auburn University
Legacy STORET
NYSDEC
EPA Region 3
EPA Region 4
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Pheophytin (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
12
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
Chlorophyll A, Trichromatic, Uncorrected
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level III ecoregions:
36, 38, 39, 66, 67, 68, 69, 70
5.1.7 Aggregate Nutrient Ecoregion 12
Data Sources:
Legacy STORET
Parameters:
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level III ecoregions:
75
5.1.8 Aggregate Nutrient Ecoregion 13
Data Sources:
Legacy STORET
13
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level III ecoregions:
76
5.2 Rivers and Streams
5.2.1 Aggregate Nutrient Ecoregion 2
Data Sources:
Legacy STORET
NASQAN
NAWQA
EPA Region 10
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Phosphorus, Total (TP) Reactive (ug/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
14
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
Turbidity (JCU)
Turbidity (NTU)
Level III ecoregions:
1, 2, 4, 5, 8, 9, 11, 15, 16, 17, 19, 21, 23, 41, 77, 78
5.2.2 Aggregate Nutrient Ecoregion 3
Data Sources:
Legacy STORET
NASQAN
NAWQA
EPA Region 10
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (JCU)
Turbidity (NTU)
Level III ecoregions:
6, 10, 12, 13, 14, 18, 20, 22, 24, 79, 80, 81
15
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04
5.2.3 Aggregate Nutrient Ecoregion 6
Data Sources:
Legacy STORET
NASQAN
NAWQA
EPA Region 5
EPA Region 7
Parameters:
Chlorophyll A, Fluorometric, Corrected
Chlorophyll A, Phytoplankton, Spectrophotometric Acid
Chlorophyll A, Phytoplankton, chromotographic- fluorometric
Chlorophyll A, Trichromatic, Uncorrected
Chlorophyll B, Phytoplankton, chromotographic- fluorometric
Phosphorous, Dissolved Inorganic (DIP)
Dissolved Oxygen (DO)
Nitrite and Nitrate, (NO2+NO3)
Nitrogen, Total (TN)
Nitrogen, Total Kjeldahl (TKN)
Organic, Phosphorus
Phosphorus, Total (TP)
Phosphorus, Orthophosphate, Total as P
Turbidity
Turbidity
Turbidity
Level III ecoregions:
46, 47, 48, 54, 55, 57
5.2.4 Aggregate Nutrient Ecoregion 7
Data Sources:
LCMPD
Legacy STORET
NASQAN
NAWQA
NYCDEP
August 8, 2000
(ug/L)
(ug/L)
(ug/L)
(ug/L)
(ug/L)
(ug/L)
(mg/L)
(mg/L)
(mg/L)
(mg/L)
(ug/L)
(ug/L)
(ug/L)
(FTU)
(JCU)
(NTU)
16
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Organic, Phosphorus (ug/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (JCU)
Turbidity (NTU)
Level III ecoregions:
51, 52, 53, 56,60,61, 83
5.2.5 Aggregate Nutrient Ecoregion 9
Data Sources:
Auburn University
Legacy STORET
NASQAN
NAWQA
EPA Region 3
EPA Region 5
EPA Region 7
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
August 8, 2000
17
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll B, Phytoplankton, Spectrophotometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Organic, Phosphorus (ug/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (JCU)
Turbidity (NTU)
Level III ecoregions:
29, 33, 35, 37, 40, 45, 64, 65, 71, 72, 74
5.2.6 Aggregate Nutrient Ecoregion 11
Data Sources:
Auburn University
Legacy STORET
NASQAN
NAWQA
EPA Region 3
EPA Region 5
EPA Region 7
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Organic, Phosphorus (ug/L)
August 8, 2000
18
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04
Phosphorus, Orthophosphate, Total as P (ug/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (JCU)
Turbidity (NTU)
Level III ecoregions:
36, 38, 39, 66, 67, 68, 69, 70
5.2.7 Aggregate Nutrient Ecoregion 12
Data Sources:
Legacy STORET
NASQAN
NAWQA
Parameters:
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, Spectrophotometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (NTU)
Level III ecoregions:
August 8, 2000
75
19
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
5.2.8 Aggregate Nutrient Ecoregion 14
Data Sources:
Legacy STORE!
NASQAN
NAWQA
NYCDEP
EPA Region 1
EPA Region 3
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Nitrogen, Total (TN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (JCU)
Turbidity (NTU)
Level III ecoregions:
59, 63, 84
20
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
APPENDIX A
Process Used to QA/QA the Legacy STORE! Nutrient Data Set
A-l
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04
August 8, 2000
1. STORET water quality parameters and Station and Sample data items were retrieved from
USEPA's mainframe computer. Table 1 lists all retrieved parameters and data items.
TABLE 1: PARAMETERS AND DATA ITEMS RETRIEVED FROM STORET
Parameters Retrieved
(STORET Parameter Code)
TN - mg/1 (600)
TKN - mg/1 (625)
Total Ammonia (NH3+NH4) - mg/1 (610)
Total NO2+NO3 - mg/1 (630)
Total Nitrite -mg/1 (6 15)
Total Nitrate - mg/1 (620)
Organic N - mg/L (605)
TP - mg/1 (665)
Chlor a - ug/L (spectrophotometric method,
32211)
Chlor a - ug/L (fluorometric method
corrected, 32209)
Chlor a - ug/L (trichromatic method
corrected, 32210)
Secchi Transp. - inches (77)
Secchi Transp. - meters (78)
+Turbidity JCUs (70)
+Turbidity FTUs (76)
+Turbidity NTUs field (82078)
+Turbidity NTUs lab (82079)
+DO - mg/L (300)
+Water Temperature (degrees C, 10/degrees
F, 11)
Station Data Items
Included
(STORET Item Name)
Station Type (TYPE)
Agency Code (AGENCY)
Station No. (STATION)
Latitude - std. decimal degrees
(LATSTD)
Longitude - std. decimal degrees
(LONGSTD)
Station Location (LOCNAME)
County Name (CONAME)
State Name (STNAME)
Ecoregion Name - Level III
(ECONAME)
Ecoregion Code -Level III
(ECOREG)
Station Elevation (ELEV)
Hydrologic Unit Code
(CATUNIT)
RF1 Segment and Mile
(RCHMIL)
RF ION/OFF tag (ONOFF)
Sample Data Items Included
(STORET Item Name)
Sample Date (DATE)
Sample Time (TIME)
Sample Depth (DEPTH)
Composite Sample Code
(SAMPMETH)
+ If data record available at a station included data only for this or other such marked parameters, data record was deleted
from data set.
The following set of retrieval rules were applied to the retrieval process:
Data were retrieved for waterbodies specified only as 'lake', 'stream', 'reservoir', or 'estuary'
under "Station Type" parameter. Any stations specified as 'well,' 'spring,' or 'outfall' were
eliminated from the retrieved data set.
Data were retrieved for station types described as 'ambient' (e.g., no pipe or facility
discharge data) under the "Station Type" parameter.
Data were retrieved that were designated as 'water' samples only. This includes 'bottom'
and 'vertically integrated' water samples.
A-2
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04
August 8, 2000
Data were retrieved that were designated as either 'grab' samples and 'composite' samples
(mean result only).
No limits were specified for sample depths.
Data were retrieved for all fifty states, Puerto Rico, and the District of Columbia.
The time period specified for data retrieval was January 1990 to September 1998.
No data marked as "Retired Data" (i.e., data from a generally unknown source) were
retrieved.
Data marked as "National Urban Runoff data" (i.e., data associated with sampling
conducted after storm events to assess nonpoint source pollutants) were included in the
retrieval. Such data are part of STORET's 'Archived' data.
Intensive survey data (i.e., data collected as part of specific studies) were retrieved.
Any values falling below the 1st percentile and any values falling above the 99th percentile
were transformed into 'missing' values (i.e., values were effectively removed from the data
set, but were not permanently eliminated).
