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

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.

Effect of Land-Use Change on Runoff in Hyrcania

“…The results indicated good accuracy, suggesting that Landsat imageries have high potential in land-use mapping and hydrological studies [21,29,37]. The use of remote sensing and GIS techniques in combination with hydrological models offers cost-effective analyses as compared with the conventional approaches discussed, for example, for example, Sajikumar and Reyma [18], Kumar et al [21], and Al-Ghobari et al [46]. The curve number method is widely used in several countries.…”

An integrated new approach for optimizing rainwater harvesting system with dams site selection in the Dewana Watershed, Kurdistan Region, Iraq

“…Drainage density has been identified as a valuable indication for assessing the suitability of an RWH site [ 40 , 41 ]. It is determined by dividing the total length of stream channels within a drainage basin by the sum of the basin's area [ 42 , 43 ] as shown in Equation (1) . where D d is the drainage density, n is the number of streams, L is the stream length (km), and A is the drainage basin (km).…”

“…This method takes into consideration the relationship between rainfall, soil texture, and land cover/use in the generation of runoff. According to the USDA, soil texture has been classified into three hydrologic soil groups (HSGs): B, C, and D [ 42 , 64 ]. The CN was obtained by combining the LULC and HSG layers in an index file created with the ArcGIS tool.…”

“…AHP is the most common MCDA method for determining the weight of criteria [ 19 , 42 , 98 ]. Enrique [ 99 ] recommends a range of 5–9 criteria for the AHP and suggests combining criteria into a main criterion with sub-criteria if there are more than 9.…”

Insights of dam site selection for rainwater harvesting using GIS: A case study in the Al- Qalamoun Basin, Syria

“…Many methods are widely used in determining the suitable sites for water harvesting, such as RS and GIS applications, hydrological modeling (HM) with RS and GIS, and multi-criteria decision analysis (MCDA) depending on the HM approach [ 11 , [17] , [18] , [19] ]. RS and GIS methods are the most effective methods, whence the cost and time consumption also provide an accurate spatial and temporal resolution for RWH site selection.…”