乡村聚落水蚀特征研究——以陕北3个典型乡村为例

A Study on the Characteristics of Water Erosion in Rural Settlements——A Case Study of Three Typical Rural Areas in North Shaanxi

通过2003-2005年定位观测资料的分析发现:(1)陕北多沙粗沙区乡村聚落特殊的下垫面容易产生地表径流,导致水的流失,而水蚀后的下垫面产流量更大(2003年全区平均径流系数为0.27,2004年为0.34),水蚀强度也更大(2003年全区平均侵蚀强度为1698.7t/km2,2004年为5434.3t/km2)。2004年全区户间道路、户间空地、庭院的平均侵蚀强度分别达7348t/km2,6873.2t/km2,2081.7t/km2,除庭院属轻度级侵蚀外,其他均达强度级侵蚀,应加强研究和防治。(2)水蚀泥沙的粒度各年均以0.01～0.05mm的粗粉沙为主,占到43%以上。泥沙粒度结构从区域来看,从南到北细粒成分愈来愈少,粗粒成分越来越多;从时间变化来看,随着时间的推移,粒径较小的泥沙(包括粒径<0.05μm的胶粒、粘粒和粉沙)含量逐年减小,而粒径>0.05μm的粗泥沙含量逐年增大。

It was found from the analysis of observation data during 2003 to 2005：（1）that the special underlying surface of rural settlements the in abundant and coarse sediment area in North Shaanxi could generate surface runoff easily,and then form water loss,which made the underlying surface generat more water flow rate（the average runoff coefficient of the whole area in 2003 was 0.27,the figure changed to 0.34 in 2004 ）,meanwhile,the water erosion intensity got stronger and stronger （the average erosion intensity of the whole area is 1 698.7 t/km^2 in 2003,while in 2004 was 5 434.3 t/km^2 ）.The average erosion intensities of the roads,open space and yards were 7 348 t/km^2,6 873.2 t/km^2,2 081.7 t/km^2,which reached serious erosion,except the courtyard erosion being slight erosion.So water erosion in rural settlements should be studied and treated.（2）Sediment size of water erosion was predominated by semi-coarse silt（ 0.01 to 0.05 mm）,occupying more than 43%.From a regional perspective,the content of granule silt was less and less from the south to the north,and the coarse was more and more.On the other hand,as time went by,the granule silt contents decreased gradually（〈0.05 μm）,while coarse silt（〉50 μm） increased.