Based on the STORET 'Remark Code' associated with each retrieved data point, the
following rules were applied (Table 2):
TABLE 2: STORET REMARK CODE RULES
STORET Remark Code
blank - Data not remarked.
A - Value reported is the mean of two or more
determinations.
B - Results based upon colony counts outside the acceptable
ranges.
C - Calculated. Value stored was not measured directly, but
was calculated from other data available.
D - Field measurement.
Keep or Delete Data Point
Keep
Keep
Delete
Keep
Keep
A-3
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04
August 8, 2000
E - Extra sample taken in compositing process.
F - In the case of species, F indicates female sex.
G - Value reported is the maximum of two or more
determinations.
H - Value based on field kit determination; results may not
be accurate.
I - The value reported is less than the practical
quantification limit and greater than or equal to the method
detection limit.
J - Estimated. Value shown is not a result of analytical
measurement.
K - Off-scale low. Actual value not known, but known to be
less than value shown.
L - Off-scale high. Actual value not known, but known to
be greater than value shown.
M - Presence of material verified, but not quantified.
Indicates a positive detection, at a level too low to permit
accurate quantification.
N - Presumptive evidence of presence of material.
O - Sample for, but analysis lost. Accompanying value is
not meaningful for analysis.
P - Too numerous to count.
Q - Sample held beyond normal holding time.
R - Significant rain in the past 48 hours.
S - Laboratory test.
T - Value reported is less than the criteria of detection.
Delete
Delete
Delete
Delete
Keep, but used one-half the reported value as the new value.
Delete
Keep, but used one-half the reported value as the new value.
Keep
Keep, but used one half the reported value as the new value.
Delete
Delete
Delete
Delete
Delete
Keep
Keep, but replaced reported value with 0.
A-4
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04
August 8, 2000
U - Material was analyzed for, but not detected. Value
stored is the limit of detection for the process in use.
V - Indicates the analyte was detected in both the sample
and associated method blank.
W - Value observed is less than the lowest value reportable
under remark "T."
X - Value is quasi vertically-integrated sample.
Y - Laboratory analysis from unpreserved sample. Data
may not be accurate.
Z - Too many colonies were present to count.
Keep, but replaced reported value with 0.
Delete
Keep, but replaced reported value with 0.
No data point with this remark code in data set.
Delete
Delete
If a parameter (excluding water temperature) value was less than or equal to zero and no remark code was present, the value
was transformed into a missing value.
Rationale - Parameter concentrations should never be zero without a proper explanation. A method detection limit should
at least be listed.
4. Station records were eliminated from the data set if any of the following descriptors were
present within the "Station Type" parameter:
MONITR - Source monitoring site, which monitors a known problem or
to detect a specific problem.
HAZARD - Site of hazardous or toxic wastes or substances.
ANPOOL - Anchialine pool, underground pools with subsurface
connections to watertable and ocean.
DOWN - Downstream (i.e., within a potentially polluted area) from a
facility which has a potential to pollute.
IMPDMT - Impoundment. Includes waste pits, treatment lagoons, and
settling and evaporation ponds.
STMSWR - Storm water sewer.
LNDFL - Landfill.
CMBMI - Combined municipal and industrial facilities.
CMBSRC - Combined source (intake and outfall).
Rationale - these descriptors potentially indicate a station location that at which an
ambient water sample would not be obtained (i.e., such sampling locations are potentially
A-5
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
biased) or the sample location is not located within one of the designated water body types (i.e,
ANPOOL).
5. Station records were eliminated from data set if the station location did not fall within any
established cataloging unit boundaries based on their latitude and longitude.
6. Using nutrient ecoregion GIS coverage provided by USEPA, all station locations with
latitude and longitude coordinates were tagged with a nutrient ecoregion identifier
(nutrient region identifiers are values 1 - 14) and the associated nutrient ecoregion name.
Because no nutrient ecoregions exist for Alaska, Hawaii, and Puerto Rico, stations located
in these states were tagged with "dummy" nutrient ecoregion numbers (20 = Alaska, 21 =
Hawaii, 22 = Puerto Rico).
7. Using information provided by TV A, 59 station locations that were marked as 'stream'
locations under the "Station Type" parameter were changed to 'reservoir' locations.
8. The nutrient data retrieved from STORET were assessed for the presence of duplicate
data records. The duplicate data identification process consisted of three steps: 1)
identification of records that matched exactly in terms of each variable retrieved; 2)
identification of records that matched exactly in terms of each variable retrieved except for
their station identification numbers; and 3) identification of records that matched exactly in
terms of each variable retrieved except for their collecting agency codes. The data
duplication assessment procedures were conducted using SAS programs.
Prior to initiating the data duplication assessment process, the STORET nutrient data set
contained:
41,210 station records
924,420 sample records
Identification of exactly matching records
All data records were sorted to identify those records that matched exactly. For
two records to match exactly, all variables retrieved had to be the same. For
example, they had to have the same water quality parameters, parameter results
and associated remark codes, and have the same station data item and sample data
item information. Exactly matching records were considered to be exact
duplicates, and one duplicate record of each identified matching set were
eliminated from the nutrient data set. A total of 924 sample records identified as
duplicates by this process were eliminated from the data set.
Identification of matching records with the exception of station identification
number
All data records were sorted to identify those records that matched exactly except
for their station identification number (i.e., they had the same water quality
A-6
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
parameters, parameter results and associated remark codes, and the same station
and sample data item information with the exception of station identification
number). Although the station identification numbers were different, the latitude
and longitude for the stations were the same indicating a duplication of station data
due to the existence of two station identification numbers for the same station. For
each set of matching records, one of the station identification numbers was
randomly selected and its associated data were eliminated from the data set. A
total of 686 sample records were eliminated from the data set through this process.
• Identification of matching records with the exception of collecting agency codes
All data records were sorted to identify those records that matched exactly except
for their collecting agency codes (i.e., they had the same water quality parameters,
parameter results and associated remark codes, and the same station and sample
data item information with the exception of agency code). The presence of two
matching data records each with a different agency code attached to it suggested
that one agency had utilized data collected by the other agency and had entered the
data into STORET without realizing that it already had been placed in STORET
by the other agency. No matching records with greater than two different agency
codes were identified. For determining which record to delete from the data set,
the following rules were developed:
> If one of the matching records had a USGS agency code, the USGS
record was retained and the other record was deleted.
> Higher level agency monitoring program data were retained. For
example, federal program data (indicated by a " 1" at the beginning
of the STORET agency code) were retained against state (indicated
by a "2") and local (indicated by values higher than 2) program
data.
> If two matching records had the same level agency code, the record
from the agency with the greater number of overall observations
(potentially indicating the data set as the source data set) was
retained.
A total of 2,915 sample records were eliminated through this process.
As a result of the duplicate data identification process, a total of 4,525 sample records and
36 individual station records were removed from the STORET nutrient data set. The
resulting nutrient data set contains the following:
41,174 station records
919,895 sample records
A-7
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
APPENDIX B
Process for Adding Aggregate Nutrient Ecoregions and Level III Ecoregions
B-l
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
Steps for assigning Level III ecoregions and aggregate nutrient ecoregion codes and names to the
Nutrient Criteria Database (performed using ESRI's ARCView v 3.2 and its GeoProcessing
Wizard). This process is performed twice; once for the Level III ecoregions and once for the
aggregate nutrient ecoregions:
Add the station .dbf data table, with latitude and longitude data, to project by 'Add
Event Theme'
Convert to the shapefile format
Create 'stcojoin' field, populate the 'stcojoin' field with the following formula:
'County.LCase+State.LCase'
Add field 'stco_flag' to the station shapefile
Spatially join the station data with the county shapefile (cntysjned.shp)
Select 'stcojoin' (station shapefile) field = 'stcojoin2' (county shapefile) field
Calculate stco_flag = 0 for selected features
Step through all blank stco_flag records, assign the appropriate stco_flags, see list
on the following page
Select all stco_flags = 4 or 7, switch selection
Calculate ctyfips (station) to cntyfips (county)
Stop editing and save edits, remove all joins
Add in 2 new fields 'x-coordl' and 'y-coordl' into station table
Select all stco_flags =1,2, and 6
Link county coverage with station coverage
Populate 'x-coordl' and 'y-coordl' with 'x-coord' and 'y-coord' from county
coverage
Select all stco_flags = 1, 2, and 6, export to new .dbf file
Add new .dbf file as event theme
Convert to shapefile format
Add the following fields to both tables (original station and station!26 shapefiles):
'eco_omer', 'name_omer', 'dis_aggr', 'code_aggr', 'name_aggr'
Spatially join station 126 and eco-omer coverage
Populate the 'eco_omer' field with the 'eco' value
Repeat the previous step using the nearest method (line coverage) to determine
ecoregion assignment for the line coverage, if some records are blank
Spatially join the ecoregion line coverage to station coverage, link the LPoly#
(from the spatially joined table) to Poly# (of the ecoregion polygon coverage)
Populate the Eco fields with the appropriate information.
