海滦河流域环境水利的几个问题

水利工程设施对防治旱涝及人民生活起了重要作用,但也出现了对环境不良影响的环境水利问题并指出了解决这些问题的措施和意见。

A DISCUSSION ON SOME ENVIRONMENTAL AND HYDRAULIC ENGINEERING PROBLEMS IN HAI HE AND LUAN HE DRAINAGE BASINS

The exploitation and utilization of water resources affects environmental development and quality. In the early 1970's water resource in Hai He and Luan He drainage basins was exploited and utilized very greatly, once the natural environment was changed enormously. In the past 35 years, the total storage of new reservoirs was 25.9 billion cubic meters, and areas of new agricultural irrigation was 100 million mu, at the same time questions of flood control and water supply in cities, industrial and mining areas were partly solved, About 10.17 million mu of saline-alkali soil were improved and 23 million mu of low-lying and frequently flooded land were treated in a comprehensive way The drainage conditions in the plain of China were improved and soil has been changed into drab soil. The distribution of water resources in time and space varied greatly. The average annual discharge to the sea has been decreased half as much as the amount of 21 billion cubic meters in 1965 Utilizing ratio of water resources increased from 23% in the 1950's to 59% in the 1970's. Annual extraction of groundwater amounted to 17.8 billion cubic meters, Groundwater levels went down and infiltration of precipitation increased. The utilizable and effective water resources that changed from evaporation of groundwater by some rational ways amounted annually to about 2 bilion cubic meters per year. The changes in the elements of water balance gave rise to harmful changes in environment, the main aspects being as follows.(1) Natural water area of river and lakes greatly decreased, and aquatic products and their quality were also decreased due to water pollution and construction of sluice gates.2) As drainge of waste water increased, the quality of surface water and ground water deteriorated. The most serious conditions were in the Long Yang He. Generally, the water quality of the first flood each year is very poor.(3) The variation of runoff of rivers often gave rise to siltation of resar-voirs, river courses and estuaries.(4) Exploitation of groundwater in depth made groundwater levels decrease greatly over large area and cause surface subsidence. For instance, the area of land subsidence in Tianjing was 2,308 square km and the highest subsidence was 2.04m. In some areas, deep groundwater contains heavy fluoride and alkali materals, having effects on human health, on soil and plant.(5) Due to decrease of discharge in some rivers, shipping was reduced, indirectly affecting environmental quality.The main reason for harmful impacts on environment is the shortage of water resources. The water transfer from south to north is a strategic measure to solve questions of environmental water conservancy When we consider water supply to cities, industry and agriculture, we must simultaneously consider water supply for fishery, shipping, treatment of siltaion, protection of water quality and tourism We must prevent water pollution and do well for management of environmental water conservancy and assessment of environmental impacts.