tailieunhanh - ENCYCLOPEDIA OF ENVIRONMENTAL SCIENCE AND ENGINEERING - GROUNDWATER RESOURCES

Nước đóng một vai trò quan trọng trong việc duy trì sự tồn tại của tất cả các sinh vật sống. Tầm quan trọng của quản lý các khía cạnh khác nhau của các nước, bao gồm cả số lượng, chất lượng, quy trình vận chuyển, sử dụng, và quản lý trở nên rõ ràng khi việc cung cấp nước, đặc biệt là uống nước, là giới hạn. Bài viết này có thể dùng để giới thiệu chủ đề của nước ngầm. Nó bao gồm một quan điểm lịch sử phát triển, thủy lực tốt, khía cạnh chất lượng, và. | GROUNDWATER RESOURCES Water plays a vital role in sustaining the existence of all living things. The importance of managing the different aspects of the water including its quantity quality transport processes utilization and management becomes apparent when the supply of water especially potable water is limited. This article is intended to be an introduction of the subject of groundwater. It includes a historical perspective of development well hydraulics the quality aspect and a number of remediation technologies. It has been estimated that approximately 300 million cubic miles of water exist on the earth at different locations and in different states phases. From Table 1 it can be seen that the ocean forms about 97 of the earth s water as saline water. The remaining 3 is freshwater. This freshwater supply would be quickly depleted if it were not for its endless interaction and exchange with the ocean. This movement of the earth s waters known as the hydrologic cycle is shown schematically in Figure 1. Due to the complexity of the hydrologic cycle not all of the components can be determined easily. A detailed discussion on the subject is presented by the United Nations Educational Scientific and Cultural Organization UNESCO USSR National Committee for the International Hydrological Decade 1978 . On a long-term average basis the total freshwater supply is to be considered constant. Therefore the budget equation for freshwater can be expressed as Total precipitation Evaporation Transpiration Here the freshwater is found in the atmosphere as water vapor on the land as water dew snow and ice and in the ground usually in the form of water. Approximately of all the Earth s water is in a form or location unavailable for use see Table 1 leaving only about of the earth s water remaining for consumption. The largest source of available water is groundwater which forms an important part of the water supply for municipalities agriculture and industry. For instance