The interlinkages between water for irrigation and for fish habitat are complex. This is particularly true in the Stung Chinit, a tributary to one of the most robust fisheries in the world, where livelihoods rely heavily on rice production and fishing and there is pressure to increase rice production with increased irrigation. This study assesses the tradeoffs between various management options and irrigation strategies in the Stung Chinit watershed under multiple projections of climate change. Due to the relative demands for instream flows and rice, if dry season rice is widely promoted, flows will be severely impacted. However, implementing a flow requirement protects these flows, while only causing minor shortages to rice when planted once or twice per year. These shortages may be alleviated with improved cooperation, management and shifting rice irrigation practices. While climate change will lead to warming temperatures and potentially higher demands for irrigation, the larger threat to rice and ecosystems appears to be water management (or lack thereof). This study suggests that there is sufficient water in the system to expand the irrigated area by 10%, grow rice twice per year and protect downstream flows under climate change; however, well-coordinated management is required to achieve this.

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roundwater is an important water supply source in California. On average, it provides 38% of California's total water supply (DWR 2015) and supports a $46 billion agricultural economy (USDA 2015). While the extent of groundwater use varies across the state, overall it has been increasing, from an estimated 9 million acre-feet in 1947 to 20.9 million acre-feet per year from 2005 to 2009 (DWR 2015). Groundwater contributes to farmers' economic stability by providing a buffer to water supply variability. However, over-reliance on groundwater has led to overdraft, which threatens its long-term sustainability. Until recently, groundwater use in California was mainly unregulated by the state and left largely to local management. With a few exceptions in adjudicated basins, groundwater could be pumped without restriction for beneficial use on the overlying land area. This has led to a "tragedy of the commons" (Hardin 1968), with individual groundwater pumpers rationally overusing the shared resource. RESEARCH ARTICLE How can we support the development of robust groundwater sustainability plans? A decision support process helped stakeholders in Yolo County understand the vulnerabilities of their groundwater situation and evaluate strategies to overcome them.

Managed aquifer recharge (or intentional recharge) is a purposeful human intervention designed to supplement natural enrichment processes of groundwater aquifers by various methods. It holds the potential to mitigate the impact of climate uncertainty on irrigated agriculture by restoring storage levels in depleted aquifers, the economic value of which increases during droughts. We use a high‐resolution dynamic regional hydroeconomic framework that endogenizes farming decisions in response to water quantity‐quality changes, as well as complex hydrogeological principles to analyze several institutional designs and climate scenarios applied to the Kings Groundwater Basin in California. Our analysis demonstrates that intentional recharge is of high benefit to the region, potentially increasing average groundwater levels in the region by 20% over a 20 year horizon. Additionally, we show how this practice could become the subject of second‐best arrangements among water users in the region in view of property rights to groundwater derived from recent legislation in California, thus increasing its materialization potential. However, we also find that the quantity recharged is sensitive to climate conditions and hydrological properties.