Impacts of agricultural use of the GaMampa wetland on the hydrology of the wetland and the Mohlapetsi River

Wetlands in southern Africa support the livelihoods of many poor people through agriculture for both food production and income. They are used to mitigate the problem of low crop yields associated with low rainfall and droughts. However, wetlands are complex and sensitive\necosystems, and they fulfill important environmental functions. Conversion of wetlands to agriculture has potential impacts not just within the wetland but also in downstream areas. While further development of wetlands for agriculture is difficult to prevent when alternative livelihood opportunities are lacking, it is important to ensure that this does not compromise the provision of goods and services by the wetlands. This paper investigates the possible contributions by the GaMampa wetland to stream flow in the Mohlapetsi River, a tributary of the Olifants River during low flow periods and the impact of the wetland use for agriculture on the hydrological\nfunctioning of the wetland. The GaMampa wetland comprises less than 1 % of the Mohlapetsi catchment and an even smaller portion of the Olifants catchment. Yet hydrological records show that the Mohlapetsi River contributes a significant amount of the Olifants flow particularly during the dry season. Because of the connectivity between wetlands and their surrounding catchments, hydrological processes upstream of wetlands impact the water balance of the wetlands, and processes within the wetlands impact on areas down stream. The results presented in this study are based on ongoing hydrological investigation focusing on rainfall, groundwater, and stream flow monitoring and analysis to understand hydrological processes within the GaMampa wetland. Further study is required to confirm them, but the preliminary results indicate that groundwater is\na significant contributor to the dry season flow in the Mohlapetsi River, but there is little contribution directly from the wetland.