Or. Admin. R. 340-041-0326

Current through Register Vol. 63, No. 6, June 1, 2024

Section 340-041-0326 - Water Quality Standards and Policies for this Basin

(1) pH (hydrogen ion concentration). pH values may not fall outside the following ranges:

(a) Marine waters: 7.0-8.5;

(b) Estuarine and fresh waters (except Cascade lakes): 6.5-8.5;

(c) Cascade lakes above 3,000 feet altitude: pH values may not fall outside the range of 6.0 to 8.5.

(2) Total Dissolved Solids. Guide concentrations listed below may not be exceeded unless otherwise specifically authorized by DEQ upon such conditions as it may deem necessary to carry out the general intent of this plan and to protect the beneficial uses set forth in OAR 340-04l-0320: 500.0 mg/l.

(3) Turbidity (Nephelometric Turbidity Units, NTU). When appropriate studies are completed by the Corps of Engineers, or others, the Environmental Quality Commission will, consistent with the provisions of ORS Chapter 468, modify the turbidity standard, on a case-by-case basis if necessary, to accommodate such specific water storage and development projects in the South Umpqua Basin as are found to be in the best overall interest of the public.

(4) Minimum Design Criteria for Treatment and Control of Sewage Wastes:

(a) During periods of low stream flows (approximately May 1 to October 31):

(A) Main stem Umpqua River, South Umpqua River, and all tributaries to the main stem and South Umpqua Rivers: Treatment resulting in monthly average effluent concentrations not to exceed 10 mg/l of BOD and 10 mg/l of SS or equivalent control;

(B) North Umpqua River from mouth to Idleyld Park (river mile 0 to 35): Treatment resulting in monthly average effluent concentrations not to exceed 10 mg/l of BOD and 10 mg/l of SS or equivalent control;

(C) North Umpqua River above Idleyld Park (river mile 35) and all tributaries to North Umpqua River: Treatment resulting in monthly average effluent concentrations not to exceed 5 mg/l of BOD and 5 mg/l of SS or equivalent control.

(b) During the period of high stream flows (approximately November 1 to April 30): A minimum of secondary treatment or equivalent control and unless otherwise specifically authorized by the Department, operation of all waste treatment and control facilities at maximum practicable efficiency and effectiveness so as to minimize waste discharges to public waters.

Or. Admin. R. 340-041-0326

DEQ 17-2003, f. & cert. ef. 12-9-03

Stat. Auth.: ORS 468.020, 468B.030, 468B.035 & 468B.048

Stats. Implemented: ORS 468B.030, 468B.035 & 468B.048