Groundwater And Nutrients Discharge Into Jiaozhou Bay From Ambient Areas

This thesis is accomplished based on the fund of the National Natural Science Foundation of China-Watersheds Nutrients Loss and Eutrophication of the Jiaozhou Bay. In recent years, the eutrophication problem of Jiaozhou Bay becomes more and more serious. It is very important for researching the progress of eutrophication of Jiaozhou Bay to determine the entire volume of groundwater discharge into Jiaozhou Bay. The author uses several different methods to estimate the quantity of SGD and nutrients around Jiaozhou Bay, and then analyses influence factors and the trend of the discharge of the groundwater and nutrients in the bay ambient areaThe thesis firstly generalizes the geographic, geological and hydrogeological characteristics of the Jiaozhou Bay ambient area, and determinate each hydrogeological parameter by comprehensive collecting and analyzing resource of the rainfall, evaporation, exploitation and observation datum of the groundwater water level. The quantity of SGD and nutrients from Dagu river area and Yanghe river watershed is calculated using section method, and the quantity of SGD and nutrients discharge into Jiaozhou Bay is estimated using section and water balance method, then the results are compared and numerical model is established to simulate the groundwater in study area.SGD becomes less and Seawater intrusion takes place in 70s especially in 80s. SGD is little for over exploitation and the effects of waterproofing dam, but other watersheds have groundwater discharge.The results indicate that the nutrients concentration is low and the nutrients discharge into Jiaozhou Bay is relative small; and SGD and nutrients discharge into Jiaozhou Bay is almost zero because the groundwater exploitation is large in 1970s-1980s especially in 1980s, which results in seawater intrusion around Jiaozhou Bay. The SGD and nutrients from Baisha river, Moshui river and Yang river watershed discharge into Jiaozhou Bay in 1990s except that the groundwater level of Dagu riverwatershed rises until 1998 for over exploitation. A waterproofing dam was built at the lower reaches of Dagu river in 1998 and the quantity of SGD decreases. There is increasing tendency of the quantity of ground water and nutrients discharged into the bay in 1990s. The thesis points out that artificial exploitation and atmospheric precipitations are main factors influencing the SGD, So SGD in wet period is larger than that in drought period in a year. The nutrients in groundwater, especially NOs", mainly come from the chemical fertilizer of the agricultural irrigation and rainfall eluviation. The increasing use of the chemical fertilizer in vegetable farm results in high nutrients concentration of groundwater.