SWSIReportMay2008 - Laserfiche WebLink

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SAN JUAN/DOLORES BASIN Basinwide Conditions Assessment The SWSI value for the month was 1.4. The Natural Resources Conservation Service reports that May 1 snowpack is 103% of normal. Storage in McPhee, Vallecito, and Lemon reservoirs totaled 102% of normal as of the end of April. Flows at the Animas River at Durango averaged 1,120 cfs (133% of normal) with a maximum average daily peak flow of 1,910 cfs on April 30th. The Dolores River at Dolores averaged 1,076 cfs (145% of normal) with a maximum average daily peak flow of 1,940 cfs on April 24th. The La Plata River at Hesperus averaged 94.3cfs (116% of normal) with a maximum average daily peak flow of 168 cfs on April 30th. Precipitation in Durango was 0.28 inches for April which is below the 30-year average of 1.51 inches. Precipitation to date in Durango, for the water year, is 13.61 inches which is above the average of 11.36 inches. Temperatures were near normal for the month. Durango was 1.10 above its 30-year average high and 1T below the 30- year average low. At the end of the month Vallecito Reservoir contained 42,460 acre-feet compared to its normal contents of 63,579 acre-feet (67% of normal). Vallecito Reservoir began releasing water in early February to prepare for the expected above average inflows. McPhee Reservoir was up to 344,641 acre-feet compared to its normal contents of 293,696 acre-feet (117% of normal), while Lemon Reservoir was up to 21,660 acre-feet as compared to its normal content of 22,612 acre-feet (96% of normal). Outlook Very little precipitation, normal temperatures and a lot of wind was the major theme of April 2008. With only 0.28 inches of precipitation in April it ranked as one of the lowest monthly totals on record for the last 112 years (102 of 112). High winds have taken their toll on the above average snow pack accumulated during December, January and February. Above average to average flows are still expected throughout the basin this spring and summer but the near normal temperatures have kept the cold storage in the mountains. Administrative/Manaqement Concerns The compact period on the La Plata between Colorado and New Mexico began on February 15th. The compact remained off call for most of the month. New Mexico placed a call starting on April 30th for half the flow at the upper index gage up to 80cfs. The compact requires that half the flow at the upper index gages (Hesperus and above) must be delivered across the Stateline the following day. The low level snow melting in the La Plata River basin has kept the flow at the Stateline well above the flows at Hesperus for most of the month. Public Use Impacts Vallecito and Navajo reservoirs began ratcheting back releases as the recent decrease in snow pack has decreased the expected above average spring runoff. May-08 SAN J..IIIN.lXl.rnESB\SIN9JIS HSTCRY f- W S w ::: <t > 0 x w o z .1 >- 0:: o .2 .3 .. .m.ffi JmDJ -""01 JmD2 .m.(lJ JmD4 .m.C6 Jm03 .m.07 Jm-08 M:N1H/YEAR ANMAS RIVER NR DURANGO, FLOW BY WATER YEAR 1,000,000 900,000 Q) 800,000 " LL " 700,000 " <t S" 600,000 0 -' 500,000 LL w > 400,000 >= <t -' 300,000 ::J ::< ::J 200,000 U 100,000 --- ~ / / / / .--- ~ / / / -' / ~ ~ ~ ~ ~ ...- .-- - o Oct Nov Cec Jan Feb March April May June July Aug Sept --<l-- WET (1973) -+- DRY (2002) -fr- AVG ""* 2CXJ8 REPRESENTATlVE RESERVQRS 400,000 350,000 3CXJ 000 Q) 2 ~ 2SJ,CCO ro <Ii ~ 2CXJ,CCO o Ii) ~ 150,000 ro <f> ::J 100,000 50,000 o MoPhee Vallecito Lerron II Avg.413O Contents 114130'08 Contents 9