Issues and Solutions for Coastal Management - Term Paper Example

Coastal management Issues and solutions Student’s Name Course code and name Instructor’s name Learning Institution City, State Date of submission 1. Introduction A study in Australian coastal area showed that there are a number of coastal management issues that need to be addressed in order to ensure efficiency in obtaining benefits derived from use of the coast as a facility. The main issues that have been necessary to manage include the possibility of erosion of the coastline or the possibility of recession at Wamberal coastline, the growth of mangrove, saltmarshes and sea grass on the coastal area, possibility of a rise in sea level and coastal squeeze and their impacts on salt marsh, possible impacts of rise in sea level on Brisbane entrance and how this situation can be controlled and dredging activities that should be performed on Brisbane waster entrance such as dredging, spoil deposition and beach nourishment (Allan, Heasman and Bennison 2008). The main contributing factor to the need for coastal zone management is that there is increased pressure resulting from tourism, growth in population and an increase in residential needs. A framework has been developed for management of coastal erosion risks such as hazard studies, land-use planning and management of costal activities. There are a number of coastal processes that have taken place in Wamebral thus affecting private development and erosion of Wamebral beach in the previous decades. It is expected that these impacts are likely to be exacerbated in the future thus, the need to develop measures of managing them. 2. Discussion 2.1 Coastal erosion and recession, options for coastal protection and management at Wamberal for the present and the year 2050 Erosion of the coastline is an example of issues that will affect Wamberal for a number of years in the future. This is expected to result from severe storm resulting from wave’s attacks, resulting into removal of beaches and dune sands, storm erosion that is expected to move constantly towards the land and oceanic inundation as a result of high water levels that is expected to occur during storms (Chapman, 2003). It has also been assessed that Terrigal-Wamberal beaches have been losing sand in the long term, resulting into a retreat in the shoreline. It is anticipated that this retreat is likely to continue and increase in the future as a result of rise in sea level due to greenhouse effect. There will also be an impact on the seawall at Terrigal which protects various recreational facilities and commercial activities. When this seawall is eroded, the size and amenity of the beach is expected to diminish over time as a result of absence of nourishment (Chapman and Bulleri, 2003). There are management strategies that have been created in order to address these issues. In order to manage these issues, strategic management plan for Terrigal-Wamberal will include protecting the narrow dune ridge and development thereon in addition to action focused on maintaining beach amenity. Erosion of the coats will also be prevented by placing on the beach of sand to be excavated from behind the seawall in the redevelopment process and also replacing them as required by the right foundation materials. For the Terrigal lagoon, management strategy will involve constructing public facilities behind the seawall to be in accordance with the requirements of the beach style of the area and designed so that risks of collapse of the beach as a result of overtopping of the seawall are prevented (Chapman and Roberts 2004). Another management process will involve monitoring beach and quantities of sand as part of efforts to achieve regional monitoring process. Figure 1. Benchmark for sea level rise planning in the modeling of the 2050 2100 hazard lines. 2.2 Issues related to saltmarshes, mangrove and ecosystems management Salt marshes management has been an issue of great concern for the Australian government. In areas where saltmarshes are high, stressful impacts have been experienced as a result of infrequent inundation by tides, potentially high salinity in the soil and prolonged periods of desiccation (Creese et al 2009). This has had an impact on growth of plants of various species. It has been observed that saltmarshes have been subjected to trampling by vehicles and people. In some cases, cattle have been allowed to graze in areas occupied by saltmarshes. In addition, horses have been allowed access to saltmarshes and in most cases, they have fed on the crops of destroyed the mangroves. In order to manage the salt-marshes, a range of activities have been suggested. For instance, it has been suggested that the community should be educated about the important of saltmarshes to the Brisbane Water estuary, and areas o the estuaries occupied by saltmarshes should be demarcated as access free zone so that they are not encroached by tramples, grazers or vehicle onset. Figure 2. Saltmarses Mangroves are also important plants in the estuaries. This is because they create habitats for other macro fauna within the coast by creating harbors for burrowing macrofauna under the pneunatophores which from their breathing roots under anaerobic conditions in the sea (Graham 2008). For instance, there are a number of crabs, mollusks and worms associated with these mangroves. The number of crabs is a function of the number of mangrove forests in the area. Management of mangroves will be achieved by ensuring people and the public do not access and trample parts of the shores occupied by the vegetations. 2.3 Potential rise in sea level and coastal squeeze impacts on salt marsh and mangrove ecosystems in Brisbane waters When there is a rise in sea level, water will cover the mangrove vegetations and salt marshes, resulting into destruction of habitats for sea animals such as mollusks and oysters and other sea animals that depend on the vegetations for habitat and source of food. In addition, water quality will be affected because the rise in sea level will result into the inability of the saltmarshes and mangroves to purify the water (Harty and Cheng 2003). A rise in sea level will result into mangroves extending towards the land while drawing in its seaward edge. Surface elevation can result into the mangroves overtaking the saltmarshes habitat and soil salinity will increase resulting into an impact on growth and seed germination of saltmarshes species (Gray and Barnes 2008). This will have an impact in species composition. In order to control the effect of se rise and coastal squeeze, it will be necessary