天山北坡典型小流域侵蚀沟形态特征及其成因

目的]揭示天山北坡典型小流域侵蚀沟发育规律,为侵蚀沟的预警及防治提供科学依据。方法]选取天山北坡典型小流域10条侵蚀沟进行分析,采用野外实地调查与地理信息技术相结合的方法,对研究区侵蚀沟形态发育特征及其成因进行分析。结果](1)研究区侵蚀沟特征值之间存在着一定的相关关系:横截面积与平均沟宽、平均沟深呈极显著正相关;沟壑面积与沟长呈显著正相关;沟壑体积与横截面积、沟壑面积呈极显著正相关关系,与平均沟宽、平均沟深呈显著正相关关系;沟长、平均沟宽、平均沟深相互之间无明显的相关关系,汇水面积与特征值之间也无明显的相关关系。(2)研究区侵蚀沟均是开析型侵蚀沟和弱度割裂型侵蚀沟。(3)研究区侵蚀沟密度与坡度呈正相关关系,坡度越大,密度越大;侵蚀沟密度与沟长无相关关系,侵蚀沟密度随沟长的增加呈先增加后减小的趋势;研究区典型侵蚀沟密度在南坡最大,西坡和西南坡的密度相对较小。结论]坡度和坡向是影响小流域尺度侵蚀沟发育的重要地形因素。

Morphological Characteristics of Erosion Gully and Its Driving Factors in a Typical Small Watershed in Northern Slope of Tianshan Mountains

Objective] The objective of this study is to reveal the development of erosion gully in a typical small watershed in the northern slope of Tianshan Mountains, in order to provide a scientific basis for early warning and control of gully erosion. Methods] This paper selected 10 erosion gullies in the northern slope of Tianshan Mountains, field survey and GIS technology was used to investigate the characteristics and morphological formation of erosion gully. Results] (1) There was a significantly positive correlation between the cross section area and the average width and the depth of the gully. Gully area was positively related to the length of gully. Significant positive correlations existed between gully volume and cross-sectional area, and between gully volume and gully area. No significant correlations were found among gully length, average width of gully and the mean depth. Similarly, no obvious correlation existed between catchment area and characteristic value. (2) Erosion gullies in the study area were all open-type and weak erosion type. (3) Gully density was positively correlated with the slope, as greater the gully density tended to occur at the steeper slope. However, there was no correlation existed between gully density and gully length. Gully density was the largest in the southern slope, while in the west and southwest slope, the gully density was relatively small. Conclusion] The slope and aspect are important geomorphological factors influencing gully development at small watershed scale.