INFEWS/T2: The sustainability-productivity tradeoff: Water supply vulnerabilities and adaptation opportunities in California?s coupled agricultural and energy sectors

水资源供应、农业生产和发电三者之间的相互依存关系已经得到了很好的确立，但要理解这些部门中的任何一个部门的决策或资源中断如何影响整个系统，仍然存在重大挑战。没有哪个地方比加州面临的挑战更紧迫了，尽管长期缺水，加州的农业产量仍以两倍的优势领先全国。在加州，不稳定的气候预计会增加干旱的频率和严重程度，对地表水的可用性产生高度不确定的影响。对加州中央谷地的发电和农业的后续影响将密切相关。山谷的地表水供应主要是由内华达山脉的融雪驱动的，这些融雪被储存并分配到灌溉区用于粮食生产。然而，在干旱期间，灌溉者必须抽取地下水来弥补稀缺的地表水。因此，地下水抽水的电力需求增加了33%，主要是在夏季，城市电力需求也达到高峰。干旱期间径流的减少也意味着水力发电的减少（约占加州发电量的20%），迫使电力公司依赖更昂贵的天然气发电。电力需求的增加和对天然气依赖的增加导致电价上涨。因此，在电价最高的时候，水资源短缺促使灌溉者抽更多的地下水，如果地下水水位继续历史下降，这一活动将变得更加昂贵。这些问题说明了加州食物-能源-水（FEW）系统所面临的耦合挑战，包括从全州范围内的基础设施规划和管理到当地灌区和农场层面的决策等多个层面的治理。本研究的主要贡献是为加州少数系统（CalFEW）设计和集成一个开源建模-仿真框架，具有交互式可视化，灵敏度分析和多目标优化工具，以发现关键漏洞和跨部门权衡。这个新的决策支持框架将实现四个主要的科学目标。首先，它将确定气候变化引起的变异对内华达山脉降水和径流的数量、时间和位置的影响。其次，这些知识将被整合到CalFEW中，以提高对耦合系统如何应对未来水资源短缺、商品价格动态和监管变化等冲击的理解。第三，它将利用CalFEW开发一套新的工具，以减少供应/金融风险，并激励农业部门更可持续的水电消费。最后，该项目将设计和测试风险管理工具组合，以平衡短期生产力和跨部门和空间尺度的长期稳健性/弹性。所有的任务都将依赖于与一组不同的决策者的合作，以了解他们对未来风险、候选政策行动和系统性能的首选度量的观点将如何影响新的、更协调的管理方法的采用。

The interdependence of water availability, agricultural production, and electric power generation is well established, yet significant challenges remain for understanding how decisions or resource disruptions in any one of these sectors impact the system as a whole. Nowhere is this challenge more pressing than California, which, despite chronic water scarcity, continues to lead the nation in agricultural production by a factor of two. In California, nonstationary climate is expected to increase the frequency and severity of drought, with highly uncertain impacts on the availability of surface water. The subsequent effects on statewide electricity generation and agriculture in California's Central Valley will be closely linked. Surface water availability in the Valley is largely driven by snowmelt from the Sierra Nevada, which is stored and distributed to irrigation districts for food production. During drought, however, irrigators must pump groundwater to compensate for scarce surface water. As a result, electricity demand from groundwater pumping rises by up to 33%, primarily during summer months when urban electricity demands also peak. Reduced runoff during drought also translates to less hydro-power generation (which accounts for ~20% of California's capacity), forcing electric utilities to rely on more expensive natural gas generation. The combination of higher electricity demand and increased reliance on natural gas leads to higher electricity prices. Thus water scarcity drives irrigators to pump significantly more groundwater when electricity prices are highest, an activity that becomes still more expensive if groundwater levels continue their historical decline. These issues illustrate the coupled challenges facing California's food-energy-water (FEW) systems, encompassing multiple scales of governance, from statewide planning and management of infrastructure to local irrigation district and farm-level decisions.The overarching contribution of this research is the design and integration of an open source modeling- simulation framework for the California FEW systems (CalFEW), with interactive visualization, sensitivity analysis, and multi-objective optimization tools to discover key vulnerabilities and tradeoffs across sectors. This new decision support framework will achieve four major scientific objectives. First, it will determine the impacts of climate change-induced variability on the amount, timing, and location of precipitation and runoff in the Sierra Nevada range. Second, this knowledge will be integrated into CalFEW to improve understanding of how the coupled systems will respond to future shocks in the form of water scarcity, commodity price dynamics and regulatory change. Third, it will leverage CalFEW to develop a suite of novel tools for reducing supply/financial risk and incentivizing more sustainable water-electricity consumption in the agriculture sector. Finally, the project will design and test portfolios of risk management tools to balance near-term productivity and long-term robustness/resilience across sectors and spatial scales. All tasks will rely on collaboration with a diverse group of decision-makers to understand how their perspectives on future risks, candidate policy actions, and preferred measures of system performance will affect the adoption of new, more coordinated management approaches.