Based on the May final April-August volume runoff forecast of 5.189
million acre-feet we are within a tier 2 operations year for Kootenai
River white sturgeon as defined in the Fish and Wildlife Service's
December 2000 Biological Opinion on operations of the Federal Columbia
River Power System. The minimum recommended release volume for sturgeon
conservation under current circumstances is 800 thousand acre-feet,
and we now recommend the following procedures for discharge of at
least this minimum volume from Libby Dam:
Thursday May 19th at about 6:00 am, increase flow at Libby Dam to
15,000 cfs (Kcfs): Ascending limb of hydrograph; USGS will conduct
suspended sediment sampling and ADCP on May 20 and 21 (Friday and Saturday)
Saturday May 21st at about 6:00 am, increase flow at Libby Dam to
20Kcfs: Ascending limb of hydrograph; USGS will conduct suspended
sediment sampling and ADCP on May 22 and 23 (Sunday and Monday)
Monday May 23rd at about 6:00 am, increase flow at Libby Dam to
25Kcfs: Peak of hydrograph; USGS will conduct suspended sediment
sampling and ADCP on May 24 and 25 (Tuesday, Wednesday), and multi-beam
bathymetic mapping in the braided reach from May 24 through 28th
(Tuesday through Saturday)
Saturday May 28th at about 6:00 am, reduce flow at Libby Dam to 20Kcfs:
Weekend low power demand
Sunday May 29th at about 6:00 am, reduce flow at Libby Dam to 15K cfs:
Weekend low power demand
Monday May 30th maintain flow at Libby Dam at 15Kcfs, Memorial Day Holiday
Tuesday May 31st at about 6:00 am, increase flow at Libby Dam to
20Kcfs: Restart the descending limb of hydrograph; USGS will conduct
suspended sediment sampling and ADCP on June 1 and 2 (Wednesday and Thursday)
Thursday June 2nd at about 6:00 am; reduce flow at Libby Dam to 15Kcfs:
Descending limb of hydrograph; USGS will conduct suspended sediment
sampling and ADCP on June 3 and 4 (Friday and Saturday)
Continue discharging at this rate through approximately June 14 to
utilize the minimum tiered volume of 800 thousand acre-feet. However,
this discharge rate may be continued beyond June 14 if you elect to
provide sturgeon flow in addition to the minimum recommended.
When it is clarified whether Lake Kooncanusa will be drafted to
elevation 2439 by the end of August or by the end of September and
releases from Libby Dam beginning June 15 are defined, we may provide
additional recommendations. However in the absence of this clarification,
beginning approximately June 15, 2005 we recommend that at least the
tiered bull trout minimum flow of 7,000 cfs from the Fish and Wildlife
Service December 2000 Biological Opinion be maintained through September.
Further, since Libby operations are anticipated to be constrained by
having only 4 turbines (with maximum release capacity of slightly more
the 20,000 cfs) in operation for much of this spring and summer, we
recommend timely releases of additional water as necessary in excess
of these recommended sturgeon or bull trout minimum flows to preclude
any amount of forced spill this year.
This is a tier 2 water year as defined in the December 2000 Jeopardy
Biological Opinion on the operations of Libby Dam. Based on these
specifications the figure below illustrates how the Fish and Wildlife
Service recommends this tiered sturgeon volume of water be shaped from
Libby Dam through approximately June 14. Note that this illustration
also depicts potential summer operations based on the current volume
runoff forecast and NOAA Fisheries' Final Remand Biological Opinion
of November 2004.