United States Environmental Protection Agency
Office of Water
Washington, DC
EPA841-B-11-003
2012 National Lakes Assessment
Site Evaluation
Guidelines
Version 1.1, September 26, 2012
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2012 National Lakes Assessment Site Evaluation Guidelines
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2012 National Lakes Assessment Site Evaluation Guidelines
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NOTICE
The intention of the 2012 National Lakes Assessment (NLA 2012) project is to provide a comprehensive
"State of the Lakes" assessment for lakes, ponds, and reservoirs across the United States. The complete
documentation of overall project management, design, methods, and standards and Quality
Assurance/Quality Control measures is contained in this document and companion documents,
including:
2012 National Lakes Assessment: Field Operations Manual (EPA841-B-11-003)
2012 National Lakes Assessment: Laboratory Operations Manual (EPA 841-B-11-004)
2012 National Lakes Assessment: Quality Assurance Project Plan (EPA 841-B-11-006)
These documents together comprise the integrated set of QAPP documents. This document (Site
Evaluation Guidelines) describes the process to compile the final list of candidate lakes for sampling. The
process includes locating a candidate lake, evaluating the lake to determine if it meets the criteria for
inclusion in the target population and is accessible for sampling, and, if not, replacing it with an
alternate candidate lake. These guidelines are revised from those developed for the 2007 NLA (USEPA
2006), and are intended for specific use in the 2012 NLA. Mention of trade names or commercial
products in this document does not constitute endorsement or recommendation for use
The suggested citation for this document is:
USEPA. 2011. 2012 National Lakes Assessment. Site Evaluation Guidelines. EPA 841-B-11-005.
U.S. Environmental Protection Agency, Washington, DC.
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2012 National Lakes Assessment Site Evaluation Guidelines
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2012 National Lakes Assessment Site Evaluation Guidelines
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TABLE OFCONTENTS
TITLE PAGE I
NOTICE Ill
TABLE OF CONTENTS V
LIST OF FIGURES V
LIST OF TABLES VI
1 INTRODUCTION 1
1.1 SELECTION OF THE MASTER LIST OF CANDIDATE LAKES 2
2 LAKE EVALUATION PROCESS 3
2.1 LAKE REPLACEMENT 3
2.2 PROCEDURE FOR SELECTING REPLACEMENT LAKES FROM THE OVERSAMPLE LIST 4
2.3 GIS-BASED EVALUATION (Q1-Q3) 6
2.4 DESKTOP EVALUATION (Q2, Q4-6) 10
2.5 FIELD EVALUATION (Q2, Q4-6) 12
3 DETERMINING IF A LAKE IS PHYSICALLY ACCESSIBLE (Q6) 14
3.1 TARGET, INACCESSIBLE-BARRIER/SAFETY 14
3.2 TARGET, >1 DAY NEEDED 14
3.3 TARGET, EXTREME EFFORT REQUIRED, INACCESSIBLE-EFFORT 14
4 OBTAINING PERMISSION TO ACCESS CANDIDATE LAKES (Q7) 15
4.1 IDENTIFY LANDOWNER 15
4.2 REQUEST PERMISSION TO ACCESS LAKE 15
4.3 DENIALS 16
4.4 FREQUENTLY ASKED QUESTIONS 16
5 LITERATURE CITED 17
APPENDIX A: EXAMPLE LETTER REQUESTING PERMISSION TO ACCESS A LAKE 19
APPENDIX B: EXAMPLE LANDOWNER PERMISSION SLIP 23
APPENDIX C: NATIONAL LAKES ASSESSMENT 2012 SURVEY DESIGN 27
APPENDIX D: NATIONAL LAKES ASSESSMENT 2012 FACT SHEET 37
APPENDIX E: CONTACTS 35
APPENDIX F: FREQUENTLY ASKED QUESTIONS 39
LIST OF FIGURES
FIGURE 1. EVALUATING A LAKE 5
FIGURE 2. PROCESS FLOW OF THE LAKE EVALUATION SPREADSHEET 6 i-
FlGURES. GIS-BASED EVALUATION 10 LU
FIGURE 4. DESKTOP EVALUATION 12 z
FIGURES. FIELD EVALUATION 13 u
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LIST OF TABLES
TABLE 1.1 EXCEPTIONS TO NLA 2012 TARGET POPULATION 1
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1 INTRODUCTION
The objectives of the 2012 National Lakes Assessment (NLA) include:
1) Using a statistically valid approach, determine the percent of the nation's lakes that are in good,
fair, and poor condition for key indicators of ecological health, trophic state, and recreation;
2) Determine the relative importance of key stressors as they relate to the condition of lakes across
the Nation;
3) Evaluate changes in the condition of the nation's lakes since the 2007 NLA;
4) Expand the capacity of State and Tribal programs to monitor and assess the condition of lakes.
The word lake in the remainder of this document includes lakes, reservoirs, and ponds. This document
describes the steps involved to evaluate candidate lakes for the NLA, and arrive at a final list of lakes to
visit and sample. Evaluation of candidate lakes serves several purposes. Lakes that do not meet the
criteria for inclusion in the NLA target population are identified and replaced. Table 1.1 lists the
exceptions for inclusion in the target population of lakes, ponds, and reservoirs:
Table 1.1 Exceptions to NLA 2012 Target Population
Ephemeral waterbodies (i.e., highly likely to be dry between May and September of the sampling
year)
Lakes or ponds along the coast or near an estuary (below the head of salt) that are tidally-influenced
(i.e., maintained solely by surface inflow of brackish water or seawater)
Run-of-the-river reservoir with retention time < 1 week
Used exclusively for aquaculture
Ponds or reservoirs with no recreational or aquatic life uses
Sewage lagoons
Disposal ponds (e.g., mine tailings)
Evaporation ponds
Stormwater retention basins
Constructed solely for storage of drinking water (e.g., upground reservoirs, p.8)
Active quarries
Borrow pits
Constructed stock or farm ponds (with no other uses)
Surface area less than 1 hectare
Total area of open water (does not have to be continuous) < 1000 m2 (at time of sampling).
Maximum depth less than 1 m (at time of sampling)
The target population is that component of the resource (i.e., lakes, ponds, and reservoirs) that you
want to assess. Lakes that meet the criteria, but that cannot be sampled, are also identified and
replaced. Information obtained about important characteristics of candidate lakes (e.g., lake origin) is
used to classify lakes for analysis and reporting. All of these activities improve the sample frame and c
allow the population of lakes assessed for ecological condition to be described more precisely. In •.§
addition, the number of field visits to lakes that should not or cannot be sampled is reduced. _g
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The evaluation process for the NLA differs from many other monitoring and assessment studies in that •£
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the accounting of candidate lakes that end up not being sampled is almost as important as identifying
the lakes that will ultimately be sampled. Accounting for the status of all candidate lakes, sampled or
not, provides the means to improve the survey design and site selection process, refine the sampling
frame to reduce the number of non-target sites, and acknowledge any potential caveats to interpreting
the results of the assessment in terms of sites that were identified as target but could not be sampled. In
the 2007 NLA, the final set of sampled lakes represented only 73% of the target population—the other
27% represented a portion of the intended target population that could not be assessed because of lack
of permission or physical inaccessibility (USEPA 2009). This unassessed portion of the target population
is likely biased towards certain types of lakes and/or geographic regions. This constrains the ultimate
objective of reporting the condition of all target lakes in the conterminous US. Any activity that reduces
the proportion of unassessed lakes results in a more robust and representative assessment.
Given the scale and time constraints of NLA, and the desire to utilize local knowledge about lakes, the
evaluation process involves many different persons. It is critical to apply the evaluation process
consistently across all lakes and evaluators. To help make the process consistent and efficient, an
electronic spreadsheet with drop-down menus and pick lists is used for the NLA 2012. For those lakes
ultimately identified for sampling, it is also important to apply a reasonable (and consistent) level of
effort to obtain permission when required, and to visit and sample lakes that are difficult to access
because of physical barriers to access (e.g., distance, terrain).
