The development and implementation of a management plan for the Seekoei Estuary, South Africa: A case study guided by socio-economic issues

Abstract

The large Temporarily Closed Seekoei Estuary has a long history of poor management. In 1969, a swimming pool complex was built in a position impinging on the mouth. The construction of a 500 m causeway across the lagoon connecting the residential townships of Paradise Beach and Aston Bay followed. Freshwater abstraction in the catchment has escalated, whereas increasing sedimentation, duration and frequency of mouth closure and hypersaline events contributed to the deteriorating health status of the estuary. Pedestrian and vehicle numbers crossing the causeway are high, particularly among Paradise Beach residents who need to access schools, medical services, work premises, business and shopping facilities. Causeway maintenance is ongoing, whereas winter storm surges deposit large volumes of sand and seawater in the estuary. The causeway becomes submerged, exacerbating threats to human safety. The mouth is then artificially breached, sometimes illegally. Although causeway removal was a key objective in the management plan, upgrading or construction of alternate roads was a first requirement. Other management objectives included guidelines for artificial mouth breaching and restoration of freshwater runoff. Without freshwater inflow the health of the estuary will continue to deteriorate; the system cannot be managed by only focussing on mouth management or other non-natural structures.

Keywords: catchment deterioration, hypersalinity, mouth breaching, temporary closure, sedimentation