Follow the same steps to the Rpoly#
Remove all table j oins
Link the useco-om table with station!26 table and populate 'name-omer' field
Spatially join station aggr coverage and populate the rest of the fields. Follow the
same procedures as outlined above
Remove all joins
Make sure the new Eco field added into the station 126 shapefile are different than
B-2
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
the ones in the original station shapefile
Join station 126 and station coverage by station-id
Populate all the Eco fields in the original station coverage
Remove all joins
Save table
Make sure that all ctyfips records are populated; the county shapefile may have to
be joined to populate the records, if the stco_flag = 4
Create 2 new fields, 'NewCounty' and 'NewState'
Populate these new fields with a spatial join to the county coverage
Select by feature (ecoregion shapefile) all of the records in the station shapefile
Switch selection (to get records outside of the ecoregion shapefile)
If any of the selected records have stco_flag = 0 (they are outside the ecoregion
shapefile boundary), calculate them to stco_flag = 3
stco_flags (state/county flags in order of importance)
0 The state and county values from the data set matched the state and county values
from the spatial join.
(Ecoregions were assigned based on the latitude/longitude coordinates.)
1 The state and county values from the data set did not match the state and county
values from the spatial join, but the point was inside the county coverage
boundary.
(Ecoregions were assigned based on the county centroid.)
2 The state and county values from the data set did not match the state and county
values from the spatial join because the point was outside the county coverage
boundary; therefore, there was nothing to compare to the point (i.e., the point
falls in the ocean/Canada/Mexico). This occurred for some coastal samples.
(Ecoregions were assigned based on the county centroid.)
3 The state and county values from the data set matched the state and county from
the spatial join, but the point was outside the ecoregion boundary.
(Ecoregions were assigned to the closest ecoregion to the point.)
(No ecoregions were assigned to AK, HI, PR, BC, and GU.)
4 Latitude/longitude coordinates were provided, but there was no county
information.
(Ecoregions were assigned based on the latitude/longitude coordinates.)
5 The state and county values from the data set did not match the state and county
values from the spatial join due to spelling or naming convention errors.
The matches were performed manually.
(Ecoregions were assigned based on the latitude/longitude coordinates.)
6 No latitude/longitude coordinates were provided, only state and county
information was available.
(Ecoregions were assigned based on the county centroid.)
7 No latitude/longitude coordinates were provided, only state information was
available; therefore, no matches were possible.
(Ecoregions were not assigned. Data is not included in the analysis.)
B-3
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
APPENDIX C
Glossary
Coefficient of Variation- Equal to the standard deviation divided by the mean multiplied by 100.
Maximum- The highest value.
Mean- The arithmetic average.
Median- The 50th percentile or middle value. Half of the values are above the median, and half of
the values are below the median.
Minimum- The lowest value.
Standard Deviation- Equal to the square root of the variance with the variance defined as the sum
of the squared deviations divided by the sample size minus one.
Standard Error- Standard error of the mean is equal to the standard deviation divided by the
square root of the sample size.
C-l
-------
INDUS
CORPORATION
Knowledge-Based Sol Lilians
Support for the Compilation and Analysis of
National Nutrient Data
15 Nutrient Ecoregion/Waterbody Type Summary
Chapters ..
Prepared for:
Robert Cantilli
Environmental Protection Agency
OW/OST/HECD
Prepared by: .
INDUS Corporation
1953 Gallows Road
Vienna, Virginia 22182
Contract Number: 68-C-99-226
Task Number: . 04
Subtask Number: . 4
August 8, 2000
-------
-------
15 Nutrient Ecoregion/ Waterbody Type Summary Chapters. Contract # 68-C-99-226, TO# 04 August 8, 2000 ,
CONTENTS
1.0 BACKGROUND 1
1.1 Purpose 1
1.2 References .1
2.0 QA/QC PROCEDURES 2
2.1 National Data Sets 3
2.2 State Data 3
2.3 Laboratory Methods 4
2.4 Waterbody Name '. 4
2.5 Ecoregion Data 5
3.0 STATISTICAL ANALYSIS REPORTS 5
3.1 Data Source Reports 6
3.2 Remark Code Reports 7
3.3 Median of Each Waterbody 7
3.4 Descriptive Statistic Reports 7
3.5 Regression Models 8
4.0 TIME PERIOD 8
5.0 DATA SOURCES AND PARAMETERS FOR THE AGGREGATE NUTRIENT
ECOREGIONS 9
5.1 Lakes and Reservoirs 9
5.1.1 Aggregate Nutrient Ecoregion 2 9
5.1.2 Aggregate Nutrient Ecoregion 6 10
5.1.3 Aggregate Nutrient Ecoregion 7 10
5.1.4 Aggregate Nutrient Ecoregion 8 11
5.1.5 Aggregate Nutrient Ecoregion 9 12
5.1.6 Aggregate Nutrient Ecoregion 11 12
5.1.7 Aggregate Nutrient Ecoregion 12 .- 13
5.1.8 Aggregate Nutrient Ecoregion 13 13
5.2 Rivers and Streams 14
5.2.1 Aggregate Nutrient Ecoregion 2 14
5.2.2 Aggregate Nutrient Ecoregion 3 15
5.2.3 Aggregate Nutrient Ecoregion 6 16
5.2.4 Aggregate Nutrient Ecoregion 7 16
5.2.5 Aggregate Nutrient Ecoregion 9 17
5.2.6 Aggregate Nutrient Ecoregion 11 18
5.2.7 Aggregate Nutrient Ecoregion 12 19
ii
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters. Contract # 68-C-99-226. TO# 04 August 8, 2000
5.2.8 Aggregate Nutrient Ecoregion 14 20
APPENDIX A Process Used to QA/QA the Legacy STORE! Nutrient Data Set
APPENDIX B Process for Adding Aggregate Nutrient Ecoregions and Level m
Ecoregions
APPENDIX C Glossary
in
-------
15 Nutnem EcoreziotvWaierbody Type Summary Chapters, Contract # 68-C-99-226. TO# 04 August 8.2000
1.0 BACKGROUND
The Nutrient Criteria Program has initiated development of a national Nutrient Criteria Database
application that will be used to store and analyze nutrient data. The ultimate use of these data
will be to derive ecoregion- and waterbody-specific nutrient criteria ranges. EPA converted
STOrage and RETrieval (STORET) legacy data, National Stream Quality Accounting Network
(NASQAN) data, National Water-Quality Assessment (NAWQA) data, and other relevant
nutrient data from universities and States/Tribes into the database. The data imported into the
Nutrient Criteria Database will be used to develop national nutrient criteria ranges.