1.1 Selection of the Master List of Candidate Lakes
Lakes were chosen from a sample frame of lake polygons represented in the National Hydrography
Dataset (NHDplus; as represented onl:100,000 scale maps), following a Generalized Random
Tessellation Stratified (GRTS) survey design for a finite resource (Stevens and Olsen 2004). Appendix C:
National Lakes Assessment 2012 Survey Design (page 27) provides additional details regarding the
survey design.
The "master" list of sites selected for the NLA 2012 using the survey design contains approximately
7,000 candidate lakes. A sufficient number of lakes from this list must be evaluated in order to produce
a final list of approximately 1,000 lakes that will be visited and sampled. The evaluation process is
conducted separately for each State to arrive at the required number of sampling sites for the entire
NLA. Additional lakes from the list may need to be evaluated if a State will be implementing a more
intensive sampling regime in order to produce a State-level assessment of lakes. Approximately 400 of
these 1,000 lakes are lakes that were previously sampled as part of the 2007 NLA, and so may not
require a detailed evaluation for 2012 (other than to confirm it is still target and accessible).
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2 LAKE EVALUATION PROCESS
For 2012, the NLA lake evaluation process consists of four phases:
1) A "rapid" Geographic Information System (GlS)-based evaluation on -2,500 candidate lakes
to assign an initial status to as many as possible;
2) A Desktop Evaluation to assign a final status to as many of the remaining candidate lakes as
possible;
3) A Field Evaluation to assign a final status to any remaining candidate lakes;
4) A final refinement of the candidate lake list based on the ability to obtain Permission to
sample.
The master list of candidate lakes (1.1) is apportioned into lists of candidate sites for each State. Each
phase assigns a final status to as many candidate lakes on a State list as possible, with the next phase
working primarily on the remaining lakes. By the end of the third phase, all candidate lakes should have
a final status assignment. The fourth phase of the process refines the list of candidate lakes to identify
those that will be visited and sampled in the NLA.
The general process for conducting the evaluation within any given phase is presented in Figure 1. The
process consists of answering a series of Yes/No questions, as shown in Figure 2. A Yes answer moves
the site to the next question, while a No answer generally involves assigning a final site status and
selecting a replacement site for evaluation. When a question cannot be answered definitively, the status
is classified as Uncertain, and the site is moved to the next phase of the evaluation.
The GIS-based evaluation phase will be done at a central location (WED-Corvallis). After the GIS phase,
the list of candidates is provided to EPA Regions, States, and Tribal Nations for desktop and field
evaluations (when required). The GIS-based, desktop, and field evaluation phases are used to determine
if a candidate lake is part of the target population, if it is safe to access, and if permission is needed (in
the case of no public access). Then, if needed, permission is requested as the fourth phase of the
process.
During any given phase, candidate lakes that are determined to be nontarget, or are determined to be
part of the target population but cannot be sampled, are replaced with alternate candidate lakes
selected from a list of oversample lakes. It is important that alternate lakes are selected properly (i.e.,
without skipping over any) to maintain the random nature of the final list of sampled lakes. The
procedure for selecting a replacement lake is described in the following section.
2.1 Lake Replacement
Lakes on the master site list are evaluated separately by State. A sufficient number of lakes on the list
for each State must be evaluated in order to arrive at the required number of target and accessible lakes
assigned to that State. Within each state, lakes evaluated for potential sampling must have all site IDs
from the largest to the lowest number evaluated. For example, if NLA12_AL-0155 is the largest site ID
evaluated within Alabama, then all lakes with site IDs that are lower than "0155" within the state must
be evaluated. Even more critical is that if NLA12_AL-0155 is the largest site ID that is actually sampled in SO
the field, then all lakes on the State list with lower site IDs that are evaluated to be a target lake and are Q
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accessible must be visited and sampled. c
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If you determine a lake to be non-target, or target but not accessible, during any phase of the evaluation ro
process, select the next available replacement lake from the master list. Section 2.2 presents the ~fc
procedure for selecting replacement lakes. The replacement process differs slightly based on whether ^
the lake being replaced is part of the national NLA 2012 design versus a state-level design (intensified to "^
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allow a State to perform its own assessment). Candidate lakes identified as part of the national design
must all be evaluated and sampled if they are determined to be target and accessible. For a state-level
design, all candidate lakes identified as part of the national design and all candidate lakes identified as
part of the state-level design must be evaluated and sampled if they are determined to be target and
accessible.
2.2 Procedure for Selecting Replacement Lakes from the Oversample List
At the end of the evaluation process, you should have a list of lakes for your state that includes the list
of "base" sites (Section 2.2.1), plus a sequential list of replacement Site ID numbers needed to have the
required number of target and accessible lakes. If your State is planning to do a separate State-scale
assessment, the "base" list of sites is expanded to include additional sites (Section 2.2.2) that must also
be evaluated (and replaced if necessary).
2.2.1 National Design
1. The initial list of "base" candidate lakes within a state that are required for the national
assessment are identified by the following values for the variable PANEL:
a. NLA07RVT2: An NLA 2007 lake that should be visited twice in 2012.
b. NLA07RVT: An NLA 2007 lake that should be visited once in 2012.
c. NLA12RVT: An NLA 2012 lake that should be visited twice in 2012.
d. NLA12NAT: An NLA 2012 lake that should be visited once in 2012.
2. You must evaluate all of these lakes within your State to meet the sample size requirements for
the national assessment. If the evaluation for a lake results in it being assigned a final status of
nontarget or target but not accessible, select the first available lake (i.e., with the lowest Site ID
number) with PANEL = NLA12ST and evaluate it.
NOTE: If you need to replace a 2007 revisit site (NLA07RVT2), attempt to replace this revisit
with another 2007 resample site (NLA07RVT). This will become your new 2007 revisit site.
This may not always be possible. If not, replace it as you typically would and make the
replacement lake a revisit site.
3. If all replacement lakes with PANEL = NLA12ST have been evaluated, and additional replacement
lakes are needed, begin using lakes with PANEL = OverSamp, starting with the lake having the
lowest Site ID number.
2.2.2 State Level Design (Intensification)
1. For a State-level (intensified) design, the "base" list of candidate lakes includes all lakes
identified as part of the national design (see 2.2.1 above), plus those with PANEL=NLA12ST
„, (these serve as replacement sites if there is no intensification).
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v 2. You must evaluate all of these lakes within your State to meet the sample size requirements for
° both the national and your State-specific assessments. If the evaluation for a lake results in it
c being assigned a final status of nontarget or target but not accessible, select the first available
+jj lake (i.e., with the lowest Site ID number) with PANEL=OverSamp and evaluate it.
a. NOTE: If your State elects not to include lakes with surface area less than 4 ha (which
-=;
m are part of the national design), you must still evaluate (and sample if target and
^ accessible) all lakes (regardless of surface area) identified as part of the national design,
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including any replacement lakes needed for these.
b. For the additional State-level lakes (PANEL=NLA12ST), you can exclude those with
surface areas < 4 ha, and skip over any replacement lakes (PANEL=OverSamp) that have
surface areas < 4 ha.
BASE LIST
List of candidate lakes from survey
design
REPLACEMENT LIST
CIS-based EVALUATION
Evaluate .'ill base list lakes per State (n 2,500)
REGIONAL, STATE, and/or TRIE*L-LEVEL DESKTOP EVALUATION
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BAL-LEVEL FIELD EVALUATION
Target
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List of
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Select next available replacement lake for evaluation
OBTAIN ACCESS PERMISSION
Select next
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lake for
evaluation
Figure 1. Evaluating a lake.
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Q1
Is water body a lake?
