Research On Water Level And Water Flow Binary Management System Of Groundwater Resources In Tianjin

Groundwater is mainly supply water resource in Tianjin City,which promotes economic development in Tianjin. But it also brings some negative effects,such as serious land subsidence, saltwater intrusion and deteriorated water quality, mainly due to over-exploitation of groundwater. Problem mainly lies in lacking of scientific and rational management in the development and utilization of groundwater. In order to achieve sustainable utilization of groundwater resources, the management of innovation is necessary. For a long time,China has implemented a groundwater extraction management mode, it is difficult to directly measure the extraction of groundwater, which is not easy to monitor, assess and actual operation. There are many defects in the management mode, and in order to compensate for these defects, a new water level and water flow binary management mode is put forward, which adopts the groundwater extraction as indicators of overall control and the critical depth of water level as characterization index. The paper mainly consists of the following research contents and results:(1) Comprehensive evaluation of groundwater resources is applied to evaluate groundwater resources function, geological environment function and vulnerability assessment function in Tianjin. In the evaluation, analytic hierarchy process as a subjective evaluation, coefficient of variation as an objective evaluation method, a combination of both is to be comprehensive weight. The value of the corresponding aggregative index was calculated according to the impact of relevant factors, and then according to the calculated aggregative index and the corresponding grading standards, groundwater resources function, geological environment function and vulnerability assessment function in Tianjin were obtained.(2) Based on existed historical observations and selected Xiqing District for a typical area, this work carried out the research on underground water level, groundwater yield, the ground settlement changing trends, and their mutual relationship in districts and counties of Tianjin.(3) A reasonable mining plan was developed, and then utilizing the pre-established numerical model of groundwater the underground water level and subsidence condition in plain areas of Tianjin was predicted.(4) The plain area in Tianjin was divided into 13 different groundwater management districts, and the aquifer groundwater control level and a reasonable range of values for each district was established in three target years (2015, 2020 and 2030). Furthermore, a new "dual" management model of groundwater resources in plain areas of Tianjin was developed.