| The Metamorphic Rock of Guizhou is the main potion of the Proterozoic strata in the middle part of the eastern part of Guizhou, which is mainly composed of the regional Metamorphic Rock.The soil layer is thick and the semi weathered layer is extremely developed in Metamorphic Rock area. Soil erosion degree would be greatly intensified once the vegetation destroyed. As a typical representative of the normal landform, the watershed topographic and waterway characteristics of Metamorphic Rock area is particular. Therefore, studying the watershed topography and waterway characteristics of Metamorphic Rock area can provide a scientific basis for the work of soil and water conservation of normal landform area. Based on the 1:50000 topographic map of the typical Metamorphic Rock area, using the method of Arc GIS spatial analysis and mathematical statistics,according to the Horton-Strahler waterway classification principle, extracting the waterway system and the landform information and doing statistical analysis. Contrasting with typical Karst area, studying the characteristics of waterway development and the law of internal development in Metamorphic Rock area; the difference of waterway system in different watershed level and the impact of major topographic factors on the development of waterway system. The results show that:1.Extracting the waterway by using Arc GIS, and extracting the number of waterway ? the length of waterway and other parameters in typical metamorphic rock area, and analyzing the relationship and correlation between the number of waterway, the length of waterway, the average length of waterway and the waterway's class by using the method of mathematical statistics. The results show that: the development law of the waterway in Metamorphic Rocks area is similar to the Karst area, with the increase of the waterway level, the number of the waterway decreases and the average length increases, and there is a semi log linear regression relationship between the waterway number, waterway total length and waterway average length of each class and the waterway's class.2. Analyzing the parameters of waterway structure in typical metamorphic rock area by using the method of mathematical statistics. The results show that: the development degree of waterway in Metamorphic Rock area is higher than that in Karst area. The density of waterway in Metamorphic Rock area is about 2.5 times of Karst area, the frequency of waterway inMetamorphic Rock area is about 3.4 times of Karst area, and the development of waterway density and frequency of each class in Metamorphic Rock area are higher than that in Karst area,meanwhile, the development of waterway density and frequency of second level of the Metamorphic Rock area are equivalent to the waterway development of the first level of the Karst area, the development of waterway density and frequency of third level of the Metamorphic Rock area are equivalent to the waterway development of the second level of the Karst area, and so on.The average length of the waterway is about 0.7 times of Karst area, the average branch ratio is0.78 times of Karst area. It shows that the waterway of Metamorphic Rock area is more and concentrated, but the length is shorter, and the waterway development degree of each class is high,the branching capacity of waterway is low, the development of waterway is perfect.3.Based on the waterway system structure map, extracting the closed watershed of each class,identifying the level of watershed, and calculating the waterway structure parameters, such as density, frequency and branching ratio of each class waterway, analyzing the difference between the parameters of waterway structure under the different watershed level. The results show that:the difference of waterway density, waterway frequency and branching ratio under different watershed level are not significant, it shows the watershed level had no significant impact on the development of waterway in Metamorphic Rock area, and there is a fixed universal relation that the development law of waterway of different scales is similar.4. Based on watershed digital map, establishing the DEN digital elevation model, extracting the watershed landform factors, such as the watershed average slope and relative height difference and analyzing the impact of watershed landform factors on waterway system development.Calculating the erosion coefficient of each watershed by the method of altitude?area analysis,identifying the erosion development stage of each watershed, calculating the waterway structure parameters, such as density, frequency and waterway catchment area of each class watershed erosion development stage, and analyzing the difference of waterway system under the different geomorphological development characteristics. The results show that: the difference of each waterway structure parameters under different watershed average slope and different landform erosion development stage are not significant, it shows the watershed average slope and development stage of watershed landform erosion had no significant impact on the development of waterway in the Metamorphic Rock area, and there is a fixed universal relation that the development law of waterway of different watershed average slope and different development stage of watershed landform erosion is similar.5. The difference of each waterway structure parameters under different watershed relativeheight difference are extremely significant, it shows the watershed relative height difference has significant impact on waterway development in Metamorphic Rock area, and the influence degree of watershed relative height difference on waterway development decrease with the increase of watershed level. |
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