CHINA-Meeting with Lishui City Delegation

Lugano, 16 GIUGNO 2015

Environmental Geology and Planning

Engineering-geological and geotechnical investigation for risk assessment

Lishui is a prefecture-level city in the southwest of Zhejiang province, People's Republic of China. It borders Quzhou, Jinhua and Taizhou to the north, Wenzhou to the southeast, and the province of Fujian to the southwest.

Environmental geology is concerned with the impact of humans on the environment, as well as the influence of the environment on humans. Accordingly, environmental geology plays an important role in planning. The importance of this role undoubtedly will increase as the world population expands since land-use planning must become more important, especially as far as the development of urban areas and the growth of megacities are concerned. Because land is the surface expression of subsurface geology, then those involved with the planning process must appreciate and understand geology; that the earth is constantly changing, sometimes slowly, sometimes with dramatic effect.
As a consequence, there is a continuing need for geological data to be gathered and processed. One of the principal ways by which geological data can be represented is on geological maps. A variety of geological maps are now being produced to help land-useplanning, and they include environmental geology maps and hazard maps. Geological hazards are of particular importance in relation to planning, and may be natural or due to humans. Some of the most notable natural geological hazards include earthquakes, floods, and landslides. These types of hazard occur again and again, and one type of hazard can trigger another. Hazards due to humans include contamination of land, pollution of groundwater, ground subsidence, and soil erosion. One of the important factors in planning therefore involves the reduction of the impact of hazards. This can be accomplished in various ways, from control measures to warning systems to restricted development, and may well involve a numbers of methods.However, before any of these methods can be put into effect an environmental evaluation must be made, which includes an assessment of the degree of risk. In other words, an environmental impact assessment allows decision-makers to formulate and implement plans. Regeneration of urban areas and of derelict land is vitally necessary in order that urban communities can live in better environments, and conservation is equally necessary. Before construction activities could begin, engineering geological and geotechnical investigations had to be approved in order to establish a map with suitable areas for safe construction. The example used in this study is Lishui City which has complex geology and geomorphology. The risk analysis was based on a large-scale land-suitability map that was prepared using Geographic Information Systems (GIS). The approach used in this study combined physical data with the geotechnical properties of Lishui City. The adopted methodology and analyses were performed to assess the risk of urban expansion and landscape management. Results are presented as a zoning map that shows the suitable area for safe extension of the urban area. The data used and multi-criterion analysis of geotechnical and geological data seems to be useful for similar case studies and the adopted methodology can be used successfully for identifying similar cities for risk assessment.