Wind River Basin (3)
February 2002

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 79 percent of average (154 percent of last year). The Little Wind SWE is 58 percent of average water content (125 percent of last year), and the Popo Agie drainage SWE is about 67 percent of average (97 percent of last year). The Wind River basin, above Boysen Reservoir, SWE is about 71 percent of average (about 144 percent of last year). See the Basin Summary of Snow Course Data at the front of this report for details.

Precipitation
Last month's precipitation in the basin varied from 25 to 154 percent of average. Precipitation for the basin was about 79 percent of average for the 8 reporting stations. Water year-to-date precipitation is 71 percent of normal. The current water-year-to-date average is about 140 percent of last year at this time. Year to date figures range from 37 to 86 percent of average.

Reservoirs
Current storage varies from 15 to 119 percent of average. Bull Lake is currently storing about 28,300 acre feet (19 percent of capacity) -- normally the reservoir is at 57 percent of capacity at this time of the year. Boysen Reservoir is storing about 15 percent of capacity 87,000 acre feet) -- normally the reservoir is at 99 percent of capacity at this time of the year. Pilot Butte is storing 75 percent of capacity (23,800 acre feet) -- normally the reservoir is at 63 percent of capacity at 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 360,000 acre feet (67 percent of average). Wind River at Riverton will yield about 330,000 acre feet (52 percent of average). Boysen Reservoir inflow will yield about 455,000 acre feet (56 percent of normal). Bull Lake Creek near Lenore is expected to yield about 105,000 acre feet (58 percent of average). Little Popo Agie River near Lander is expected to yield about 26,000 acre feet (57 percent of average). South Fork of Little Wind near Fort Washakie will yield about 48,000 acre feet (57 percent of average). Little Wind River near Riverton will yield about 175,000 acre feet (56 percent of average). 

==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - February 1, 2002
==================================================================================================================================
                                              |  <<====== 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       232       308    |      360        67    |       412       488            535
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP        94       235    |      330        52    |       425       566            640
                                                                    |                       |
BOYSEN RESERVOIR Inflow (2)          APR-SEP       133       325    |      455        56    |       585       777            809
                                                                    |                       |
BULL LAKE CR near Lenore (2)         APR-SEP        51        83    |      105        58    |       127       159            182
                                                                    |                       |
LT POPO AGIE RIVER nr Lander         APR-SEP      11.1        20    |       26        49    |        38        56             53
                                                                    |                       |
SF LT WIND nr Fort Washakie          APR-SEP      19.0        36    |       48        57    |        60        77             84
                                                                    |                       |
LT WIND RIVER nr Riverton            APR-SEP        92       141    |      175        56    |       235       324            315
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of January               |        Watershed Snowpack Analysis - February 1, 2002
==================================================================================================================================
                                      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     28.3     62.6     85.9 |   WIND RIVER above Dubios     7       160        79
                                                                        |
BOYSEN                                 596.0     87.0    445.5    592.0 |   LITTLE WIND                 2       137        58
                                                                        |
PILOT BUTTE                             31.6     23.8     23.5     20.0 |   POPO AGIE                   7       125        67
                                                                        |
                                                                        |   WIND above Boysen Resv     14       145        71
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual volume will exceed the volumes in the table.

(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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