The contributions of nutrients derived from lacustrine groundwater discharge on Chinese lake system

Abstract

Lacustrine groundwater discharge (LGD) of 32 worldwide lakes are compiled from literatures and empirical formula to delineate the control mechanism of LGD in terms of three aspects: recharge control, discharge control and topographic control. Then 20 representative lakes on both sides of Hu Huanyong Line are employed to study the major regulators of groundwater borne nutrients to the lakes. The amount of nutrients derived from LGD is calculated based on the multiply approaches and nutrient concentrations in the adjacent groundwater, which helps to identify the contribution of groundwater borne nutrient to the lake nutrient inventories. With ArcGIS, the magnitudes of worldwide LGD and groundwater borne nutrients to the lakes are signified. In the interpretation of the contributions of nutrients derived from lacustrine groundwater discharge on Chinese lake system, this thesis aims to achieve the following items: 1) Obtain the major controlling factors on the driving forces of LGD; 2) Explore major regulators of groundwater borne nutrient to the lakes; 3) Clarify relationship between the contributions of nutrients derived from LGD and lake nutrient states in China. With ArcGIS, a significant spatial difference is signified on the worldwide LGD and the groundwater borne nutrients. According to the data interpreted from 20 Chinese lakes, the nutrients from LGD to the lake is higher on the east side of Hu Huanyong Line than that on the west side in general. The results of single factor and multivariate regression analysis shows that LGD values have relatively low correlation to precipitation, evaporation and topographic metric. Secondly, it is shown that a low relationship exists between groundwater borne nutrient to the lakes and the recharge, discharge and topographic items respectively. Similarly, A low correlation exists between lake nutrient states and the contribution of groundwater borne nutrient. The fulfillment of the study is believed to be contributive to the exploration of LGD controlling factors and provide a certain reference for water management.