Upscaling Catchment Processes for Sustainable Water Management in Peninsular India

印度半岛的经济发展和人口增长导致了土地利用、土地管理和水需求的迅速变化，这些共同严重影响和退化了水资源。城市化、毁林、农业集约化、灌溉农业与雨水灌溉作物之间的转变、地下水使用的增加以及小规模地表水储存干预措施的激增，如农场一级的堤坝(通常是为了保持田间土壤水分)和淤地坝(为了补充当地含水层)，所有这些都促使集水区的水文功能发生了重大变化。这些变化和干预措施对当地水文过程的影响，如径流、地下水补给和蒸散，受到的限制很小，我们对这些不同的局部变化如何累积影响更广泛的流域规模的水供应的了解也非常有限。我们的研究聚焦于极具争议性的州际考弗里河流域(面积约80,000平方公里，考弗里是印度最大的流域之一)，解决了在更大范围内表现印度半岛许多当地的小规模干预措施的关键科学挑战。利用农村和城市环境中已建立的试验性集水区的观测，该项目将首先探讨土地利用、土地覆盖、灌溉做法和小规模水管理干预措施的变化如何影响当地的水文过程。随后，我们将开发新的放大方法，在更大的子流域(Kabini，~10,000 km2)和盆地(Cauvery)尺度上表示改进的过程理解。在这样做的过程中，该项目将展示概括地反映全流域水资源综合管理模式中大量小规模变化的累积影响的能力。地方规模干预措施的影响将进一步与人口增长、气候和土地利用变化以及水需求的预测相结合，以评估未来对整个流域水安全的影响。主要利益攸关方参与整个项目的不同阶段，以确保项目产出反映他们的利益和关切，并为他们的决策提供有用的投入。

Economic development and population growth in Peninsular India have resulted in rapid changes to land-use, land-management and water demand which together are seriously impacting and degrading water resources. Urbanization, deforestation, agricultural intensification, shifts between irrigated agriculture and rain-fed crops, increased groundwater use, and the proliferation of small-scale surface water storage interventions, such as farm-level bunds (usually to conserve soil moisture in fields) and check-dams (to replenish local aquifers) all have contributed to significant changes in the hydrological functioning of catchments. The impact of such changes and interventions on local hydrological processes, such as streamflow, groundwater recharge and evapotranspiration, are poorly constrained, and our understanding of how these diverse local changes cumulatively impact water availability at the broader basin-scale is very limited. Focussing on the highly contentious inter-state Cauvery River basin (with an area of c.80,000 km2, the Cauvery is one of India's largest river basins) our study addresses the key scientific challenge of representing the many local, small-scale interventions in Peninsular India at larger scales. Using observations from established experimental catchments in both rural and urban settings, the project will first explore how changes in land-use, land-cover, irrigation practices and small-scale water management interventions locally affect hydrological processes. In tandem we will then develop novel upscaling methods to represent the improved process-understanding in models at the larger sub-basin (Kabini, ~10,000 km2) and basin (Cauvery) scales. In so doing, the project will demonstrate the capability to generically represent the cumulative impact of abundant small-scale changes in basin-wide integrated water resources management models. The impact of local-scale interventions will further be modelled alongside projections of population growth, climate- and land-use-change and water demand to assess future impacts on water security across the basin. Key stakeholders are involved throughout the different stages of the project to ensure that project outputs reflect their interests and concerns and provide useful input to their decision making.