低丘红壤区不同降雨类型对浅层地下水位动态变化的影响——以江西省余江县为例

Dynamic Changes of Underground Water Tables Affected by Different Rainfall Types in Low Hilly Red Soil Area——A Case Study of Yujiang County,Jiangxi

为研究低丘红壤区不同降雨类型对浅层地下水埋深的影响,在江西省余江县选择受自然因素影响较大的7口井进行分析。结果表明:影响浅层地下水水位变化的因素除了与降雨量、蒸发量、地表径流以及降雨过程中入渗土壤的雨水量外,还与降雨历时、降雨前期土壤的湿度等因素有关;据监测2 a的地下水位、降雨量等动态变化,从中选出三种降雨类型(Ⅰ降雨强度小且历时长,Ⅱ降雨强度大且历时短,Ⅲ干旱无雨时突然一场中雨),其中一场中雨就可以使Ⅰ的井水位剧烈变化,一场大雨可以使Ⅱ中的井水位明显抬升,偶尔一场大雨仅能湿润Ⅲ的土壤,对地下水位没有太多的影响;在浅层地下水位与降雨量、地表径流及进入土壤的雨水(RO)的相关性分析中,以降雨类型Ⅱ的相关系数的绝对值最大,且均呈极显著负相关,而降雨量与地表径流和RO呈极显著正相关。这表明在土壤周年盈水期且连续降雨时期,可对浅层地下水进行存储,以备在干旱少雨且作物需水时使用。

7 wells whose underground water tables were affected by nature factors were monitored with an objective to find different impacts by different rainfall types in Yujiang Country,Jiangxi Province,China.Dynamic changes of underground water table were affected by rainfall duration and prophase humid degree of soil,also including rainfall,evaporation,surface flow and other water which leaked into soil profile in precipitation period.Three rainfall types were found out accounting to changes of underground water tables and rainfall during 2 monitored years.They were Type Ⅰ（lasted long period with stretching rain）,Type Ⅱ（lasted short period with drencher） and Type Ⅲ（no rainfall of prophase period then had moderate rain）.The underground water tables were changed greatly by a middle rainfall in Type Ⅰ,so did drencher in Type Ⅱ.An occasional drencher or storm leaked into soil,couldn＇t arrive at underground water table,so it had a little bit effect of water table in Type Ⅲ.The absolute values of correlation coefficient of Type Ⅱ were highest among three types,significantly and negatively between underground water tables,rainfall,surface flow and leaked flow during rainfall.Rainfall was significantly and positively correlated with surface flow and leaked flow in Type Ⅱ.Thus,underground water was collected for drought and plants required water phase at surplus water and continual rainfall period.