Research On Optimal Allocation Of Land Use Based On Pollution Control Of Dianchi Lake Basin

Regional development is based on land resources and changes in land use structure will directly alter its developing direction and prospect. Optimal allocation of land use structure, which is an effective way of achieving regional economic, social and ecological benefits, is the main part of regional macro-control. Optimization of land use structure includes quantity structure optimization and spatial structure optimization of land resources. Land use plans calculated through models can provide effective theoretical basis for regional planning to achieve regional sustainable development.Dianchi Lake Basin is the political, economic and cultural centre of Yunnan Province. Water quality, which is deteriorating during the latest few years, has become a major limiting factor that restricts regional developments. In order to improve regional ecological environments, this paper selects Dianchi Lake Basin as the study area and attempts to improve water quality of the study area from a macro perspective which mainly indicates the thought of optimal allocation of land use structure. Firstly, according to the scale of population development, three different development scenarios are set. The quantity structure, which is evaluated by indicators of ecosystem service value equivalents of Dianchi Lake Basin, is optimized through establishing a multi-objective linear programming model. Secondly, the simulation of spatial structure layout is brought about by the improved CLUE-S model. At last, through analyzing and comparing three quantity and spatial allocation results of land resources under different scenarios, the land-use planning program of Dianchi Lake Basin in2020is summarized. Conclusions generalized through optimizing land use structure of Dianchi Lake Basin are as follows:(1) The land use structure of Dianchi Lake Basin shows high stability. During the study period of1988to2009, with the development of economy and society, quantity and spatial structure of land resources changed little except a characteristic of shift between arable land and construction land.(2) The optimal quantity allocation results of land resources change much compared with the land use structure of2008. The area of meadows and woodland increase a lot and construction land vary in different scenarios according to the scale of population development. The area of water remains virtually unchanged while the unused land decreases significantly.(3) Spatial structures in different scenarios change much, especially for the construction land. In the positive scenario, the construction land not only expands more than the historical scenario, but also increases in urban areas at the county level, which indicates that counties will be the focus in the future development of the basin.(4) Driving forces that form the land use pattern include natural and geographical environmental factors, socio-economic factors, land space autocorrelation and so on. Slopes and elevations of the region, regional GDP and the proportion of secondary industry in regional GDP are main land use driving forces; while aspects and soil types of land use resources are secondary land use driving forces. At the same time, Changes of a certain land use type are also subject to the impacts from other land use types surrounding that.(5) Circulation of land resources is the basic form of formation of new land-use types. The planning program of Dianchi Lake Basin of land resources are as follows:(a) the amount of arable land and unused land should be substantially reduced. The arable lands which should be transformed in gardens are allocated to be located mountainous and hilly areas in the northern part of the basin and southeastern parts of the lake coastal areas.(b) The grassland mainly distributed in the southeastern parts of the lake coastal areas and in the north main city subdivision and the woodland, which is mainly contiguously distributed in the north and east part of the basin in mountainous and hilly areas, both should be substantially increased.(c) Increase of construction land should not exceed10%on the base of that in2008. Key developing areas should be shifted from city to the county-level areas and basically form the prototype of satellite cities.(d) Ensure that no significant changes would occur in water area and water quality could be improved effectively.(6) Multi-objective linear programming model and improved CLUE-S model can achieve the goal of optimizing land use structure. Through changing the objective functions and constraint equations in the multi-objective programming model, some certain objectives could be achieved.