Khoshoei, M., Safavi, HR., Sharma, A., Relationship of drought and engineered water supply: Multivariate index for quantifying sustained water stress in anthropogenically affected subbasins, Journal of Hydrologic Engineering (ASCE)

Relationship of drought and engineered water supply: A multivariate index for quantifying sustained water stress in anthropogenically affected sub-basins

Mehrdad Khoshoei, PhD Candidate, Department of Civil Engineering, Isfahan University of Technology, Isfahan, Iran.

Hamid R. Safavi, Prof., Department of Civil Engineering, Isfahan University of Technology, Isfahan, Iran.

Ashish Sharma, Prof., School of Civil and Environmental Engineering, University of New South Wales, Sydney, Australia.

Abstract:

Drought occurs across all climates worldwide, but has different impacts from one region to another. As water is the most basic of human needs, drought and water shortage can result in severe socio-economic difficulties that take years to overcome. While drought has traditionally been classified on the basis of deficiencies in precipitation, with the advent of climate change and the increase in evapotranspiration that is occurring, efforts have been made to focus instead on derived soil moisture anomalies. A less recognized factor modulating soil moisture anomalies is the use of engineered water supply, through canals or river diversions, and also through groundwater pumping. This paper attempts to formulate a multivariate metric of sustained water stress severity that attempts to incorporate these additional sources of water supply in engineered sub-basins. The proposed index uses entropy theory as the basis of its formulation, and is compared against traditional indices and differences noted. Remotely sensed vegetation products are used as an independent means of assessing the validity of the proposed index. It is found that the proposed index collapses to the more traditional drought indices in sub-basins without significant un-natural water supply, while presenting a more accurate picture of water stress in sub-basins where engineered water supply is present, as interpreted by the vegetation (or its lack thereof) the water supply is able to sustain.

DOI: 10.1061/(ASCE)HE.1943-5584.0001779.