1.1 Purpose
The purpose of this deliverable is to provide EPA with information regarding the data used to
create the statistical reports which will be used to derive ecoregion- and waterbody-specific
nutrient criteria ranges for Level HI ecoregions. There are fourteen aggregate nutrient
ecoregions. Each aggregate nutrient ecoregion is divided into smaller ecoregions referred to as
Level HI ecoregions. EPA will determine criteria ranges for the waterbody types and Level HI
ecoregions within the following aggregate nutrient ecoregions:
• Lakes and Reservoirs
Aggregate Nutrient ecoregions: 2,6,7, 8,9,11,12,13
• Rivers and Streams
- Aggregate Nutrient ecoregions: 2,3,6, 7,9, 11, 12, 14
1.2 References
This section lists documents that contain baselines, standards, guidelines, policies, and references
that apply to the data analysis. Listed editions were valid at the time of publication. All
documents are subject to revision, but these specific editions govern the concepts described in
this document.
Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs (Draft).- EPA, Office of
Water, EPA 822-D-99-001, April 1999.
Nutrient Criteria Technical Guidance Manual: Rivers and Streams (Draft). EPA. Office of
Water. EPA 822-D-99-003, September 1999.
Guidance for Data Quality Assessment: Practical Methods for Data Analysis. EPA, Office of
Research and Development, EPA-QA/G-9, January 1998.
-------
15 Nutrient Ecorcgion/Waterbody Type Summary Chapters, Contract # 68-C-99-226. TO# 04 August 8, 2000
2.0 QA/QC PROCEDURES
In order to develop nutrient criteria, EPA needed to obtain nutrient data from the states. EPA
requested nutrient data from the states and forwarded the data sets to INDUS via e-mail and/or
US mail. In addition, EPA tasked INDUS to convert data from three national data sets. EPA
provided INDUS with a Legacy STORET extraction to convert into the database. The United '
States Geologic Survey (USGS) sent INDUS a CD-ROM with NASQAN data to convert.
INDUS downloaded NAWQA files from the USGS Web site to convert the data. In total,
INDUS converted and imported the following national and state data sets into the Nutrient
Criteria Database:
Legacy STORET
NAWQA
NASQAN
• Region I
• Region 2 - Lake Champlain Monitoring Project
Region 2 - NYSDEC Finger Lakes Monitoring Program
• Region 2 - NY Citizens Lake Assessment Program
• Region 2 - Lake Classification and Inventory Survey
Region 2 - NYCDEP (1990-1998)
Region 2 - NYCDEP (Storm Event data)
• Region 2 - New Jersey Nutrient Data (Tidal Waters)
• RegionS
• RegionS.
• Region 3 - Nitrite Data
• Region 3 - Choptank River files
• Region 4 - Tennessee Valley Authority '
Region 7 - Central Plains Center for BioAssessment (CPCB)
Region 7 - REMAP
Region 2 - Delaware River Basin Commission (1990-1998)
Region 3 - PA Lake Data
• RegionS-University of Delaware
• Region 10 .
• University of Auburn
As part of the conversion process, INDUS performed a number of Quality Assurance/Quality
Control (QA/QC) steps to ensure that the data was properly convened into the Nutrient Criteria
Database. Section 2 explains the steps performed by INDUS to convert the data.
-------
! 5 Nutrient Ecoregiorv Waterbody Type Summary Chapters. Contract # 68-C-99-226, TOtt 04 August 8. 2000
2.1 National Data Sets
INDUS converted three national data sets into the Nutrient Criteria Database: Legacy STORET
data, NASQAN data, and NAWQA data. A previous EPA contractor performed the extraction of
Legacy STORET data and documented the QA/QC procedures used on the data. This
documentation is included in Appendix A. INDUS performed minimal QA/QC on the Legacy
STORET data set because the previous contractor completed the steps outlined in Appendix A.
INDUS and EPA also agreed to convert the NAWQA and NASQAN data sets with minimal
QA/QC on the assumption that the source agency, the USGS, QA/QC'd the data.
For each of the three national data sets, INDUS ran queries to determine if 1) samples existed
without results and 2) if stations existed without samples. Per Task Order Project Officer
(TOPO) direction, these records were deleted from the system. For analysis purposes, EPA
determined that there was no need to keep station records with no samples and sample records
with no results. INDUS also confirmed that each data set contained no duplicate records.
In addition, INDUS deleted all composite results from the Legacy STORET data. Per TOPO
direction, it was decided that composite sample results would not be used in the statistical
analysis.
2.2 State Data
Each state data set was delivered in a unique format. Many of the data sets were delivered to
INDUS without corresponding documentation. INDUS analyzed each state data set in order to
determine which parameters should be converted for analysis. INDUS obtained a master
parameter table from EPA and converted the parameters in the state data sets according to those
that were present in the EPA parameter table. INDUS converted all of the data elements in the
state data sets that mapped directly to the Nutrient Criteria Database; data elements that did not ,
"map to the Nutrient Criteria Database were not converted. In some cases, state data elements that
did not directly map into the Oracle database were inserted into a comment field within the
database. Also, INDUS maintained an internal record of which state data elements were inserted
into the comment field.
As part of the data clean-up efforts, INDUS determined whether or not there were any duplicate
records in the state data sets and deleted the duplicate records. INDUS checked the waterbody,
station, and sample entities for duplicate records. In addition, INDUS deleted station records
with no samples and sample records with no results. INDUS also deleted waterbody records that
were not associated with a station. In each case, INDUS maintained an internal record of how
many records were deleted.-
If INDUS encountered referential integrity errors, such as samples that referred to stations that
did not exist, or if INDUS was unsure of whether a record was a duplicate, INDUS contacted the
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226. TO# 04 August 8, 2000 •
agency directly via e-mail or phone to resolve any issues that arose. INDUS saved an electronic
copy of each e-mail correspondence with the states to ensure that a record of the decision was
maintained. INDUS also contacted each agency to determine which laboratory methods were
used for each parameter.
Finally, INDUS examined the remark codes of each result record in the state data sets. INDUS
mapped the remark codes to the STORET remark codes listed in Table 2 of Appendix A. If any
of the state result records were associated with remark codes marked as "Delete" in Table 2 of
Appendix A, the result records were not converted into the database.
2.3 Laboratory Methods
Many of the state data sets did not contain laboratory method information. In addition,
laboratory method information was not available for the three national data sets. In order to
determine missing laboratory method information, EPA tasked another contractor to contact the
data owners to obtain the laboratory method. In some cases, the data owners responded and the
laboratory methods were added to the database.
2.4 Waterbody Name and Class Information
A large percentage of the data did not have waterbody-specific information. The only waterbody
information contained in the three national data sets was the waterbody name, which was
embedded in the station 'location description' field. Most of the state data sets contained
waterbody name information; however, much of the data was duplicated throughout the data sets.
Therefore, the waterbody information was cleaned manually. For the three national data sets, the
'location description' field was extracted from the station table and moved to a temporary table.
The 'location description' field was sorted alphabetically. Unique waterbodies were grouped
together based on name similarity and whether or not the waterbodies fell within the same .
county, state, and waterbody type. Finally, the 'location description' field was edited to include
only waterbody name information, not descriptive information. For example, 110 MILE CREEK
AT POMONA DAM OUTFLOW, KS PO-2 was edited to 110 MILE CREEK. Also, if 100
MILE CREEK was listed ten times in New York, but in four different counties, four 100 MILE
CREEK waterbody records were created.
Similar steps were taken to eliminate duplicate waterbody records in the state data sets. If a
number of records had similar waterbody names and fell within the same state, county, and
waterbody type, the records were grouped to create a unique waterbody record.
Most of the waterbody data-did not contain depth, surface area, and volume measurements. EPA
needed this information to classify waterbody types. EPA attempted to obtain waterbody class
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226. TO# 04 August 8,2000
information from the states. EPA sent waterbody files to the regional coordinators and requested
that certain class information be completed by each state. The state response was poor; therefore,
EPA was not able to perform statistical analysis for the waterbody types by class.
2.5 Ecoregion Data
Aggregate nutrient ecoregions and Level HI ecoregions were added to the database using the
station latitude and longitude coordinates. If a station was lacking latitude and longitude
coordinates or county information, the data were not included in the statistical analysis.
