摘要：Declining water tables are causing wells to run dry in California, but the prevalence and spatial distribution of wells that have run dry are not known beyond anecdotal and voluntary reports. Here, we apply a new, simple, and measurement‐driven method to calculate a localized water table; we show, for the first time using observations, that up to one‐in‐five wells now runs dry in California's Central Valley. The spatial distribution of wells identified as having dried up replicates hot spots of wells identified as having run dry in a voluntary reporting system, while also capturing impacts on groundwater wells that have not reportedly run dry. We assess the rates of drilling throughout the Central Valley and find, surprisingly, that domestic wells are being drilled deeper at a rate that exceeds agricultural wells across much of the central Central Valley. Because new groundwater wells are costly (i.e., $10,000 to $100,000), we suggest explicitly considering dry wells in groundwater sustainability planning to protect homes and farms from the loss of access to reliable water supplies in the future. Plain Language Abstract Anecdotal evidence suggests that groundwater level declines are causing wells to run dry in California's Central Valley, threatening access to reliable water supplies. Here we show with observational data that thousands of wells ran dry at the peak of the recent drought, especially in the southeastern Central Valley. We use groundwater well construction data to show that domestic water wells ran dry in disproportionate numbers, because typical domestic wells are shallower than typical agricultural wells. The results of this work can be used as water agencies are considering current and future impacts of groundwater depletion on groundwater users.
