Hydrological Simulation And Reservoir Leakage Analysis Of Ming Tombs Reservoir Watershed

The Ming Tombs Reservoir is one of the most important reservoirs of Beijing. In the early planning stage, the reservoir was designed with the multiple functions, such as flood control, power generation. The reservoir had also been designed as one of the water sources for domestic, industrial and agricultural water uses of Beijing. However, the water leakage problem has been noticed ever since the reservoir in service; in addition to the leakage issue, the change of watershed weather condition over the years has greatly reduced the water inflow to the reservoir. Therefore, the functionality and performance of the Ming Tombs Reservoir has been impaired. Hence, an in-depth investigation and study over the watershed runoff and reservoir leakage issues has become a dire necessity.By gathering meteorological and other natural conditions of Ming Tombs Reservoir watershed, as well as watershed land use, reservoir water level record, reservoir water supplement records, a SWAT model of the Ming Tombs Reservoir watershed has been established. Water cycle status of the watershed from 1975 to 2010(36 years) has been calculated; Based on water balance equation, reservoir leakage has also been estimated. The main factors of reservoir leakage has been speculated. Main results of this research are as follows:(1) The meteorological data and underlying surface information of Ming Tombs Reservoir watershed are collected and analyzed. