Environmental Monitoring and Assessment Program (EMAP)

Objectives of EMAP Monitoring

DEQ’s monitoring in the US Environmental Protection Agency’s (EPA) Environmental Monitoring and Assessment Program (EMAP) uses a probabilistically based monitoring design in order to make statistically valid, regional descriptions of the conditions of streams and rivers. This approach is similar to how public opinion polls are conducted for large groups of people. EMAP is an EPA-funded program to help states better assess and report on the condition all their waters. The EMAP approach assesses the condition of water bodies using a range of indicators including biological condition, chemical water quality and physical habitat condition. More can be learned about EMAP from the EPA's EMAP web page. EMAP is administered by the EPA’s Research Laboratory in Corvallis, Oregon.

Oregon Plan for Salmon and Watersheds monitoring by DEQ and ODFW have used the EMAP probabilistic survey approach extensively to make regional descriptions of stream conditions.

Extent of DEQ’s Past EMAP Monitoring

Since 1994 DEQ had received several EPA grants to fund EMAP monitoring programs to assess the condition of wadeable streams in a number of ecoregions and basins across the state. Monitoring reports are available on the Oregon Coast Range, and the Upper Deschutes basin vertebrates, temperature, and water quality. DEQ also participated in a 5 year EMAP survey of the streams and rivers of the 11 western states. The report on Oregon’s portion of this monitoring is in progress and the completed report should be available on this web site soon.

Extent of DEQ’s Future EMAP Monitoring

EPA’s EMAP program has changed to a notational scale monitoring program. Starting in 2007 EPA will be collecting data to report on the status of all the water resources on a nation-wide scale using a probabilistic survey approach. Different water body types will be surveyed in different years on a repeating 5-year rotation. Monitoring will be done by state water quality agencies or EPA. The following is the monitoring rotation schedule:

2007 Lakes and reservoirs
2008 Large rivers
2009 Wadeable streams
2010 Coastal waters and estuaries
2011 Wetlands

The national-scale EMAP assessment will not result in enough random sample locations in Oregon and most other states for an adequate assessment of water resources on a state-wide scale. A minimum random sample of 50 samples is needed to describe a population with a confidence interval of approximately + 10%. Smaller sample sizes result in larger confidence intervals that make the condition estimates less useful.
DEQ’s Watershed Assessment program will participate in the 2007 EMAP lake monitoring work. It is not clear at this point if DEQ’s commitment to this program will continue beyond 2007.