T327 Remote Sensing Applications in Hydrology and Geology

Wednesday, 25 October 2017
1:30 PM - 5:30 PM
Room 615/616/617

MAPPING ANNUAL IRRIGATION DYNAMICS IN THE NORTHERN US HIGH PLAINS AQUIFER USING LANDSAT SATELLITE DATA

Paper number: T327-2
Program: Technical Sessions
Time: 1:45 PM – 2:00 PM

Authors

Abstract

Irrigated agriculture is the largest consumer of freshwater globally. Effective water management is crucial to support ongoing agricultural intensification to meet increasing demand for food, fuel, and fiber production. Knowledge of where and when irrigation occurs is needed for management and hydrological modeling, yet data on patterns of irrigation through time are not common. Here, we produced annual, high resolution (30 m) irrigation maps across the greater Republican River Basin region of the High Plains Aquifer for 1999-2016 by combining all available Landsat satellite imagery with climate and soil covariables in Google Earth Engine. Random forest classification had accuracies from 92-100% and generally agreed with county statistics (r2 = 0.88-0.96). Two novel indices we developed to integrate plant greenness and moisture information scored highest on variable importance metrics, suggesting they may improve satellite classification of irrigation in other regions. We found considerable interannual variability in irrigation location and extent, including fields added and/or removed from irrigation, that correspond to sub-regional differences in regulations and water source. Statistical modeling suggested precipitation and commodity price interact to influence irrigated extent through time. High prices incentivized expansion to increase crop yield and profit, but dry years required greater irrigation intensity, thus reducing area in this supply-limited region. We then combined our satellite-derived estimates of irrigated area with existing volumetric datasets to examine trends in irrigation depth over time. Datasets produced with this approach can provide a basis for enhancing water sustainability by providing consistent, spatially explicit tracking of irrigation dynamics over time.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-304275

© Copyright 2017 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.