Tributary stream systems provide an important source of water for sustaining adjacent irrigated agricultural enterprises. Unfortunately, irrigation withdrawals, depending on the timing and amounts, can have substantial negative impacts on critical aquatic ecosystems in the tributaries. Current regulatory trends in many regions point to increased restrictions on irrigation diversions for ecosystem protection, which could lead to increased risk of shortfalls in agricultural crop production. A geospatial decision support system (geo-DSS) integrating a spatially gridded hydro-meteorological flow estimation model (HL-RDHM) with a GIS-based river basin management model (GeoMODSIM) is presented for evaluating water management alternatives for maintaining the viability of irrigated agriculture while mollifying detrimental impacts on aquatic ecosystems and maintaining environmental flow requirements. As a case study, the geo-DSS is applied to the Feliz Creek basin tributary to the Russian River of northern coastal California which is home to a thriving viticulture industry while supporting spawning habitat for endangered and threatened fish species. The geo-DSS is applied on spatial (~1 km grid size) and temporal (daily) scales that are ecologically relevant for modeling agricultural operations and water rights priorities. The geo-DSS utilizes extensive sets of hydrologic forcing data varying from dry to wet conditions to assess baseline conditions and evaluate management alternatives. Baseline model results show that with minimum bypass flow restrictions in place for instream flow protection, the cumulative effects of upstream diversions can still be significant during low flow periods, while creating substantial risk of agricultural irrigation supply shortages. The case study application demonstrates that the geo-DSS is capable of locating, sizing, and managing off-stream farm ponds receiving optimally timed diversions from adjacent streams that are necessary for maintaining agricultural water supply while complying with environmental flow requirements for sustaining aquatic ecosystems.

支流系统为维持邻近的灌溉农业企业提供了重要的水源。不幸的是，取水的时间和时间长短，可能会对支流中的关键水生生态系统产生实质性的负面影响。许多地区目前的监管趋势表明，对用于生态系统保护的灌溉改道的限制日益严格，这可能导致农业作物减产的风险增加。提出了一种地理空间决策支持系统（geo-DSS），该系统将空间网格化水文气象流量估计模型（HL-RDHM）与基于GIS的流域管理模型（GeoMODSIM）集成在一起，用于评估水管理替代方案以维持灌溉的可行性农业，同时减轻对水生生态系统的不利影响并保持对环境流量的要求。作为一个案例研究，geo-DSS被应用到加利福尼亚北部沿海俄罗斯河的费利斯河流域支流，那里是蓬勃发展的葡萄种植业的所在地，同时为濒危和受威胁的鱼类提供了产卵栖息地。geo-DSS适用于在空间上（约1 km的网格大小）和时间上（每日）的尺度，这些尺度在生态上与对农业运营和水权优先级的建模有关。geo-DSS利用从干旱到潮湿的各种水文强迫数据集来评估基准条件并评估管理方案。基线模型结果表明，在为溪流保护设置最小旁通流量限制的情况下，在低流量时期，上游引水的累积影响仍然很明显，同时也造成了农业灌溉供应短缺的巨大风险。案例研究应用表明，geo-DSS能够定位，定型和管理下游农场池塘，这些池塘从相邻溪流中获得最佳定时分流，这对于维持农业水供应是必要的，同时又符合维持水生生态系统的环境流量要求。