通过分析地表水和地下水中氯离子浓度和δD、δ18O值的空间分布特征,揭示了秦皇岛洋戴河平原地下水的形成演化规律.结果发现,洋戴河平原地表河水来源于中上游水库水和大气降水的混合,且河水沿程受到δD、δ18O值、氯离子浓度更低的支流或灌渠水补给,从而使δD、δ18O值、氯离子浓度呈现沿程逐渐降低的现象.山前丘陵区地下水主要接受大气降水的直接补给,洪积扇及山麓地带地下水受到了一定的蒸发作用影响,除了接受丘陵区地下水的侧向补给外,洋河附近地下水还受到洋河水库水的混合.研究区西部咸水带的地下水由上游地下水和大泥河地热咸水混合而成,地热咸水的混合比率约为13%,而东部咸水带的地下水由上游地下水、本地污水和地热咸水混合而成,地热咸水的混合比率不超过9%.在海水入侵区,地下水主要由本区地下淡水和海水(海水混合比率不超过10%)混合而成,并且受到了不同程度的地表水或农田灌溉水的补给,其中,浦河一带是地表水或灌溉水补给较为明显的地段.
The aim of this paper is to reveal the origin and evolution of surface water and groundwater by analyzing the spatial distribution of chloride ion concentration and δD and δ18O values in surface water and groundwater in Yang-Dai River Plain. The Yang-Dai River originates from the mixing of water of reservoir and meteoric water, and river water is also from the recharge in the tributary and irrigation ditch which have much lower chloride ion concentration and δD and δ18O values. Therefore, chloride ion concentration and δD and δ18O values in river water decreases gradually from upstream to downstream. The groundwater in hilly area is primarily recharged by meteoric water, and the groundwater in pluvial fan and piedmont experiences evaporation partly. The groundwater in pluvial fan and piedmont is recharged not only laterally by upstream groundwater from mountainous and hilly area, but also by Yang River reservoir water. In the study area, the groundwater in the west part of salty water region is mixed between upstream groundwater and salty geothermal water originated from Danihe area, with a mixing radio of 13% salty geothermal water. In comparison, the groundwater in the east part of salty water region is mixed by upstream groundwater, sewage water and salty geothermal water, with a mixing radio of up to 9% salty geothermal water. In the seawater intrusion region, the groundwater was mainly constituted of local fresh groundwater and intrusive seawater with a mixing ratio of up to 10% seawater, and is also partly recharged by surface water and agricultural irrigation water which have higher contribution to the groundwater recharge in Pu River area.