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Naivasha Virtual Fieldcourse

Streams & rivers

In Kenya, which is arid and semi-arid for nearly as much as 90% of the country's surface, streams are vital assets for community development. At the same time, they represent indispensable resources for the survival of aquatic, semi-aquatic and terrestrial wild fauna.
Lake Naivasha receives drainage from two perennial rivers, the Malewa, coming down
the Nyandarwa (Aberdare) Mountains (drainage area: 1730 km 2 ), and the Gilgil, draining the Rift Valley escarpment ridges from the North (drainage area: 420 km 2 ).
Human impact in these river catchments is pervasive. Damage to the riverine fringe through deforestation and cattle husbandry are perhaps of greater concern than the organic pollution that reaches the river channel. Stakeholders recognise that riparian zones provide them with water, food, medicinal plants, fuel wood, building materials, habitats for rearing honey bees, means of waste disposal and treatment, and sources of inspiration related to cultural and religious activities. despite this, their survival instinct is determining a progressive degradation of these highly valuable assets, with loss and/or replacement of the original riparian vegetation.
A moderate diversity of stream invertebrates dwells in the sediment-laden rivers. Riverine fish include catfish (Clarias gariepinus, Clariidae), "adel" (Barbus paludinosus/amphigramma, Cyprinidae), and introduced Rainbow trout (Oncorhynchus mykiss, Salmonidae) which is found in the Upper Malewa catchment.
Forest birds such as Turacos, colonise much of the riparian environment, to find refuge after extensive deforestation affecting the Lake Basin forests.