Strategies for sustainable coast protection

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1.11.2 Recommended future work to fill in the information gaps for

management First and foremost, it is essential to review critically any available material such as topographic maps, aerial photos and satellite images. Use may be made of the World Wide Web sites of various national and international organisations. The web sites may contain coastal bibliographies, databases, and tools as well as numerous links to other relevant information and organisations on the Internet. Examples include the Dutch Coastal Zone Management Centre http:www.minvenw.nlprojectsnetcoast , the Coastal Services Center of the US National Oceanic and Atmospheric Administration http:www.csc.noaa.gov , and the Land-Ocean Interactions in the Coastal zone core project of the International Geosphere-Biosphere Programme IGBP http:www.nioz.nlloicz . On global sea level changes, there are a number of databases that may provide information. Examples include the Permanent Service for Mean Sea Level PSMSL and the World Atlas of Holocene Sea Level Changes. Although all these sources could provide an indication of long-term, regional and relative sea-level changes, it is recommended to use this type of information with caution because, especially for Tanzania, the small spatial and temporal scales of the data reduce the reliability of its application at larger scales. The only option for Tanzania is to install additional tide gauges and commission an institution to manage and analyse the data. Suitable stations are Tanga, Pangani, Bagamoyo, Kilwa and Mtwara. On topography, geomorphology and land use, ordinary surveying can be conducted to provide basic and essential data. In combination with elevation data derived from satellite measurements r vertical aerial photography, surveying and echo-sounding can yield topographical and near-shore batymetric maps that can be used in refraction and diffraction analysis of waves and currents. Aerial video-tape-assisted vulnerability analysis AVVA method in combination with ground-truthing can be used to characterise the coastal topography and geomorphic features of the coastline. This study also allows for estimates of the biogeophysical effects of different sea level scenariosn and provides information on the types of coastline environments, land-use practices, infrastructure and population indicators. Mwandosya et al. 1998 did the AVVA only for Dar es Salaam and it is recommended that it be done for the entire coastline of Tanzania.

1.11.3 Strategies for sustainable coast protection

In Tanzania, and elsewhere in the world, the coastal ecosystem has a tremendous value from environmental, biological and socio-economic point of view. The coastal zone is increasingly becoming a sitting of industries and commercial activities and, consequently, this trend results in the increase of human settlement, more intensive land use, sea-borne transport and even mining. The recreational value of beaches is growing fast due to new beach development schemes, development of marinas and other socio-economic activities. With this in mind, the following strategies are designed to encourage the provision of adequate, technically, environmentally and economically sound and sustainable coast protection methods and management in Tanzania. Need for legislative and administrative framework A survey conducted along the entire coastline of Tanzania shows that various structures have been erected close or on beaches and dunes. Due to shoreline retreat, these structures are threatened by the advancing sea. Although the primary responsibility for dealing with coastal erosion at a given location rests with the land owner, a statutory law which will vest powers in specific local authorities and bodies should be passed. This law which could be known as The Coast Protection and Management Act will have the function to define, protect and regulate the use 34 of the shore areas. In particular, it should ensure and safeguard the public nature of the beaches, preserve its natural features, balance the need of development with conservation. After the enactment, a department of the Government should administer the legislation through the creation of a central body, e.g. Coast Directorate, with objectives to spearhead co-ordinated planning, finance and administration. It should be the duty of this body to define the rights, obligations and responsibilities of all parties concerned in coastal development. One of the priority tasks of this body, immediately after its formation, should be a survey to identify Erosion Prone Areas EPA and compile a coastal vulnerability data base containing information on several variables relating to inundation and erosion risks of the different areas along the entire coastline. Such variables could be, for example, relief elevation, lithology rock type, coastal landforms e.g. dunes, escarpments, etc., vertical land movement relative sea level changes, horizontal shoreline changes erosion and accretion, tides, wave heights, data on storm frequency and intensity, storm surges and sediment transport quantity and direction and climate change variability of winds, waves and storm surges. Local authorities should obtain the views of the Coast Directorate with respect to town planning matters affecting land in the EPA. Property holders should require permit to erect or alter buildings in the EPA. Once the EPA have been identified, buffer zones of the appropriate width are determined to define areas where controls are required. Need for establishing a Coastal Observation Programme The next step following the identification of EPAs is the establishment of a Coastal ObservationMonitoring Programme. This programme will contribute to technical aspects of the Coast Directorate’s operations and management. Its functions should be to: Establish an extensive data collection programme to include nation-wide wave recording system using waverider buoys for offshore waters and pressure gauges for coastal waters at representative locations. Wave measurements could be supplemented by a network of voluntary observers who would make regular beach and surf zone observations at specific sites. Collect and archive historical, geological, geomorphologic, botanical and meteorological aspects of the entire coast as well as normal engineering aspects. Install storm tide recorders at all major coastal population centres as the basis of a warning and response for impeding disasters from tropical-cyclone-induced storm surges. There is also a need to introduce awareness workshops, introduce coastal processes and engineering in university curriculum, install hydraulics laboratory for physical modelling and manufacture simple instruments and the use numerical modelling

1.12 REFERENCES