The landform types in Lu 'an city are complex and diverse. There are mountains, hills, hills and plains, which are trapezoidal in distribution, and rivers, basins and lakes alternate. The urban area can be divided into four geomorphic units: the northern slope of Dabie Mountain, Jianghuai Hill, Jianghuai Hill and Plain. It is distributed in the south bank of Huaihe River, along the downstream of Cuigu, Jiping, Yanhe, Hangbu River and Fengle River. The area is 9,949,700 mu, accounting for 36.9% of the city's area. Among them; The plain along the Huaihe River covers an area of 8.485 million mu, with three lakes and depressions alternately distributed, covering an area of 2.005 million mu, accounting for 23.6% of the plain along the Huaihe River. Low-lying and fertile land, but there are many opportunities for flooding; The converted area of Hangfeng Khan is 654.38+0.465 million mu, and the altitude is less than 30 meters. The ground is composed of alluvium, with deep soil layer and fertile soil.
The total land area of the city is 17976 square kilometers, equivalent to 26.964 million mu. The land use structure is basically: "five mountains, one water, three fields, one road and one manor", in which: the cultivated land area is 6,699,600 mu, accounting for 24.8% of the total land area; The forestland area is 9.087 million mu, accounting for 33.7%; Grassland1010.3 million mu, accounting for 3.8%; The garden area is 297,000 mu, accounting for1.1%; The water area is 6.5438+0.646 million mu, accounting for 6.65438+0% (including 955,000 mu of arable water). 1986 per capita arable land 1. 16 mu, woodland 1.58 mu, grazing land 0. 18 mu, and water surface 0.29 mu. The paddy fields in the city are large, and there are 1 1.38 million mountain fields in the southern mountainous areas and hills, among which there are woodland, and the area of the three gardens only accounts for 52.9%. There are also large areas of sparse forests, shrubs and grasslands that need to be rationally developed and utilized. The hilly and plain areas of Jianghuai are mainly cultivated land, and 80% of the cultivated land in the city is concentrated in this area. Due to the influence of topography, parent material, climate, vegetation, farming and other soil-forming factors, the soil types in the city can be divided into 8 soil types, 15 subcategories, 60 soil genera and 237 soil types. The zonal soil is yellow brown soil, which is also granted in the vertical belt spectrum of Zhongshan area. Non-zonal soils include fluvo-aquic soil, paddy soil, sand ginger soil, purple soil and lime (rock) soil. Paddy soil and yellow brown soil account for 82.9% of the total soil area.
The water resources in this city are mainly surface runoff caused by rainfall, and the groundwater resources are poor. The average annual precipitation in the city is between 8-1600 mm, and the surface water resources in normal years are about 921100,000 cubic meters. Its spatial distribution is 60% in Dabie Mountain area, 33.8% in Jianghuai hilly area, 4.7% in Huaihe Lake depression area and 65,438 0.5% in Hangfeng Xu Fan area. In time distribution, the annual ratio of high and low water resources is 2.5. In terms of annual distribution, the runoff in flood season accounts for about 50-60% of the whole year.
The rivers in this area belong to Huaihe River and Yangtze River. Larger rivers: Pi River, Shi River, Pan River, Ji River, Dong Fei River and so on. Originated in Dabie Mountain (or remnant vein) and flowed into Huaihe River from south to north; Hangbu River and Fengle River flow into Chaohu Lake from west to east and join the Yangtze River. 1984, the total storage capacity of existing water storage projects in the city was 8.062 billion cubic meters, including 7.057 billion cubic meters of reservoirs and 989 million cubic meters of ponds and dams. Among them, the total storage capacity of Li Xing is 3.629 billion cubic meters, and the average water supply per mu is 54 1.28 cubic meters. Supply and demand of water resources in the city: more than normal.