Assessment Of Floodwater Harvesting Infrastructures In The Namibian Cuvelai-Etosha Basin

Abstract

The Cuvelai-Etosha Basin lies in north-central Namibia and due to the prevailing climatic situation, the basin is dominated by strong seasonal and annual variations of either very dry conditions with drought or heavy flooding in certain years.

A growing population in the Cuvelai-Etosha Basin has resulted in increased demand for water for daily use and agricultural activities. Floodwater Harvesting Infrastructures are considered to be a more effective way to solve those problems. Hence the current status of the initiatives taken to harvest floodwater for use in the dry seasons needs to be determined by means of remote sensing, secondary data and field validation.

The main objective of the study was to assess the condition and performance of Floodwater Harvesting Infrastructures in the Cuvelai-Etosha Basin. The Ministry of Agriculture, Water and Forestry constructed 34 earth dams in this Basin from 2008 to 2011. Out of these newly constructed earth dams, 18 were randomly selected for the study. The research design was based on using both qualitative and quantitative data on a completely randomised basis. Sentinel data was used to identify the water bodies by means of remote sensing. Information was gathered by means of structured interviews from the locals or people acquainted with the sites. The results from the interviews taken among 96% of the participants showed that the highest usage of earth dams is livestock watering while few people use them for irrigation purposes.

Due to sedimentation in the earth dams, depth has reduced and surficial area has increased; hence the dams can no longer retain the quality and quantity of water they were designed for. In conclusion, the method developed from GIS successfully identified 94% of the existing earth dams.