Modelling Small-Scale Storage Interventions in Semi-Arid India at the Basin Scale

Robyn Horan,Mike Simpson,Helen E Baron,Pawan S Wable,Virginie J D Keller,Veena Srinivasan,H Gwyn Rees,Helen A Houghton-Carr,Nathan Rickards,Kaushal K Garg

doi:10.3390/su13116129

Abstract

There has been renewed interest in the performance, functionality, and sustainability of traditional small-scale storage interventions (check dams, farm bunds and tanks) used within semi-arid regions for the improvement of local water security and landscape preservation. The Central Groundwater Board of India is encouraging the construction of such interventions for the alleviation of water scarcity and to improve groundwater recharge. It is important for water resource management to understand the hydrological effect of these interventions at the basin scale. The quantification of small-scale interventions in hydrological modelling is often neglected, especially in large-scale modelling activities, as data availability is low and their hydrological functioning is uncertain. A version of the Global Water Availability Assessment (GWAVA) water resources model was developed to assess the impact of interventions on the water balance of the Cauvery Basin and two smaller sub-catchments. Model results demonstrate that farm bunds appear to have a negligible effect on the average annual simulated streamflow at the outlets of the two sub-catchments and the basin, whereas tanks and check dams have a more significant and time varying effect. The open water surface of the interventions contributed to an increase in evaporation losses across the catchment. The change in simulated groundwater storage with the inclusion of interventions was not as significant as catchment-scale literature and field studies suggest. The model adaption used in this study provides a step-change in the conceptualisation and quantification of the consequences of small-scale storage interventions in large- or basin-scale hydrological models.

Highlights

Introduction published maps and institutional affilWater resources management is becoming increasingly challenging [1] with rapid population growth [2], a changing climate [3], and increasing competition over limited natural resources [4]
The modified version of Global Water Availability Assessment (GWAVA) provided a valuable tool to investigate the effects of interventions at a sub-catchment and basin scale
Conceptualised interventions play an important part in the allocation and better representation of simulated surface water within the basin

Summary

Introduction

Introduction published maps and institutional affilWater resources management is becoming increasingly challenging [1] with rapid population growth [2], a changing climate [3], and increasing competition over limited natural resources [4]. In semi-arid regions of the world, people have relied on large-scale infrastructures, such as dams and water transfer schemes, and small-scale infrastructures, such as check dams, farm bunds (rainfall harvesting method used in agriculture fields consisting of a raised soil perimeter), and tanks (small informal reservoirs with a catchment area of less than 34 hectares), to provide and store water for urban and rural use. In India, the shortfall in renewable water resources to meet the increasing demand has resulted in aggressive abstraction of the deep groundwater storage and the construction of iations.

Methods

Results

Conclusion