Work

Kaleya River Catchment Regional Estimation of Reservoir Capacities Using Sonar and GIS Approaches

Year: 2022

Type: article

Abstract: Small reservoirs in arid and semi-arid areas help rural communities cope with prolonged dry spells and hence, the need for their continuous monitoring and assessments. However,it is challenging to survey many reservoirs using the traditional sounding methods. In this regard, bathymetric information could be used as a tool to monitor the available surface water to provide data for water allocation decisions and sustainable management of reservoirs. Despite the availability of new remote sensing-based methods forbathymetric surveys,their utilizationin Africa in general and,Zambia in particular, remained low by the time this study was conducted.This paper presents modern bathymetric survey and analysis techniques applied for quantifying the capacities of small reservoirs, using the case of the Kaleya River Basin in southern Zambia. The objectives of the survey were to: i) create a database of reservoir storage capacities; and ii) introduce an efficient modern approach of monitoring small reservoir storage capacities. A remote-controlled Coden hydrographic survey boat equipped with a SONAR device mounted with Trimble OmniSTAR VBS providing DGPS was used to capture and record hydrographic data with a millimeter accuracy. Data was analyzed using Surfer 13 Golden software to produce contoured bathymetric maps of surveyed reservoirs. From this information, the reservoir capacities were computed, thus providing information on water stored in reservoirs in the basin. A regional model was also developed for faster and simpler estimation of reservoir capacities from their surface areas. The study concluded that the quantification of storage capacity of small reservoirs using SONAR and GIS provides a quicker and cost-effective way of obtaining accurate bathymetric data. Such data is important in guiding water allocation decisions at farm level and water permit allocation decisions at a catchment scale.

Source: Journal of Natural and Applied Sciences

DOI: 10.53974/unza.jonas.6.1.391