to create barriers in the areas where mangroves and saltmarshes are located so that they are not accessed by sea waters. This can be achieved through creation of dunes of sand which keeps sea water away from reaching the mangroves and saltmarshes (Harty and Cheng 2003). Figure 3. Mangrove vegatations 2.4 Brisbane water entrance management, dredging, deposition and beach nourishment Water entrance into the shore will result into squeezing of the coastline and a resulting deposition of sediments into the shore. The deposition of sediments will result into blockage of estuaries and other long-term impacts such as increase turbidity due to deposition of fine sediments in shallow areas which are remobilized by wave action, mud flats will be formed in areas that have been initially occupied by clean sand and amount of sediment-bound nutrients will be increased at the estuaries thus resulting into a range of ecological impacts such as mangrove propagation and sea-grass dieback (St. Omer 2004). In order to manage impacts of water entrance, constant dredging will be performed on regular basis at the estuaries. The dredging activities will mainly involve sediment transportation into areas far away from the beaches or dumping sites and rehabilitation of the beaches for use by the community through maintenance of the present beach profile. A dredging program which is expected to be adopted by a hopper-badge dredge facility has been designed and is expected to be used for the purpose (Macbeth 2009). Beach nourishment will also include desalinization of the water within the area used for recreation activities, constructing Beach facilities at the shores such as toilets to be used by people at the beach and construction of walkways and cycle ways that can be used by people at the beach. Figure 4. Section of Brisbane susceptible to erosion and deposition of sediments 2.5 Potential sea-level rise impacts on the Brisbane water entrance A rise in sea-level is likely to result in increased flood frequency, extent in height in lower areas of coastal flood plains, an increase in intensity of flood-producing rainfall is expected to contribute to flood change behaviors. Rise in seal level and changes in rainfall patterns will result into an increase in sediment shedding from the hinterland, contributing to a change in stream channels such as erosion of banks (Macbeth, Johnson and Gray 2008). In addition, as a result of rise in sea level and increased storms, erodible coastline will recede by between 20-40m by 2050 and 50-95 by 2100 but could be above this range as defined by local factors. These impacts will be based on factors such as rainfall intensity, river flows, winds and waves actions. Runoff and increased seepage flows are expected to result into increased gulley erosion in affected areas. High temperatures in the winter is expected to result into enhanced ground cover with more concentrations on the frost-hollow areas in the west regions where the impacts of winter results into a limit on growth rates of grass (Saintilan and Williams 2000). The management process for sea-level rise and the impacts on water entrance can involve ensuring gulleys is constructed at the estuaries so that gulley erosion is prevented (Sainty and Jacobs 2003). It can also involve addition of chemical at the estuaries which reduce salinity of the water thus enabling growth of planktons that can be consumed by marine organisms and reinforcement walls should constructed around residential commercial beach fronts, tower blocks near the shores and commercial premises for the purpose of protecting them from the impacts of sea level rise. Figure 4. Locations of Spoil Deposition Sites at Wamberal-Terrigal Coastline 3. Conclusion This paper shows that there are many activities that are dependent on the coastline of Wamebral-Terrigal Lagoon. Thus, the idea of maintaining the natural state of the feature is of great significance to the residents of the area as well as the Government of Australia. This is bases of the economic and social benefits derived from the feature. Thus, it is highly recommended that factors should be made with the focus on ensuring the feature is not eroded, impacts of sea rise are controlled, and impacts such as global warming are addressed so that social, environmental and natural processes are preserved along the cost and more specifically in the Wamberal-Terrigal Lagoon. 4. References Allan, G.L., Heasman, H. and Bennison, S., 2008. Development of industrial-scale inland saline aquaculture: Coordination and communication of R&D in Australia. 245pp. Chapman, M. G. 2003. Paucity of mobile species on constructed seawalls: effects of urbanization on biodiversity. Marine Ecology Progress Series 264: 21-29. Chapman, M. G., Bulleri, F. 2003. Intertidal seawalls: new features of landscape in intertidal environments. Landscape and Urban Planning 62: 159-172. Chapman, M. G., Roberts, D. E. 2004. The use of seagrass wrack in restoring disturbed Australian saltmarshes. Ecological Management and Restoration 5: 183-190. Creese, R.G., Glasby, T.M., West, G. and Gallen, C., 2009. Mapping the habitats of NSW estuaries. 95pp. Graham, K.J., 2008. The Sydney inshore trawl-whiting fishery: codend selectivity and fishery characteristics. 153pp. Gray, C.A and Barnes, L.M., 2008. Reproduction and growth of dusky flathead (Platycephalus fuscus) in NSW estuaries. 26pp. Harty, C., Cheng, D. 2003. Ecological assessment and strategies for the management of mangroves in Brisbane Water – Gosford, New South Wales, Australia. Landscape and Urban Planning 62: 219-240. St. Omer, L. 2004. Small-scale resource heterogeneity among halophytic plant species in an upper salt marsh community. Aquatic Botany 78: 337-448. Macbeth, W.G., Geraghty, P.T., Peddemors, V.M. and Gray, C.A., 2009. Observer-based study of targeted commercial fishing for large shark species in waters off northern New South Wales. 82pp. Macbeth, W.G., Johnson, D.D. and Gray, C.A., 2008. Assessment of a 35-mm square-mesh coded and composite square-mesh panel configuration in the ocean prawn-trawl fishery of northern New South Wales. 104pp. Saintilan, N., Williams, R. J. 2000. The decline of saltmarsh in southeast Australia: Results of recent surveys. Wetlands (Australia) 18: 49-54. Sainty, G. R., Jacobs, S. W. L. 2003. Waterplants in Australia – a field guide. Sainty & Associates, Potts Point. Scandol, J.P., Ives, M.C. and Lockett, M.M., 2009. Development of national guidelines to improve the application of risk-based methods in the scope, implementation and interpretation of stock assessments for data-poor species. 186pp. Read More