Appendix B lists the steps taken to add the two ecoregion types (aggregate and Level HI) to the
Nutrient Criteria Database. The ecoregion names were pulled from aggregate nutrient ecoregion
and Level HI ecoregion Geographical Information System (GIS) coverages. In summary, the
station latitude and longitude coordinates were used to determine the ecoregion under the
following circumstances:
The latitude and longitude coordinates fell within the county/state listed in the station
table.
The county data was missing.
•
The county centroid was used to determine the ecoregions under the following circumstances:
• The latitude and longitude coordinates were missing, but the state/county information was
available.
• The latitude and longitude coordinates fell outside the county/state listed in the station
table. The county information was assumed to be correct; therefore, the county centroid
was used. .
If the latitude and longitude coordinates fell outside the continental US county coverage file
(i.e., the point fell in the ocean or Mexico/Canada), the nearest ecoregion was assigned to the
station.
3.0 STATISTICAL ANALYSIS REPORTS
Aggregate nutrient ecoregion tables were created by extracting all observations for a specific
aggregate nutrient ecoregion from the nutrient criteria database. Then, the data were reduced to
create tables containing only the yearly median values. To create these tables, the median value
for each waterbody was calculated using all observations for each waterbody by Level III
ecoregion, year, and season. Tables of decade median values were created from the yearly
median tables by calculating the median for each waterfaody by Lsvel IE ecoregion by decade and
seasonv
-------
15 Numem Ecoregion/Waierfaody Type Summary Chapters, Contract # 68-C-99-226. TO# 04 August 8,2000'
The Data Source and the Remark Code reports were created using all observations (all reported
values). All the other reports were created from either the yearly median tables or the decade
median tables. In other words, the descriptive statistics and regressions were run using the
median values for each waterbody and not the individual reported values.
Statistical analyses were performed under the assumption that this data set is a random sample.
If this-assumption cannot be verified, the observations may or may not be valid. Values below
the 1st and 99th percentile were removed from the Legacy STORET database prior to the creation
of the national database. Also, data were treated according the Legacy STORET remark codes in
Appendix A.
The following contains a list of each report and the purpose for creating each report:
• Data Source—Created to provide a count of the amount of data and to identify the
source(s).
• Remark Codes—Created to provide a description of the data.
Median of Each Waterbody by Year—This was an intermediate step performed to obtain
a median value for each lake to be used in the yearly descriptive statistics reports and the
regression models.
• Median of Each Waterbody by Decade—This was an intermediate step performed to
obtain a median value for each lake to be used in the decade descriptive statistics.
• Descriptive Statistics—Created to provide EPA with the desired statistics for setting
criteria levels.
• Regression Models—Created to examine the relationships between biological and
nutrient variables.
Note: Separate reports were created for each season.
t
3.1 Data Source Reports
Data source reports were presented in the following formats:
• The number and percentage of data from each data source were summarized in tables for
each aggregate nutrient ecoregion by season and waterbody type.
• The number and percentage of data from each data source were summarized in tables for
each Level III ecoregion by season and waterbody type.
The 'Frequency' represents" the number of data values from a specific data source for each
parameter by data source. The 'Row Pet' represents the percentage of data from a specific data
source for each parameter.
-------
15 Nutnent Ecoregion/ Waterbody Type Summary Chapters. Contract # 68-C-99-226, TO# 04 August 8.2000
3.2 Remark Code Reports
Remark code reports were presented in the following formats:
• The number and percentage of data associated with a particular remark code for each
parameter were summarized in tables by Level HI ecoregion by decade and season.
• The number and percentage of data associated with a particular remark code for each
parameter were summarized in tables by Level in ecoregion by year and season.
The 'Frequency' represents the number of data values corresponding to the remark code in the
column. The 'Row Pet' represents the percentage of data that was associated with the remark
code in that row.
In the database, remark codes that were entered by the states were mapped to Legacy STORET
remark codes. Prior to the analysis, the data were treated according to these remark codes. For
example, if the remark code was 'K,' then the reported value was divided by two. Appendix A
contains a complete list of Legacy STORET remark codes.
Note: For the reports, a remark code of 'Z' indicates that no remark codes were recorded. It does
not correspond to Legacy STORET code 'Z.'
3.3 Median of Each Waterbody
To reduce the data and to ensure heavily sampled waterbodies or years were not over represented
in the analysis, median value tables (described above) were created. The yearly median tables
and decade median tables were delivered to the EPA in electronic format as csv (comma
separated value or comma delimited) files.
3.4 Descriptive Statistic Reports
The number of waterbodies, median, mean, minimum, maximum, 5th, 25th, 75th, 95th percentiles,
standard deviation, standard error, and coefficient of variation were calculated. The tables
(described above) containing the decade median values for each waterbody for each parameter
were used to create descriptive statistics reports for:
• Level IE ecoregions by decade and season
• Aggregate nutrient ecoregions by decade and season
-------
15 Nument Ecoregion/Waterbody Type Summary Chapters. Contract tt 68-C-99-226, TO# 04 August 8, 2000
In addition, the tables containing the yearly median values for each waterbody for each parameter
were used to create descriptive statistics reports for:
• Level El ecoregions by year and season
3.5 Regression Models
Simple linear regressions using the least squares method were performed to examine the
relationships between biological and nutrient variables in lakes and reservoirs, and rivers and
streams. Regressions were performed using the yearly median tables. Chlorophyll(s) in
micrograms per liter (ug/L), secchi in meters (m), dissolved oxygen in milligrams per liter
(mg/L), turbidity, and pH were the biological variables in these models. When there was little or
no data for chlorophyll, then pH or dissolved oxygen was substituted for chlorophyll. .Secchi-
data were used in the lake and reservoir models, and turbidity data were used in the river and
stream models. The nutrient variables in these models include: total phosphorus in ug/L, total
nitrogen in mg/L, total kjeldahl nitrogen in mg/L, and nitrate and nitrite in mg/L, Regressions
were also run for total nitrogen and total'phosphorus for ecoregions where both these variables
were measured.
Note: At the time of creation of this document only regressions for aggregate nutrient ecoregion 7
for lakes and reservoirs were delivered to the EPA. Regressions for the remaining aggregate
nutrient ecoregions will be delivered in August 2000.
4.0 TIME PERIOD
Data collected from January 1990 to December 1999 were used in the statistical analysis reports.
To capture seasonal differences, the data were classified as follows: • ,
• Aggregate nutrient ecoregions: 6, 7, and 8
- Spring: April to May
- Summer: June to August
- Fall: September to October
- Winter: November to March
• Aggregate nutrient ecoregions: 1,2. 9. 10, 11,12, and 13
- Spring: - March to May
- Summer: June to August
Fall: September to November
Winter: December to February
-------
15 Nutrient Ecoregion/ Waterbody Type Summary Chapters, Contract» 68-C-99-226. TO# 04 August 8,2000
5.0 DATA SOURCES AND PARAMETERS FOR THE AGGREGATE NUTRIENT
ECOREGIONS
This section provides information for the nutrient aggregate ecoregions that were analyzed by
waterbody type. Each section lists the data sources for the aggregate nutrient ecoregion
including: 1) the data sources, 2) the parameters included in the analysis, and 3) the Level HI
ecoregions within the aggregate nutrient ecoregions.
Note: For analysis purposes, the following parameters were combined to form Phosphorous,
Dissolved Inorganic (DIP):
Phosphorus, Dissolved Inorganic (DIP)
Phosphorus, Dissolved (DP)
Phosphorus, Dissolved Reactive (DRP)
Orthophosphate, dissolved, mg/L as P
Orthophosphate (OPO4JPO4)
5.1 Lakes and Reservoirs
5.1.1 Aggregate Nutrient Ecoregion 2
Data Sources:
Legacy STORE!
