Wash. Admin. Code § 173-549-020

Current through Register Vol. 24-20, October 15, 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.