A numerical surface-water/groundwater model was developed for the lower San Antonio River Basin to evaluate the responses of low base flows and groundwater levels within the basin under conditions of reduced recharge and increased groundwater withdrawals. Batch data assimilation through history matching used a simulation of historical conditions (2006-2013); this process included history-matching to groundwater levels and base-flow estimates at several gages, and was completed in a high-dimensional (highly parameterized) framework. The model was developed in an uncertainty framework such that parameters, observations, and scenarios of interest are envisioned stochastically as distributions of potential values. Results indicate that groundwater contributions to surface water during periods of low flow may be reduced from 6% to 25% with a corresponding 25% reduction in recharge and a 25% increase in groundwater pumping over an 8-year planning period. Furthermore, results indicate groundwater-level reductions in some hydrostratigraphic units are more likely than in other hydrostratigraphic units over an 8-year period under drought conditions with the higher groundwater withdrawal scenario.

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美国德克萨斯州圣安东尼奥河流域下游基于风险的决策支持地下水模型

为圣安东尼奥河流域下游开发了一个地表水/地下水数值模型，以评估在补给减少和地下水抽取增加的条件下流域内低基流和地下水位的响应。通过历史匹配的批量数据同化使用模拟历史条件（2006-2013）；这个过程包括与地下水位的历史匹配和几个计量器的基流估计，并在高维（高度参数化）框架中完成。该模型是在不确定性框架中开发的，因此参数、观察和感兴趣的场景被随机预想为潜在值的分布。结果表明，在 8 年的规划期内，低流量期间地下水对地表水的贡献可能会从 6% 减少到 25%，相应地补给量减少 25%，地下水抽取量增加 25%。此外，结果表明，在具有较高地下水抽取情景的干旱条件下，某些水文地层单元的地下水位在 8 年期间比其他水文地层单元更有可能下​​降。