Remote detection of water management impacts on evapotranspiration in the Colorado River Basin. Issue 10 (27th May 2016)

• Record Type: Journal Article
• Authors: Castle, Stephanie L.; Reager, John T.; Thomas, Brian F.; Purdy, Adam J.; Lo, Min‐Hui; Famiglietti, James S.; Tang, Qiuhong
• Is Part Of: Geophysical research letters. Volume 43:Issue 10(2016)
• Page Start: 5089
• Page End: 5097
• Publication Date: 2016-05-27
• Subjects: Colorado River Basin -- evapotranspiration -- GRACE -- land surface models -- water management -- water budget; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL068675
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The complexity involved in accurate estimation and numerical simulation of regional evapotranspiration (ET) can lead to inconsistency among techniques, usually attributed to methodological deficiencies. Here we hypothesize instead that discrepancies in ET estimates should be expected in some cases and can be applied to measure the effect of anthropogenic influences in developed river basins. We compare an ensemble of corrected ET estimates from land surface models with Gravity Recovery and Climate Experiment and Moderate Resolution Imaging Spectroradiometer satellite‐based estimates in the intensively managed Colorado River Basin to contrast the roles of natural variability and human impacts. Satellite‐based approaches yield larger annual amplitudes in ET estimates than land surface model simulations, primarily during the growing season. We find a total satellite‐based ET flux of 142 ± 7 MAF yr −1 (175 ± 8.63 km 3 yr −1 ), with 38% due to anthropogenic influences during summer months. We evaluate our estimates by comparison with reservoir storage and usage allotment components of the basin water management budget. Key Points: Satellite observations used to infer role of water management in ET rates Satellite estimates of ET are larger during summer months compared to model estimates Basin‐wide observed ET is 142 MAF/yr (175 km3 yr −1 ) with 38% due to management impacts in summer