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PDFWAC 173-507-020

Establishment of instream flows.

(1) Instream flows are established for stream management units with monitoring to take place at certain control stations as follows:
STREAM MANAGEMENT UNIT INFORMATION
Control Station No.
Stream Management
Unit Name
Control Station
by River Mile and
Section, Township
and Range
Affected Stream
Reach Including
Tributaries
12.1330.00
So. Fk. Skykomish
River
51.6
28-27-10E
From confluence with N. Fk. Skykomish River to headwaters.
12.1381.50
Sultan River
5.1
17-28-8E
From mouth to headwaters.
12.1411.00
Skykomish River
25.0
12-27-6E
From mouth to headwaters, excluding So. Fk. Skykomish River and Sultan River.
12.1430.00
No. Fk. Snoqualmie
2.2
26-24-8E
From mouth to headwaters.
12.1445.00
Snoqualmie River
40.0
19-24-8E
From Snoqualmie Falls to headwaters, excluding No. Fork Snoqualmie River.
12.1485.00
Tolt River
8.7
31-26-8E
From mouth to headwaters.
12.1490.00
Snoqualmie River
23.0
9-25-7E
From confluence with Harris Creek to Snoqualmie Falls, excluding Tolt River.
12.
Snoqualmie River
2.5
26-27-6E
From mouth to confluence with Harris Creek, including Harris Creek.
12.1554.00
Pilchuck River
1.9
18-28-6E
From mouth to headwaters.
12.1508.00
Snohomish River
20.4
16-27-6E
From influence of mean annual high tide at low base flow levels to confluence with Skykomish River and Snoqualmie River, excluding Pilchuck River.
(2) Instream flows established for the stream management units in WAC 173-507-020(1) are as follows:
INSTREAM FLOWS IN THE SNOHOMISH RIVER BASIN
(in Cubic Feet per Second)
Month
Day
12.1330.00
So. Fk.
Skykomish
12.1411.00
Skykomish
12.1430.00
No. Fk.*
Snoqualmie
No. Fk.**
Snoqualmie
Jan.
1
900
2200
260
200
 
15
900
2200
260
200
Feb.
1
900
2200
260
200
 
15
900
2200
260
200
Mar.
1
900
2200
260
200
 
15
900
2200
300
200
Apr.
1
1100
2650
300
200
 
15
1250
3250
300
200
May
1
1250
4000
300
200
 
15
1250
4900
300
200
June
1
1250
4900
300
200
 
15
1250
4900
300
200
July
1
1250
3250
300
200
 
15
950
2170
195
140
Aug.
1
650
1450
130
100
 
15
450
1000
130
100
Sept.
1
450
1000
130
100
 
15
450
1000
130
100
Oct.
1
550
1300
130
130
 
15
700
1700
165
165
Nov.
1
900
2200
210
200
 
15
900
2200
260
200
Dec.
1
900
2200
260
200
 
15
900
2200
260
200
- - - -
*
Normal year flows must be maintained at all times unless a critical condition is declared by the director. The director, or his designee, may authorize, in consultation with the state departments of fisheries and wildlife, a reduction in instream flows during a critical condition period. At no time are diversions subject to this regulation permitted for any reason when flows fall below the following critical year flows, except where a declaration of overriding considerations of public interest is made by the director.
**
Critical year flows represent flows below which the department believes substantial damage to instream values will occur.
Month
Day
12.1381.50
Sulton
12.1445.00
Snoqualmie
(above Falls)
12.1485.50
Tolt River*
Tolt River**
Jan.
1
 
1550
280
190
 
15
 
1550
280
190
Feb.
1
 
1550
280
190
 
15
 
1550
280
190
Mar.
1
 
1550
280
190
 
15
 
1550
280
190
Apr.
1
 
1550
280
190
 
15
 
1550
280
190
May
1
 
1550
280
190
 
15
 
1550
280
190
June
1
 
1550
280
190
 
15
 
1550
280
165
July
1
 
1550
280
140
 
15
 
1100
240
120
Aug.
1
 
770
170
120
 
15
 
600
120
120
Sept.
1
 
600
120
120
 
15
 
600
120
120
Oct.
1
 
820
190
185
 
15
 
1100
280
190
Nov.
1
 
1550
280
190
 
15
 
1550
280
190
Dec.
1
 
1550
280
190
 
15
 
1550
280
190
- - - -
*
Normal year flows must be maintained at all times unless a critical condition is declared by the director. The director, or his designee, may authorize, in consultation with the state departments of fisheries and wildlife, a reduction in instream flows during a critical condition period. At no time are diversions subject to this regulation permitted for any reason when flows fall below the following critical year flows, except where a declaration of overriding considerations of public interest is made by the director.
**
Critical year flows represent flows below which the department believes substantial damage to instream values will occur.
Month
Day
12.1490.00
Snoqualmie
(Carnation)
12.
Snoqualmie
(mouth)
12.1554.00
Pilchuck
R.
12.1508.00
Snohomish
R.
Jan.
1
2500
2800
300
6000
 
15
2500
2800
300
6000
Feb.
1
2500
2800
300
6000
 
15
2500
2800
300
6000
Mar.
1
2500
2800
300
6000
 
15
2500
2800
300
6000
Apr.
1
2500
2800
300
6000
 
15
2500
2800
300
6500
May
1
2500
2800
300
7200
 
15
2500
2800
300
8000
June
1
2500
2800
300
8000
 
15
2500
2800
300
8000
July
1
1850
2180
220
5700
 
15
1300
1550
160
4000
Aug.
1
950
1080
120
2800
 
15
700
800
85
2000
Sept.
1
700
800
85
2000
 
15
700
800
85
2000
Oct.
1
1050
1200
130
2900
 
15
1650
1850
200
4000
Nov.
1
2500
2800
300
6000
 
15
2500
2800
300
6000
Dec.
1
2500
2800
300
6000
 
15
2500
2800
300
6000
(3) Instream flow hydrographs, as represented in the document entitled "Snohomish River instream resource protection program," shall be used for definition of instream flows on those days not specifically identified in WAC 173-507-020(2).
(4) All consumptive water rights hereafter established shall be expressly subject to the instream flows established in WAC 173-507-020 (1) through (3).
(5) At such time as the departments of fisheries and/or wildlife and the department of ecology agree that additional stream management units should be defined, other than those specified in WAC 173-507-020(1), the department of ecology shall identify additional control stations and management units on streams and tributaries within the basin and shall set instream flows where possible for those stations as provided in chapters 90.22 and 90.54 RCW.
[Statutory Authority: Chapters 43.21B, 43.27A, 90.22 and 90.54 RCW. WSR 88-13-037 (Order 88-11), § 173-507-020, filed 6/9/88. Statutory Authority: Chapters 90.22 and 90.54 RCW. WSR 79-10-003 (Order DE 79-8), § 173-507-020, filed 9/6/79.]
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