为确定某工程地下水环境影响评价的目标和范围，以其滨海厂址为研究对象，基于水文地质调查工作成果， 采用水位动态监测、水化学分析和氢氧稳定同位素示踪技术，开展大气降水、地表水和地下水之间的相互转化规 律研究。结果表明：研究区地下水水位动态随着降水量变化存在显著的季节变动，不同水体水化学特征和氢氧稳 定同位素组成存在差异，大气降水补给浅层地下水和地表水，浅层地下水与不同的地表水之间存在相互转化的水 力联系且受到明显的蒸发影响，深层地下水主要接受更新世冰期古水的补给，与浅层地下水联系微弱。

Due?to?the?uneven?seasonal?distribution?of?atmospheric?precipitation?during?the?year,?densely?distributed surface?water?bodies,?and?complex?hydrogeological?conditions,?the?mechanism?of?mutual?conversion?among?the?3 types?of?water?in?coastal?plain?areas?is?very?complex.?Once?a?pollution?accident?occurs,?the?pollutants?are?easily transferred?through?the?three?waters?conversion,?which?pose?a?threat?to?the?health?and?safety?of?the?surrounding public.?Therefore,?in?order?to?provide?technical?basis?for?the?preparation?and?review?of?the?environmental?impact report?of?the?site,?it?is?necessary?to?study?and?reveal?the?conversion?laws?between?atmospheric?precipitation,?surface water,?and?groundwater,?determine?the?impact?range?of?pollutant?migration?in?the?3?types?of?water?under?accident conditions,?and?determine?the?goals?and?scope?of?environmental?impact?assessment?in?the?selection?and?evaluation?of engineering?project?sites?in?the?region. ??????This?paper?has?maked?full?use?of?the?hydrological?and?geological?survey?data?in?the?vicinity?of?the?coastal?plant site?of?a?project,?collected?the?hydrological?data?in?the?coastal?area?of?the?North?China?Plain,?analyzed?the?water levels?dynamic?change?characteristics?of?the?surface?water?and?the?groundwater?in?different?aquifers,?studied?the hydrochemical?characteristics?of?different?water?bodies?and?their?water?quality?changes,?compared?the?composition and?differences?of?hydrogen?and?oxygen?isotopes?in?different?water?bodies,?and?judged?the?mutual?transformation relationship?between?atmospheric?precipitation,?surface?water?and?groundwater,?analyzed?the?hydraulic?connection of?groundwater?between?different?aquifers,?and?comprehensively?studied?the?transformation?law?of?the?three?water systems?around?the?plant?site. ??????Results?indicate?that?there?was?a?significant?seasonal?variation?in?the?groundwater?level?dynamics?of?the?study area?with?changes?in?precipitation.?The?overall?performance?was?that?the?water?level?gradually?decreases?during?the dry?season?and?increases?during?the?wet?season.?There?were?differences?in?hydrochemical?characteristics?between shallow?groundwater?and?different?surface?waters,?which?were?similar?to?the?deep?groundwater?of?the?Ⅱ?water- bearing ?rock ?group. ?The ?hydrochemical ?characteristics ?of ?groundwater ?in ?the ?Ⅲ?and ?Ⅳ?water-bearing ?rock formations ?were ?similar, ?but ?there ?was ?a ?significant ?difference ?between ?them ?and ?the ?Ⅱ?water-bearing ?rock formations.?The?δ(D)?value?of?shallow?groundwater?was??59.1‰?to??43.3‰,?with?an?average?value?of??48.93‰, and ?the?δ(18O) ?value ?was ??8.02 ‰?to??4.87‰, ?with ?an ?average ?value ?of ??6.05 ‰. ?The?δ(D) ?value ?of ?deep groundwater?of?the?II?water-bearing?rock?group?was??66.5‰?to??65.5‰,?with?an?average?value?of??66.13‰,?and?the δ(18O)?value?was??9.20‰?to??8.86‰,?with?an?average?value?of??8.99‰.?The?δ(D)?value?of?deep?groundwater?of?the Ⅲ?water-bearing?rock?group?was??69.6‰,?and?the δ(18O)?value?was??9.24‰.?There?were?obvious?differences?and spatial?changes?in?the?hydrogen?and?oxygen?isotope?composition?of?groundwater?in?different?water-bearing?rock groups,?and?the?shallow?groundwater?was?the?most?enriched.?It?showed?a?trend?of?change?from?large?to?small?as?the depth?increases?in?vertical?direction. ??????The ?atmospheric ?precipitation ?supplied ?shallow ?groundwater ?and ?surface ?water. ?There ?was ?the ?hydraulic connection?between?shallow?groundwater?and?different?surface?water.?The?general?performance?was?that?shallow groundwater?received?seepage?recharge?from?surface?water?bodies,?such?as?Yangcheng?trunk?ditch,?Yangcheng wetland,?Yangcheng?reservoir?and?pond,?and?runoff?was?discharged?to?Zhangweixin?River,?Xuanhui?River?and Yangcheng?branch?ditch.?The?runoff?of?the?shallow?groundwater?was?from?southwest?to?northeast?on?the?whole,?and finally?entered?the?sea.?The?shallow?groundwater?was?obviously?affected?by?the?evaporation.?The?deep?groundwater was?mainly?supplied?by?Pleistocene?glacial?water,?and?the?hydraulic?connection?with?the?shallow?groundwater?was weak.