黑河流域土地利用变化对地下水资源的影响

Impacts of Land Use Changes on Groundwater Resources in the Heihe River Basin

土地利用与覆被变化对区域水文过程具有深刻影响。利用1960s以来的三期遥感数据和1980年以来的地下水长期观测数据,从地下水补给和排泄系统两方面,分析了近30年来甘肃省黑河流域中游地区土地利用与覆被变化对地下水系统的影响,结果表明:以1985年为界,随土地利用与覆被变化强度不同,前后15年土地利用变化对地下水系统补给的影响分别达到2.602亿m3/a和0.218亿m3/a,对排泄系统的影响分别为2.035亿m3/a和4.91亿m3/a,在保持区域人工开采量不超过3.0亿m3/a的合理幅度下,土地利用变化对区域地下水资源变化起着决定作用;在区域土地利用与覆被变化和近10年来人类较大规模开采影响下,甘肃省张掖盆地地下水资源变化出现了显著的区域差异性。认识土地利用变化对流域地下水系统的作用与区域地下水资源的时空变化特征,对流域水土资源合理利用规划与管理有重要意义。

Land-use and land-cover changes have great influence on the regional h ydrological process. With three periods of remote sensing data since the 1960s a nd the long-term observed data of groundwater since the 1980s, the impacts of la nd-use and land-cover changes on the groundwater system in the middle reaches of Heihe River Basin in recent three decades are analyzed with the aspects of grou ndwater recharge and discharge system. The results indicate that with different intensities of land-use and land-cover changes, the impacts on the recharge were 2.602×108 m3/a and 0.218×108 m3/a in the former (1969-1985) and latter (1986- 2000) fifteen years and those on the discharge were 2.035×108 m3/a and 4.91×10 8 m3/a. As long as under the reasonable range of exploitation (less than 3.0×10 8 m3/a), the land-use changes would control the changes of regional groundwater resources. Influenced by the land-use and land-cover changes and the large-scale exploitation in the recent decade, the groundwater resources present apparent r egional differences in Zhangye Basin. Realizing the impact of land-use changes o n groundwater system and the characteristics of spatial-temporal variations of r egional groundwater resources may make the programming and management of water a nd soil resources more scientific and reasonable.