Snake River at Minimum Operating Pool Beginning April 3, 2018, USACE

US ARMY CORPS OF ENGINEERS

ATTN: CENWW-DE
201 NORTH THIRD STREET
WALLA WALLA WA 99362-1976
HTTP://WWW.NWW.USACE.ARMY.MIL/

DATE: 03/30/2018

POC: Richard Turner
CENWW-ODB
Navigation Business Line
Manager
Walla Walla District
(509) 527-7112

NOTICE NUMBER: 8613

LOCAL NUMBER: 18-16
WTRWY/CHNL: SNAKE RIVER
LOCK(S): SN 01|SN 02|SN 03|SN 04
EFFECTIVE: 04/03/2018 00:01 thru 09/01/2018
00:01 PDT

____________________________________________

Beginning 3 April 2018, the Snake River will transition to Minimum Operating Pool (MOP) and spring spill for fish passage in accordance with the 2018 Fish Operations Plan.

Facilities affected: Ice Harbor Lock & Dam (SN river mile 9.7); Lower Monumental Lock & Dam (SN river mile 41.6); Little Goose Lock & Dam (SN river mile 70.3); and variable MOP at Lower Granite Lock & Dam as described below (SN river mile 107.3). MOP ranges for each Snake River pool is listed below. Elevations are in NGVD 29 datum.

Pool Elevation (in feet)
Ice Harbor, Lake Sacajawea 437-438
Lower Monumental, Lake Herbert G. West 537-538
Little Goose, Lake Bryon 633-634
Lower Granite, Lake Franklin D. Roosevelt 733-736

The Variable MOP operation at Lower Granite is based on the inflows.

INFLOW                               FOREBAY RANGE
120,000+ CFS                     733.0-734.0 (MOP)
80,000-120,000 CFS        734.0-735.0 (MOP+1)
50,000-80,000 CFS         734.5-735.5 (MOP+1.5)
0-50,000 CFS                    735.0–736.0 (MOP+2)

Given that the Corps will be spilling additional water over the spillways up to the total dissolved gas limits established by Washington state water quality standards, navigators are encouraged to contact dam operators listed below and report any unsafe navigation conditions. If the conditions prevent safe navigation at a lock, the dam operators can adjust spill patterns to provide for safe transit.

The contact numbers are listed below.
Ice Harbor Chief Operator at (509)-543-3231. Call Sign WUJ42 Ice Harbor.
Lower Monumental Operator at (509) 282-7231. Call Sign WUJ43 Lower Monumental.
Little Goose Operator at (509) 399-2233 x231. Call Sign WUJ44 Little Goose.
Lower Granite Operator at (509) 843-2231. Call Sign WUJ45 Lower Granite.

For additional information contact the NWW Operations Division at (509) 527-7112.

//signed//
PAUL A OCKER
Chief, Operations Division
Walla Walla District
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