You are here:
LANDSCAPE SCALE NON-POINT SOURCE POLLUTION TEMPERATURE ASSESSMENT AND TMDL DEVELOPMENT
Impact/Purpose:
This work is intended to provide land managers, watershed councils, and State/Federal employees an accurate and inexpensive technique to develop landscape scale temperature assessments and Total Maximum Daily Loads (TMDLs).
Description:
THIS IS AN ONGOING PROJECT. Elevated river temperature is a significant water quality issue in the Pacific Northwest. For example, over 12,000 miles of perennial streams are designated 303(d) water quality limited due to temperature violation in the State of Oregon. Over the past five years EPA staff have worked closely with the Oregon Department of Environmental Quality (ODEQ) and Washington Department of Ecology (Ecology) to develop a new methodology for non-oint source (NPS) pollution temperature assessment and Total Maximum Daily Load (TMDL) development. The new methodology utilizes (1) collected ground level data; (2) sampled GIS (Graphical Information System) information; and (3) remote sensed temperature data (e.g., Forward Looking Infrared Radiometry - (FLIR)) to descrive local conditions and cumulative impacts throught a watershed. Simply put, stream temperature is complex in both pollutant dynamics and pollutant source extent, and the developed analytical technique is designed to capture this complexity. Specifically, this technique incorporates GIS based stream network analysis that simulates landscape processes such as shade production from topographic and riparian features and in-stream processes such as low flow condition, thermodynamic parameters, and ultimately, temperature. This methodology has been applied to several large watershed regions in Oregon and is currently being used to develop landscape scale source assessments and TMDLs throughout Washington and Oregon. Examples of this work are available on the ODEQ and Ecology web pages. In addition, the GIS tool used to sample GIS data sets, and the accompanying user manual, is available from the ODEQ web page. Finally, efforts are currently underway to develop a complete documentation of this methodology. Once completed, both the "Heat Source" model and technique documentation are scheduled to be placed on the ODEQ web page. The "Heat Source" temperature model used during these efforts, and associated documentation, is available on the "Heat Source" webpage.
