Wind River Basin
January 1997

Snow
The Wind River basin has plenty of snow for this time of the year. Snow Water Equivalent (SWE) is about 78 percent above normal, for January 1, in the Wind River drainage above Boysen Reservoir. Above Dubois, the water content is double that normally found this time of the year, while the Popo Agie drainage is about 66 percent 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
December precipitation in the basin, varied from 53 percent of average at Lander WSO to 480 percent of average Dubois. Lander WSO was the only station that had below average precipitation this month. December's average precipitation for the basin was 173 percent above average (average of 13 reporting stations). Water year-to-date precipitation is 55 percent more than normal. The current water year to date average is about 26 percent more than last year at this time.

Reservoirs
Current storage varies from 89 to 153 percent of average. Current storage compared to average for the three storage reservoirs in the basin is as follows; Bull Lake 89% (78,800 acre feet), Boysen 91% (556,700 acre feet), and Pilot Butte 153% (23,700). Bull Lake is about 21 percent below last years storage amount, while Boysen is 5 percent less and Pilot Butte is 8 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 170,000 acre feet (about 67 percent above normal) during the April to September period. Other forecast points on the Wind River drainage include Wind River above Bull Lake 805,000 acre feet (50% above normal), at Riverton 935,000 acre feet (44% above average), and below Boysen 1,440,000 acre feet (78 % above normal). Bull Lake Creek near Lenore is expected to yield about 235,000 acre feet (28% above normal), Little Popo Agie River near Lander about 90,000 acre feet (73% 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 530,000 acre feet (64 percent more than normal). All forecasts are for the April to September period. 

==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - January 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       142       159    |      170       167    |       181       198            102
                                                                    |                       |
WIND RIVER abv Bull Lake Cr (2)      APR-SEP       625       732    |      805       150    |       878       985            538
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP       684       833    |      935       144    |      1037      1186            648
                                                                    |                       |
WIND RIVER below Boysen (2)          APR-SEP      1088      1298    |     1440       178    |      1582      1792            809
                                                                    |                       |
BULL LAKE CREEK near Lenore (2)      APR-SEP       176       211    |      235       128    |       259       294            183
                                                                    |                       |
LITTLE POPO AGIE RIVER near Lander   APR-SEP        68        81    |       90       173    |        99       112             52
                                                                    |                       |
SF LITTLE WIND RIVER nr Fort Washaki APR-SEP        80        95    |      105       130    |       115       130             81
                                                                    |                       |
LITTLE WIND RIVER near Riverton      APR-SEP       405       480    |      530       164    |       580       655            324
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 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     78.8     99.6     88.8 |   WIND RIVER above Dubios     3       131       201
                                                                        |
BOYSEN                                 596.0    556.7    588.1    613.5 |   LITTLE WIND                 2       111       142
                                                                        |
PILOT BUTTE                             31.6     23.7     22.0     15.5 |   POPO AGIE                   4       144       166
                                                                        |
                                                                        |   WIND above Boysen Resv      8       136       180
                                                                        |
==================================================================================================================================
 * 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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