Colorado State Basin Outlook Report

Home Browse Search

State Basin Outlook Reports ? ARKANSAS RIVER BASIN as of January 1, 2008 The 2008 water year started out with a dry October in the Arkansas River Basin, and remained very dry into November based on data from six Snotel sites. A very wet December, however, has left year to date precipitation in the Arkansas at an impressive 121% of average as of January 1. After starting out with 88% of its average precipitation in October, then a dismal 38% of average precipitation in November, the snow started flying early in December. December saw an incredible 232% of its average precipitation. Snow water eqwivalent numbers have followed suit, as the Arkansas basin as a whole has 141% of its average snowpack as of January 1, the highest January 1 snowpack since 1997. Snow levels are slightly higher in the southern sub-basins, as the Cucharas and Huerfano basins are at 164% of average (based on two Snotel sites), and the Purgatoire basin is at 156% of average (also based on two Snotel sites), while the Upper Arkansas has 118% of its average snowpack based on data from three Snotel sites. Based on data from 13 reservoirs, reservoir storage in the Arkansas Basin is slightly below average at 92% of average. At this time, expected streamflow volume for April through September is above average throughout the Arkansas Basin. Streamflow volumes are forecasted to range from 109% of average on the inflows to both Pueblo Reservoir and Trinidad Lake to 143% of average on Grape Creek near Westcliffe. -------------------------------------- -------------------------------------- ARKANSAS RIVER BASIN Streamflow Forecasts - January 1, 2008 Drier =_= Future Conditions =_= Wetter Forecast Pt Chance of Exceeding Forecast 1 90% 70% 1 50% 1 30% 10% 1 30 Yr Avg Period ----------- 1(1000AF) (1000AF)1(1000AF) ------------------------------ (% AVG.)1(1000AF) ------------------ (1000AF)I ---------- (1000AF) ----------- ----------- CHALK CK at ------------------- Nathrop ----------- ---------- -------- ---------- ----------- APR-JUL 14.2 21 26 113 32 41 23 APR-SEP 16.9 24 30 111 36 47 27 ARKANSAS RIVER at Salida (2) APR-JUL 198 245 280 110 315 375 255 APR-SEP 245 300 340 110 385 455 310 GRAPE CK nr Westcliffe APR-JUL 6.8 15.3 23 143 32 49 16.1 APR-SEP 13.0 21 28 143 36 49 19.6 PUEBLO RESERVOIR Inflow (2) APR-JUL 255 350 420 109 500 625 385 APR-SEP 340 450 530 109 620 765 485 HL7ERFANO RIVER nr Redwing APR-JUL 8.4 11.5 13.8 112 16.4 21 12.3 APR-SEP 11.0 14.6 17.3 112 20 25 15.5 CUCHARAS RIVER nr La Veta APR-JUL 4.7 9.0 12.7 112 17.0 25 11.3 APR-SEP 6.0 10.7 14.6 112 19.2 27 13.0 TRINIDAD LAKE Inflow (2) MAR-JUL 14.0 27 38 112 51 74 34 APR-SEP 21 36 48 109 62 87 44 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- * 90%, 70;s, 50%, 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 1971-2000 base period. Page 10 of 15 http://www.wcc.nres.usda.gov/cgibin/bor2.p1?state=co&year=2008&month=l&format=text 4/14/2008