Q1a. Not a lake
Q1b. Compare lake polygon to lake shape
Q1c
Record lake name from map if different from NHD
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Q2
Does the lake meet any nontarget criteria
Yes
No
Q3
GIS evaluation status
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Q4
> 1000 m2 of open water?
Yes j
No
Q5
Maximum depth > 1 m?
No
Yes
Q6
Physically accessible?
No
Yes
Q7
Access permission obtained?
No
Yes
Q8
Is lake natural or man-made?
Q9
Target or nontarget lake?
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Q10
Final evaluation status?
Figure 2. Process Flow of the Lake Evaluation Spreadsheet.
2.3 CIS-based Evaluation (Q1-Q3)
Figure 3 presents an overview of the GIS-based phase of lake evaluation. At this phase, evaluate all base
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lakes on each State list (i.e., those with PANEL= NLA07RVT2, NLA07RVT, NLA12RVT, and NLA12NAT). The
GIS-based phase makes use of two ESRI map service layers loaded in ArcMap®: a background United
States Geologic Survey (LJSGS) topographic map service and a map service of world imagery from ESRI
loaded as layer files in ArcMap". Examine each lake (there will be about 2,500) in ArcMap" using
background topographic maps and imagery. Use the procedure presented in Section 2.3.1 to attempt to
answer the questions in the evaluation spreadsheet file (see Figure 2) based on just these layers in
ArcMap". The GIS-based phase is designed primarily to address questions Ql and Q2 of the evaluation
questionnaire (Figure 2). All lakes evaluated during the GIS phase are assigned a GIS status (Q3 of the
questionnaire).
The intent of the GIS phase is to reduce the number of candidate lakes that must be reviewed in more
detail during the Desktop and Field phases of the evaluation. Ideally, decisions will be made quickly for
the vast majority of lakes based on background topographic maps and imagery alone. For any lake in the
initial list of base lakes to which you cannot definitively assign a GIS status of Candidate target or Non-
target, assign a GIS status of Uncertain. Lakes with GIS status of Candidate target and Uncertain are
moved to the Desktop phase of the evaluation process. For large, named lakes, the review should be
very fast. For smaller lakes and for unnamed lakes, responding to the evaluation questionnaire will likely
take more time and there will be more lakes assigned to a GIS status of Uncertain.
The GIS phase also identifies instances where the lake polygon as rendered in NHDPIus does not match
up with the lake shape depicted on either the image and/or the topographic map. Examples include:
1) where part of a lake (an arm or other embayment) is not represented within the lake polygon;
2) where part of a lake is not represented by a polygon because of a bridge or causeway; or
3) a single polygon encompasses more than one lake.
These inconsistencies may be due to mapping or delineation errors in NHDPIus, or to more recent
changes in basin morphology as a result of precipitation patterns. In the case of the latter, it may not
become evident until the desktop evaluation (Section 2.4) or even later (i.e., when you visit the lake to
sample it). If you encounter one of these errors during the GIS evaluation (Qlb of the evaluation
questionnaire), notify Marc Weber of the NLA design staff at WED-Corvallis so the error can be
corrected in the sample/analysis frame, and then proceed with evaluating the lake. These errors affect
the sampling frame in two ways: they result in an incorrect delineation of the catchment, and, in the
case of a single polygon representing more than one lake, they might impact the sample weighting
factor.
Ephemeral lakes that are expected to be dry during the index period (May through September) of the
sampling year are not part of the target population. Coastal lakes, or lakes near an estuary that are
under tidal influence, are not part of the target population. A tidally-influenced lake is operationally
defined as being maintained solely by the surface inflow of brackish or salt water due to water level
changes during tidal cycles. Permanent lakes near the coast, or near an estuary below the head of salt,
with no surface connection to the ocean at high tide are considered part of the target population (even
if saline). Dune lakes (primarily located along the Gulf Coast), are part of the target population. These i/>
lakes are permanent and almost always isolated from the ocean, but periodically will flood or "blow u
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out," forming a connection with the ocean or estuary and incur an influx of brackish or salt water. £
Waterbodies along the coast that are considered to be estuarine or part of a larger coastal wetland area g
are not part of the target population. Inland lakes that are saline or have high conductivity (> 1000 "S
u.S/cm) are part of the target population (the Great Salt Lake has already been excluded as part of the ~^
survey design). Oxbows are considered target lakes if they are completely separated from a river (no ^
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surface connection). However, oxbows that have either flowing water or a wetland connection to a river -*•
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are not lakes, and should be assigned a GIS evaluation status (Q3) of Nontarget. Side-channel reservoirs
and drinking water reservoirs (where water is pumped from nearby rivers, termed upground reservoirs
in some parts of the US) that do not have recreation or aquatic life uses are not considered part of the
target population. Abandoned mine lakes used for recreation or other beneficial uses (e.g., wildlife) are
considered to be part of the target population.
The GIS-based phase (Section 2.4) will likely not provide definitive information to address whether a
candidate lake is ephemeral, has sufficient open water, or a maximum depth of at least 1 m, especially
for smaller lakes. You can attempt to use the surrounding topography to make these determinations - if
there is not much relief, chances are it will not be very deep. Do not answer the open water or lake
depth questions (Q4 and Q5), or conclude the lake is ephemeral, unless you are sure that a Yes or No
response applies based on the available imagery for the lake. Lakes that are assigned a status of
Uncertain during the GIS evaluation phase are further evaluated as part of the Desktop evaluation phase
of the evaluation process.
2.3.1 Lake Evaluation using GIS Layers and Imagery
This procedure assumes that the GIS phase of the evaluation process will be conducted at a central
location. If questions come up, contact Marc Weber (541-754-4469) or Dave Peck (541-754-4426).
1. Open ArcMap® and load the two NLA_2012 integrated design shapefiles. These files contain all
of the candidate lakes for all states:
a. NLA2012_lntegrated_Design_20110706_points.shp
b. NLA2012_lntegrated_Design_20110706_polys.shp
2. Load US topographic maps as a layer service from arcgis.com:
a. Go to File > Add Data from ArcGIS Online.
b. Click on 'US Topo Maps' at the bottom of the web page that opens up
c. In the pop-up window that appears, choose 'Open with ArcGISHandler EXE.'. This will
open a read-only 'layer' in your ArcGIS project.
3. Load background imagery
a. Go to File > Add Data from ArcGIS Online.
b. Click on 'Imagery' in the web page that opens up -
c. In the pop-up window that appears, choose 'Open with ArcGISHandler EXE.'. This will
open a read-only 'layer' in your ArcGIS project.
4. Records are sorted by state (ST_NLA2012), then in ascending order by SITE ID. Evaluate lakes by
State in order of SITEJD.
5. Set the minimum scale so that both the topography and imagery layers are visible in ArcMap®
(this will speed up the rendering in ArcMap® when zooming from site to site):
a. Right click each layer, go to the General tab, and under Scale Range, click on the second
option - Don't show layer when zoomed: then choose 1:400,000 for Out beyond.
b. Leave default of None for In beyond in Scale Range. If you need to adjust the Out beyond
y, scale choose an option that works best for you.
" c. Turn imagery and topographic map layers on and off by checking Layers in the ArcMap
ol table of contents so that they can be used separately to evaluate a given lake.
o 6. Open the NLA 2012 Lake Evaluation Spreadsheet available on the NARS Sharefile
re (NLA_2012_LAKE_EVAL_FORM_20110524.xls, or the corresponding State workbook if not being
"re done centrally).
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a. The worksheet has key variables from the shapefile, sorted in the same order
~ro b. The evaluation questionnaire begins with the column labeled Ql. Is Waterbody a Lake?
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7. Evaluate all lakes on the base list for the State (usually the first 50 lakes, but 50 in the case of
Minnesota) using just the imagery provided in ArcMap® Evaluate lakes in order, looking at lakes
in ArcMap" and filling in columns in the spreadsheet. All of the evaluation questionnaire
columns have drop down lists for entries.
