Wind River Basin (3)
February 2001

Snow
The Wind River basin has much below average snow water equivalent (SWE) for this time of the year. SWE in the Wind River above Dubois is 50 percent of average (67 percent of last year). The Little Wind SWE is 42 percent of average water content (78 percent of last year), and the Popo Agie drainage SWE is about 50 percent of average (82 percent of last year). The Wind River basin, above Boysen Reservoir, SWE is about 49 percent of average (about 72 percent of last year). See the Basin Summary of Snow Course Data at the front of this report for details.

Precipitation
January precipitation in the basin varied from 3 to 122 percent of average, but most of the basin was less than 30 percent of average. January precipitation for the basin was about 13 percent of average for the 12 reporting stations; that is about 12 percent of last year's amount. Water year-to-date precipitation is 50 percent of normal. The current water- year-to-date average is about 79 percent of last year at this time. Year to date figures range from 33 to 99 percent of average.

Reservoirs
Current storage varies from 72 to 142 percent of average. Bull Lake is currently storing about 62,600 acre feet (41 percent of capacity) -- normally the reservoir is at 57 percent of capacity at this time of the year. Boysen Reservoir is storing about 75 percent of capacity 445,500 acre feet) -- normally the reservoir is at 97 percent of capacity at this time of the year. Pilot Butte is storing 74 percent of capacity (23,500 acre feet) -- normally the reservoir is at 52 percent of capacity at this time of the year.

Streamflow
Water supply is estimated to be much 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 360,000 acre feet (67 percent of average). Wind River at Riverton will yield about 365,000 acre feet (56 percent of average). Boysen Reservoir inflow will yield about 500,000 acre feet (62 percent of normal). Bull Lake Creek near Lenore is expected to yield about 120,000 acre feet (66 percent of average). Little Popo Agie River near Lander is expected to yield about 23,500 acre feet (45 percent of average). South Fork of Little Wind near Fort Washakie will yield about 51,000 acre feet (63 percent of average). Little Wind River near Riverton will yield about 190,000 acre feet (59 percent of average). 
==================================================================================================================================
                                                         WIND RIVER BASIN
                                               Streamflow Forecasts - February 1, 2001
==================================================================================================================================
                                              |  <<====== 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       280       328    |      360        67    |       409       480            538
                                                                    |                       |
WIND RIVER at Riverton (2)           APR-SEP       233       311    |      365        56    |       460       601            648
                                                                    |                       |
BOYSEN RESERVOIR Inflow (2)          APR-SEP       299       421    |      500        62    |       630       822            809
                                                                    |                       |
BULL LAKE CR near Lenore (2)         APR-SEP        93       110    |      120        66    |       137       161            183
                                                                    |                       |
LT POPO AGIE RIVER nr Lander         APR-SEP       9.9      18.2    |       24        45    |        36        54             52
                                                                    |                       |
SF LT WIND nr Fort Washakie          APR-SEP        32        44    |       51        63    |        63        80             81
                                                                    |                       |
LT WIND RIVER nr Riverton            APR-SEP       104       156    |      190        59    |       250       339            324
                                                                    |                       |
==================================================================================================================================
                            WIND RIVER BASIN                            |                    WIND RIVER BASIN
             Reservoir Storage (1000 AF) - End of January               |        Watershed Snowpack Analysis - February 1, 2001
==================================================================================================================================
                                      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     62.6     95.0     86.6 |   WIND RIVER above Dubios     7        71        50
                                                                        |
BOYSEN                                 596.0    445.5    531.3    580.7 |   LITTLE WIND                 2        77        42
                                                                        |
PILOT BUTTE                             31.6     23.5     22.5     16.5 |   POPO AGIE                   6        85        50
                                                                        |
                                                                        |   WIND above Boysen Resv     14        74        49
                                                                        |
==================================================================================================================================
 * 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.
To February 2001 Basin Outlook Report Contents Page