基于USLE模型的长株潭城市群生态绿心区水土流失研究

A Study on Soil and Water Loss in Ecological Green Heart Area of Changsha-Zhuzhou-Xiangtan Urban Agglomeration Based on USLE Model

[目的]研究2018年长株潭(长沙市—株州市—湘潭市)城市群生态绿心区最佳植被覆盖和水土流失状况,为区域综合治理提供理论依据。[方法]运用GIS和RS技术,以长株潭区域降雨、土壤、地形、土地利用等数据为基础,采用归一化植被指数(NDVI)模型和USLE国际通用土壤流失方程为优选模型。[结果]长株潭绿心区总面积为52287 hm^2,整体植被状况较好,高覆盖度(75%~100%)面积最大,占绿心区总面积一半以上,为26598.40 hm^2;中低覆盖度(30%~40%)面积最小,占区域总面积的8.61%,为4501.91 hm^2。长株潭城市群生态绿心区总侵蚀(不含微度)面积为3654.24 hm^2,占总面积的6.99%。湘潭市侵蚀比重最高,为8.51%,长沙市次之,为6.67%,株洲市侵蚀总比例最小,为5.68%。工程建设用地在禁止开发区、限制开发区和控制建设区的侵蚀面积分别为963.92,310.74,735.11 hm 2。[结论]受人为因素、城市建设、产业分布等影响,长株潭城市群生态绿心区覆盖度空间呈现西部低,中东部高的格局,工程建设是造成绿心区土壤侵蚀的主要原因。

[Objective]The optimal vegetation coverage of the ecological green heart area of Changsha-Zhuzhou-Xiangtan urban agglomeration and the regional soil and water loss status in 2018 were studied to provide a theoretical basis for comprehensive management of regional soil erosion.[Methods]Using GIS and RS technology,based on rainfall,soil,terrain,land use and other data in the Changsha-Zhuzhou-Xiangtan area,the normalized difference vegetation index and USLE were adopted as the preferred models.[Results]The total area of the Changsha-Zhuzhou-Xiangtan green heart area was 52287 hm^2,and the overall vegetation condition was above par.The high coverage(75%~100%)area was the largest,constituting more than half of the total area of the green heart area(26869.79 hm^2);the low coverage(30%~40%)area was the smallest,being only 8.61%of the total area(4501.90 hm^2).The total area of erosion(excluding microdegree)in the green heart area was 3654.24 hm^2(which was 6.99%of the total area).The proportion of erosion in Xiangtan City was the highest(8.51%),followed by Changsha City(6.67%)and Zhuzhou City(5.68%).The erosion area of construction land was 963.92,310.74,and 735.11 hm^2 in the prohibited development zone,restricted development zone,and the controlled construction zone,respectively.[Conclusion]The coverage space of the ecological green heart area of Changsha-Zhuzhou-Xiangtan urban agglomeration appeared to be low in the west and high in the middle-east part,which might have resulted from man-made factors,urban construction,and industrial distributions.Engineering construction was the main reason for soil and water loss in the green heart area.