Why is the Arkavathy River drying? A multiple-hypothesis approach in a data-scarce region
Why is the Arkavathy River drying? A multiple-hypothesis approach in a data-scarce region
复制标题
阿尔卡瓦西河为何干涸？
DOI：
10.5194/hess-19-1905-2015
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发表时间：
2015
影响因子：
6.3
通讯作者：
S. Lele
中科院分区：
文献类型：
--
作者：
V. Srinivasan;S. Thompson;K. Madhyastha;G. Penny;K. Jeremiah;S. Lele
水资源规划决策的好坏取决于我们解释历史趋势和合理预测未来可用水量的能力。但在快速发展的地区，预测水资源的可用性可能是一个挑战，人类对土地和水域景观的改造正在改变水文系统。然而，世界上许多地区缺乏了解过去变化和预测未来趋势所需的长期水文监测记录。我们调查了这一“变化下的预测”的数据稀缺Thippagondanahalli（TG Halli）在印度南部的Arkavathy次盆地集水区的问题。自20世纪70年代以来，流入TG Halli水库的水量急剧下降。人们对干旱的原因知之甚少，导致管理层的反应方向错误或适得其反。利用实地调查和二手资料对五种可能解释这种下降的假设进行了检验：（1）降雨量、季节性和强度的变化;（2）温度的升高;（3）地下水的开采;（4）桉树种植园的扩张;（5）河道的破碎。我们的研究结果表明，地下水抽水，桉树种植园的扩张，并在较小程度上，通道碎片更有可能造成的下降，在TG Halli集水区的地表流量比气候变化。多重假设方法提供了一种系统的方法来量化人类和气候驱动因素对水文变化的相对贡献。这一方法不仅对政策辩论作出了有意义的贡献，而且还有助于确定今后研究的优先次序和进行设计。该方法是在流域进行使用启发的社会水文研究的第一步。
Water planning decisions are only as good as our ability to explain historical trends and make reasonable predictions of future water availability. But predicting water availability can be a challenge in rapidly growing regions, where human modifications of land and waterscapes are changing the hydrologic system. Yet, many regions of the world lack the long-term hydrologic monitoring records needed to understand past changes and predict future trends. We investigated this "predictions under change" problem in the data-scarce Thippagondanahalli (TG Halli) catchment of the Arkavathy sub-basin in southern India. Inflows into TG Halli reservoir have declined sharply since the 1970s. The causes of the drying are poorly understood, resulting in misdirected or counter-productive management responses. Five plausible hypotheses that could explain the decline were tested using data from field surveys and secondary sources: (1) changes in rainfall amount, seasonality and intensity; (2) increases in temperature; (3) groundwater extraction; (4) expansion of eucalyptus plantations; and (5) fragmentation of the river channel. Our results suggest that groundwater pumping, expansion of eucalyptus plantations and, to a lesser extent, channel fragmentation are much more likely to have caused the decline in surface flows in the TG Halli catchment than changing climate. The multiple-hypothesis approach presents a systematic way to quantify the relative contributions of proximate anthropogenic and climate drivers to hydrological change. The approach not only makes a meaningful contribution to the policy debate but also helps prioritize and design future research. The approach is a first step to conducting use-inspired socio-hydrologic research in a watershed.