太湖流域平原水网区浅层地下水动态特征及影响因素

鉴于浅层地下水在维持区域生态功能方面的重要作用,基于2005-2015年太湖平原水网地区苏州市的14个浅层地下水监测井水位及2005-2014年降水、河道水位和蒸发等日尺度数据,开展浅层地下水埋深动态特征及影响因素研究.结果显示:苏州市浅层地下水总体呈由北往南、自西向东的流场方向,主要受地形因素的影响;年际及丰水期埋深有所减小,枯水期反之,各区域变化过程不一致;枯水期浅层地下水动态特征受不同量级降水总量和次数的显著影响,且与地表水过程关系密切,汛期反之.此外均受到引排水和下垫面变化等因素的影响;浅层地下水埋深对降水具有滞后性,多滞后1~2 d;通过对地形地貌条件、土地利用类型、河湖密度以及浅层地下水埋深状况等因素的综合分析,浅层地下水动态特征可表达为耕地区、水网密布区、高度城镇化区及低山林区4种特征类型.

Characteristics of shallow groundwater and its influences in plain river network region of Taihu Basin

In view of the important role in the maintenance of regional ecologic function, the spatio-temporal characteristics of shallow groundwater burial depth (SGBD) and its influential factors were studied based on the daily SGBD data (from 2005 to 2015) and regional precipitation, water level and evaporation data (from 2005 to 2014) in Taihu Basin. The results indicated that:The shallow groundwater in Suzhou showed a flow direction from north to south, and from west to east, which is mainly affected by regional topographic conditions. The regional SGBD showed a slightly reduction in annual and flood season scale, while increase in non-flood seasons. The change processes varied among regions. The variation of SGBD is significantly related to the amount and frequency of different precipitation ranks in non-flood seasons, and affected by surface water. Moreover, the diversion and drainage, and underlying surface change were also the influential variables. While these features were opposite in flood seasons. The variation of SGBD often lags 1 to 2 days to precipitation. The characterization of shallow groundwater could be divided to four types, such as the agricultural, watery, urbanized and low mountainous regions, through the overlay of the influential variables, such as geomorphologic conditions, land use types, densities of rivers and lakes, and shallow groundwater burial depth.