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Loss Rates from Lake Powell and Their Impact on Management of the Colorado River
Author(s) -
Myers Tom
Publication year - 2013
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/jawr.12081
Subject(s) - inflow , environmental science , hydrology (agriculture) , water storage , groundwater , water balance , tributary , water resources , geology , meteorology , geography , cartography , geomorphology , ecology , geotechnical engineering , inlet , biology
As demand for water in the southwestern U nited S tates increases and climate change potentially decreases the natural flows in the C olorado R iver system, there will be increased need to optimize the water supply. L ake P owell is a large reservoir with potentially high loss rates to bank storage and evaporation. Bank storage is estimated as a residual in the reservoir water balance. Estimates of local inflow contribute uncertainty to estimates of bank storage. Regression analyses of local inflow with gaged tributaries have improved the estimate of local inflow. Using a stochastic estimate of local inflow based on the standard error of the regression estimator and of gross evaporation based on observed variability at L ake M ead, a reservoir water balance was used to estimate that more than 14.8 billion cubic meters (Gm 3 ) has been stored in the banks, with a 90% probability that the value is actually between 11.8 and 18.5 Gm 3 . Groundwater models developed by others, observed groundwater levels, and simple transmissivity calculations confirm these bank storage estimates. Assuming a constant bank storage fraction for simulations of the future may cause managers to underestimate the actual losses from the reservoir. Updated management regimes which account more accurately for bank storage and evaporation could save water that will otherwise be lost to the banks or evaporation.