Wind River Basin (3)
February 1998

Snow
The Wind River basin has above average snow water equivalent (SWE) for this time of the year; measured snow depths ranged from 21 to 35 inches. SWE, in the Wind River basin above Boysen Reservoir is about 16 percent above normal (About 31 percent less than last year). Above Dubois, the water content is about 16 percent above normal for this time of the year, while the Little Wind is about 8 percent above normal and the Popo Agie drainage is about 1 percent below normal. SWE, for nearly all reporting stations, is lower than last year at this time. See the Basin Summary Of Snow Course Data at the front of this report for details.

Precipitation
January precipitation in the basin, varied from 20 percent of average at Diverson Dam to 184 percent of average for Burroughs Creek. Jauuary's average precipitation for the basin was about 31 percent above normal for the 13 reporting stations; that is about 4 percent above last year's amount. Water year-to-date precipitation is 15 percent above normal. The current water-year-to-date average is about 69 percent of last year at this time.

Reservoirs
Current storage varies from 95 to 111 percent of average. Current storage, compared to average for the three storage reservoirs in the basin, is as follows; Bull Lake 111% (96,400 acre feet), Boysen 95% (549,300 acre feet), and Pilot Butte 132% (21,700 acre feet). Bull Lake is about 20 percent above last year's storage amount, while Boysen is 1 percent more and Pilot Butte is 8 percent less than last year at this time.

Streamflow
Water supply is estimated to be below normal this year. In the upper portion of the drainage, Wind River near Dubois is expected to yield about 96,000 acre feet (about 6 percent below normal) during the April to September period. Other forecast points on the Wind River drainage include Wind River above Bull Lake 515,000 acre feet (4% below normal), Wind River at Riverton 615,000 acre feet (5% below average), and below Boysen 760,000 acre feet (6 % below normal). Bull Lake Creek near Lenore is expected to yield about 175,000 acre feet (4% below normal), Little Popo Agie River near Lander about 50,000 acre feet (4% below normal), South Fork of Little Wind near Fort Washakie about 72,000 acre feet (11% below normal), and Little Wind River near Riverton about 275,000 acre feet (15 percent less than normal). 

==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - February 1, 1998
==================================================================================================================================
                                              |  <<====== 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 near Dubois               APR-SEP        70        85    |       96        94    |       107       122            102
                                                                    |                       |
WIND RIVER abv Bull Lake Cr (2)      APR-SEP       399       468    |      515        96    |       562       631            538
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP       441       545    |      615        95    |       685       789            648
                                                                    |                       |
WIND RIVER below Boysen (2)          APR-SEP       438       630    |      760        94    |       890      1082            809
                                                                    |                       |
BULL LAKE CREEK near Lenore (2)      APR-SEP       134       158    |      175        96    |       192       216            183
                                                                    |                       |
LITTLE POPO AGIE RIVER near Lander   APR-SEP        30        42    |       50        96    |        58        70             52
                                                                    |                       |
SF LITTLE WIND RIVER nr Fort Washaki APR-SEP        54        65    |       72        89    |        79        90             81
                                                                    |                       |
LITTLE WIND RIVER near Riverton      APR-SEP       137       219    |      275        85    |       331       413            324
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of January               |        Watershed Snowpack Analysis - February 1, 1998
==================================================================================================================================
                                      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     96.4     80.5     86.6 |   WIND RIVER above Dubios     7        64       116
                                                                        |
BOYSEN                                 596.0    549.3    542.9    580.7 |   LITTLE WIND                 2        81       108
                                                                        |
PILOT BUTTE                             31.6     21.7     23.6     16.5 |   POPO AGIE                   6        64        99
                                                                        |
                                                                        |   WIND above Boysen Resv     14        65       109
                                                                        |
==================================================================================================================================
 * 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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