EPA Region 10
Parameter:
i
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous. Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus. Total (TP) (ug/L)
Phosphorus. Total Reactive (ug/L)
SECCHI " (m)
PH
-------
15 Nument Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8.2000'
Level in ecoregions:
1, 2,4, 5, 9, 11, 15, 16, 17, 19, 21, 23, 41, 77, 78
5.1.2 Aggregate Nutrient Ecoregion 6
Data Sources:
Legacy STORE!
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level Hf ecoregions:
46,47,48,54,55,57
5.1.3 Aggregate Nutrient Ecoregion 7
»
Data Sources:
LCMPD
Legacy STORET
NYCDEP
EPA Region I
Parameters:
Chlorophyll A, Fluorometric Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton. Spectrophotometric. Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
10
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters. Contract # 68-C-99-226, TO# 04 August 8. 2000-
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level HI ecoregions:
51,52,53,56,60,61,83
5.1.4 Aggregate Nutrient Ecoregion 8
Data sources:
LCMPD
Legacy STORET
NYCDEP
NYCDEC
EPA Region 1
EPA Region 3
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotorhetric Acid (ug/L)
Chlorophyll A. Phytoplankton, Spectrophotometric, Uncbrrected (ug/L)
Chlorophyll A, Trichromatic, Unconnected (ug/L)
Chlorophylls . (ug/L)
Chlorophyll C (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L) •
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level III ecoregions:
49, 50, 58, 62. 82
11
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters. Contract # 68-C-99-226, TO# 04 August 8.2000
5.1.5 Aggregate Nutrient Ecoregion 9
Data sources:
Auburn University
Legacy STORET
EPA Region 4
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Pheophytin (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate. (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kj'eldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level in ecoregions:
29,33,35,37,40,45,64,65,71,72,74
5.1.6 Aggregate Nutrient Ecoregion 11
Data sources:
Auburn University
Legacy STORET
NYSDEC
EPA Region 3
EPA Region 4
Parameters:
Chlorophyll A. Fluorometric, Corrected (ug/L)
Chlorophyll A. Pheophytin (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
12
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000 •
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level HI ecoregions:
36,38,39,66,67,68,69,70
5.1.7 Aggregate Nutrient Ecoregion 12
Data sources:
Legacy STORET
Parameters:
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
.Nitrogen, Total Kjeldahl (TKN) (mg/L) ' .
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level in ecoregions:
75
5.1.8 Aggregate Nutrient Ecoregion 13
Data sources:
Legacy STORET
13
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8. 2000
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
SECCHI (m)
Level in ecoregions:
76
5.2 Rivers and Streams
5.2.1 Aggregate Nutrient Ecoregion 2
Data sources:
Legacy STORET
NASQAN
NAWQA
EPA Region 10
Parameters: • . '
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Phosphorus. Orthophosphate, Total as P (ug/L)
Phosphorus, Total (TP) Reactive (ug/L)
Nitrogen, Total (TN) " (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
14
-------
i 5 Nutrient Ecoregion/ Waterbody Type Summary Chapters. Contract # 68-C-99-226. TO# 04 August 8, 2000
Turbidity (FTU)
Turbidity (JCU)
Turbidity (NTU)
Level IB ecoresions:
1, 2,4, 5, 8, 9, 11, 15, 16, 17, 19,21, 23,41, 77, 78
5.2.2 Aggregate Nutrient Ecoregion 3
Data sources:
Legacy STORET
NASQAN "
NAWQA
EPA Region 10
Parameters:
»
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) . (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (JCU)
Turbidity (NTU) .
Level IE ecoregions:
6, 10, 12,13. 14. 18.20,22, 24, 79, 80, 81
15-
-------
15 Numcnt Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226. TO* 04 August 8, 2000
5.2.3 Aggregate Nutrient Ecoregion 6
Data sources:
Legacy STORE!
NASQAN
NAWQA
EPA Region 5
EPA Region 7
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
• Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Organic, Phosphorus (ug/L)
Phosphorus, Total (TP) (ug/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Turbidity . (FTU)
Turbidity (JCU)
Turbidity " (MTU)
Level III ecoregions:
46, 47, 48. 54, 55, 57
5.2.4 Aggregate Nutrient Ecoregion 7
Data sources:
LCMPD
Legacy STORET
NASQAN
NAWQA
NYCDEP
16
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters. Contract # 68-C-99-226. TO# 04 August 8. 2000 •
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Organic, Phosphorus (ug/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (JCU)
Turbidity (NTU)
Level IH ecoregions:
51,52,53,56,60,61,83
5.2.5 Aggregate Nutrient Ecoregion 9
Data sources:
Auburn University
Legacy STORET
NASQAN
NAWQA
EPA Region 3
EPA Region 5
EPA Region 7 .
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
17
-------
15 Nutnent Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226. TO# 04 August 8. 2000
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll B, Phytoplankton, Spectrophotometric (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Organic, Phosphorus (ug/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (JCTJ)
Turbidity (NTU)
Level III ecoregions:
29, 33,35,37, 40, 45, 64, 65, 71, 72, 74
5.2.6 Aggregate Nutrient Ecoregion 11
Data sources:
Auburn University
Legacy STORET
NASQAN
NAWQA •
EPA Region 3 • ,
EPA Region 5
EPA Region 7
Parameters:
Chlorophyll A, Fluorometric, Corrected . (ug/L)
Chlorophyll A, Phytoplankton, chromotographic- fluorometric (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected . (ug/L)
Chlorophyll B, Phytoplankton, chromotographic- fluorometric (ug/L)
Phosphorous, Dissolved Inorganic (DEP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Organic, Phosphorus (ug/L)
18
-------
15 Nutrient Ecorcgion/Waterbody Type Summary Chapters. Contract # 68-C-99-226, TO# 04 August 8, 2000
Phosphorus, Orthophosphate, Total as P (ug/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity . (FTU)
Turbidity (JCU)
Turbidity (NTU)
Level HI ecoregions:
36, 38, 39, 66, 67,68,69, 70
5.2.7 Aggregate Nutrient Ecoregion 12
Data sources:
Legacy STORET
NASQAN
NAWQA
Parameters:
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Chlorophyll B, Phytoplankton, Spectrophotometric (ug/L)
Phosphorous. Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L) '
Nitrite and Nitrate, (NO2-f-NO3) (mg/L)
Nitrogen, Total (TN) (mg/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity (NTU)
Level HI ecoregions:
75
19
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226. TO# 04 August 8, 2000 •
5.2.8 Aggregate Nutrient Ecoregion 14
Data sources:
Legacy STORET
NASQAN
NAWQA
NYCDEP
EPA Region 1
EPA Region 3
Parameters:
Chlorophyll A, Fluorometric, Corrected (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric Acid (ug/L)
Chlorophyll A, Phytoplankton, Spectrophotometric, Uncorrected (ug/L)
Chlorophyll A, Trichromatic, Uncorrected (ug/L)
Phosphorous, Dissolved Inorganic (DIP) (ug/L)
Dissolved Oxygen (DO) (mg/L)
Nitrite and Nitrate, (NO2+NO3) (mg/L)
Phosphorus, Orthophosphate, Total as P (ug/L)
Nitrogen, Total Kjeldahl (TKN) (mg/L)
Nitrogen, Total (TN) (mg/L)
Phosphorus, Total (TP) (ug/L)
Turbidity (FTU)
Turbidity . (JCU)
Turbidity (NTU)
•
Level HI ecoregions:
59,63,84
20
-------
15 Nutnent Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8, 2000
APPENDIX A
Process Used to QA/QA the Legacy STORET Nutrient Data Set
-------
15 Nutnent Ecoregion/Waterbody Type Summary Chapters. Contract # 68-C-99-226, TO# 04 August 8,2000
I. STORET water quality parameters and Station and Sample data items were retrieved
from USEPA's mainframe computer. Table 1 lists all retrieved parameters and data
items.
