Hydrological processes in the Middle Mohlapitsi Catchment/Wetland, Capricorn District of Limpopo Province, South Africa

摘要

The hydrology of the Middle Mohlapitsi Catchment/Wetland, Limpopo Province of South Africa was studied from November 2005 to April 2008, involving both fieldwork and laboratory analyses. This paper presents the results of an investigation of the hydrology of the catchment and wetland and its contribution to dry season flow in the Mohlapitsi and Olifants Rivers. Forty piezometers were installed along seven transects and water levels monitored in order to understand water table level characteristics with time. The river in the wetland environment is a gaining stream because the water table level elevation is above that of the river, indicating the wetland is feeding the river. Transects 2 is affected by artificial drains by farmers and most of the piezometers closest to the river channel showed the lowest variations. The relationships between rainfall, groundwater, and surface water at this research site shows that stream flow did not respond quickly to precipitation as expected. Furthermore, the groundwater levels did not show significant fluctuations, indicating that groundwater responds gradually to precipitation, and that the relationship between rainfall, groundwater and surface water is complex.