基于SLEUTH模型的滇池流域城市扩展模拟分析

通过滇池流域1992～2010年城市扩张研究，发现城市建设用地增长主要表现为两种形态：一是边缘增长，表现为城市建成区范围不断扩大；二是道路影响增长，表现为环滇池道路两边新城市单元的产生。基于滇池流域城市扩展变化遥感数据，对SLEUTH城市扩展模型进行校准，模拟30 a间（2010～2040年）3种预案下的昆明城市扩展变化过程，并对模拟结果进行分析。3种模拟预测结果表明：任意管理预案下城市无序扩张，大量农林用地被城市建设用地占用，人口和城市建设用地呈现爆发式增长，滇池沿岸被城市包围，会对滇池水环境产生极大的压力；土地总量控制预案下城市的发展完全按照城市总体规划内容进行，没有考虑城市实际发展过程中的经济、人口等因素影响，没有达到滇池生态环境保护的需要；生态环境保护预案下，能相对有效控制建设用地，减少对农林用地、湿地的侵占，利于滇池环境保护。预测发现，从滇池流域水资源现状来看，即使实施了环境保护模式，人均水资源量仍处于“严重短缺”状态。需要通过调整昆明城镇体系和产业布局，降低城市首位度和人口；采取更为严格的空间管制策略，有效控制城市空间扩展，以减少对滇池流域的环境压力

SIMULATION STUDIES OF URBAN GROWTH IN THE DIANCHI LAKE BASIN BASED ON SLEUTH MODEL

Dianchi Lake basin is the core area of the Kunming City, which accounts for 0.7% of land area and 24% of GDP of Yunnan Province. Cities around the basin are the most developed area of Yunnan Province. Based on the urban growth in Dianchi Lake basin during 1992-2010, urban construction land growth showed two kinds of patterns. One was Boundary Growth which showed sustained growth of the existing urban area. The other pattern was Roads affected Growth which showed new urban units came into being along with roads surrounding the Dianchi Lake. According to the remote sensing data of the urban growth of Dianchi Lake basin, calibration model of SLEUTH urban growth simulated three pre arranged plans of the Kunming City growth in 30 years (2010-2040). Three kinds of simulation results showed as follows. Arbitrary Growth plan led to unlimited urban sprawl. Population and urban land presented an explosive growth pattern. Great quantity of farm land and forest land were transformed to urban construction land. Dianchi Lake coast was surrounded by urban land, and the construction land area reached to 495 km2 (an increase of 200 km2) in 2040, and the population reached to 5.4 million, which were almost close to the upper limits of admissible capacities of land and population of the Dianchi Lake basin, and would greatly threaten the water environment of the Dianchi Lake. Land Total Quantity Control plan showed that Kunming City growth was controlled by urban master planning, without population and economic factors taken consideration. The construction land area was going to be 411 km2 and the population was 411 million in the year of 2040. South area of the city was the main development direction of Kunming. This kind of plan could not meet the need of the Dianchi Lake environment protection. Dianchi water resource protection was the aim of Ecological Protection plan. The construction land area and population were strictly controlled. Urban growth speed obviously slowed down. Population was 3.17 million in 2030, less than the current amount of the population and 3.92 million in 2040, lower than the upper limit of admissible capacity of population. Ecological Protection plan could effectively control urban construction land growth, and reduce the occupation of the forest land, farm land and wet land, which helped to protect Dianchi Lake environment. According to the prediction, per capita water resources were still in the situation of “critical shortage” in three urban growth plans. In order to improve the water resource situation, measures should be taken to adjust urban system layout and industry distribution, to reduce urban primacy ratio and population, to employ more stringent spatial regulations, which would effectively control urban growth. Diversion works may help to relieve strain on water