Informing groundwater policies in semi-arid agricultural production regions under stochastic climate scenario impacts

Abstract

Region-specific groundwater policies are required to regulate groundwater extraction for agricultural irrigation and reduce climate change adaption externalities. We examine the semi-arid Seewinkel region in Austria and explore interactions between climatic, agronomic, hydrological, and socio-economic conditions and processes to provide policy advice. The assessment is conducted with a spatially explicit integrated modeling framework to analyze impacts on land and irrigation water use, land management, and net benefits of agricultural production. The model results show that with imposed groundwater restrictions for irrigation, land use shifts from irrigated vineyards to mostly rainfed cropland with declining regional net benefits of agricultural production. The direction of change is similar for a DRY, SIMILAR, and WET climate scenario, while the magnitude differs. We estimate that an increase of the marginal value of groundwater extraction for irrigation by 0.1 €/m3 results in an average decrease in groundwater extraction volumes by 17.2 Mm3 in DRY, 6.3 Mm3 in SIMILAR, and 6.4 Mm3 in WET. Furthermore, regional net benefits of agricultural production decrease by 3.4 M€ in DRY and SIMILAR, and by 1.6 M€ in WET, on average. Our assessment highlights that efficient groundwater policies can help to sustain groundwater availability in semi-arid regions, particularly under climate change.