Spatial variation of groundwater response to multiple drivers in a depleting alluvial aquifer system, northwestern India
Spatial variation of groundwater response to multiple drivers in a depleting alluvial aquifer system, northwestern India
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DOI：
10.1177/0309133319871941
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发表时间：
2019-08
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通讯作者：
W. V. van Dijk;A. Densmore;C. Jackson;J. Mackay;S. Joshi;R. Sinha;S. Shekhar;Sanjeev Gupta
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作者：
W. V. van Dijk;A. Densmore;C. Jackson;J. Mackay;S. Joshi;R. Sinha;S. Shekhar;Sanjeev Gupta
印度西北部地下水的不可持续开采已导致该地区冲积含水层系统的极端但在空间上可变的枯竭。缓解和管理地下水资源需要了解地下水枯竭模式和规模背后的驱动因素，但一直缺乏对这些驱动因素的区域视角。这项研究的目的是(1)了解观测到的地下水位变化模式可以在多大程度上由降水、潜在蒸散量、抽水和渠道灌溉的驱动因素来解释，以及(2)了解这些驱动因素的影响如何根据系统潜在的地质异质性而变化。我们使用传递函数-噪声时间序列方法，基于预定义的脉冲响应函数(θ)来量化1974年至2010年期间各种驱动因素的影响。由响应M0的零阶矩概括的对抽水的动态反应在空间上是可变的，但在研究区的近端和中部通常很大，特别是在抽水较高但冲积含水层较少的地区。相比之下，整个研究区的降水响应迅速且相当均匀。在距离喜马拉雅前缘较远的地方，观测到的地下水位上升主要可以用运河灌溉来解释。结果表明，地貌环境对含水层系统的地质非均质性影响着含水层系统对驱动因素的响应。因此，这种异质性提供了一个有用的框架，可以指导缓解工作；例如，降低抽出率的努力应侧重于含水层较薄和丰度较低的地区。
Unsustainable exploitation of groundwater in northwestern India has led to extreme but spatially variable depletion of the alluvial aquifer system in the region. Mitigation and management of groundwater resources require an understanding of the drivers behind the pattern and magnitude of groundwater depletion, but a regional perspective on these drivers has been lacking. The objectives of this study are to (1) understand the extent to which the observed pattern of groundwater level change can be explained by the drivers of precipitation, potential evapotranspiration, abstraction, and canal irrigation, and (2) understand how the impacts of these drivers may vary depending on the underlying geological heterogeneity of the system. We used a transfer function-noise (TFN) time series approach to quantify the effect of the various driver components in the period 1974–2010, based on predefined impulse response functions (θ). The dynamic response to abstraction, summarized by the zeroth moment of the response M0, is spatially variable but is generally large across the proximal and middle parts of the study area, particularly where abstraction is high but alluvial aquifer bodies are less abundant. In contrast, the precipitation response is rapid and fairly uniform across the study area. At larger distances from the Himalayan front, observed groundwater level rise can be explained predominantly by canal irrigation. We conclude that the geological heterogeneity of the aquifer system, which is imposed by the geomorphic setting, affects the response of the aquifer system to the imposed drivers. This heterogeneity thus provides a useful framework that can guide mitigation efforts; for example, efforts to decrease abstraction rates should be focused on areas with thinner and less abundant aquifer bodies.