环境变化对河北省可利用水资源的影响

环境变化及其对可利用水资源的影响是复杂的，根据20世纪50年代以来的大量统计数据分析表明，近30年来，由于自然环境的变化、人类活动的增强，河北省可利用水资源量处于减少的态势。地下水超采所引起的地下水位持续下降，不仅造成地表产流减少，而且使降水对地下水的补给量减少。作物产量水平的提高，在直接消耗大量水资源和土壤水分的同时，也使农田蒸散发加强，从而造成地表径流量和地下水补给量的减少。在新一轮水资源评价中，要充分考虑环境变化对水资源的影响，加强地下水位大埋深条件下，地表产流量，地下水补给量，以及作物产量水平提高对水资源影响的实验研究，以提高新一轮水资源评价成果的精度。

Environmental Variations on Available Water Resources in Hebei Province

Environmental variations and the influences on available water resources are complicated. According to a great number of statistical and survey data since the 1950s, the data that were analyzed indicated that the available water resources in Hebei Province trended towards decreasing during the last 30 years as the variations of natural environment and human activities increasing. Precipitation reducing and air temperature rising are the basic causes leading to the water resources decreasing. The continual lowering of groundwater level created by the excess development of groundwater, not only caused surface runoff decreasing but groundwater recharge lessening. The level increase of crop output directly consumed a great lot of water resources and soil water, simultaneously had farmland evapotranspiration strengthened, and also brought about surface runoff and groundwater recharge decreasing. In the new turn of water resources evaluation, the influences of environmental variations on the water resources will be fully considered. The experimental researches of surface runoff, groundwater recharge, and impact of crop output increase on water resources under the condition of large groundwater depth will be reinforced to enhance the precision of the water resources evaluation of the new turn.