Large-Scale Hydrologic Modeling of the Michigan and Wisconsin Agricultural Regions to Study Impacts of Land Use Changes
Large-Scale Hydrologic Modeling of the Michigan and Wisconsin Agricultural Regions to Study Impacts of Land Use Changes
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密歇根州和威斯康星州农业区的大规模水文模型，以研究土地利用变化的影响
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发表时间：
2012
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通讯作者：
J. D. Muñoz
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作者：
A. Nejadhashemi;B. Wardynski;J. D. Muñoz
在五大湖地区的水文变量已经改变了相对于定居前的条件，在过去150年的主要土地使用的变化。目前工作的目标之一是制定一个基线设想方案，据此可以评估土地利用变化对水文和环境过程的影响。此外，这项研究可以帮助量化未来预计的土地利用变化的潜在影响，以减轻这些变化的负面影响，特别是在向城市化和第二代生物能源作物生产的转变方面。本研究探讨了密歇根州和威斯康星州的农业区内的土地利用变化和水文指标之间的关系。使用两组土地利用数据（大约1800个县的数据集和2001年全国土地覆盖数据集）来建立土壤和水评估工具（SWAT）模型。首先，敏感性分析进行了沉降前和目前的土地利用方案的基础上。结果表明，参数敏感性分析可能并不总是解释模型输出的变化如何归因于模型输入的不同来源。因此，应努力通过考虑敏感参数在模型算法中的位置来确定敏感参数的真正重要性。然后，该模型进行了校准，从八个美国地质调查测量站获得的每日径流数据。土地利用变化的影响进行了研究，在三个尺度：子流域，流域和流域。在子流域尺度上，大部分的水文行为可以用土地覆盖的百分比变化来描述。然而，从混合林地到城市和农业用地的土地用途转换的趋势比其他土地用途转换更为明显。在流域尺度上，根据当前和沉降前情景下的长期平均水文变量，观察到显著差异。此外，还检测到蒸散（高达16.5%）和地表径流（高达93.9%）对径流的贡献增加，含水层（高达-51.5%）和基流（高达-50.1%）的补给减少，以及对产水量的混合影响（-21.5%至24.6%）。然而，在流域尺度上，超过70%的研究区域经历了地下水横向流量和补给含水层减少，而65%的区域经历了增加的地表径流和蒸散量和产水量的微小变化。
Hydrologic variables in the Great Lakes region have been altered relative to pre-settlement conditions in response to major land use changes during the past 150 years. One of the goals of the present work is to develop a baseline scenario relative to which the impacts of land use changes on hydrological and environmental processes can be evaluated. In addition, this study can help in quantifying the potential impacts of future projected changes in land use in order to mitigate the negative impacts of these changes, especially in regard to a shift toward urbanization and second-generation bioenergy crop production derived from lignocellulosic crops. The present study explores the relationship between land use changes and hydrologic indicators within the agricultural regions of Michigan and Wisconsin. Two sets of land use data, the circa 1800 county base and the 2001 National Land Cover Dataset, were used to set up the Soil and Water Assessment Tool (SWAT) model. First, sensitivity analyses were performed based on both pre-settlement and current land use scenarios. Results showed that parameter sensitivity analysis may not always explain how the variation in model output can be attributed to different sources of variation in the model input. Therefore, effort should be made to determine the true importance of sensitive parameters by considering their placement in model algorithms. The model was then calibrated against measured daily streamflow data obtained from eight U.S. Geological Survey gauging stations. The impacts of land use changes were studied at three scales: subwatershed, watershed, and basin. At the subwatershed scale, most of the hydrologic behavior can be described by percent change in land cover. However, the trend was more apparent for land use conversion from mixed forest to urban and agriculture lands than for other land use conversions. At the watershed scale, significant differences were observed based on the long-term average hydrologic variables under the current and pre-settlement scenarios. In addition, an increase in evapotranspiration (up to 16.5%) and surface runoff (up to 93.9%) contribution to streamflow, a decrease in recharge to aquifers (up to -51.5%) and baseflow (up to -50.1%), and mixed impacts on water yield (-21.5% to 24.6%) were detected. However, at the basin scale, more than 70% of the study area experienced decreased lateral subsurface flow and recharge to aquifers, while 65% of the area experienced increased overland flow and minor changes in evapotranspiration and water yield.