Research On The Land Use Change And Its Ecological Effect In The Coal Mining Area Based On The RS And GIS

This paper is based on the item of the environment evolution mechanism and the research of Geo-Information-Tupu in coal mining area(40471049), founded by the national nature science fund. It used RS and GIS technologies to analysis the space-time changing trend of the various land use types based on the land use status in different years. This paper takes the aerial photos of 1978, the topographic and image map of 1997, the aerial photos of 2004, and the spot5 satellite image of 2007 as the RS data source.In the process of remote sensing interpretation, we used ERDAS8.7 software to do the geometric correction, the coordinate transformation, and then we established remote sensing interpret tags and used the visual image interpretation method to interpret the images. We used GIS software ARCGIS 8.3 to vector the images of every period, and used the ARCVIEW3.3's statistical function to get the topography variation information and the land use change information based on the results of the vectorizaion by spatial overlay analysis technique.Based on the topography variation information, the subsidence area in the research district is much larger than the area of water-logged subsidence, which occupies 5.55% of the whole area in 2004. However, the subsidence area whose depth is more than 3 meters takes 21%, and the subsidence area whose depth is more than 2 meters is 40.3% in 2000. So the subsidence problem caused by coal mining in the coal mine area is very serious.Based on the information of land use changes, we get the results as fellows:(1)The area of farmland is seduced by 15.61% from 1978 to 1997. The building area increased by 90.91%. And the unutilized land area increased by 135.66%. The area of mining-induced collapse water-logged zone area achieved to 3.34km2.(2)From 1997 to 2004, the building area increased by22.20%, and the water-logged area increased by 76.87%. In this period, the mining-induced collapse water-logged zone area increased faster than that of the other periods. The annual average increasing speed of subsidence area is 10.98%. And the increasing range of woodland is the biggest as the woodland area increased by 103.49%. This is related to the treatment in the subsidence area.(3)From 2004 to 2007, the woodland area increased rapidly as before, with the annual average increasing speed of 9.58%; the area of mining-induced collapse water-logged zone increased by 14.83%; the building area is almost the same size with that of 2004.(4)According to the entire changing situation from 1978 to 2007, the areas of farmland and waters in the research district decreased, and the areas of woodland, building and unutilized land increased. This paper analysises the reasons for the various land types changing base on the above information . We discuss and analysis the environment's changing situation in the research district based on the land use status, RS data and the information of topography changes.(1)The soil environment is getting worse. The mining subsidence accelerates the erosion of the soil and the loss of water and soil. The mining subsidence had the most obvious effect on the soil moisture and the soil salt. The soils of the upper and middle parts of the subsidence farmland have the trend of the soil salinization and the bottom part is becoming sandy.(2)The spatial distribution of the water has been changed: the river was cut off that caused the decreasing of the river's influence area. The underground water was lowered which caused the wells'drying up. But because the number of the motor-pumped wells increased, the wells density increased from 4.79 ind/km2 in 1978 to 8.32 ind/km2 in 1997, which caused the enlargement of the motor– pumped wells'influence area. The writer puts forward calculation formula of the dependence degree on water well and quantitatively analysis the affection of the water well to various land types.(3)The NDVI decreased: the average value of the NDVI reduced from 0.223 in 1979 to 0.083 in 2002, which is caused by the increasing of building area and mining subsidence area in the research district.(4)The artificial environment was destructed: the distortion of ground surface caused by the mining subsidence brought the demolish of the farmland, the cracking and falling of houses, the breaking of highway and railway, the damage of river bank and electricity transmission tower.According to the problems that exist in the research district, this paper offers some advice and countermeasure about the development of the mine area in the future. And at the very ending, the paper makes a summary of the whole thesis, and makes an forecasting analysis about the future development in the research district based on all the data.