Characterizing Groundwater-Climate-Irrigation Dynamics in the United States
Tuesday, April 26, 2016: 2:50 p.m.
Confluence Ballroom B (The Westin Denver Downtown)
Groundwater is a vital and dynamic resource which needs to be properly assessed, especially in a changing climate. In the United States and many developing agricultural regions around the world, groundwater is a major source of irrigation. Unfortunately, climate change and increasing demand for freshwater has threatened its sustainability and significant depletion has been noticed in most principal aquifers across the United States. Therefore, the understanding of long-term impacts of climate variability and change is a key challenge in order to address sustainability management strategies at regional/global scales. This study analyzes groundwater level spatio-temporal variability with response to changing climate and surface hydrologic conditions. Several studies have investigated relationships between groundwater levels and large scale climate patterns, however we present a high resolution analysis of groundwater level with local precipitation, ET, stream discharge, and modeled irrigation consumption over the contiguous United States. Several statistical methods were applied to assess the influence of these variables on groundwater level fluctuations and to explain the spatio-temporal variance of the time-series. These methods include spectral analysis, coherence analysis, and cross-correlation analysis along with impact of lags in the hydrologic time-series. The results obtained through these statistical techniques show significant impacts of climate signals on groundwater levels and thus, improve our understanding of the aquifer system behavior as well as how water level sensitivity varies with forcing changes across the United States.