Wind River Basin
February 1997

Snow
The Wind River basin has near record 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 80% above normal for this time of the year, while the Popo Agie drainage is about 58 percent and the Little Wind is about 33% 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
January precipitation in the basin, varied from 65 percent of average at Diversion Dam to 307 percent of average for Pavillion. January's average precipitation for the basin was 23 percent above average (average of 11 reporting stations). Water year-to-date precipitation is 50 percent more than normal. The current water year to date average is about 17 percent more than last year at this time.

Reservoirs
Current storage varies from 53 to 91 percent of average. Current storage, compared to average for the three storage reservoirs in the basin, is as follows; Bull Lake 53% (78,800 acre feet), Boysen 91% (556,700 acre feet), and Pilot Butte 75% (23,700). Bull Lake is about 19 percent below last year's storage amount, while Boysen is 5 percent less and Pilot Butte is 7 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 155,000 acre feet (about 52 percent above normal) during the April to September period. Other forecast points on the Wind River drainage include Wind River above Bull Lake 795,000 acre feet (48% above normal), Wind River at Riverton 970,000 acre feet (50% above average), and below Boysen 1,300,000 acre feet (61 % 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 75,000 acre feet (44% above normal), South Fork of Little Wind near Fort Washakie about 115,000 acre feet (42% 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 - February 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       129       144    |      155       152    |       166       181            102
                                                                    |                       |
WIND RIVER abv Bull Lake Cr (2)      APR-SEP       679       748    |      795       148    |       842       911            538
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP       796       900    |      970       150    |      1040      1144            648
                                                                    |                       |
WIND RIVER below Boysen (2)          APR-SEP       978      1170    |     1300       161    |      1430      1622            809
                                                                    |                       |
BULL LAKE CREEK near Lenore (2)      APR-SEP       194       218    |      235       128    |       252       276            183
                                                                    |                       |
LITTLE POPO AGIE RIVER near Lander   APR-SEP        55        67    |       75       144    |        83        95             52
                                                                    |                       |
SF LITTLE WIND RIVER nr Fort Washaki APR-SEP        97       108    |      115       142    |       122       133             81
                                                                    |                       |
LITTLE WIND RIVER near Riverton      APR-SEP       392       474    |      530       164    |       586       668            324
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of January               |        Watershed Snowpack Analysis - February 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     80.5     99.1     86.6 |   WIND RIVER above Dubios     7       125       183
                                                                        |
BOYSEN                                 596.0    542.9    572.4    580.7 |   LITTLE WIND                 2       108       133
                                                                        |
PILOT BUTTE                             31.6     23.6     22.1     16.5 |   POPO AGIE                   7       132       158
                                                                        |
                                                                        |   WIND above Boysen Resv     15       128       168
                                                                        |
==================================================================================================================================
 * 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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