Deschutes Basin

​Beaver-South Fork Subbasin

TMDL initiated (Initial scoping and data collection phase)

Lower Crooked Subbasin

TMDL initiated (Initial scoping and data collection phase)

Lower Deschutes Subbasin

TMDL not started (Minimal or no activity)

Trout Subbasin

TMDL not started (Minimal or no activity)

Upper Crooked Subbasin

TMDL initiated (Initial scoping and data collection phase)

​

​DEQ has been working with partners in the Upper Deschutes and Little Deschutes subbasins for over 10 years to assess water quality in rivers, streams and lakes. The data gathered as part of this process indicate that, at some locations and times, water is not healthy for fish and aquatic life. The main water quality issues of concern include high temperatures, low dissolved oxygen concentrations, high pH levels, excessive amounts of algae (chlorophyll a) and excessive amounts of fine-grained sediment and turbidity.   

Temperature Modeling

DEQ contracted some of the temperature modeling work to Watershed Sciences, Inc., with financial support from EPA. This contract work was done from 2007-2011. Watershed Sciences completed Temperature Modeling Reports for this work. It is likely this initial modeling work done by Watershed Sciences will be modified by DEQ during TMDL development. The existing models may be revised to incorporate more site-specific input gathered from local stakeholders during the advisory committee process.

Collaboration

During the period 2000-2012, DEQ informally met with different groups and individuals around the region, discussing the upcoming TMDLs. These groups have included Upper Deschutes Watershed Council, Local Advisory Committee for the Upper Deschutes Agriculture Water Quality Management Area Plan, Deschutes Water Alliance, Working Group for the Deschutes Basin Habitat Conservation Plan, Water and Soils staff with the Confederated Tribes of Warm Springs, and others. 

Technical Advisory Committee

In March, 2012, DEQ convened the  Upper Deschutes and Little Deschutes Technical Advisory Committee The committee met five times in 2012 and provided valuable local input to DEQ on our technical analyses. DEQ postponed additional committee meetings and work on the models for temperature, dissolved oxygen, pH and nutrients in response to litigation on Oregon's temperature standard and the resulting court-ordered schedule for temperature TMDL replacement in 15 basins. DEQ has continued to implement nutrient monitoring that will support TMDL development.​

​​Several technical reports were written by Watershed Sciences, Inc. (under contract with DEQ or the Upper Deschutes Watershed Council) and DEQ prior to TMDL development. These reports provide technical information which may be used to support TMDL development.

Thermal Infrared Remote Sensing Survey Reports

Thermal infrared surveys were done by Watershed Sciences in the Upper and Little Deschutes Subbasins in 2000 and 2001. Similar surveys were done in the Crooked River Subbasins in 2005. Thermal infrared remote sensing is an effective method for mapping spatial temperature patterns in rivers and streams. The thermal infrared imagery illustrates the location and thermal influence of point sources, tributaries, and surface springs. Thermal infrared information is an important data source for temperature modeling. 

• 2006 Airborne Thermal Infrared Remote Sensing Report - Crooked River, OR
  
• 2002 Aerial Surveys in the Deschutes River Basin 
  • Appendix A - Selected Images
    
• 2001 Aerial Surveys in the Upper Deschutes Subbasin: Whychus Creek and Indian Ford Creek
  

Temperature Modeling Reports

Heat Source is the computer model DEQ uses to simulate stream thermodynamics and hydrology. DEQ uses the model to develop temperature TMDL requirements for Oregon’s rivers and streams.

DEQ contracted with Watershed Sciences, Inc. to conduct some of the preliminary temperature modeling in the Upper and Little Deschutes and Crooked River Subbasins. The final reports written for DEQ by Watershed Sciences are included at the links below. These reports provide background material on the Heat Source model, model calibration and a first draft of models evaluating natural flow and vegetation conditions. It is likely that this initial modeling work done by Watershed Sciences will be modified by DEQ during TMDL development. The existing models may be revised to incorporate more site-specific input gathered from local stakeholders during the advisory committee process. 

During 2007-2008, Watershed Sciences calibrated temperature models for Tumalo Creek, Whychus Creek and Deschutes River between Wickiup Reservoir and Lake Billy Chinook. 

• Temperature Modeling - Deschutes River, Whychus Creek and Tumalo Creek (2008)

During 2008-2011, Watershed Sciences did additional modeling on Metolius River, Little Deschutes River, Crescent Creek and Deschutes River above Wickiup Reservoir. Under this contract, models were also developed for a number of streams in the Crooked River Subbasins.  DEQ is not working on TMDLs in the Crooked River Subbasins at this time so the information provided in the Watershed Sciences reports for the streams in this area are very preliminary in nature.

• Data Summary - Little Deschutes River, Crescent Creek, Metolius River, Deschutes River (2009)
  
• Model Calibration - Little Deschutes River, Crescent Creek, Metolius River, Deschutes River (2011) 

Remote Sensing of Chlorophyll a Concentrations

Chlorophyll a is a common measure of algal biomass which in turn impacts the dissolved oxygen and pH of a waterbody. There are several impaired lakes/reservoirs in the Deschutes Basin which are 303(d) listed for algae related parameters. DEQ conducted a study looking at the possibility of using Landsat data to determine algae concentrations in lakes, providing information on lakes where there is limited or no data. Although the focus of the work was to evaluate lakes within the Deschutes Basin, some areas of the surrounding basins are within the boundary of the satellite data

• Remote sensing of chlorophyll a concentrations to support the Deschutes Basin lake and reservoir TMDLs