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Understanding satellite‐based monthly‐to‐seasonal reservoir outflow estimation as a function of hydrologic controls
Author(s) -
Bonnema Matthew,
Sikder Safat,
Miao Yabin,
Chen Xiaodong,
Hossain Faisal,
Ara Pervin Ismat,
Mahbubur Rahman S. M.,
Lee Hyongki
Publication year - 2016
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2015wr017830
Subject(s) - outflow , inflow , precipitation , surface runoff , environmental science , hydrology (agriculture) , structural basin , water balance , snow , estimation , satellite , geology , meteorology , geography , ecology , paleontology , geotechnical engineering , management , economics , biology , aerospace engineering , engineering
Growing population and increased demand for water is causing an increase in dam and reservoir construction in developing nations. When rivers cross international boundaries, the downstream stakeholders often have little knowledge of upstream reservoir operation practices. Satellite remote sensing in the form of radar altimetry and multisensor precipitation products can be used as a practical way to provide downstream stakeholders with the fundamentally elusive upstream information on reservoir outflow needed to make important and proactive water management decisions. This study uses a mass balance approach of three hydrologic controls to estimate reservoir outflow from satellite data at monthly and annual time scales: precipitation‐induced inflow, evaporation, and reservoir storage change. Furthermore, this study explores the importance of each of these hydrologic controls to the accuracy of outflow estimation. The hydrologic controls found to be unimportant could potentially be neglected from similar future studies. Two reservoirs were examined in contrasting regions of the world, the Hungry Horse Reservoir in a mountainous region in northwest U.S. and the Kaptai Reservoir in a low‐lying, forested region of Bangladesh. It was found that this mass balance method estimated the annual outflow of both reservoirs with reasonable skill. The estimation of monthly outflow from both reservoirs was however less accurate. The Kaptai basin exhibited a shift in basin behavior resulting in variable accuracy across the 9 year study period. Monthly outflow estimation from Hungry Horse Reservoir was compounded by snow accumulation and melt processes, reflected by relatively low accuracy in summer and fall, when snow processes control runoff. Furthermore, it was found that the important hydrologic controls for reservoir outflow estimation at the monthly time scale differs between the two reservoirs, with precipitation‐induced inflow being the most important control for the Kaptai Reservoir and storage change being the most important for Hungry Horse Reservoir.