厦门岛西水东调对海岛地下水质的影响分析

海岛是一种独特的生态系统, 由于其特殊的水文地质条件, 水资源相对比较贫乏, 一般都依靠地下水维持岛上生产生活用水, 如果地下水质受到影响, 则会带来较大的风险。岛内地表淡水湖泊水体污染严重。为了解决岛内地表淡水湖泊水体污染问题, 决定调用海水对其进行稀释, 而这一方案则有可能造成引水工程沿线海水侵入地下水问题。本文采用有限元方法分析从厦门西侧的筼筜湖经松柏湖调水到钟宅湾对周围地下水质和湖库水体的影响, 以及在丰水年和枯水年湖库水体和海水水体之间的补给关系。分析表明: 工程在一年左右对周围地下水的影响将趋于稳定, 工程沿线150～800m 范围内地下水的盐度产生了明显变化。在枯水年, 由于地下水位下降, 海水有可能会补给湖库, 引起湖泊盐度升高, 对工程沿线特别是饮用水备用水源湖边水库造成潜在的威胁。

IMPACT OF WEST TO EAST SEA WATER DIVERSION PROJECT ON GROUND WATER QUALITY IN XIAMEN ISLAND

D rastically in fluenced by hum an activ ities, the w ater qua lity of theM iddle Lake of X iamen Island has been seriously polluted. In order to allev iate w ater pollution of the lake, a projectw as planned. It is the sea wa ter diversion pro ject from w est to eas.t The pro ject w ill change groundw ater environm en.t The most important the im pact in on the g round w ater environm ent o f the who le island. W ill the pro ject improvew ater qua lityw ithout causing ex tra prob lem s? W ill it decrease sea w ater invasion, groundw ater- seaw ater interaction, and nutriment reciproca t ion betw een freshw ater bodies and seaw ater as w el?l By adopting the F in ite E lementMethod, a conceptualmode l is set up to ana lyze groundw ater flow and sea w ater transportation w ith a mathem atica lmode.l The conclusions are ( 1) in annual average precip itation years, the sea w ater invasion w ill persist in one year after the pro ject is fin ished, and ( 2) seaw ater levelw ill be c lose to adjacent place on the lakeside. Consequently, theremay be, in low w ater years, reverse supply o f seaw ater to lake w ater through g roundw ater f low, w hich w ill cause salinity rise, w a ter quality decline, and deterio ration of drink ing w ater sources o f som e areas