Simulating Groundwater‐Streamflow Connections in the Upper Colorado River Basin
Simulating Groundwater‐Streamflow Connections in the Upper Colorado River Basin
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DOI：
10.1111/gwat.13000
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发表时间：
2020-03
期刊：
影响因子：
2.6
通讯作者：
Hoang Tran;Jun Zhang;J. Cohard;L. Condon;R. Maxwell
中科院分区：
文献类型：
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作者：
Hoang Tran;Jun Zhang;J. Cohard;L. Condon;R. Maxwell
在山区，积雪驱动集水区，融雪应该是春季河流流量的主要贡献。在这些集水区，地下水的贡献没有得到很好的记录，因为很难在这样复杂的环境中监测深层含水层的地下水。在这项研究中，我们使用一个集成的水文模型进行数值实验，帮助量化的影响，横向地下水流量的总的年度和峰值径流在开发前的条件。我们的模拟集中在上科罗拉多河流域（UCRB; 2.8 × 105 km 2），这是一个有据可查的山区流域，几个重要的子流域都有径流和地下水位测量。对于模拟水年，我们的研究结果表明，峰值流量的增加高达57%时，包括横向地下水流过程的洪水条件下，通常假设独立于地下水的一个意想不到的结果。此外，纳入横向地下水流适度提高了模型的观测匹配。年平均径流量的相关系数从无地下水侧向流模拟的0.84提高到有地下水侧向流模拟的0.98。在空间上，我们看到更明显的差异，横向和没有横向地下水流的情况下，在该领域的地形陡峭。我们还发现，上科罗拉多河子流域之间有和没有横向地下水流的径流变化的幅度和空间分布存在明显差异。对地下水横向流动模拟进行了敏感性试验，将水力传导系数缩放到两个数量级以上。这些结果表明，地下水横向流动的影响是大的或大于一个数量级的变化，在水力传导性。虽然我们的结果集中在UCRB，我们认为，这些模拟具有相关性，全球其他水源系统。
In mountain, snow driven catchments, snowmelt is supposed to be the primary contribution to river streamflows during spring. In these catchments the contribution of groundwater is not well documented because of the difficulty to monitor groundwater in such complex environment with deep aquifers. In this study we use an integrated hydrologic model to conduct numerical experiments that help quantify the effect of lateral groundwater flow on total annual and peak streamflow in predevelopment conditions. Our simulations focus on the Upper Colorado River Basin (UCRB; 2.8 × 105 km2) a well‐documented mountain catchment for which both streamflow and water table measurements are available for several important sub‐basins. For the simulated water year, our results suggest an increase in peak flow of up to 57% when lateral groundwater flow processes are included—an unexpected result for flood conditions generally assumed independent of groundwater. Additionally, inclusion of lateral groundwater flow moderately improved the model match to observations. The correlation coefficient for mean annual flows improved from 0.84 for the no lateral groundwater flow simulation to 0.98 for the lateral groundwater flow one. Spatially we see more pronounced differences between lateral and no lateral groundwater flow cases in areas of the domain with steeper topography. We also found distinct differences in the magnitude and spatial distribution of streamflow changes with and without lateral groundwater flow between Upper Colorado River Sub‐basins. A sensitivity test that scaled hydraulic conductivity over two orders of magnitude was conducted for the lateral groundwater flow simulations. These results show that the impact of lateral groundwater flow is as large or larger than an order of magnitude change in hydraulic conductivity. While our results focus on the UCRB, we feel that these simulations have relevance to other headwaters systems worldwide.