Impact of Increases in Irrigated Grain Production on Groundwater in the Shijiazhuang Plain
LIU Zhongpei,ZHANG Guanghui,YAN Mingjiang,WANG Jinzhe (Institute of Hydrogeology and Environmental geology, CAGS, Shijiazhuang 050061, China)
In the Shijiazhuang Plain, surface water has been almost drying up. To this end, groundwater has been pumping for agriculture irrigation, accounting for about 80% of the total groundwater exploitation. In order to reserve and protect groundwater resources, it is critical to examine the relationship between groundwater exploitation and grain production. In the present work, the authors first analyzed variation characteristics of grain production and groundwater exploitation as well as buried depth. Then the authors utilized certain statistical methods to explore the mechanism of the impact of increases in grain production on groundwater. The results showed that groundwater buried depth did not change significantly with changes in precipitation; it was a major recharge item in normal years. However, in dry years and wet years, it fluctuated with variations in precipitation. In addition, variations in the water buried depth showed a similar variation trend with groundwater exploitation; it was taken as a major discharge item in this case. Before the year 1982, there exists a linear relationship between the water buried depth and groundwater exploitation, showing decreases in the water buried depth with increases in groundwater exploitation. After the year 1982, water buried depth varied with accumulated over-exploitation of groundwater because the exploitation in each year exceeded groundwater resources available. From the derived relationship curve of the groundwater exploitation and buried depth, it was estimated that a mean of exploitation was 2.262×109 m3 in the 1970s as available groundwater exploitation. On the one hand, the groundwater buried depth varied with groundwater exploitation year by year during the period. On the other hand, exploitation in year 1981 was found to be so close to the mean in the 1970s, which was obviously a turning point for the relationship. In the study areas, winter wheat and summer maize are major water consumption crops. Therefore, increases in wheat and maize productions were considered a primary cause for variations in groundwater exploitation and buried depths. Before 1982, the groundwater exploitation increased by 0.014×109 m3 and the groundwater buried depth increased by 0.0448 m under the condition that the production of wheat and maize increased by 10×103 t. But after 1982, the total wheat and maize production was closely related to the accumulated over-exploitation quantity of groundwater, showing that the over-exploitation and buried depth increased by 0.03×109 m3 and 0.0705 m, respectively, under the condition that the total production increased by 10×103 t. As a result, in order to slow down the increasingly aggravated trends in groundwater buried depths, controlling agricultural exploitation within certain degree would be an effective way, with confining groundwater exploitation to a suggested quantity of 2.262×109 m3 .
【Fund】： “十一五”国家科技支撑计划项目课题:“区域水资源特征与农作物布局结构适应性研究”(编号:2007BAD69B02);; “973”国家重点基础性研究项目课题:“海河流域二元水循环模式与水资源演变机理”(编号:2006CB403401)
【CateGory Index】： P641.8
【CateGory Index】： P641.8