The upper Umatilla subbasin has historically been valued as a source area for abundant clean, cold water and habitat for resident and migratory fish. For the last 25 years however, increased demands on the watershed have caused some streams to be state-listed as "water quality limited" (WQL) (Table 3; Figure 15 and Figure 16). In addition, the Umatilla Tribes have requested to be treated as a state (pursuant to the water quality act of 1987) and have coordinated with the Environmental Protection Agency (EPA) to develop water quality standards pertaining specifically to Reservation lands (Confederated Tribes of the Umatilla Indian Reservation 1999).
Table 3. 1998 §303(d) listed stream segments in the Umatilla subbasin (Oregon Department of Environmental Quality 2000)
Figure 15. Stream segments in the Umatilla subbasin listed on the Oregon State 303(d) list
Figure 16. Stream segments in the Umatilla subbasin listed on the Oregon State 303(d) list (continued)
Oregon Water Quality Standards for the Umatilla River Basin
Temperature: The basic absolute criterion is 64F (17.8C). Two exceptions exist: when salmonid spawning, egg incubation, and fry emergence for native fish occur, standards for the specific times of use are 55F (12.8C); and when the waters support bull trout the standards are 50F (10.0C) (Boyd et al. 1999).
Dissolved Oxygen (DO): For water bodies providing salmonid spawning during periods from spawning until fry emergence from the gravels, the following criteria apply: DO shall not be less than 11.0 mg/l, but if the minimum intergravel DO measured as a spatial median is 8.0 mg/l or greater, then the DO criterion is 9.0 mg/l. Where conditions of barometric pressure, altitude, and temperature preclude attainment of the 11.0 mg/l or 9.0 mg/l criteria, DO levels shall not be less than 95% of saturation. For water bodies identified by the Oregon Department of Environmental Quality (ODEQ) as providing cold-water aquatic life, the DO shall not be less than 8.0 mg/l as an absolute minimum. The DO level for cool-water aquatic life shall not be less than 6.5 mg/l. The minimum DO level for warm-water aquatic life is 5.5 mg/l.
Turbidity (Nephelometric Turbidity Units, NTU): No more than a 10% cumulative increase in natural stream turbidities are allowed, as measured relative to a control point immediately upstream of the turbidity causing activity. In special situations (construction, emergencies) the NTU limit can be exceeded provided turbidity control techniques have been implemented and affected agencies have given authorization. A specific turbidity target of 30 NTU was developed for the Umatilla basin TMDL (ODEQ 2000).
pH (hydrogen ion concentration): pH shall not fall outside the range of 6.5 to 9.0. The ODEQ will determine if any pH values higher than 8.7 are anthropogenic or natural in origin. Where it is proven that any waters impounded by dams existing on January 1, 1996 would not have a pH exceedance if the impoundment was removed, exceptions will be made.
Bacteria standard: A 30-day log mean of 126 E. coli organisms per 100 ml based on a minimum of five samples; or no single sample shall exceed 406 E. coli organisms per 100 ml.