TABLE 1: PARAMETERS AND DATA ITEMS RETRIEVED FROM STORET
Parameters Retrieved
(STORET Parameter Code)
TN - mg/1 (600)
TKN - mg/1 (625)
Total Ammonia (NH3+NH4) - mg/1 (6 1 0)
Total NO2+NO3 - mg/1 (630)
Total Nitrite -mg/I (6 1 5)
Total Nitrate - mg/1 (620)
Organic N - mg/L (605)
TP - mg/1 (665)
Chlor a - ug/'L (spectrophotometric method.
32211)
Chlor a - ug/L (fluorometric method corrected.
32209)
Chlor a - ug/L (trichromatic method corrected,
32210)
Sccchi Transp. - inches (77)
Secchi Transp. - meters (78)
+Turbidity JCUs (70)
^•Turbidity FTUs (76)
i-Turbidiry NTUs field (82078)
-Turbidity NTUs lab (82079)
-DO - mg/L (300)
+ Water Temperature (decrees C, 10/degrees F,
11)
Station Data Items Included
(STORET Item Name)
Station Type (TYPE)
'Agency Code (AGENCY)
Station No. (STATION)
Latitude - std. decimal degrees
(LATSTD)
Longitude - std. decimal degrees
(LONGSTD)
Station Location (LOCNAME)
County Name (CONAME)
State Name fSTNAME)
Ecoregion Name - Level III
(ECONAME)
Ecoregion Code -Level III
(ECOREG)
Station Elevation (ELEV)
Hydrologic Unit Code
(CATUNIT)
RF1 Segment and Mile
(RCHMIL)
RF1 ON/OFF tag (ONOFF)
Sample Data items
Included
(STORET Item Name)
Sample Date (DATE)
Sample Time (TIME)
Sample Depth (DEPTH)
Composite Sample Code
(SAMPMETH)
- If data record available at a station included data only for this or other such marked parameters, data record was
deleted from data set.
The following set of retrieval rules were applied to the retrieval process:
• Data were retrieved for waterbodies specified only as 'lake', 'stream', 'reservoir',
or 'estuary' under "Station Type" parameter. Any stations specified as 'well,'
'spring,' or 'outfall' were eliminated from the retrieved data set.
• Data were retrieved for station types described as 'ambient' (e.g., no pipe or facility
discharge data) under the "Station Type" parameter.
• Data were retrieved that were designated as 'water' samples only. This includes
"bottom' and 'vertically integrated' water samples.
A-l
-------
15 Nutrient Ecorcgion/Waierbody Type Summary Chapters, Contract * 68-C-99-226, TO# 04
August 8, 2000"
• Data were retrieved that were designated as either 'grab' samples and 'composite'
samples (mean result only).
• No limits were specified for sample depths.
• Data were retrieved for all fifty states, Puerto Rico, and the District of Columbia.
• The time period specified for data retrieval was January 1990 to September 1998.
• No data marked as "Retired Data" (i.e., data from a generally unknown source) were
retrieved.
• Data marked as "National Urban Runoff data" (i.e., data associated with sampling
conducted after storm events to assess nonpoint source pollutants) were included in
the retrieval. Such data are part of STORET's 'Archived' data.
• Intensive survey data (i.e., data collected as part of specific studies) were retrieved.
Any values falling below the 1st percentile and any values falling above the 99th
percentile were transformed into 'missing' values (i.e., values were effectively removed
from the data set, but were not permanently eliminated).
Based on the STORET 'Remark Code' associated with each retrieved data point, the
following rules were applied (Table 2):
TABLE 2: STORET REMARK CODE RULES
»
STORET Remark Code
blank - Data not remarked.
A-
B-
C-
D-
E-
F-
G-
Value reported is the mean of two or more determinations.
Results based upon colony counts outside the acceptable ranges.
Calculated. Value stored was not measured directly, but was
calculated from other data available.
Field measurement.
Extra sample taken in compositing_process.
In the case of species. F indicates female sex.
Value reported is the maximum of two or more determinations.
Keep or Delete Data Point
Keep
Keep
Delete
Keep
Keep
Delete
Delete
Delete
A-2
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters. Contract # 68-C-99-226. TO# 04
August 8. 2000
TABLE 2: STORET REMARK CODE RULES
H-
I-
J-
K-
L-
M-
N-
O-
P-
Q-
R-
S-
T-
U-
V-
W-
X-
Y-
Z-
Value based on field kit determination; results may not be accurate.
The value reported is less than the practical quantification limit and
greater than or equal to the method detection limit.
Estimated. Value shown is not a result of analytical measurement.
Off-scale low. Actual value not known, but known to be less than
value shown.
Off-scale high. Actual value not known, but known to be greater
than value shown.
Presence of material verified, but not quantified. Indicates a
positive detection, at a level too low to permit accurate
quantification.
Presumptive evidence of presence of material.
Sample for, but analysis lost. Accompanying value is not
meaningful for analysis.
Too numerous to count.
Sample held beyond normal holding time.
Significant rain in the past 48 hours.
Laboratory test.
Value reported is less than the criteria of detection.
Material was analyzed for, but not detected. Value stored is the
limit of detection for the process in use.
Indicates the analyte was detected in both the sample and associated
method blank.
Value observed is less than the lowest value reportable under
remark "T."
Value is quasi vertically-integrated sample.
Laboratory analysis from unpreserved sample. Data may not be
accurate.
Too many colonies were present to count.
Delete
Keep, but used one-half the
reported value as the new value.
Delete
Keep, but used one-half the reported
value as the new value.
Keep
Keep, but used one half the reported
value as the new value.
Delete
Delete
4
Delete
Delete
Delete
Keep
Keep, but replaced reported value with
0.
Keep, but replaced reported value with ,
0.
Delete
Keep, but replaced reported value with
.0.
No data point with this remark code in
data set.
Delete
Delete
A-3
-------
15 Numem Ecoregion/'Waterbody Type Summary Chapters, Contract tt 68-C-99-226. TOtt 04 August 8. 2000
TABLE 2: STORET REMARK CODE RULES
If a parameter (excluding water temperature) value was less than or equal to zero and no remark code was present,
the value was transformed into a missing value.
Rationale - Parameter concentrations should never be zero without a proper explanation. A method detection limit
should at least be listed.
4. Station records were eliminated from the data set if any of the following descriptors were
present within the "Station Type" parameter:
* MONITR - Source monitoring site, which monitors a known problem or to detect
a specific problem.
* HAZARD - Site of hazardous or toxic wastes or substances.
>• ANPOOL - Anchialine pool, underground pools with subsurface connections to
watertable and ocean.
> DOWN - Downstream (i.e., within a potentially polluted area) from a facility
which has a potential to pollute.
»• IMPDMT - Impoundment. Includes waste pits, treatment lagoons, and settling
and evaporation ponds.
»• STMSWR-Storm water sewer.
> LNDFL - Landfill.
»• CMBMI - Combined municipal and industrial facilities.
»• CMBSRC - Combined source (intake and outfall).
Rationale - these descriptors potentially indicate a station location that at which an
ambient water sample would not be obtained (i.e., such sampling locations are potentially
biased) or the sample location is not located within one of the designated water body types
(i.e, ANPOOL).
5. Station records were eliminated from data set if the station location did not fall within any
established cataloging unit boundaries based on their latitude and longitude.
6. Using nutrient ecoregion GIS coverage provided by USEPA. all station locations with
latitude and longitude coordinates were tagged with a nutrient ecoregion identifier
(nutrient region identifiers are values 1-14) and the associated nutrient ecoregion name.
Because no nutrient ecoregions exist for Alaska, Hawaii, and Puerto Rico, stations located
in these states were tagged with "dummy" nutrient ecoregion numbers (20 = Alaska, 21 =
Hawaii, 22 = Puerto Rico).
A-4
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract tt 68-C-99-226. TO# 04 August 8. 2000
7. Using information provided by TV A, 59 station locations that were marked as 'stream'
locations under the "Station Type" parameter were changed to 'reservoir' locations.
