CLIMATE CHANGE CONTRIBUTES TO RELOCATION OF BEACH CAR PARKS
The Mossel Bay Town Council at its monthly meeting yesterday (Monday, 20 September 2010) gave approval for the relocation further inland of four beach car parks at Dana Bay and Reebok respectively as a longer term strategy to protect the car parks from the effects of beach erosion.
A fifth car park, at Bayview, will be retained in its current position but remedial measures must be taken to protect the dune system from pedestrian and stormwater erosion.
According to a preliminary report compiled by consulting engineers and submitted to Council, excessive scouring of the dune faces took place over the last five years at the Bayview central car park, the Dana Bay eastern and western car parks and the Reebok eastern and western car parks. The causes included sea level changes, storms and tidal variations and reduced sediment supply.
The report states that some of the parking areas have already been undermined and pose a safety risk to the public. It says that future erosion of these sites can be expected due to sea level rise and sediment changes in the catchments feeding the coast. Some of the causes of sediment reduction in rivers supplying the coast are drought, the construction of dams and sand extraction from rivers for building.
The relocation is subject to provision being made on future capital budgets for the relocation of the car parks as well rehabilitation of the areas concerned. No time frames were included in the Council resolution. It does, however, require that interim and remedial safety measurements be implemented within the available budget.
The Council also gave approval for provision to be made in its 2011/2012 operational budget for the compilation of a Municipal Coastal Management Programme.
It must inter alia include a study of sea level rise, a hazard analysis and risk mitigation study to inform a coastal setback line as a priority to reduce risks to future “inappropriately located infrastructure and developments.” It must also include a regional sediment supply study to address the issue of sediment reduction to the coastal environment.
With regard to the Bayview central car park, the report states that a retreat inland is not possible because of the built-up nature of the area. Urgent attention is, however, required to control the storm water runoff from the toilet block and the paved area, which is currently impacting on the dune system. The pedestrian movement down the sides of the dune system, which is currently destroying the vegetation cover, results in a loss of material from the dune.
The report mentions several possible temporary and long-term remedial measures such as geo-containers, rock-filled gabions, concrete blocks, groins and breakwaters that could be implemented to protect the car parks and dune toes. They are, however, expensive and in some cases not considered ideal for aesthetic, environmental and other practical reasons such as impeding access.
The reconstruction of the car parks inland appears to be the cheapest option, ranging from R950 354 for the reconstruction at Dana Bay east to R10,4 million for a breakwater. The estimated cost at Reebok east is R11 million for the installation of geo-containers and R9,2 million for gabions, compared to the reconstruction cost of R844 967.
The existing car park areas will require the removal of all dump rock, asphalt and other materials that were used in the construction of the car parks and which are foreign to the beach environment.