Assessment of the potential adoption of infield rainwater harvesting technique in the communal farming areas of the upper and middle Modder River Basin, South Africa

Abstract

River basin is a geographical unit that defines an area where various users of the basin's water interact. In a river basin there are many water-related human interventions that modify the natural systems and impact on those who live downstream. Researchers from the Agricultural Research Council's Institute for Soil, Climate and Water (ISCW) have developed an infield rainwater harvesting (IRWH) technique for small-scale farmers in the Modder River basin. This technique increased crop yield significantly compared to conventional practices. Since the start of its dissemination by the ISCW programme, adoption at a homestead level grew from six to more than 950 households. The suitable land for the IRWH in the study area is estimated to be 80 667 hectares, of which approximately 14 500 hectares are in the communal farming area. If all the suitable areas were to be put under IRWH practice, a decrease in the runoff could be expected, with consequences on downstream water users. A field survey conducted using a participatory methodology on a sample of 21 villages selected randomly, revealed that there are strong positive motivators, such as increase in crop yield and more food available for the household which explain the rapid expansion of IRWH in homestead application. However, some very strong demotivators were identified, such as high levels of poverty, limited family labour for the preparation of the plots, lack of tools, and the lack of fences around community gardens which could lead to theft and damage by animals. It appears that the demotivators identified are strong enough to prevent a significant expansion of the IRWH technique beyond homestead scale. Hence the expected impact on water availability for downstream users is expected to be minimal.