8. The nutrient data retrieved from STORET were assessed for the presence of duplicate data
records. The duplicate data identification process consisted of three steps: 1) identification
of records that matched exactly in terms of each variable retrieved; 2) identification of
records that matched exactly in terms of each variable retrieved except for their station
identification numbers; and 3) identification of records that matched exactly in terms of
each variable retrieved except for their collecting agency codes. The data duplication
assessment procedures were conducted using SAS programs.
Prior to initiating the data duplication assessment process, the STORET nutrient data set
contained:
41,210 station records
924,420 sample records
• Identification of exactly matching records
All data records were sorted to identify those records that matched exactly. For two
records to match exactly, all variables retrieved had to be the same,' For example,
they had to have the same water quality parameters, parameter results and associated
remark codes, and have the same station data item and sample data item information.
Exactly matching records were considered to be exact duplicates, and one duplicate
record of each identified matching set were eliminated from the nutrient data set. A
total of 924 sample records identified as duplicates by this process were eliminated
from the data set.
• Identification of matching records with the exception of station identification number
All data records were sorted to identify those records that matched exactly except for
their station identification number (i.e., they had the same water quality parameters,
parameter results and associated remark codes, and the same station and sample data
item information with the exception of station identification number). Although the
station identification numbers were different, the latitude and longitude for the
stations were the same indicating a duplication of station data due to the existence of
two station identification numbers for the same station. For each set of matching
records, one of the station identification numbers was randomly selected and its
associated data were eliminated from the data set. A total of 686 sample records
were eliminated from the data set through this process.
• Identification of matching records with the exception of colleoting aeencv codes
All data records were sorted to identify those records that matched exactly except for
their collecting agency codes (i.e., they had the same water quality parameters,
parameter results and associated remark codes, and the same station and sample data
item information with the exception of agency code). The presence of two matching
A-5
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters. Contract # 68-C-99-226, TO# 04 August 8,2000
data records each with a different agency code attached to it suggested that one
agency had utilized data collected by the other agency and had entered the data
into STORET without realizing that it already had been placed in STORET by the
other agency. No matching records with greater than two different agency codes
were identified. For determining which record to delete from the data set, the
following rules were developed:
*• If one of the matching records had a USGS agency code, the USGS record
was retained and the other record was deleted.
>• Higher level agency monitoring program data were retained. For example,
federal program data (indicated by a "1" at the beginning of the STORET
agency code) were retained against state (indicated by a "2") and local
(indicated by values higher than 2) program data.
»• If two matching records had the same level agency code, the record from the
agency with the greater number of overall observations (potentially indicating
the data set as the source data set) was retained.
A total of 2,915 sample records were eliminated through this process.
As a result of the duplicate data identification process, a total of 4,525 sample records and
36 individual station records were removed from the STORET nutrient data set. The
resulting nutrient data set contains the following:
41,174 station records
919,895 sample records
A-6
-------
15 Nutrient EcoregionAVaterbody Type Summary Chapters, Contract # 68-C-99-226, TO# 04 August 8. 2000
APPENDIX B
Process for Adding Aggregate Nutrient Ecoregions and Level in Ecoregions
-------
15 Nutrient Ecoregion/Waterbody Type Summary Chapters, Contract # 68-C-99-226, TO* 04 August 8. 2000
Steps for assigning Level EH ecoregions and aggregate nutrient ecoregion codes and names to the
Nutrient Criteria Database (performed using ESRI's ARCView v 3.2 and its GeoProcessing
Wizard). This process is performed twice; once for the Level HI ecoregions and once for the
aggregate nutrient ecoregions:
Add the station .dbf data table, with latitude and longitude data, to project by 'Add Event
Theme1
Convert to the shapefile format
Create 'stcojoin1 field, populate the 'stcojoin1 field with the following formula:
'County.LCase+State.LCase'
Add field 'stco_flag' to the station shapefile
Spatially join the station data with the county shapefile (cntysjned.shp)
Select 'stcojoin' (station shapefile) field = 'stco Join2' (county shapefile) field
Calculate "stco_flag = 0 for selected features
Step through all blank stco_flag records, assign the appropriate stco_flags, see list on the
following page
Select all stco_flags = 4 or 7, switch selection
Calculate ctyfips (station) to cntyfips (county)
Stop editing and save edits, remove all joins
Add in 2 new fields 'x-coordl1 and 'y-coordl' into station table
Select all stco_flags =1,2, and 6
Link county coverage with station coverage
Populate 'x-coordl' and 'y-coord I' with 'x-coord* and 'y-coord' from county coverage
Select all stco_flags =1,2, and 6, export to new .dbf file
Add new .dbf file as event theme
Convert to shapefile format
Add the following fields to both tables (original station and station 126 shapefiles):
'ecojamer1, Iname_omer', Idis_aggr1, 'code_aggrl, lname_aggrl
Spatially join station!26 and eco-omer coverage
Populate the 'eco^mer1 field with the 'eco' value
Repeat the previous step using the nearest method (line coverage) to determine ecoregion
assignment for the line coverage, if some records are blank
Spatially join the ecoregion line coverage to station coverage, link the
LPoly# (from the spatially joined table) to Poly# (of the ecoregion polygon
coverage)
Populate the Eco fields with the appropriate information.
Follow the same steps to the Rpolytf
Remove all table joins
Link the useco-om table with stationl26 table and populate 'name-omer1 field
Spatially join station aggr coverage and populate the rest of the fields. Follow the same
procedures as outlined above
Remove all joins
B-l
-------
15 Nutrient EcoregioivWaierbody Type Summary Chapters. Contract» 68-C-99-226, TOO 04 August 8,2000
Make sure the new Eco field added into the station 126 shapefile are different than the
ones in the original station shapefile
Join station!26 and station coverage by station-id
Populate all the Eco fields in the original station coverage
Remove all joins
Save table
Make sure that all ctyfips records are populated; the county shapefile may have to be
joined to populate the records, if the stco_flag = 4
Create 2 new fields, "NewCounty1 and 'NewState1
Populate these new fields with a spatial join to the county coverage
Select by feature (ecoregion shapefile) all of the records in the station shapefile
Switch selection (to get records outside of the ecoregion shapefile)
If any of the selected records have stco_flag = 0 (they are outside the ecoregion
shapefile boundary), calculate them to stco_flag = 3
stco_flags (state/county flags in order of importance)
0 The state and county values from the data set matched the state and county values
from the spatial join.
(Ecoregions were assigned based on the latitude/longitude coordinates.)
1 The state and county values from the data set did not match the state and county
values from the spatial join, but the point was inside the county coverage
boundary.
(Ecoregions were assigned based on the county centroid.)
2 The state and county values from the data set did not match the state and county
values from the spatial join because the point was outside the county coverage
boundary; therefore, there was nothing to compare to the point (i.e., the point
falls in the ocean/Canada/Mexico). This occurred for some coastal samples.
(Ecoregions were assigned based on the county centroid.) '
3 The state and county values from the data set matched the state and county from
the spatial join, but the point was outside the ecoregion boundary.
(Ecoregions were assigned to the closest ecoregion to the point.)
(No ecoregions were assigned to AK, HI, PR, BC, and GU.)
4 Latitude/longitude coordinates were provided, but there was no "county
information.
(Ecoregions were assigned based on the latitude/longitude coordinates.)
5 The state and county values from the data set did not match the state and county
values from the spatial join due to spelling or naming convention errors.
The matches were performed manually.
(Ecoregions were assigned based on the latitude/longitude coordinates.)
B-2
-------
15 Nutneiu'Ecoregion/Waierbody Type Summary Chapters. Contract # 68-C-99-226, TO# 04 August 8.2000
6 No latitude/longitude coordinates were provided, only state and county
information was available.
(Ecoregions were assigned based on the county centroid.)
7 No latitude/longitude coordinates were provided, only state information was
available; therefore, no matches were possible.
(Ecoregions were not assigned. Data is not included in the analysis.)
B-3
------- |