8. The GIS evaluation involves answering the first 2 questions of the lake evaluation questionnaire
and assigning a status of Nontarget, Candidate Target, or Uncertain as Q3 of the evaluation.
a. If the polygon for the lake from the NHDPIus-based shapefile does not match up with
the lake outline as shown on either the imagery or the topographic map, notify Marc
Weber so corrections can be made to the shapefile and sampling frame.
9. If you can determine a final status of Nontarget (e.g., a nontarget evaporation pond), assign the
appropriate responses to Q3, Q9 and Q10 of the evaluation questionnaire and proceed to
evaluate the next site on the list.
10. If the responses to questions Ql and Q2 indicate that the lake is a candidate target lake, or you
cannot determine its status, assign a GIS status (Q3) of Candidate Target or Uncertain,
respectively. Proceed to the next lake on the list. Lakes categorized as Candidate Target or
Uncertain will be evaluated further during the Desktop phase.
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List of candidate sites
(base and replacement) from survey design
i
Base list of candidate lakes for a State
(-50 lakes per State, 150 for MN)
NOTE: State sample size and lake list includes Tribal lakes,
wliich may i e<|iiiie sepal ate evaluation and sam pi in <| '
Select next
lake
Notify NLA
Design Team
(ORD-Cotvallis)
Does polygon
match lake shape?
Does lake name
match NHDname?
Desktop Evaluation
GIS Status=
Candidate Target
Determine and ]
assign lake origin '
(if possible)
Assign final
status of
Nontarget
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Figure 3. CIS-based evaluation.
2.4 Desktop Evaluation (Q2, Q4-6)
Continue the second phase of the evaluation process to complete the evaluation questionnaire for any
remaining lakes assigned an interim status of Uncertain during the GIS-based phase. For the desktop
evaluation, the master evaluation file will be split into separate files for each state. The general process
for conducting the desktop phase is presented in Figure 4. Use a variety of available information sources
to proceed through the evaluation questionnaire (Figure 2). Google Earth" and other ancillary layers
(e.g., Wikipedia , Panoramic photos, geographic features, etc.) may provide sufficient information to
answer all of the questions in the evaluation questionnaire successfully. A Google Earth" kmz (or kml)
file of all lake polygons is available.
In addition to Google Earth", conduct Web searches for each remaining lake based on the lake name or
location information to try to answer the questions in the evaluation questionnaire and assign a final
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status category for each lake. Some lakes may require an investigation of maps, reports, or
conversations with local experts who are familiar with the current conditions of the lake being
evaluated. Obtaining information from local experts will help to minimize the number of lakes that will
require a field visit. If possible, determine the lake origin using these resources. For a run-of the river
reservoir, it is important to determine if the estimated residence time is greater than 1 week; if less, it is
considered to be nontarget and requires replacement.
For the NLA, the status of a lake is that existing in the year (and ultimately on the day) of sampling.
There will be lakes (more likely smaller ones) that will meet the target criteria one year but not meet
them in another year due to precipitation (or lack of) or other natural causes. Temporary changes to a
lake's status due to deliberate management/restoration activities (e.g., weed control, rotenoning,
dredging, etc.) do not render a lake as nontarget for that year. Criteria pertaining to open water area
and maximum depth may not be able to be determined until you actually visit the lake to sample. Note
that the open water criterion is based on a total area of 1000 m2; and does not have to be continuous.
In some areas, there is the possibility that neighboring lake basins may become joined during periods of
heavy precipitation, and this will be evident from the available images. In these cases, treat the
combined lakes as a single waterbody and sample it if it meets the target criteria. Do not just consider
the part of the lake represented by the NLA polygon. Note the presence of the combined waterbodies
and the reason (e.g., is it temporary or does it appear to be a permanent change). Notify the NLA design
staff in Corvallis so that the sample/analysis frame can be adjusted if necessary.
There is also the possibility that a single lake may become divided into two or more neighboring basins
because of drought conditions. You must look at the NLA polygon coverage and determine which basin
has the NHDPIus labeling point associated with it and treat this basin as the "official" lake for the
purposes of evaluating and sampling in 2012. If the basin meets the target criteria, sample it (but not
any of the neighboring basins). If the basin does not meet the target criteria, assign it as non-target and
select a replacement lake. In either case, note the presence of the separated waterbodies and the
reason (e.g., is it temporary or does it appear to be a permanent change). Notify the NLA design staff in
Corvallis so that the sample/analysis frame can be adjusted if necessary. Lakes on Tribal lands require
some additional considerations. Tribal lakes are included as parts of individual state lists (and are part of
the total sample size assigned to the state). Tribal lakes need to be evaluated by someone (the Tribal
nation, EPA Region, State, or a third party), and a final status assigned. For lakes identified as target,
distinguish between those lakes where no permission to sample was ever sought (Tribal-Other), from
lakes where permission was requested from a Tribal nation, but was not granted (Target-Access denied).
At this phase of the evaluation, you should begin to compile a dossier of access-related information for
each lake that has been definitively identified as target and accessible. This information includes any
issues associated with accessing the lake such as steep terrain; livestock; thick, nuisance vegetation;
locked gates and the presence and type of boat ramps available at a lake. You can obtain some of this
information from a local expert during the Desktop phase, from the Field evaluation (if needed), or
when you attempt to obtain permission to sample a lake (Section 4.0). Lakes that are still assigned a
status of Uncertain after the Desktop evaluation phase are moved to the Field evaluation phase of the $
evaluation process. o
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Base list of remaining
candidate lakes for a State or Tribe
(GIS Status assigned)
NOTE: Suite sample sizeiind Like list includes Tribal kikes.
which may lequiie separate evaluation and sampling
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Desktop Evaluation (EPA Regions/States/Tribes)
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available
replacement lake
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Final status=
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Inaccessible
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2.5 Field Evaluation (Q2, Q4-6)
Continue the third phase of the evaluation process to complete the evaluation questionnaire for any
remaining lakes assigned an interim status of Uncertain during the Desktop phase. The general process
for conducting the Field phase is presented in Figure 5. The field evaluation phase differs from previous
phases in that lakes whose status is still uncertain after a field visit are considered candidate target
lakes. The final status of these lakes may not be determined until a field crew actually visits the lake with
the intent to sample it.
Get as close as you can to the lake during a field visit. For remote lakes, this may require hiking to, or
possibly flying over, the lake. For other lakes, you may be able to drive near the lake and use binoculars
to conduct the evaluation. Determine the lake origin during the field visit if it has not been determined
in a previous phase. While at the lake, remember to gather information that will be useful to a field crew
when they come to sample it (e.g., launch facilities, surrounding terrain, best access routes, etc...).
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After completing the field evaluation phase, you will have a list of candidate lakes that are physically
accessible. The last phase of the process involves obtaining access permission for those lakes that
require it.
List of candidate lakes for a State or Tribe
Status after CIS and Desktop phases=
Uncerra/n
NOTE: State sample size
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3 DETERMINING IF A LAKE is PHYSICALLY ACCESSIBLE (Q6)
Lakes for the National Lakes Assessment were selected from the population of lakes across the U.S.
through a probabilistic survey design. In order to achieve the most robust results possible with the
probabilistic sampling design, a concerted effort is required to sample the base lakes on your list.
It is very important not to reject a lake that meets the criteria for the target population based on
inconveniences in access. At some lakes, a field crew can drive its truck to a boat ramp and launch.
Other lakes may require a lengthy hike or portage with a small boat. Some lakes in extremely remote
areas are impossible to safely access (e.g., trail conditions, temperature extremes). A lake is considered
permanently inaccessible if it is unlikely to be sampled by anyone due to physical barriers that prevent
access (e.g., cliffs). Safety concerns that may prohibit access include the presence of dangerous wildlife
or potentially threatening groups of people.
