Assessing Land Suitability for Rainwater Harvesting Using Geospatial Techniques: A Case Study of Njoro Catchment, Kenya

Abstract

Water demand increases as population increases leading to overexploitation of water resource. Consequently, there is need for improved water resources management complemented with rain water harvesting within the catchments. This study sought to assess land suitability for surface runoff harvesting using geospatial techniques. Land use/land cover maps of the area were derived from Landsat image. Land use and soils data were used in generating curve number map of the catchment. Lineaments greatly affect the storage depending on whether runoff is for surface storage or ground water recharge purposes. As a result, ArcGIS was used in delineating the lineaments from Digital Elevation Model (DEM) of the catchment. Further, using weighted overlay the catchment was grouped into categories of restricted, not suitable, moderately suitable, suitable, or highly suitable. The study found that forest, agriculture, and built-up areas occupied about 39.42%, 36.32%, and 1.35% of catchment area, respectively. A large part of catchment was found to have curve number range of 82-89. About 50% of the catchment was found to fall within suitable and highly suitable categories. This implied that a great potential exists for rain water harvesting within the catchment.

Integrating a GIS-based approach and a SWAT model to identify potential suitable sites for rainwater harvesting in Rwanda

“…A large portion of the study area (55.3%) fell under the high runoff potential class with an area extent of 903.27 km 2 , while a very small part (1.8%) fell under the very low runoff potential class. The settlement areas increased the impervious layers, thus reducing the infiltration rate, and this leads to an increase in runoff (Maina & Raude 2016;Harka et al 2020). Settlement areas are the most vulnerable in the catchment, where the retention capacity is low.…”

Environmental resilience and sustainability through green technologies: A case evidence from rural coastal India

“…Hence, the water holding capacity was lower (47.86%), and porosity was higher (52.14%), the reason behind the need for a high frequency of watering in agriculture in the study area. However, the advantage of sandy loam soil is its low runoff and high infiltration capacity [56], which makes it viable for artificial groundwater recharging using RWH [57]. Meanwhile, the particle size between 0.106-2 mm of sand is also suitable for sand media [13], which was primarily available in the soil samples.…”

Potential rainwater harvesting suitable land selection and management by using GIS with MCDA in Ebenat District, Northwestern Ethiopia

“…RWH potential site selection and mapping by using Geospatial technology and multi-criteria analysis is a new approach to tackle drought and water scarcity for domestic use, especially, for a better agricultural activity. According to Alem (1999), Sharma and Smakhtin (2006), Prasad et al (2014), Maina and Raude (2016), Ibrahim et al (2019), and Shadeed et al (2019), land-use/land-cover, textural suitability, rainfall, lineament proximity, slope, curve number (CN), and runoff density and distance from settlement and road are the parameters for rainwater harvesting suitability site area identification.…”

“…The database of the World Overview of Conservation Approaches and Technologies defined RWH as: "The collection and management of floodwater or rainwater runoff to increase water availability for domestic and agricultural use as well as ecosystem sustenance". Adequate water supply is a serious issue for the development of drinking water supplies and related activities (Maina and Raude, 2019). Rainwater harvesting is consequently necessary to guarantee storage while avoiding wastage (Mekdaschi and Liniger, 2013;Asala, 2017;Ammar et al, 2018) Ethiopia is the part of Horn of Africa with a population of approximately 80 million.…”