Wind River Basin (3)
March 2001

Snow
The Wind River basin has much below average snow water equivalent (SWE) for this time of the year. SWE in the Wind River above Dubois is 60 percent of average (76 percent of last year). The Little Wind SWE is 45 percent of average water content (75 percent of last year), and the Popo Agie drainage SWE is about 53 percent of average (84 percent of last year). The Wind River basin, above Boysen Reservoir, SWE is about 56 percent of average (about 78 percent of last year). See the Basin Summary of Snow Course Data at the front of this report for details.

Precipitation
February precipitation in the basin varied from 35 to 248 percent of average. February precipitation for the basin was about 73 percent of average for the 11 reporting stations; that is about 70 percent of last year's amount. Water year-to-date precipitation is 54 percent of normal. The current water-year-to-date average is about 76 percent of last year at this time. Year to date figures range from 41 to 117 percent of average.

Reservoirs
Current storage varies from 74 to 132 percent of average. Bull Lake is currently storing about 62,500 acre feet (56 percent of capacity) -- the reservoir is at 74 percent of average at this time of the year. Boysen Reservoir is storing about 73 percent of capacity 434,500 acre feet) -- the reservoir is at 78 percent of average for this time of the year. Pilot Butte is storing 74 percent of capacity (23,400 acre feet) -- the reservoir is at 132 percent of average for this time of the year.

Streamflow
Water supply is estimated to be much below normal this year. The following values reflect the 50 percent chance yields for the April through September runoff period. The Wind River above Bull Lake Creek is expected to yield 325,000 acre feet (60 percent of average). Wind River at Riverton will yield about 315,000 acre feet (49 percent of average). Boysen Reservoir inflow will yield about 370,000 acre feet (46 percent of normal). Bull Lake Creek near Lenore is expected to yield about 110,000 acre feet (60 percent of average). Little Popo Agie River near Lander is expected to yield about 22,000 acre feet (42 percent of average). South Fork of Little Wind near Fort Washakie will yield about 50,000 acre feet (62 percent of average). Little Wind River near Riverton will yield about 190,000 acre feet (59 percent of average). 


==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - March 1, 2001
==================================================================================================================================
                                              |  <<====== Drier ======  Future Conditions  =======  Wetter =====>>  |             
                                              |                                                                     |
  Forecast Point                     Forecast |  ==================== Chance Of Exceeding * ======================  |
                                      Period  |    90%       70%    |  50% (Most Probable)  |      30%       10%    |  30-Yr Avg.
                                              | (1000AF)  (1000AF)  |   (1000AF)  (% AVG.)  |    (1000AF)  (1000AF) |    (1000AF)
====================================================================|=======================|=====================================
WIND RIVER abv Bull Lake Cr (2)      APR-SEP       264       301    |      325        60    |       368       431            538
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP       207       272    |      315        49    |       404       534            648
                                                                    |                       |
BOYSEN RESERVOIR Inflow (2)          APR-SEP       227       307    |      370        46    |       500       692            809
                                                                    |                       |
BULL LAKE CR near Lenore (2)         APR-SEP        86       101    |      110        60    |       126       150            183
                                                                    |                       |
LT POPO AGIE RIVER nr Lander         APR-SEP      14.0      18.7    |       22        42    |        30        41             52
                                                                    |                       |
SF LT WIND nr Fort Washakie          APR-SEP        32        43    |       50        62    |        61        78             81
                                                                    |                       |
LT WIND RIVER nr Riverton            APR-SEP       100       156    |      190        59    |       251       342            324
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of February              |        Watershed Snowpack Analysis - March 1, 2001
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
BULL LAKE                              151.8     62.5     95.2     85.0 |   WIND RIVER above Dubios     7        76        60
                                                                        |
BOYSEN                                 596.0    434.5    527.3    555.2 |   LITTLE WIND                 2        75        45
                                                                        |
PILOT BUTTE                             31.6     23.4     22.4     17.7 |   POPO AGIE                   6        84        53
                                                                        |
                                                                        |   WIND above Boysen Resv     14        78        56
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual volume will exceed the volumes in the table.

The average is computed for the 1961-1990 base period.

(1) - The values listed under the 10% and 90% Chance of Exceeding are actually 5% and 95% exceedance levels.                  
(2) - The value is natural volume - actual volume may be affected by upstream water management.
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