3.1 Target, Inaccessible-Barrier/Safety
Occasionally, a lake is determined to be target, but cannot be sampled due to physical barriers or safety
concerns. Assign these lakes a response of NO to 0.6, Target to 0.9, and Inaccessible-Barrier/Safety to
Q10 (Figure 2). Describe why the lake is inaccessible in the COMMENTS column of the evaluation
spreadsheet. You will then need to select and evaluate a replacement lake.
3.2 Target, > 1 Day Needed
Very large lakes may require either more than one day to sample completely (including travel time), or
require more than one field crew to complete the sampling in a single day (including shoreline stations.
Assign these lakes a response of YES, BUT > 1 DAY/CREW NEEDED to Q6 (Figure 2). If you determine that
these lakes cannot be sampled, assign a response of Target to Q9 and a final status of TargetOtherior
Q10. Remember that on large lakes (>10,000 ha), shoreline stations are not established, so these lakes
should be sampled at the index site if at all possible.
3.3 Target, Extreme Effort Required, Inaccessible-Effort
Some remote lakes may be physically accessible, but the effort required to reach them to sample is
prohibitive in terms of the time and or cost required, or because an extreme effort (in terms of time
^j- and/or cost), as opposed to inconvenience, is required to obtain access. Assign these lakes a response
2. of YES, BUT EXTREME EFFORT IS REQUIRED to 06, Target to 09, and Inaccessible-Effort to Q10 (Figure
J5 2). Describe the extreme effort constraint (i.e., the time or cost that would be needed) in the
'y, COMMENTS column of the evaluation spreadsheet. You will then need to select and evaluate a
y replacement lake.
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4 OBTAINING PERMISSION TO ACCESS CANDIDATE LAKES (Q7)
Many of the lakes will be publicly accessible with either boat ramps or convenient small boat access. In
these cases, explicit permission to access the lake is not needed and little prior work needs to be done
outside of determining the best access routes for the sampling crew. However, for those lakes on
privately owned land, landowner permission is required to obtain access and sample these lakes.
Obtaining permission well in advance of the sampling day is important to minimize loss of time on the
part of the field team. Many states have an existing protocol for securing landowner permission; if this is
the case for your state, use the existing protocol for this study.
4.1 Identify Landowner
The initial lake list file contains an initial assignment of ownership as federal (and which agency has
jurisdiction), non-Federal, or possibly Tribal. For non-Federal ownership, determine whether the lake is
publicly accessible or located on private property. If the lake is on private property, you will need to
obtain the name and address of the landowner. Some states or EPA Regions may provide you with
additional identification of public versus private lakes and some landowner information. If no landowner
information was obtained for a lake, contact the county office. The county office can direct you to the
agency that is responsible in your state/county for holding landowner records, and you can work with
the appropriate agency to obtain the information.
Be aware that this process can be time consuming, as you may need to work with several different
agencies and numerous people. Be prepared to submit maps via fax machine, as some counties do not
have landowner information in a GIS database and are unable to use coordinates to obtain the
information. In addition, if your state or county uses the township/range/section system for identifying
parcels of land, you will need to know this information for your lake also, and this may require
contacting yet another agency. You may need to visit the records office to obtain this information. Each
county will be different in terms of the organization of its records and its ability (and willingness) to
assist you.
4.2 Request Permission to Access Lake
Once you identify the landowner and confirm that a lake is part of the target population and is physically ___
accessible, you can begin to request permission to access and sample the lake following whatever ^
protocol is in effect for your organization. If no protocol exists, use the most personal contact j/>
practicable. Obtaining permission (or denial) early does provide you with more time to select and -%
evaluate any replacement lakes before sampling begins.
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fieldwork in the area that is occurring before the NLA sampling begins. This would maximize
efficiency and ensure the best possible responses from the landowners.
4.2.2 Contact Landowner through Other Means
If you cannot visit the landowner to obtain permission, attempt to contact him or her by telephone. A
local representative may be more effective in securing permission, so it is important to request
assistance at this level if you are not local to the area. If you cannot reach the landowner by telephone,
prepare and mail out a cover letter (Appendix A: Example Letter requesting Permission to Access a
Lake) with an updated fact sheet (Appendix D: National Lakes Assessment 2012 Fact Sheet) and a
permission slip (Appendix B: Example Landowner Permission Slip) for the landowner to return.
4.2.3 Signed Permission Slip
A signed permission slip is important for the field crew to use as documentation on the day of sampling
if questions arise about the field crew's presence on a lake.
4.3 Denials
If one landowner denies access, check to see if there are other landowners that may allow access to the
lake via their property. If no other landowner options exist, or all other landowners deny access, select
NO as the response to Q7, Target as the response to Q9, and Access Denied as the response to Q10 in
the evaluation spreadsheet (Figure 2). Select the next available replacement lake to evaluate. For
landowners contacted by phone or mail, no response is considered denial.
4.4 Frequently Asked Questions
Some frequently asked questions pertaining to the overall evaluation process are presented in Appendix
D. Use this as the first resource to try to answer any questions that may come up as you attempt to
evaluate a lake. If you cannot find an answer there, contact the EPA NLA Regional Coordinator
(Appendix E: Contacts). He or she will either answer your question or pass it along to someone who can
answer it.
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5 LITERATURE CITED
Stevens, D. L, Jr. and A. R. Olsen. 2004. Spatially balanced sampling of natural resources. Journal of the
American Statistical Association 99:262-278.
USEPA (United States Environmental Protection Agency). 2006. Survey of the Nation's lakes: lake
evaluation guidelines. EPA841/B-06/003, U.S. Environmental Protection Agency, Office of Water
and Office of Environmental Information, Washington, DC.
USEPA (United States Environmental Protection Agency). 2009. National Lakes Assessment: a
collaborative survey of the Nation's lakes. EPA 841/R-09/001, U.S. Environmental Protection
Agency, Office of Water and Office of Research and Development, Washington, DC.
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APPENDIX A: EXAMPLE LETTER REQUESTING PERMISSION TO ACCESS A LAKE
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(Date)
Dear Landowner,
The US Environmental Protection Agency, in cooperation with State Agencies, is conducting an
environmental assessment of lakes across the United States. A computer was used to randomly select
these lakes. A total of 910 sampling lakes were selected for sampling in 2012. Water quality, chemistry,
aquatic life, recreation use and habitat will be evaluated at each lake. The findings of the study will be
used to give a broad scale picture of the health of our nation's lakes and are not intended for
enforcement or regulatory purposes.
We are contacting you to request your permission to access a lake from your property. We will respect
your landowner rights at all times, ensure that you know in advance when the sampling will occur, and
recognize that access to your property is a privilege granted by you. The sampling of your lake will be
used to help guide the protection of waters across the United States.
Enclosed with this letter is a map of the sampling location and an Access Permission Form. Please return
the completed Form in the enclosed, postage paid envelope by (DATE). If you have any questions
concerning this request, please feel free to contact me at (phone / e-mail). I look forward to your reply
and appreciate your help in this important survey.
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APPENDIX B: EXAMPLE LANDOWNER PERMISSION SLIP
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I grant permission to the biological field crew from (state agency or contractor) to access the lake
sampling lake located on my property as part of the EPA's National Lakes Assessment project.
Do grant permission
Do grant permission but with the following restrictions:
Do not grant permission
Landowner Name (Please print):
Landowner Signature:
Date:
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APPENDIX C: NATIONAL LAKES ASSESSMENT 2012 SURVEY DESIGN
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NATIONAL LAKES ASSESSMENT 2012 SURVEY DESIGN
Target Population
All lakes, reservoirs, and ponds within the 48 contiguous United States greater than 1 hectare in surface
area that are permanent waterbodies. The word "lake" in the remainder of this document includes
lakes, reservoirs and ponds. Lakes that are saline are excluded as are those used for aquaculture,
disposal-tailings, sewage treatment, evaporation, or other unspecified disposal use.
