Wind River Basin (3)
March 2000

Snow
The Wind River basin has well below average snow water equivalent (SWE) for this time of the year. The Wind River above Dubois is 81 percent of average (67 percent of last year). The Little Wind is 61 percent of average water content (51 percent of last year), and the Popo Agie drainage is about 63 percent of average (65 percent of last year). The Wind River basin, above Boysen Reservoir, SWE is about 67 percent of average (about 65 percent of last year). See the Basin Summary of Snow Course Data at the front of this report for details.

Precipitation
February precipitation in the basin varied from 44 to 240 percent of average. February precipitation for the basin was about 100 percent of average for the 8 reporting stations; that is about 66 percent of last year's amount. Water year-to-date precipitation is 72 percent of normal. The current water-year-to-date average is about 62 percent of last year at this time. Year to date figures range from 15 to 79 percent of average.

Reservoirs
Current storage varies from 95 to 127 percent of average. Bull Lake is currently storing about 95,200 acre feet (63 percent of capacity) -- normally the reservoir is at 56 percent of capacity at this time of the year. Boysen Reservoir is storing about 88 percent of capacity 527,300 acre feet) -- normally the reservoir is at 93 percent of capacity at this time of the year. Pilot Butte is storing 71 percent of capacity (22,400 acre feet) -- normally the reservoir is at 56 percent of capacity at this time of the year.

Streamflow
Water supply is estimated to be 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 475,000 acre feet (88 percent of average). Wind River at Riverton will yield about 540,000 acre feet (83 percent of average). Boysen Reservoir inflow will yield about 590,000 acre feet (73 percent of normal). Bull Lake Creek near Lenore is expected to yield about 156,000 acre feet (85 percent of average). Little Popo Agie River near Lander is expected to yield about 36,000 acre feet (69 percent of average). South Fork of Little Wind near Fort Washakie will yield about 60,000 acre feet (74 percent of average). Little Wind River near Riverton will yield about 210,000 acre feet (65 percent of average). 

==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - March 1, 2000
==================================================================================================================================
                                              |  <<====== 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       369       432    |      475        88    |       518       581            538
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP       321       451    |      540        83    |       629       759            648
                                                                    |                       |
BOYSEN RESERVOIR Inflow (2)          APR-SEP       268       460    |      590        73    |       720       912            809
                                                                    |                       |
BULL LAKE CR near Lenore (2)         APR-SEP       116       140    |      156        85    |       172       196            183
                                                                    |                       |
LT POPO AGIE RIVER nr Lander         APR-SEP      17.2        28    |       36        69    |        44        55             52
                                                                    |                       |
SF LT WIND nr Fort Washakie          APR-SEP        32        49    |       60        74    |        71        88             81
                                                                    |                       |
LT WIND RIVER nr Riverton            APR-SEP        58       149    |      210        65    |       271       362            324
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of February              |        Watershed Snowpack Analysis - March 1, 2000
==================================================================================================================================
                                      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     95.2     97.8     85.0 |   WIND RIVER above Dubios     7        67        80
                                                                        |
BOYSEN                                 596.0    527.3    550.0    555.2 |   LITTLE WIND                 2        51        61
                                                                        |
PILOT BUTTE                             31.6     22.4     22.0     17.7 |   POPO AGIE                   6        65        63
                                                                        |
                                                                        |   WIND above Boysen Resv     14        65        72
                                                                        |
==================================================================================================================================
 * 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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