Integrated catchment management and sustainable water resource development in semi-arid Zimbabwe
This thesis reports the results of a three year cross disciplinary investigation of the water resources of a small headwater catchment and their role existing and future in the livelihoods of the local community. In addition the potential for micro-catchment management to improve the water resources and water based livelihoods of the catchment community was also examined. Physical examination of the shallow aquifer revealed higher than expected levels of groundwater recharge, matched by high levels of naturally occurring discharge. A groundwater modelling study suggested that this discharge was caused by both deep and shallow rooted vegetation, rather than by drainage losses, and that the catchment aquifer was largely isolated from any larger regional groundwater system.
Research into the historical development of the catchment community revealed an ongoing process of agricultural intensification, driven by increasing population and expectations. One manifestation of this intensification is a rapid development of groundwater resources for small scale irrigation. The study suggested that the increased development of and reliance on water points exploiting shallow groundwater resources could lead to increased risk in dry periods associated with generally low groundwater levels. The work highlighted the crucial importance of correct siting and design of water points if widespread failure is to be avoided. However, it also suggested that irrigated agriculture could be sustainably increased at least ten-fold by using suitably sited high yielding water points. Finally, a prototype decision support system was developed using Bayesian Belief Networks, and this was used to integrate the physical and human aspects of the study within a single framework. This framework was then used to examine the likely affects on livelihoods of adopting a micro-catchment management approach to managing groundwater resources.