Wind River Basin
March 1997

Snow
The Wind River basin has near record snow for this time of the year. The Wind River basin above Boysen Reservoir averages about 43 percent above normal snow water equivalent (SWE) for March 1. Above Dubois, the water content is about 59% above normal for this time of the year, while the Popo Agie drainage is about 23 percent and the Little Wind is about 26% above normal. Nearly all drainages are well above last year at this time. See the Basin Summary Of Snow Course Data at the front of this report for details.

Precipitation
February precipitation in the basin, varied from 21 percent of average at Christina Lake to 204 percent of average for Dubois. February's average precipitation for the basin was 62 percent of average (average of 12 reporting stations); that is 76 percent of last years amount. Water year-to-date precipitation is 32 percent more than normal. The current water-year-to-date average is about 11 percent more than last year at this time.

Reservoirs
Current storage varies from 94 to 133 percent of average. Current storage, compared to average for the three storage reservoirs in the basin, is as follows; Bull Lake 95% (81,100 acre feet), Boysen 94% (524,000 acre feet), and Pilot Butte 133% (23,500). Bull Lake is about 18 percent below last year's storage amount, while Boysen is 5 percent less and Pilot Butte is 6 percent more than last year at this time.

Streamflow
In the upper portion of the drainage, Wind River near Dubois is expected to yield about 140,000 acre feet (about 37 percent above normal) during the April to September period. Other forecast points on the Wind River drainage include Wind River above Bull Lake 725,000 acre feet (35% above normal), Wind River at Riverton 890,000 acre feet (37% above average), and below Boysen 1,190,000 acre feet (47 % above normal). Bull Lake Creek near Lenore is expected to yield about 225,000 acre feet (23% above normal), Little Popo Agie River near Lander about 69,000 acre feet (33% above normal), South Fork of Little Wind near Fort Washakie about 105,000 acre feet (30% above normal), and Little Wind River near Riverton about 450,000 acre feet (39 percent more than normal). All forecasts are for the April to September period.

==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - March 1, 1997
==================================================================================================================================
                                              |  <<====== 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       116       130    |      140       137    |       150       164            102
                                                                    |                       |
WIND RIVER abv Bull Lake Cr (2)      APR-SEP       614       680    |      725       135    |       770       836            538
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP       720       821    |      890       137    |       959      1060            648
                                                                    |                       |
WIND RIVER below Boysen (2)          APR-SEP       868      1060    |     1190       147    |      1320      1512            809
                                                                    |                       |
BULL LAKE CREEK near Lenore (2)      APR-SEP       185       209    |      225       123    |       241       265            183
                                                                    |                       |
LITTLE POPO AGIE RIVER near Lander   APR-SEP        51        62    |       69       133    |        76        87             52
                                                                    |                       |
SF LITTLE WIND RIVER nr Fort Washaki APR-SEP        88        98    |      105       130    |       112       122             81
                                                                    |                       |
LITTLE WIND RIVER near Riverton      APR-SEP       313       395    |      450       139    |       505       587            324
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of February              |        Watershed Snowpack Analysis - March 1, 1997
==================================================================================================================================
                                      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     81.1     98.5     85.0 |   WIND RIVER above Dubios     7       116       159
                                                                        |
BOYSEN                                 596.0    524.0    553.9    555.2 |   LITTLE WIND                 2       108       126
                                                                        |
PILOT BUTTE                             31.6     23.5     22.1     17.7 |   POPO AGIE                   7       109       123
                                                                        |
                                                                        |   WIND above Boysen Resv     15       112       140
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual flow 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 flow - actual flow may be affected by upstream water management.

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