Washington Administrative Code
Title 173 - Ecology, Department of (See also Titles 197, 317, 372, and 508)
Chapter 173-507 - Instream resources protection program - Snohomish River basin, water resource inventory area (WRIA) 7
Section 173-507-020 - Establishment of instream flows

Universal Citation: WA Admin Code 173-507-020

Current through Register Vol. 24-06, March 15, 2024

(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. 88-13-037 (Order 88-11), § 173-507-020, filed 6/9/88. Statutory Authority: Chapters 90.22 and 90.54 RCW. 79-10-003 (Order DE 79-8), § 173-507-020, filed 9/6/79.

Disclaimer: These regulations may not be the most recent version. Washington may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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