Adaptation of Multiobjective Reservoir Operations to Snowpack Decline in the Western United States
Adaptation of Multiobjective Reservoir Operations to Snowpack Decline in the Western United States
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DOI：
10.1061/(asce)wr.1943-5452.0001300
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发表时间：
2020-12-01
影响因子：
3.1
通讯作者：
Herman, Jonathan D.
中科院分区：
文献类型：
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作者：
Cohen, Jonathan S.;Zeff, Harrison B.;Herman, Jonathan D.
长期积雪减少是气候变化对水资源系统的最佳影响之一。这种趋势已经观察了几十年，即使在总径流量没有显着变化的气候预测中，预计也会持续下去。对于积雪在历史上提供年内蓄水的流域，积雪减少造成了几个问题，可能需要适应基础设施，运营或两者兼而有之。本研究开发了一种方法来分析脆弱性和适应性，特别是侧重于积雪下降的挑战，使用北方加州水库系统作为案例研究。我们首先介绍了一个开源的每日时间步长模拟模型，该系统，这是对操作的历史观察进行验证。多目标脆弱性积雪下降，然后检查使用一套缩小规模的气候情景，以捕捉温度上升的物理基础的影响。统计分析表明，主要影响是由于径流时序的季节性变化导致的供水短缺和水库蓄水量减少。从脆弱性评估中确定的这些挑战为拟议的业务调整提供了信息，以在未来可能的情景中保持多目标性能，其中包括其他不确定的水文变化。为了适应季节性水库管理，而无需额外的基础设施的成本，我们特别提出和测试适应参数化的结构，现有的运营政策：一个动态的洪水控制规则曲线和修改积雪径流预测方法，以提高季节性径流的可预测性下降积雪。这些适应性，以减轻大多数的脆弱性所造成的积雪下降的情况下合奏，其余的机会，使用正式的政策搜索和动态适应技术的改进。脆弱性评估和适应的结合方法可推广到其他因气温上升而面临季节性储存损失的以融雪为主的水资源系统。(c)2020年美国土木工程师协会
Long-term snowpack decline is among the best-understood impacts of climate change on water resources systems. This trend has been observed for decades and is projected to continue even in climate projections in which total runoff volumes do not change significantly. For basins in which snowpack has historically provided intra-annual water storage, snowpack decline creates several issues that may require adaptation to infrastructure, operations, or both. This study develops an approach to analyze vulnerabilities and adaptations specifically focused on the challenge of snowpack decline, using the northern California reservoir system as a case study. We first introduce an open-source daily time-step simulation model of this system, which is validated against historical observations of operations. Multiobjective vulnerabilities to snowpack decline are then examined using a set of downscaled climate scenarios to capture the physically based effects of rising temperatures. A statistical analysis shows that the primary impacts include water supply shortage and lower reservoir storage resulting from the seasonal shift in runoff timing. These challenges identified from the vulnerability assessment inform proposed adaptations to operations to maintain multiobjective performance across the ensemble of plausible future scenarios, which include other uncertain hydrologic changes. To adapt seasonal reservoir management without the cost of additional infrastructure, we specifically propose and test adaptations that parameterize the structure of existing operating policies: a dynamic flood control rule curve and revised snowpack-to-streamflow forecasting methods to improve seasonal runoff predictability given declining snowpack. These adaptations are shown to mitigate the majority of vulnerabilities caused by snowpack decline across the scenario ensemble, with remaining opportunities for improvement using formal policy search and dynamic adaptation techniques. The coupled approach to vulnerability assessment and adaptation is generalizable to other snowmelt-dominated water resources systems facing the loss of seasonal storage due to rising temperatures. (c) 2020 American Society of Civil Engineers.