Sample Frame
The sample frame was derived from the National Hydrography Dataset (NHDPIus). Once the initial
shapefile that included all lake objects in NHDPIus was prepared additional attributes were created to
identify lakes included in the sample frame and other properties used to construct the survey design.
Lakes included in the sample frame were those lakes with DES_FYTPE values equal to:
Lake/Pond
Lake/Pond: Hydrographic Category = Perennial
Lake/Pond: Hydrographic Category = Perennial; Stage = Average Water Elevation
Lake/Pond: Hydrographic Category = Perennial; Stage = Normal Pool
Reservoir
Reservoir: Reservoir Type = Water Storage
Reservoir: Reservoir Type = Water Storage; Hydrographic Category = Perennial
Lakes excluded in the sample frame were those lakes with DES_FYTPE values equal to:
Lake/Pond: Hydrographic Category = Intermittent
Lake/Pond: Hydrographic Category = Intermittent; Stage = Date of Photography
Lake/Pond: Hydrographic Category = Intermittent; Stage = High Water Elevation >
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Reservoir: Reservoir Type = Cooling Pond
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Finally, lakes that were less than or equal to 1 hectare were excluded.
Survey Design
A Generalized Random Tessellation Stratified (GRTS) survey design for a finite resource was used with
stratification and unequal probability of selection. The design includes reverse hierarchical ordering of
the selected lakes.
Stratification
The survey design was stratified by state and by NLA12_CLS. NLA12_CLS has three classes:
1) NLA07RVT - defined as all NLA 2007 lakes that were target and sampled,
2) NLA12NEW - remaining lakes in NHDPIus that are included in the sample frame, and
3) Exclude - lakes in NHDPIus that are excluded from the sample frame (see Sample Frame
section above).
Each state design has two strata, ST_ NLA07RVT and ST_ NLA12NEW (where ST is replaced by the two
letter state abbreviation. The total number of strata is 96 (two for each state).
Unequal Probability Categories
The 48 state strata for lakes from the NLA 2007 that would be revisited in 2012 was an equal probability
design within each stratum. The 48 state strata NLA12NEW was an unequal probability design within
each state stratum. The unequal probability categories were defined based on lake area: 1 to 4 ha, 4 to
10 ha, 10 to 20 ha, 20 to 50 ha and greater than 50 ha.
Panels
The survey design has four panels: NLA07RVT - identifies lakes from NLA 2007 that will be visited in
2012, NLA12NAT - identifies new lakes that will be sampled along the lakes in panel NLA07RVT as part
.50 of the NLA2012 national survey design, NLA12ST- identifies additional lakes that a state may sample to
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<|J achieve a total sample size of 50 lakes for the state, and OverSamp - identifies lakes to be used to
>• replace lakes that cannot be sampled for some reason (not a lake, denied access, physically inaccessible,
£ etc).
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° NLA12NEW.
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maximum at 43 (column F). Although aggregated ecoregions were not explicitly used in the survey
design or setting sample sizes, they are implicitly used since the NLA 2007 allocated sample sizes using
aggregated ecoregions. Once these two sample sizes were set for a state, an additional sample size
(column I) was allocated to a state so that the total number of sites in a state would be 50 lakes.
Lakes in the NLA 2007 Revisit stratum were selected with equal probability and did not depend on lake
area. Note that the NLA 2007 did depend on lake area. New lakes in the design were selected with
unequal probability based on five lake area categories. The total number of lakes for a state in this strata
(sum columns D, E, and I) was divided by five and that sample size (approximately) was assigned to the
"(10, 20]" lake area category. Sample sizes for lake area categories "(20, 50]" and ">50" were decreased
successively by one and for lake area categories "(4, 10]" and "(1, 4]" were increased successively by
one. This process was adjusted to meet the total sample size requirement for the stratum. The rationale
for this assignment of sample sizes is based on experience that smaller lakes are more likely not to be
lakes or be inaccessible than larger lakes. When lakes are replaced, the process is expected to more
likely result in an equal number of lakes sampled by lake area category.
Lake Use and Replacement
Each lake selected to be sampled is given a unique site identification (sitelD). Site numbers consist of
NLA12_ST-XXX where ST is the two letter state abbreviation and XXX is a number between 101 and 999.
It is critical that this site ID be used in its entirety to make sure that the lakes are correctly identified.
Within each state, lakes evaluated for potential sampling must have all site IDs from the largest to the
lowest number evaluated. For example, if NLA12_AL-0155 is the largest site ID evaluated within
Alabama, then all site IDs that are lower than "0155" within the state must be evaluated. Even more
critical is that if NLA12_AL-0155 is the largest site ID that is actually sampled in the field, then all lower
site IDs within the state that are evaluated to be a target lake and are accessible must be sampled in the
field.
National Design Lakes and Replacement Process
Lakes scheduled to be sampled for the national design are identified by the attribute "panel" having .5P
values of "NLA07RVT2," "NLA07RVT," "NLA12RVT" and "NLA12NAT". These lakes must all be evaluated |j
and sampled if they meet the definition of a lake and are accessible. If one of these lakes cannot be >•
sampled for any reason, then the replacement lakes are taken within the state from the lakes for which £
"panel" is equal to "NLA12ST". The first replacement lake will be the lake within that list that has the £
lowest site ID; the second will have then next lowest site ID; etc. If all the lakes for which "panel" is Q
equal to "NLA12ST" have been evaluated and additional lakes are still required, then lakes are used from +^
lakes identified as "OverSamp" in "panel" in site ID order (i.e. lowest site ID within the OverSamp lakes £
within the state). The national design includes all lakes larger than 1 hectare. $
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Lakes designated "NLA07RVT2" and "NLA12RVT" are lakes that are to be sampled twice in 2012. If a lake £
designated "NLA07RVT2" cannot be revisited, then the next lake designated as "NLA07RVT" should be £
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sampled twice. If a lake designated "NLA12RVT" cannot be revisited, then the next lake designated as jo
"NLA12NAT" should be sampled twice. In each case the same process is used if the second lake cannot ft
be sampled. .9.
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State Design L akes an d Replacem en t Process -
If a state implements a state level design with 50 lakes, then the lakes scheduled to be sampled for the .^
state design are identified by the attribute "panel" having values of "NLA07RVT2," "NLA07RVT," <=
"NLA12RVT," "NLA12NAT" and "NLA12ST.". These lakes must all be evaluated and sampled if they meet §:
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the definition of a lake and are accessible. If one of these lakes cannot be sampled for any reason, then
the replacement lakes are taken within the state from the lakes for which "panel" is equal to
"OverSamp.". The first replacement lake will be the lake within that list that has the lowest site ID; the
second will have then next lowest site ID; etc.
If a state implements a state level design and elects not to include 1-4 hectare lakes in the state design,
then the state must first follow the procedures for the national design, which includes 1-4 hectare lakes.
After the required number of lakes for the national design is sampled, then the remaining lakes for the
state design may exclude 1-4 hectare lakes during the lake evaluation process. Otherwise the lake
replacement process follows the procedure described in the previous paragraph.
Sample Frame Summary
See accompanying spreadsheet NLA2012 Design Summary 20110320.xlsx
Site Selection Summary
See accompanying spreadsheet NLA2012 Design Summary 20110320.xlsx
Description of Sample Design Output
The dbf file for the shapefile ("NLA Lake Sites Final") has the following variable definitions:
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mdcaty Categories used for unequal probability selection within a stratum.
wgt Weight (number of lakes) to be used in the statistical analyses. It is the inverse of the
inclusion probability.
stratum Strata used in design. All equal to NLALake.
panel Panel_l identifies the 1000 lakes in the base design. Oversamp identifies lakes to be used as
replacements as necessary.
EvalStatus Placeholder to record the results of the lake recon evaluation (see below).
