Integrating GIS-Based MCDA Techniques and the SCS-CN Method for Identifying Potential Zones for Rainwater Harvesting in a Semi-Arid Area

Hussein Al-Ghobari,Ahmed Z Dewidar

doi:10.3390/w13050704

Abstract

An increasing scarcity of water, as well as rapid global climate change, requires more effective water conservation alternatives. One promising alternative is rainwater harvesting (RWH). Nevertheless, the evaluation of RWH potential together with the selection of appropriate sites for RWH structures is significantly difficult for the water managers. This study deals with this difficulty by identifying RWH potential areas and sites for RWH structures utilizing geospatial and multi-criteria decision analysis (MCDA) techniques. The conventional data and remote sensing data were employed to set up needed thematic layers using ArcGIS software. The soil conservation service curve number (SCS-CN) method was used to determine surface runoff, centered on which yearly runoff potential map was produced in the ArcGIS environment. Thematic layers such as drainage density, slope, land use/cover, and runoff were allotted appropriate weights to produced RWH potential areas and zones appropriate for RWH structures maps of the study location. Results analysis revealed that the outcomes of the spatial allocation of yearly surface runoff depth ranging from 83 to 295 mm. Moreover, RWH potential areas results showed that the study areas can be categorized into three RWH potential areas: (a) low suitability, (b) medium suitability, and (c) high suitability. Nearly 40% of the watershed zone falls within medium and high suitability RWH potential areas. It is deduced that the integrated MCDA and geospatial techniques provide a valuable and formidable resource for the strategizing of RWH within the study zones.

Highlights

In many countries around the world, water shortage is the main challenge, especially in developing countries [1]
Other than the finding of rainwater harvesting (RWH) potential zones in the study location, this study considered suitable locations/zones for farm ponds
It is apparent that both farmlands and bare soils which take up 32% of the study region are the most favorable areas for collecting runoff rainwater

Summary

Introduction

In many countries around the world, water shortage is the main challenge, especially in developing countries [1]. One way of managing water scarcity is rainwater harvesting (RWH), ensuring safe, affordable, and accessible water for drinking and domestic use [3]. RWH is extremely valuable, especially in dry areas, to address water shortage, reduce groundwater extraction, increase crop yields, increase growth and development of pastures, combat erosion, and conserve water resources [4]. RWH is defined as the collection, storage, distribution, and use of rainwater. RWH includes techniques for collecting and storing runoff from rainwater for domestic and agricultural use in the wider sense [5]. RWH benefits include decreased runoff, flood protection in upstream areas, soil moisture improvement, and soil conservation [1]

Methods

Results

Conclusion