华北平原缺水盐渍区浅层地下水位动态分析

A Study on the Dynamic Variation of Shallow Groundwater Table in the Saline and Water Deficit Region in North China Plain

本文以国家农业科技攻关南皮试区为例,分析了华北缺水盐渍区地下水水位动态及其与降水量的关系,应用灰色系统理论的GM(1,1)预测方法,建立了地下水位动态的模拟、预测模型。结果表明,在目前供水、用水和水文地质条件下,未来地下水水位呈缓慢下降趋势,年均下降速度为0.12～0.14m/年。单靠平水年甚或丰水年降水难以维持地下水采补平衡,必须进行多年径流调节或跨流域调水,以丰补歉,互济余缺,并实施农田综合节水技术,防止区域水环境的恶化。

The property of precipitation and dynamics variation of shallow groundwater level in the saline and water deficit region, North China Plain, were discussed in this paper by taking Nanpi Testing Area as a case study.The annual precipitation concentrates in a few of rainstorm process within the monsoon climate region. The shallow groundwater is recharged mainly by the permeated runoff of rainstorm. So the resuming extent of groundwater level can express the active water resource status. The average annual precipitation from 1965 to 2001 was 5457mm. Simple statistics revealed that there was a linear relationship between the groundwater level and the annual rainfall amount. The correlation coefficient was 06317 and 04249 in the two periods of 1980~1989 and 1995~2001 respectively.The biggest annual fluctuation amount of the groundwater level was 41m, and season resuming amount was among 19~38m.According to the results measured by artificial rainfall, there was no runoff in grassland when it rained continually with 569mm of the total water amount. The runoff coefficient was 013 when it rained continually with 1143mm of the total water amount at 106mm/min of the raining intensity. But the coefficient was 021 for bare farmland at alike raining intensity. The resuming amounts of groundwater level were 141~397m in the Nanpi Testing Area when a heavy rainstorm with 252mm water amount occurred in July 13, 1997.The Grey Dynamic Model results show that the shallow groundwater level will be declining gradually in the future based on the water supplying, water utilization and water geohydrological condition at present. The decline ratio is about 012~014m/y. It is difficult to keep the water balance only with the recharge of rainfall. Therefore it is emphasized to take the comprehensive watersaving measures and to regulate the runoff of many years as well as to introduce water from outside watersheds etc. in order to prevent the water environment deterioration of the area.