东北黑土区近40年沟谷侵蚀动态及影响因素分析

在遥感和地理信息系统的支持下获取了乌裕尔河流域中上游地区1965年和2005年的侵蚀沟分布数据,同时基于1:5万地形图获取了等高线、水系、道路和居民点数据,在GIS空间分析模块支持下,揭示了典型黑土区40年里侵蚀沟的动态变化特点及与其影响因素之间的关系.结果表明,近40年里侵蚀沟密度具有明显增加的趋势,2005年出现侵蚀沟密度高于500 m/km~2的高值区,侵蚀沟密度的变化是以位于克东和克山县内的剧烈增加区为核心,呈现出向两侧递减的变化趋势.2°～3°坡范围内为该区沟蚀最严重的坡度地区;坡长增加,侵蚀沟密度减少,小于1 000 m的范围是沟蚀严重区;侵蚀沟密度具有距水系距离增加而减少的特点.侵蚀沟主要是发育在小于距道路1 500 m的范围内,大于2 000m的地区侵蚀沟发育微弱;人类开发活动的从优性、从易性使得离居民点越近,侵蚀沟密度越大.

Dynamics and Effect Factors of Gully in the Black Soil Area of Northeast during the Past 40 Years

Gully erosion is very serious in Black Soil Area of Northeast China. Based on RS and GIS, gully distribution data in 1965 and 2005 were get in middle and upper reaches of Wuyuer river basin. At the same time, taken 1 :50000 relief maps as data sources, contour, water system, road and residential area data were obtained. On the support of GIS spatial analysis function, the characteristics of gully dynamics in 40 years were analysed and the relationship between gully and effect factors (slope, slope length, road et al. ) were also analysed. It shows that gully density has obviously increased during the past 40 years. The change of gully density take actue increase region in Kedong county and Keshan county as core zone and corresponding decrease by the cores to sides. Slope in 2°～3° is the most serious gully erosion slope region;With the increase of slope length, gully density is decrease and slope length which is lower than 1 000 m is the gully erosion central zone. Otherwise, the more far away water, the lower of the gully density. The gully mainly form in the distance of 1 500 m to the road, and there is few gully more than 2 000 m. The effect of residential area on gully formation appears the trend of decrease with the distance.