Statutes, codes, and regulations
Washington Administrative Code
Title 173 - Ecology, Department of (See also Titles 197, 317, 372, and 508)
Chapter 173-549 - Water resources program in the Okanogan River basin, WRIA-49
Section 173-549-020 - Establishment of minimum instream flows

Wash. Admin. Code § 173-549-020

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Current through Register Vol. 24-21, November 1, 2024
Section 173-549-020 - Establishment of minimum instream flows
(1) Minimum instream flows are established for stream management units with monitoring to take place at certain control points as follows:

Stream Management Unit Information

Stream Management

Unit Name, Control

Station Name and

Number

Control Station

Location by River

Mile, Section,

Township, Range

Affected Stream

Reach

Lower Okanogan

Okanogan R.

at Malott

(12447200)

17.0,

9-32-25E

Okanogan River

confluence with

Wells Pool to confluence of Chewiliken Cr.

Middle Okanogan

Okanogan R.

nr. Tonasket

(12445000)

50.8,

8-36-27E

Okanogan River confluence of Chewiliken Creek to confluence Similkameen River

Upper Okanogan

Okanogan R.

at Oroville

(12439500)

77.3,

27-40-27E

Okanogan River confluence of Similkameen River to Osoyoos Lake

Similkameen

Similkameen R.

at Nighthawk

(12442500)

15.8,

7-40-26E

Similkameen River confluence with Okanogan River to Canadian Border

(2) Minimum instream flows established for the stream management units in WAC 173-549-020(1) are as follows:

Minimum Instream Flows in the Okanogan River

(All Figures in Cubic Feet Per Second)

Month

Day

Lower

Okanogan

12447200

Middle

Okanogan

1244500

Upper

Okanogan

124426000

Similkameen

12439500

Jan.

1

860

800

320

400

15

830

800

320

400

Feb.

1

820

800

320

400

15

850

800

320

400

Mar.

1

880

800

320

425

15

900

800

320

450

Apr.

1

925

910

330

510

15

1,100

1,070

340

640

May

1

1,750

1,200

350

1,100

15

3,800

3,800

500

3,400

Jun.

1

3,800

3,800

500

3,400

15

3,800

3,800

500

3,400

Jul.

1

2,100

2,150

420

1,900

15

1,200

1,200

350

1,070

Aug.

1

800

840

320

690

15

600

600

300

440

Sept.

1

620

600

300

400

15

700

600

300

400

Oct.

1

750

730

330

450

15

960

900

370

500

Nov.

1

950

900

370

500

15

950

900

320

500

Dec.

1

930

900

320

500

15

900

850

320

450

(3) Minimum instream flow hydrographs, as represented in WAC 173-549-900, shall be used for definition of minimum instream flows on those days not specifically identified in WAC 173-549-020(2).
(4) Future consumptive water right permits hereafter issued for diversion of surface water from the mainstem Okanogan River and the Similkameen River shall be expressly subject to minimum instream flows established in WAC 173-549-020(1) through (3) except those described in WAC 173-549-070.
(5) Projects that would reduce the flow in a portion of a stream's length (e.g. hydroelectric projects that bypass a portion of a stream) will be considered consumptive only with respect to the affected portion of the stream. Such projects will be subject to instream flows as specified by the department. These flows may be those established in WAC 173-549-020 or, when appropriate, may be flows specifically tailored to that particular project and stream reach. When studies are required to determine such reach- and project-specific flow requirements, the department may require the project proponent to conduct such studies.

Wash. Admin. Code § 173-549-020

Statutory Authority: Chapters 90.54 and 90.22 RCW. 84-13-076 (Order DE 84-15), § 173-549-020, filed 6/20/84; Order DE 76-25, § 173-549-020, filed 7/14/76.