Research Article
Assessing Land Suitability for Rainwater Harvesting Using
Geospatial Techniques: A Case Study of Njoro Catchment, Kenya
C. W. Maina
1
and J. M. Raude
2
1
Department of Agricultural Engineering, Egerton University, P.O. Box 536-20115, Egerton, Kenya
2
Soil, Water and Environmental Engineering Department, Jomo Kenyatta University of Agriculture and Technology,
P.O. Box 62000-00200, Nairobi, Kenya
Correspondence should be addressed to C. W. Maina; mainawcaroline@gmail.com
Received 13 April 2016; Revised 5 August 2016; Accepted 19 October 2016
Academic Editor: Rafael Clemente
Copyright © 2016 C. W. Maina and J. M. Raude. Tis is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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. Tis study sought to
assess land suitability for surface runof 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 afect
the storage depending on whether runof 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. Te 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. Tis implied that a great potential exists for rain water harvesting within the catchment.
1. Introduction
One of the vital requirements for life, economic, and social
development is water [1]. Water is required by human beings,
plants, and animals and for ecosystem functions. Adequate
water supply is critical in the development of drinking water
supplies, agricultural and industrial activities. Te demand of
water increases linearly as population increases. According
to WWO [2], the global water consumption rate doubles in
every 20 years a rate that is twice the population growth rate.
As a result, optimum, efcient use and management of fresh
water resources with increase in population are paramount
to counter the concerns caused by the observed dwindling
trends of the water resources. Further, there are many sectors
facing serious water shortage. For instance, approximately
over 50% of rural household and at least 25% of urban
households do not have access to adequate clean water [3].
Kenya is among the water scarce countries in Africa and has
also seen water storage per capita deteriorate with time to
critical levels. By year 2003, the available fresh water supply
was 647 m
3
per capita and it was estimated that, by year 2025,
per capita water availability would drop to 235 m
3
as a result
of population growth [4]. Water scarcity is a major concern
in Kenya and urgent measures are required to arrest the
situation and reverse the trend to an internationally accepted
per capita consumption of 1,000 m
3
. As a result there is need
for improved water resources management and one of the
viable options is to direct more eforts in rain water harvesting
within the catchments.
Priority should be given to rainwater harvesting either
for surface storage or for artifcial recharge since this assists
in sustainable management of water resources [5]. Rainwater
harvesting is the process of concentrating runof from a large
area within the catchment. Te concentrated runof can later
be used in a smaller area [5] for various activities. Rain water
harvesting deals with a large number of spatial data that
Hindawi Publishing Corporation
Applied and Environmental Soil Science
Volume 2016, Article ID 4676435, 9 pages
http://dx.doi.org/10.1155/2016/4676435