Land use and land cover changes and the water quality of the Orange river at Aussenkehr, Namibia
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Date
2021
Authors
Journal Title
Journal ISSN
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Publisher
University of Namibia
Abstract
River systems are essential to the human populations and aquatic organisms. However, they are greatly influenced by land use activities. It is therefore important to understand the effects of land use activities on river systems for environmental protection and resources planning. This study assessed the land use and land cover (LULC) changes and the water quality of the Orange River in the Aussenkehr area where agricultural activities and human settlements have increased over
the last three decades. Water quality was tested at three sampling locations situated 26 km upstream, next to, and 3 km downstream of the Aussenkehr farms. Water quality measurements were carried out during the wet and dry seasons to allow for spatial and temporal comparison. Parameters examined included water pH, electrical conductivity (EC), and dissolved oxygen (DO), using handheld equipment. A total of 54 measurements were taken for each parameter. Changes
in LULC were quantified using Landsat images for the years 1990, 2000, 2010 and 2019. The analysis showed that EC next to and downstream of the farms was much higher than at the upstream point of the farms. The high values recorded for EC and pH exceeded the category of excellent water quality based on the guidelines set by the Namibian Ministry of Agriculture, Water and Forestry (MAWF). Analysis of LULC revealed that agriculture (vineyards) and human settlements are the main land use in this area. Therefore, the lower water quality at and downstream of the farms could be attributed to fertilisers from irrigation, and the lack of waste management
and proper sanitation in informal settlements. With more than 30% of the households in Aussenkehr consuming untreated water from the river, many people may be at risk of waterborne diseases from this low water quality. There is thus a need at Aussenkehr for urgent intervention measures in farm management, settlement development and the provision of essential services. Further research is also needed to investigate how farmers along the Orange River manage the
application of fertilisers.
Description
A thesis submitted in fulfillment of the requirements for the Degree of Master of Science (Geo-Information Studies)
Keywords
Drinking water, Land use activities, Random forest classification, Satellite images, Settlement, Vineyard