Print







WACs > Title 173 > Chapter 173-549 > Section 173-549-020











173-549-016    

173-549-025







No agency filings affecting this section since 2003







WAC 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.
[Statutory Authority: Chapters 90.54 and 90.22 RCW. WSR 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.]