资源环境科技发展态势分析平台

Irrigation enhances agricultural yields and stabilizes farmer incomes, but overexploitation has depleted groundwater resources around the globe. Strategies to address this sustainability challenge differ widely. Socio-ecological systems research suggests that management of common pool resources like groundwater would benefit from localized approaches that combine self-organization along with active monitoring. In 2012, the US state of Kansas established a Local Enhanced Management Area (LEMA) program, empowering farmers to work with local and state officials to develop five-year, enforceable groundwater conservation programs. Here, we assessed the efficacy of the firstLEMA implemented from 2013 to 2017 using a causal impact methodology based on Bayesian structural time series that is new to agrohydrology. Compared to control scenarios, we found that the LEMAreduced water use by 31% over the five-year period, with early indications of stabilizing groundwater levels. Three main conservation strategies can lead to reduced water use: (1) reducing irrigated area, (2) reducing irrigation amount applied to existing crops through improved efficiency, and/or (3) switching to crops that require less water. To partition water savings among these strategies, we combined satellite-derived irrigated areas and crop type maps with well records. Wefound that farmers were able to largely maintain irrigated area and achieved the majority of pumping reductions (72%) from improvements in irrigation efficiency, followed by expansion of crops with lower water demand (19%). The results of this analysis demonstrate that conservation programs that are irrigatordriven with regulatory oversight can provide a path toward sustainability in stressed aquifers.