土地利用对地下水位下降的影响--以河北平原为例

本文利用简化的水量平衡模型,模拟了河北平原1985-1995年多年平均降水入渗系数和含水层给水度,在此基础上计算出各用水部门和各种农作物平均每年引起的地下水位下降幅度。结果表明:农业用水是引起河北平原地下水位下降的主要因素,其次是工业用水和生活用水。小麦引起的地下水位下降幅度最大,谷子最小。生产单位产值的小麦消耗地下水量最大,引起的地下水位下降幅度也最大,生产单位产值的蔬菜消耗地下水量最小,引起的地下水位下降幅度也最小。实现河北平原地下水资源可持续利用,调整种植业结构当务之急。

Impact analysis of land use on groundwater level drawdown:a case study of the Hebei Plain

Adopting the simplified water balance model, the average infiltration coefficient of precipitation and specific yield in the Hebei Plain between 1985-1995 are simulated, and the annual average groundwater level dropping down by water use sectors and crops is calculated on the basis of the above simulations. The results show that the water use in agriculture is the main factor resulting in the decline of groundwater level in the Hebei Plain, and the industrial and domestic factors are the secondary. In the piedmont plain, agriculture has led to a decrease of 0. 63 m per year, industry of 0. 08 m and domestic of 0. 03 m, with the individual ratios being 85. 1% , 10. 8% and 4. 1% respectively. While in the low plain, the order of the decrease is 0. 23 m, 0. 005 m and 0. 015 m per year with the ratios being 92. 1%, 2. 0%, and 5. 9% accordingly. In both areas, as to the major role causing the decline of groundwater level among the crops, wheat is the first, being 0. 33 m and 0. 127 m per year, while millet is the least, being 0.01m and 0. 004 m annually. As for water consumed in producing unit output value, wheat also occupies the first place, being 1. 35m3/yuan and 0. 91m3/yuan, or resulting in the largest decline of 0. 02 m and 0. 008 m in producing 100 million yuan of wheat each. While vegetable is the least, being 0. 25 m3/ yuan and 0. 19 m3/yuan, or 0. 004 m and 0. 002 m decline per 100 million yuan. With the decline of groundwater level, a series ecological and environmental disasters have been caused which have become the key factors restricting the socio-economic sustainable development of the Hebei Plain. Therefore, it is high time to adjust planting structure in order to achieve sustainable use of the groundwater in the Hebei Plain.