Water Wheel Nov/Dec 2021: Catchment Management

Abstract

Water pollution – Are farmers bearing the cost of poor catchment management? Eutrophication refers to the enrichment of a water body by nutrients and minerals. Eutrophication of lakes is a natural process and takes place over centuries. However in recent years, human activities have enhanced the eutrophication process due to discharges of nutrients (nitrogen and phosphorous) from various sources into the waterways (Chislock et al., 2013). Over the last few decades, aquatic scientists have related algal blooms to the enrichment of waters by nutrients as a result of human related activities such as industrial activities, disposal of sewage and agriculture. Among the unfortunate consequences of cultural eutrophication is the proliferation and the dominance of blue-green algae (cyanobacteria). These blooms reduce the aesthetic value of recreational waters, affect drinking water and deprive lakes of oxygen. Figure 1 shows some of the main causes and effects of human-induced eutrophication.

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