Science Inventory



The purpose of this research project is to provide methods, tools and guidance to Regions, States and Tribes to support the TMDL program. This research will investigate new measurement methods and models to link stressors to biological responses and will use existing data and knowledge to develop strategies to determine the causes of biological impairment in rivers and streams. Research will be performed across multiple spatial scales, site, subwatershed, watershed, basin, ecoregion and regional/state.


To achieve the nation's water quality goals of "fishable and swimmable" waters, the Agency is tasked with implementation of the Total Maximum Daily Load (TMDL) program. The objective of the TMDL program is attainment of ambient water quality standards through the control of both point and non-point sources of pollution. As stated in the National Resource Council report "Assessing the TMDL Approach to Water Quality Management", the most pressing and significant regulatory water quality challenge for the states since the passage of the Clean Water Act is the ability to identify the amount by which point and non-point sources of pollution must be reduced in order for waterbodies to meet water quality standards. NERL is currently undertaking research to provide states methods, tools and guidance for the identification of the sources and quantity of pollutants that are causing impairments to our Nation's water bodies. This research encompasses methods to evaluate levels of potential stressors in streams and rivers, development of models to link environmental stressors to biological responses, evaluation of approaches for site selection for assessments, guidance for determining the causes of impairments to rivers and streams, and development of a Causal Analysis and Diagnosis Decision Information System (CADDIS). Research in this task is closely coordinated with research in Task 8734: Development of Ecological Indicators for Aquatic Systems.

Record Details:

Record Type: PROJECT
Start Date: 10/01/2000
Projected Completion Date: 10/01/2008
OMB Category: Other
Record ID: 29206