The Oregon Department of Environmental Quality prepared a geodatabase containing Geographic Information System layers relevant to the Temperature TMDLs for the Lower Columbia-Sandy Subbasin. The GIS layers summarize TMDL project area, model extents, shade data, data monitoring sites, 303(d) listed waters, and point source discharge locations.

The temperature TMDLs for the Lower Columbia-Sandy Subbasin were adopted by the Environmental Quality Commission into rule at OAR 340-042-0090(4) on Aug. 6, 2024. EPA approved the TMDL on Sept. 12, 2024.

The TMDL rule documents and supporting information can be found on DEQ's website.

The fish and spawning use designations included in the geodatabase are intended to be as accurate as possible, however some errors may exist. In addition, the Oregon Environmental Quality Commission has approved and DEQ has submitted to the Environmental Protection Agency updates to the fish and aquatic life use designations. As of April 2025, EPA has not taken action on these updates. If approved, these updates will change the fish use designation and applicable temperature criteria for some AUs. In the case of any discrepancy, the applicable temperature criteria and geographic extent described in rule at OAR-340-041 shall take precedence over the layers in the GIS data. In addition, not all monitoring sites supporting CE-QUAL-W2 models developed by Portland State University for City of Portland (Annear et al, 1999; Annear and Wells 2002) are included. Please refer to these reports for summary of data supporting those models.

Annear, Robert L., Scott A. Wells and David T. Evonuk. 1999. “Bull Run River – Reservoir Model: Boundary Conditions and Model Setup.” Portland State University Technical Report EWR-6-99.

Annear, Robert L., Scott A. Wells. 2002. “Bull Run River – Reservoir Model: River Model Calibration.” Portland State University Technical Report EWR-03-02.