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The Environment
ALTHOUGH Hong Kong has one of the highest population densities in the world, country parks and low density rural development still make up more than three-quarters of the territory's 1 070 square kilometres. Natural plant and animal life is abundant and beautiful, and there is plenty of spectacular hill and coastal scenery. The remaining quarter of the land area is intensively developed, with high density, high rise residential and industrial building, and much commercial and tourist activity adding to pressures on the environment.
This chapter looks at the natural and physical environment of Hong Kong, its geology, topography and climate, its wildlife and its vegetation. The four elements of the govern- ment's programme aimed at protecting the environment against pollution are considered in turn - planning against pollution, legislation on environmental protection, the collec- tion, treatment and disposal of wastes and environmental monitoring and investigations.
The monitoring of the territory's weather is reviewed, and the chapter is concluded with a look at consultation and collaboration on environmental management.
Topography and Geology
Hong Kong is part of an ancient Cathaysian landmass that extended from Shandong in northern China to the Gulf of Hainan some 1 000 million years ago. After intensive folding of its metamorphic and crystalline rocks, intense mountain building with granitic intrusions and volcanic outpouring occurred during the Mesozoic period, about 250 million years ago. From the beginning of the Quaternary period, two or three million years ago, the low lying areas were alternately flooded and exposed as masses of water were locked up or released from ice sheets on a global scale. The last marine incursion was about 10 000 years ago. Since that time, deposition of sedimentary material eroded from the hills has continued sporadically. Erosion of the hills and deposition in the valleys increased rapidly under the influence of man following the widespread colonisation of the Hong Kong area during the Song Dynasty (960–1279).
Large volumes of sedimentary material are brought to Hong Kong's waters by the Zhu Jiang (Pearl) River. In recent years, the consequent sedimentation has been added to by extensive reclamation projects along the coastline. Hong Kong's granitic and volcanic rocks are deeply weathered and are prone to landslides if disturbed, but they can be excavated quite easily for use as reclamation material. In the developed portion of the territory the natural landscape is changing dramatically as hills are removed and the fill is used at the various reclamation sites to be found around Victoria Harbour and in the New Territories.
Apart from providing decomposed rock as fill for reclamation, the hills that make up most of Hong Kong's land area have little practical use. Soils are thin and nutrient- deficient, supporting only a sparse cover of grass or scrub except in protected valleys or in