EvalReason Placeholder to record reason for the evaluation result.
COMID From original NHD lake frame shapefile.
FCODE NHD feature code field.
FTYPE NHD feature type field.
DES_FTYPE Design Ftype based on NHD Ftype.
REACHCODE NHD Reach code.
NLA07_RCHC NHD reach code from NLA 2007 sample frame.
COMID2007 NHD COMID from NLA 2007 sample frame (primary).
COMIDs2007 NHD COMIDs from NLA 2007 sample frame when multiple polygons from 2007 sample frame
were combined for 2012 sample frame.
GNISJD GNIS identification.
GNIS_Name GNIS name.
LAT_DD_N83 Latitude in decimal degrees from NHD.
LON_DD_N83 Longitude in decimal degrees from NHD.
X_ALBERS X-coordinate from Albers projection for latitude above.
Y_ALBERS Y-coordinate from Albers projection for longitude above.
STATECTY FIPS state and county code.
ST State two-letter codes for all states in which lake polygon occurs.
ST_NLA2012 State lake is assigned to for NLA 2012.
STATE_PCNT Percent of lake area that occurs in state.
BORD_LAK State border lake = Yes; state non-border lake = No.
CNTYNAME County name.
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NESLAKEJD
STORETNUM
NES lake identification number.
STORE! number for NES Lake.
Projection Information
PROJCS["USA_Contiguous_Albers_Equal_Area_Conic",
GEOGCS["GCS_North_American_1983",
DATUM["D_North_American_1983",
SPHEROID["GRS_1980",6378137.0,298.257222101]],
PRIMEM["Greenwich",0.0],
UNIT["Degree",0.0174532925199433]],
PROJECTION["Albers"],
PARAMETER["False_Easting",0.0],
PARAMETER["False_Northing",0.0],
PARAMETER["Central_Meridian",-96.0],
PARAMETER["Standard_Parallel_l",29.5],
PARAMETER["Standard_Parallel_2",45.5],
PARAMETER["Latitude_Of_Origin",37.5],
UNIT["Meter",1.0]
Evaluation Process
The survey design weights that are given in the design file assume that the survey design is implemented
as designed. Typically, users prefer to replace sites that cannot be sampled with other sites to achieve
the sample size planned. The site replacement process is described above. When sites are replaced, the
survey design weights are no longer correct and must be adjusted. The weight adjustment requires
knowing what happened to each site in the base design and the over sample sites. EvalStatus is initially
set to "NotEval" to indicate that the site has yet to be evaluated for sampling. When a site is evaluated
for sampling, then the EvalStatus for the site must be changed. Recommended codes are:
60
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2012 National Lakes Assessment Site Evaluation Guidelines
Version 1.1, September 26, 2012 Page 37 of 42
APPENDIX D: NATIONAL LAKES ASSESSMENT 2012 FACT SHEET
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2012 National Lakes Assessment Site Evaluation Guidelines
Version 1.1, September 26, 2012 Page 38 of 42
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2012 National Lakes Assessment
Version 1.1, September 26, 2012
Site Evaluation Guidelines
Page 39 of 42
&EPA
United Stales
Environmental Protection
Agency
National Lakes Assessment 2012:
A Fact Sheet for Communities
During the summer of 2012, the U.S. Environmental
Protection Agency (EPA), states, tribes and other part-
ners will conduct the second nationwide survey of the
condition of the nation's lakes. The National Lakes As-
sessment (NLA) will help citizens and governments
measure the health of our waters, take actions to pre-
vent pollution, and evaluate the effectiveness of pro-
tection and restoration efforts. The NLA 2012 is one in
a series of national surveys of the condition of the na-
tion's waters (see www.epa.gov/aquaticsurveys).
Designed to estimate the percentage of lakes that are
in good, fair, or poor condition, the survey will serve as
a scientific report card on America's lakes. It will exam-
ine ecological, water quality, and recreational indica-
tors, and assess how widespread key stressors (such as
nitrogen, phosphorus, and acidification) are across the
country.
The survey is a collaborative effort that involves dozens
of state environmental and natural resource agencies,
9 the National Lakes /
federal agencies, universities and other organizations.
In most states, state water quality staff will conduct the
water quality sampling and habitat assessments.
How were the lakes selected?
Design Sites for the
2012 National Lakes Assessment
A total of 904 natural lakes, ponds, and res-
ervoirs across the lower 48 states are in-
cluded in the survey. To be included in the
survey, these lakes must be at least one
meter deep and over 2.5 acres (1 hectare)
in size. The survey does not include the
G real La kes or the G real Sa It La ke. La kes
were selected randomly using a statistical
survey design to represent the population
of lakes in their ecological region -the geo-
graphic area in which climate, ecological
features, and plant and animal communi-
ties are similar. In addition to these 904
sites, some sites will be re-sampled for
quality assurance purposes: reference sites
representing least-disturbed conditions will
also be sampled.
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Distribution of base sites in the 2012 National Lakes Assessment.
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2012 National Lakes Assessment
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Site Evaluation Guidelines
Page 40 of 42
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What about my lake?
If your lake is sampled for this survey, it was most likely part of the randomly selected sites based on the population
of lakes in your part of the country. There are a number of hand-selected sites (around 100), called reference sites,
included in the survey as representative of the least-disturbed condition. Sites were not selected because the lake
exhibits any particular problem or water quality condition. When the final report on the NLA 2012 is written, data
from your lake will contribute to the regional and national picture of lake condition.
If your lake is not sampled for this survey, it was not omitted for any particular reason, but rather because it was not
randomly selected or did not fit into the target population of lakes (e.g., those greater than 2.5 acres in area and at
least one meter deep).
Many volunteer monitoring groups and lake associations have years of sampling data for their lakes, data vital to lo-
cal lake management activities. This survey will provide a regional and national - and in some cases, statewide - as-
sessment of lake condition. It will also allow those with sampling data on their lake to compare the condition of their
lake to the range of lakes in their region or state.
O
What will researchers measure?
Field crews take many measurements at each selected lake. They use consistent procedures at all sites so that re-
sults can be compared across the country. They measure such things as:
• Temperature, dissolved oxygen, nutrients, chlorophyll a, water clarity, turbidity, and color
• Condition of the habitat alongthe shoreline
• Zooplankton and phytoplankton—microscopic animals and plants in the water that are an important part of the
food chain
• Aquatic macroinvertebrates—small animals such as insects and snails that are a source of food forfish and birds
• Microcystin—a common type of algal toxin, often associated with algal blooms in lakes
• Bacteria—indicators of fecal contamination from animals or humans
• Pesticide Screen—occurrence of common pesticides in water samples
They also take sediment cores from the bottom of the lake to look at sediment diatoms—or microscopic algae—
from present day and 100 years ago. This information allows scientists to evaluate nutrient changes over time.
For more informal on on the National
Lakes Assessment.indudingthe find-
ings of the 2007 survey:
www.epa.pQV/lakessiirvev
Or email us at:
ency
U.S. Environmental Protection
Office of Water
Monitoring Branch (4503T)
Washington, DC 20460
November 2011, EPA S41-F-11-007
What happens next?
Sampling is scheduled for
the summer of 2012.
EPA intends to issue a
report on the findings in
2014. Between the time
that lakes are sampled
and the national report is
published, samples will
be analyzed in the lab,
the data entered into a
database and analyzed,
and a draft report written
and reviewed. The public
will have the opportunity
to review and comment
on the draft report.
Lake sampled during the National Lakes Assessment in 2007.
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2012 National Lakes Assessment
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APPENDIX E: CONTACTS
Site Evaluation Guidelines
Page 35 of 42
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2012 National Lakes Assessment
Version 1.1, September 26, 2012
EPA HQ Project Lead
Amina Pollard, OW
EPA HQ NARS QA Lead
Sarah Lehmann, OW
EPA HQ Logistics Lead
Marsha Landis, OW
EPA ORD Site Evaluation
Coordinator
Dave Peck
Marc Weber
Contract Field Logistics
Coordinator
Chris Turner, GLEC, Inc.
