滹滏平原漏斗区地下水溶解性总固体演变特征研究

Evolution characteristics of total dissolved solids in the groundwater level funnel area in the Hufu piedmont plain

为揭示滹滏平原漏斗核心区地下水溶解性总固体(TDS)增大对水位下降的响应特征以及驱动TDS增大的主要化学组分,应用地学数理统计分析、时间序列异变分析和GIS空间特征分析技术,分析了近50年(19722017)研究区地下水水位埋深、TDS及化学组分变化特征。结果表明:(1)随着水位降幅变化,地下水TDS增幅具有阶段性变化特征,在漏斗形成初期(19721980年),地下水水位年均降幅最大,TDS年均增幅也最大;中期(19812000年)地下水水位年均降幅最小,TDS年均增幅也最小;末期(20012017年)地下水水位年均降幅居中,TDS年均增幅也居中。(2)随着水位埋深增大,漏斗核心区地下水水位埋深大小对TDS增大影响呈递减效应。漏斗形成初期水位埋深9.10~23.20 m,中期水位埋深13.40~42.28 m,末期水位埋深21.41~50.29 m,漏斗核心区地下水水位年均降幅每增大1.0 m条件下,TDS年均增幅分别增大21.96,13.54,12.32 mg/L。(3)自初期、中期至末期,地下水中Na^(+)、SO_(4)^(2-)含量增幅占TDS增幅的比率呈不断增大特征,为漏斗核心区TDS增大的主要影响因素。但末期Ca^(2+)、Mg^(2+)、HCO_(3)-和Cl^(−)含量增幅占TDS增幅的比率合计仍达65.88%,对漏斗核心区地下水TDS增大仍然发挥至关重要的作用。

In order to reveal the response characteristics of total dissolved solids(TDS)increase to groundwater level decline and the main chemical components that drive TDS to increase in the core area of the groundwater level funnel in the Hufu piedmont plain,geological statistical analysis,time series variation analysis and GIS spatial feature analysis technology are applied to analyze the variation characteristics of groundwater level depth,TDS and chemical compositions in the study area in the past 50 years(1972-2017).The results show that(1)the increase of TDS is characterized by stages along with the decrease of groundwater levels.In the initial stage of the funnel formation(1972-1980),the annual decrease of groundwater levels was the largest,and the annual increase of groundwater TDS was also the largest.In the middle period(1981-2000),the average annual decrease of groundwater level was the lowest,and the average annual increase of groundwater TDS was also the lowest.At the end of the period(2001-2017),the average annual decline of groundwater level was in the middle,and the average annual increase of groundwater TDS was also in the middle.(2)The influence of groundwater level on the increasing TDS presents a decreasing effect with the increase of the depth of groundwater level.For each increase of groundwater level of 1.0 m,the average growth rate of groundwater TDS increased by 21.96 mg/L at the initial stage of the funnel formation(the groundwater level buried depth ranged from 9.10 m to 23.20 m),the average growth rate of groundwater TDS increased by 13.54 mg/L at the middle stage(the groundwater level buried depth ranged from 13.40 m to 42.28 m),and the average growth rate of groundwater TDS increased by 12.32 mg/L at the end stage(the groundwater level buried depth ranged from 21.41 m to 50.29 m).(3)The increase of concentrations of Na^(+)and SO_(4)^(2-) in groundwater is the main reason for the increase of TDS in the funnel core area.From the initial stage to the final stage of the funnel formation,with the increasing depth of groundwater level and TDS,the ratio of the increment of Na^(+)and SO_(4)^(2-) in groundwater to the increment of TDS in each stage shows an increasing characteristic.However,the total ratio of the increment of Ca^(2+),Mg^(2+),HCO_(3)-and Cl^(−)contents in the final stage to the increment of TDS is still 65.88%,which still plays a crucial role in the increasing of groundwater TDS in the funnel core area.