Environmental geology in urban development

Abstract

Environmenta l geology, although well est ablished in the geological fra ternity, is still little understood by the rest of the community. This lack of appreciation on its u sefulness in urban planning and land development has resulted, to some extent, in the sterilisation or non-optimal use of mineral resources in Malaysia, particularly with respect to non-metallic minerals. In a ddition, development over geologically hazardous areas, without proper mitigating measures, has contributed towards man-ma de disasters, thus addili.g to the cost of remedial and maintenance work. Another outcome, especially during periods of rapid development and without appropriate environmental geological inputs, has been increased erosion, landslides, flash floods , pollution of waters, rapid runoff and even lowering of the groundwater table. The long-term effect ofthis is a n increase of water-stressed areas, especially during the dry season. Environmental geology can also be applied in many other areas of urba n planning such as for the disposal of solid and toxic waste, determination of sources for water supply, infrastructure development (roads , dams, airports, seaports etc.), recreation and tourism, land reclamation, identification and clean-up of contaminated sites, as well as conservation, among others. Inspite of its wide variet y of applications insufficient use of geology is m ade in urban planning. Environmental geology maps and reports (also known as engineering geology maps in Europe) can significantly assist the planner in planning of townships , preparation of structure and local plans or in drawing up oflayout plans for specific projects. Even during the development stage advantage should be taken to update the geological database and consultants and developers should, with the help of geologists, translate it into potential environmental impa cts and thus put in place appropriate mitigating measures. Although the applications of environmental geology are numerous yet it is insufficiently used. The reasons include insufficient or lack of cross professional interaction and lack of training in maximising the use of geology for urban planning and land development. This is compounded by the fact that reports written by geologists are too technical in nature and understood m a inly by geological specialists. Furthermore the scale of maps is critical as, more often than not, they tend to be on a reconnaissance scale that are more appropriate for macro landuse planning. For site specific projects, maps on a detailed scale (1:1,500-1:5,000) will be more useful to enable the incorporation of elements of environmental geology in planning. There is certainly an urgent need to close this communication gap in Malaysia, in particular, and Southeast Asia, in general. In North America, Europe and Australia, progress h as been made but more can be done. There is also an urgent need to produce simple thematic maps and reports, understandable to planners, architects, engineers, developers and even politicians, to ensure that maximum advantage is taken of geological inputs for urban planning and development. The thematic maps should cover geology, geochemistry of rocks, soils and water s, geotechnical properties of soils and rocks, mineral resources, especially construction materials, geotechnical classification of slopes, landslides, flood-prone areas, thickness of overburden (rock line), distribution and thickness of peat, groundwater flow pattern etc. Howev er maps such as gen eral foundation suitabili ty, potential waste disp osal sites, relative compressibility, sinkhole susceptibility, ripperbility potential, landslide susceptibility etc., derived from the raw data collected, will be easier to use and more useful to th e planner or developer. The additional cost is very small when compared to th e cost of the proj ect or the potential benefits expected. Since the early nin eties and subs.equently after the 1995 amendments to the Town and Country Planning Act (1976), geological inputs are now a requirement. For bigger projects such as the Kuala Lumpur International Airport at Sepang, the new a dmini strative centre for Kuala Lumpur (Putrajaya), the information technology city named Cyberj aya and th e International Commonwealth University of Malaysia, appropriate geological inputs were provided for layout plans. However this practice is not the norm and for the State level it is recommended that the Geological Survey Department be co-opted into Footnote: ' i'Public Services Commission Malaysia 330 FATEH CHAND committees dealing with regulation and control of development. The department will be able to help set up geological standards for land use and geohazard mitigation and formulate, jointly with Town and Country Planning Department, guidelines to assist in the provision of geological information to local authorities for preparing structure and local plans and to developers for preparing the Development Proposal Reports. It would not be out of place to introduce statutory requirements covering development within hazard areas, once geological standards and guidelines for development have been drawn up. Finally, with the use of environmental geology we hope to promote sustainable development by facilitating pre-disaster mitigation instead of post-disaster remedial action.