NARS Information Management Marlys Cappaert, SRA
Coordinator International Inc.
EPA Regional NLA Coordinators Hilary Snook, Region 1
Site Evaluation Guidelines
Page 37 of 42
Contact Information
pollard.amina@epa.gov
202-566-2360
EPA Wetlands, Oceans, and
Watersheds
1200 Pennsylvania Ave NW
(4503T)
Washington, DC 20460
lehmann.sarah@epa.gov
202-566-1379
EPA Wetlands, Oceans, and
Watersheds
1200 Pennsylvania Ave NW
(4503T)
Washington, DC 20460
landis.marsha@epa.gov
202-564-2858
EPA Wetlands, Oceans, and
Watersheds
1200 Pennsylvania Ave NW
(4503T)
Washington, DC 20460
peck.david@epa.gov
541-754-4426
weber.marc@epa.gov
541-754-4469
cturner@glec.com
715-829-3737
cappaert.marlys@epa.gov
541-754-4467
541-754-4799 (fax)
snook.hilary@epa.gov
617-918-8670
EPA Region 1
11 Technology Drive
North Chelmsford, MA 01863
Jim Kurtenbach, Region 2
kurtenbach.james@epa.gov
732-321-6695
EPA Region 2
2890 Woodbridge Avenue
Edison, NJ 08837
Frank Borsuk, Region 3
borsuk.frank@epa.gov
304-234-0241
EPA Region 3
1060 Chapline Street, Suite 303
Wheeling WV 26003
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Site Evaluation Guidelines
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Marion Hopkins, Region 4
Contact Information
hopkins.marion@epa.gov
404-562-9481
EPA Region 4
61 Forsythe Street SW
Atlanta, GA 30303
Mari Nord, Region 5
nord.mari@epa.gov
312-886-3017
EPA Region 5
77 West Jackson Blvd
Chicago, IL 60604
Mike Schaub, Region 6
schaub.mike@epa.gov
214-665-7314
EPA Region 6
1445 Ross Avenue, Suite 1200
Dallas, TX 75202
Gary Welker, Region 7
welker.gary@epa.gov
913-551-7177
EPA Region 7
901 N. Fifth Street
Kansas City, KS 66101
Kris Jensen, Region 8
Jeff McPherson, Region 8
jensen.kris@epa.gov
303-312-6237
EPA Region 8
1595 Wynkoop Street
Denver, CO 80202
mcpherson.ieffrey@epa.gov
303-312-7752
EPA Region 8
16194 West 45th Drive
Golden, CO 80403
Sue Keydel, Region 9
keydel.susan@epa.gov
415-972-3106
EPA Region 9
75 Hawthorne Street
San Francisco, CA 94105
Lil Herger, Region 10
herger.lillian@epa.gov
206-553-1074
EPA Region 10
1200 Sixth Avenue, Suite 900
Seattle, WA 98101
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APPENDIX F: FREQUENTLY ASKED QUESTIONS
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2012 National Lakes Assessment Site Evaluation Guidelines
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2012 National Lakes Assessment Site Evaluation Guidelines
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Frequently Asked Questions
Q ~ If questions arise concerning lake status, who should I contact?
A ~ Please e-mail a detailed description of your concerns about the lake to your EPA Regional NLA
Coordinator and to Amina Pollard of the EPA Office of Water (Pollard.Amina@epa.gov ). They will
work with the EPA ORD lab to help you determine the final status of the lake.
Q ~ Some reservoirs may be < 1 m deep or < 1 ha in area late in the irrigation season - should
these lakes be sampled?
A ~ Reservoirs that are expected to be more than 1 m deep and more than 1 ha during the index
period (generally May through September) ARE part of the target population and should be
scheduled for sampling. However, on the day of the sampling visit, if the depth at the deepest point
is less than 1 m (or the lake area is < 1 ha), then the lake is assigned a status of Nontarget and is not
sampled. If time permits, select the next available replacement lake, evaluate it, and schedule it to
be sampled.
Q ~ What criteria should be used to determine if a lake should be dropped from the sample
population due to salinity?
A ~ Inland lakes that are saline or have high conductivity (>1000 u.S/cm) ARE part of the target
population, with the exception of the Great Salt Lake.
In the case of a coastal lake or lake adjacent to an estuary, tidally-influenced lakes are not part of
the target population. A tidally-influenced lake is operationally defined as being maintained solely
by the surface inflow of brackish or salt water due to water level changes during tidal cycles.
Permanent lakes near the coast or near an estuary below the head of salt, with no surface
connection to the ocean at high tide are considered part of the target population (even if saline).
Dune lakes (primarily located along the Gulf Coast), are part of the target population. These lakes
are permanent and almost always isolated from the ocean, but periodically will flood or "blow out"
forming a connection with the ocean or estuary and incur an influx of brackish or salt water.
Waterbodies along the coast that are considered to be estuarine or part of a larger coastal wetland
area are not part of the target population. These represent waterbodies that should be included in
the sampling frames for the National Coastal Condition Assessment or the National Wetlands
Condition Assessment.
Q ~ Should oxbows, backwaters, and side-channel reservoirs be sampled?
A ~ Oxbows ARE lakes if they are separated from a river. However, oxbows that have either flowing
water or a wetland connection to a river are NOT lakes. Side-channel reservoirs and drinking water
reservoirs where water is pumped from a ne
uses ARE NOT part of the target population.
Q ~ Should ephemeral lakes be sampled?
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A ~ Ephemeral lakes are operationally defined as being highly likely to be dry during the index
period of the sampling year, but you may not be able to make this decision until you actually visit
the lake to sample it. Lakes that do not meet the inclusion criteria on the date of a sampling visit
ARE NOT part of the target population.
Q ~ Should mining pits be sampled?
A ~ Actively used quarry pits, mine tailing disposal lakes, borrow pits, and stormwater treatment
ponds ARE NOT in the target population. Abandoned mine lakes that are used for recreation or
other beneficial uses (e.g., wildlife) ARE part of the target frame. The lake evaluation spreadsheet
includes a place (Q8) to note lake origin to assist in data interpretation.
Q ~ What constitutes difficulty of access in sampling a lake?
A ~ The objective of the National Lake Assessment is to sample lakes that are representative of the
full range of conditions found across the country. Therefore, make a concerted attempt should to
sample remote lakes that are identified as being part of the target population. Lakes that pose
safety risks because of their remoteness, or where the cost and effort required are prohibitive in
terms of completing the rest of the NLA sampling, are considered to be target but not accessible and
are replaced with a lake from the oversample list.
It is recognized that sampling remote lakes may result in samples being shipped and/or received
past the target holding times (esp. for water chemistry). As long as you can keep the samples cold
and in darkness (or as close to frozen as possible if the sample requires it), there is a high probability
that the samples will maintain their integrity past the target holding times.
Q ~ What if extreme weather hits, the lake is in flood stage, or there are other unsafe conditions?
A ~ If it is unsafe to sample the lake and the lake cannot be re-scheduled within the index period,
then it is removed from the draw and the next lake on the oversample list is chosen.
Q ~ What if boats are not allowed on a publicly-accessible lake?
A ~ Try to gain permission to sample by boat or other means such as rafts. If permission cannot be
§ obtained, then assign the lake a final status of Target Other and select a replacement lake from the
" oversample list.
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^. until the replacement is assigned by my Regional Lake Coordinator?
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QJ A ~ If a lake is dropped, replace it with the first available site on your state's oversample list and
g" conduct a GIS (if necessary), desktop and/or field evaluation; DO NOT skip lakes on your oversample
LL list. Please report the dropped lake to your Regional NLA Coordinator as soon as possible.
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