1 A. 1 Lecture # 1 - EARTH SCIENCE INFORMATION FOR PRUDENT LANDUSE AND MANAGEMENT OF NATURAL HAZARDS
Based on manuscripts submitted for publications by R. Ahmad and Avijit Gupta.
" LAND IS THE COMMON THREAD. IT IS A FINITE RESOURCE, AND WE HAVE TO FIND ENOUGH FOR ALL OUR NEEDS- HOMES, JOBS, SHOPS, FOOD, TRANSPORT, FUEL, BUILDING MATERIALS AND RECREATION- WHILE PROTECTING WHAT WE VALUE MOST IN OUR SURROUNDINGS."
(From: This Common Inheritance, Britain's Environmental Strategy 1990)
The island states of the Caribbean are undergoing urbanization at a rapid pace. Major urban centres in these islands are not older than a few centuries, having been established to function as regional trading posts or administrative centres by either colonial or regional powers. It is doubtful that the site conditions were taken into consideration, and consequently many of these cities were established in geologically hazardous or environmentally sensitive areas. As these cities developed over time, they spread across a wide range of terrain conditions much of which are unsuitable, such as alluvial fans located at the mouth of small and steep rivers, narrow floodplains, coastal swamps, and steep slopes. A number of case studies from different parts of the world (dealing with increased landslide activity, effects of seismicity, increased flooding) have demonstrated the utility of earth science information to planners, city managers and urban planners. But a lack of effective communication frequently occurs between these groups and geologists, although exceptions do exist.
This communication failure is particularly true for cities that are located in regions where active geologic processes have a profound influence on the physical environment. The failure to take the local geologic features and processes into consideration either at the planning or the management stage leads to losses of life and property. Problems of slope failure or floods are usually dealt with after their occurrence, rather than at the planning or construction stage.
The rapid expansion of urban communities in Jamaica is having a serious and negative impact on island's limited land, soil, and water resources including its offshore ecosystems (coral reefs). The impact is due to both physical expansions in geomorphologically unsuitable terrain and ever increasing urban demand for land and water in areas where such resources are very limited. As a consequence, it is inevitable that the frequency of landslides, flooding and accelerated soil erosion is also significantly increasing. The effects are more widespread in some locations compared to others. This is against the background that there are a number of initiatives in place in Jamaica (supported by international, governmental and non-governmental agencies) with the aim of " trying to do best for the country". However, the recurring economic costs related to active geologic processes and disasters are undoubtedly very high. It appears that as a society we are unable to appreciate the actual reasons for these problems and that these costs may be significantly reduced and/or avoided provided earth science information is rigorously used in landuse planning. The extent of the problem and the ability to deal with it, depend on both location and prosperity of the concerned urban centre/s.
It is possible, based on the experiences of past events, to hypothesize possible environmental impacts of active geologic processes, but these data only serve as broad guidelines on prudent landuse policies. Such studies and recommendations are readily available, e.g., Landslide Hazard Zonation Maps for the Kingston Metropolitan Area. However, since every urban centre is unique and also for the purposes of practical applications detailed and site-specific studies and monitoring are required.
The earth science information should be useful to planners and city engineers. It is more efficient and less expensive to plan for the adverse impacts of active geologic processes than tackle them afterwards. Numerous studies have demonstrated that a proactive response to natural hazards is more cost effective than a reactive response. The preferred instrument of communication between the earth scientists and planners and engineers seems to be a set of thematic maps prepared by geologists in consultation with the users. Using these techniques, it is possible to form a GIS database for each urban centre and study future impacts according to proposed plans to cope with the urban spread. Finally, unsuccessful communication with the urban managers and planners keeps technical capabilities unutilized.
Unit for Disaster Studies, e.g., has analyzed the impact of landslides on roads in KMA. This information should be an asset to the agencies responsible for maintaining the road network on the island.

" NATURE TO BE COMMANDED MUST BE OBEYED" (Francis Bacon, Novum Organum, 1620) "TO BE OBEYED, NATURE MUST BE UNDERSTOOD"

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