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Map of 2003 EMAP sites in Wyoming.


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There is a USGS Water Science Center office in each State. Washington Oregon California Idaho Nevada Montana Wyoming Utah Colorado Arizona New Mexico North Dakota South Dakota Nebraska Kansas Oklahoma Texas Minnesota Iowa Missouri Arkansas Louisiana Wisconsin Illinois Mississippi Michigan Indiana Ohio Kentucky Tennessee Alabama Pennsylvania West Virginia Georgia Florida Caribbean Alaska Hawaii New York Vermont New Hampshire Maine Massachusettes South Carolina North Carolina Rhode Island Virginia Connecticut New Jersey Maryland-Delaware-D.C.
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Wyoming Department of Environmental Quality

Aquatic Ecology Monitoring and Assessment (EMAP)

The following information is from the draft Region 8 Surface Waters Plan for EMAP (U.S. EPA, 2000). The Environmental Monitoring and Assessment Program was developed in EPA's Office of Research and Development (ORD) to monitor status and trends in the condition of the nation's aquatic ecological resources at regional and national scales. The EMAP Western Pilot (Western EMAP) is a five-year effort (1999-2003) by EPA Regions 8, 9, and 10 in partnership with States, Tribes and other parties to advance the science of aquatic ecosystem health monitoring and to demonstrate the applicability and usefulness of EMAP indicators in environmental assessments. Western EMAP is intended to demonstrate the value of monitoring based on a randomized design in the western United States by applying these techniques to assessment questions of regional and state interest.

EMAP sample sites are selected with a stratified randomized design that uses the EPA River Reach File (RF3) as the hydrographic base layer ("the sampling frame"). EMAP uses a statistical sampling design based on a systematic grid, which provides uniform spatial coverage and ensures that each ecological resource is sampled in proportion to its geographical presence. There will be at least 50 stream sites sampled in each western state over a 5-year period, providing 12 independent state reporting units. The design will also permit the combination of results into a Regional and West-wide assessment of flowing waters (rivers and streams), or to divide the West into other assessment units  (e.g., ecoregions, river basins, etc.), providing there are a sufficient number of sites in these units. Comprehensive assessments resulting from the Western EMAP will serve as a baseline against which future assessments can be compared in order to reveal improvements in biological conditions resulting from regulation and restoration efforts.

Previous EMAP efforts have revealed that error rates within RF3 can be very high, including errors of inclusion (where digital maps show a stream trace, but no stream actually exists, a common error in arid areas), and errors of exclusion (where more streams exist than are mapped). One of the goals of Western EMAP is to make accurate estimates of these error rates for the western U.S. This is important because RF3 is the common sample frame used by States and EPA's Office of Water to estimate the number of miles of streams in a state. 
The base sampling design will allow comparisons to be made across Region 8 (Colorado, Montana, Wyoming, South Dakota, North Dakota, Utah) and across EPA Regions 8, 9 and 10. This will be accomplished by allocating approximately 50 sites per State (Table 1) over a four-year sampling period (beginning in the year 2000). Because randomly selected sites may have problems for a variety of reasons (e.g., site access, safety, RF3 errors, impoundment), the initial design will over-select sites to ensure that a sufficient number of target sites are chosen. 

Table 1. Expected sample sizes by state for base EMAP, the Upper Missouri River  Basin Focus Area, including Regional EMAP (REMAP) sites.
State Base EMAP (Overlay with Focus area and REMAP) Missouri Basin
Focus Area
N. Glaciated plains REMAP Interior CO Plateau REMAP Focus area plus REMAP overlap Total discounted for overlap with base EMAP
Colorado 50 (6) -- -- 29 -- 73
Utah 50 (14) -- -- 48 -- 84
North Dakota 50 (41) 37 37 -- 10 93
South Dakota 50 (50) 57 6 -- 39 102
Montana 50 (33) 120 -- -- -- 137
Wyoming 50 (24) 61 -- -- -- 87
Region 8 300 (162) 275 43 77 49 576

View maps depicting proposed sampling locations in Wyoming.

The second relevant scale, the focus area, is based on the desire of Region 8 to better characterize the ecological conditions of aquatic resources in the Upper Missouri River Basin. This focus area will be sampled over the same four-year period as the base sample sites. Resources to be examined within the Upper Missouri River Basin focus area include streams, large rivers, mainstem Missouri River Reservoirs and riverine wetlands. For streams and rivers (excluding the mainstem Missouri River), about 275 sites will be sampled within the Upper Missouri River Basin.

In Region 8, the surface water program will be integrated with Western EMAP's landscape characterization program. The objectives of this integrated effort are to quantify and validate watershed-level indicators of ecological condition, identify areas contributing the most to nonpoint source pollution, and to identify factors contributing to water quality impairment and stream habitat degradation (e.g., through correlative analyses with landscape indicators).

Biotic assemblages and their physical and chemical habitat vary among seasons and among years at each site. To minimize the effect of temporal variation at each site, samples will be collected during a restricted "index" period. Index periods are selected based on logistical (safety, accessibility to sites) and biological criteria (development of biotic assemblages). While short index periods of a few weeks may be ecologically optimal, logistic considerations make a longer index period preferable. For the past and ongoing REMAP projects in Region 8, the index period is in late summer and early fall. 

The Corvallis Laboratory of EPA's Western Ecology Division (WED) will have primary responsibility for data management for Western EMAP. WED will provide standardized field data sheets. The field data sheets will be returned to Corvallis where they will be optically scanned and entered into the EMAP database by WED. All data collected by this study will be publicly available following verification and validation of the data sets. Data will be made available over the EMAP Website and through the STORET database.

All data sets generated by this study will be made available on the EMAP public web site. These data sets will be described (metadata) and a quality assessment provided. All such data set descriptions will be made available for inclusion in the EMAP Data Directory/Data Catalog, accessible on the EMAP web site. In addition, steps will be taken to assure their continuing availability.

References Cited:

Peck, D.V., Lazorchak, J.M., and Klemm, D.J., in prep., Environmental Monitoring and Assessment Program—Surface waters—Western Pilot Study field operations manual for wadable streams [Draft, April 2000]: Corvallis, Ore., U.S. Environmental Protection Agency, 230 p.


Scientific Investigations Report 2006-5117: Comparison of Macroinvertebrate Community Structure between Two Riffle-Based Sampling Protocols in Wyoming, Colorado, and Montana, 2000-2001 by David A. Peterson and Jeremy R. Zumberge

Abstract: Peterson, D.A., Wright, P.R., and Zumberge, J.R., A Case Study for Comparison of NAWQA and EMAP Protocols for Benthic Macroinvertebrates and Habitat: San Jose, Calif., National Water-Quality Monitoring Council, 5th National Monitoring Conference, May 7-11, 2006. View a poster presented at the conference: Sheet 1 (PDF 1.21 mb), Sheet 2 (PDF 1.65 mb)

To view the PDF document, you need the Adobe Acrobat® Reader installed on your computer. (A free copy of the Acrobat® Reader may be downloaded from Adobe Systems Incorporated.)

Scientific Investigations Report 2007-5130: Ecological Status of Wyoming Streams, 2000–2003 by David A. Peterson, Eric G. Hargett, Peter R. Wright, and Jeremy R. Zumberge


Jill Frankforter
Supervisory Hydrologist
3162 Bozeman Avenue
Helena, MT 59601
(406) 457-5917
Email: jdfrankf@usgs.gov

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