Long-term (1986-2015) water use characterization over the upper Rio Grande basin using Landsat-based evapotranspiration

Authors: SENAY, GABRIEL - U.S. GEOLOGICAL SURVEY (USGS); SCHAUER, MATTHEW - INNOVATE!, INC.; VELPURI, NAGA - ASRC RESEARCCH AND TECHNOLOGY SOLUTIONS; SINGH, RAMESH - ASRC RESEARCCH AND TECHNOLOGY SOLUTIONS; KAGONE, STEFANIE - ASRC RESEARCCH AND TECHNOLOGY SOLUTIONS; FRIEDRICHS, MACKENZIE - ASRC RESEARCCH AND TECHNOLOGY SOLUTIONS; LITVAK, MARCY - UNIVERSITY OF NEW MEXICO; Mankin, Kyle

Submitted to: Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/2019
Publication Date: 7/4/2019
Citation: Senay, G.B., Schauer, M., Velpuri, N.M., Singh, R.K., Kagone, S., Friedrichs, M., Litvak, M.E., Douglas-Mankin, K.R. 2019. Long-term (1986-2015) water use characterization over the upper Rio Grande basin using Landsat-based evapotranspiration. Remote Sensing. 11(13):1-25. https://doi.org/10.3390/rs11131587.
DOI: https://doi.org/10.3390/rs11131587

Interpretive Summary: Evaluation of historical water use in the Upper Rio Grande Basin (URGB) using Landsat-derived actual evapotranspiration (ETa) from 1986 to 2015 is presented here as a first of its kind study applying satellite observations for quantifying long term, basin-wide crop consumptive use at a large basin. The rich archive of Landsat imagery combined with the Operational Simplified Surface Energy Balance (SSEBop) model was used to estimate and map ETa across the basin and over irrigated fields for historical characterization of water use dynamics. Monthly ETa estimates were evaluated using six eddy covariance flux towers showing strong correspondence (R2 > 0.80), with reasonable error rates (root mean square error between 6 and 19 mm/month). Detailed spatiotemporal analysis using peak growing season (June-August) ETa over irrigated areas revealed declining regional crop water use patterns throughout the basin, a trend reinforced through comparisons with gridded ETa from the Max Planck Institute. Seasonal ETa in Colorado, New Mexico, and Texas/Mexico regions were shown to use 50%, 33%, and 17% of the basin’s irrigated crop water, respectively. All regions showed a decline in water use during recent years as compared to the 1990s, but only Texas (-27%) and New Mexico (-16%) regions showed a statistically significant decline. The interrelationships among seven agrohydroclimatic variables (ETa, Normalized Difference Vegetation Index, Land Surface Temperature, Maximum Air Temperature, potential ET, precipitation, and runoff) are all summarized to support the assessment and context of historical water use dynamics over 30 years in the URGB.

Technical Abstract: Evaluation of historical water use in the Upper Rio Grande Basin (URGB) using Landsat-derived actual evapotranspiration (ETa) from 1986 to 2015 is presented here as a first of its kind study applying satellite observations for quantifying long term, basin-wide crop consumptive use at a large basin. The rich archive of Landsat imagery combined with the Operational Simplified Surface Energy Balance (SSEBop) model was used to estimate and map ETa across the basin and over irrigated fields for historical characterization of water use dynamics. Monthly ETa estimates were evaluated using six eddy covariance (EC) flux towers showing strong correspondence (R2 > 0.80), with reasonable error rates (root mean square error between 6 and 19 mm/month). Detailed spatiotemporal analysis using peak growing season (June-August) ETa over irrigated areas revealed declining regional crop water use patterns throughout the basin, a trend reinforced through comparisons with gridded ETa from the Max Planck Institute (MPI). The interrelationships among seven agrohydroclimatic variables (ETa, Normalized Difference Vegetation Index (NDVI), Land Surface Temperature (LST), Maximum Air Temperature (Ta), potential ET (ETo), precipitation, and runoff) are all summarized to support the assessment and context of historical water use dynamics over 30 years in the URGB.