Lower North Platte River Basin
February 1997

Snow
Higher than normal snowfall across the basin has caused near record snow water equivalent (SWE). Deer and LaPrele Creeks are currently at 175 percent of average. The Sweetwater drainage is 179 percent. The North Platte above the Laramie river drainage is about 60 percent above average. The basin average SWE is now 158 percent of normal. This is 28 percent ahead of what it was last year at this time. For more information see Basin Summary of Snow Courses at beginning of report.

Precipitation
January precipitation in the basin varied quite a lot. Of the reporting stations, Leo came in with 30 percent of average precipitation for the month, while Bates Creek reported 248 percent of the January average. Three stations reported over 200 percent for the month. January precipitation for the basin was 148 percent of average (101 percent of last year). The water year-to-date precipitation for the basin is currently 154 percent of average (21 percent ahead of last year).

Reservoir
Basin Reservoir storage is in good shape. Storage at all of the reservoirs is near average to well above average. Reservoir storage is as follows: Alcova 155,800 acre feet (100 percent of average), Glendo 330,800 acre feet (95 percent of average), Guernsey 6,800 acre feet (221 percent of normal), Pathfinder 553,000 acre feet (156 percent of average), Seminoe 467,000 acre feet (151 percent of average), and Wheatland No. Two 40,100 acre feet (127 percent of average).

Streamflow
At this time, above average yields are expected over the entire basin during the April to September forecast period. All the following values are based on the fifty percent chance probability runoff. The highest forecast is the Sweetwater Drainage at 219 percent of average (160,000 acre feet). Below Guernsey, the North Platte River should flow near 169 percent of average (1,670,000 acre feet). Deer Creek is forecast to flow 70,000 acre feet (180 percent of average). LaPrele Creek should yield 160 percent of average (40,000 acre feet). North Platte below Glendo should yield about 166 percent of average (1,600,000 acre feet). Laramie River near Woods should yield about 180 percent of average (133,000 acre feet). The Little Laramie near Filmore should flow 90,000 acre feet (141 percent of average).

==================================================================================================================================
                                      LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS
                                               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)
====================================================================|=======================|=====================================
SEMINOE RESERVOIR INFLOW             APR-JUL      1165      1305    |     1400       175    |      1495      1635            800
                                                                    |                       |
SWEETWATER RIVER nr Alcova           APR-JUL        96       127    |      150       217    |       175       216             69
                                     APR-SEP       131       141    |      160       219    |       179       193             73
                                                                    |                       |
DEER CREEK at Glenrock               APR-SEP        39        58    |       70       180    |        83       101             39
                                                                    |                       |
LaPRELE CREEK above Reservoir        APR-SEP        25        34    |       40       160    |        46        55             25
                                                                    |                       |
NORTH PLATTE RIVER blw Glendo        APR-SEP      1204              |     1600       166    |                2013            963
                                                                    |                       |
NORTH PLATTE R. blw Guernsey         APR-SEP      1256              |     1670       169    |                2097            989
                                                                    |                       |
LARAMIE RIVER near Woods             APR-SEP       127       159    |      180       133    |       201       233            135
                                                                    |                       |
LITTLE LARAMIE RIVER near Filmore    APR-SEP        71        82    |       90       141    |        98       109             64
                                                                    |                       |
==================================================================================================================================
          LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS         |  LOWER NORTH PLATTE, SWEETWATER & LARAMIE RIVER BASINS
             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
========================================================================|=========================================================
ALCOVA                                 184.3    155.8    156.7    156.1 |   SWEETWATER                  4       151       179
                                                                        |
GLENDO                                 506.4    315.9    270.1    330.8 |   DEER & LaPRELE CREEKS       4       132       175
                                                                        |
GUERNSEY                                45.6     15.0     18.2      6.8 |   N PLATTE abv Laramie R.    28       129       160
                                                                        |
PATHFINDER                            1016.5    861.9    723.9    553.0 |   LARAMIE RIVER abv Laramie   8       112       138
                                                                        |
SEMINOE                               1016.7    707.3    783.7    467.0 |   LITTLE LARAMIE RIVER        4       131       155
                                                                        |
WHEATLAND #2                            98.9     51.0     65.0     40.1 |   LARAMIE RIVER above mouth  11       119       145
                                                                        |
NORTH PLATTE PROJ                     1062.1    764.3    984.2    601.0 |   NORTH PLATTE               35       128       158
                                                                        |
KENDRICK PROJECT                      1201.7    981.3    654.9    819.1 |
                                                                        |
GLENDO PROJECT USERS                   183.2    149.6    157.6    119.8 |
                                                                        |
==================================================================================================================================
 * 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.

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