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PDFWAC 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.]
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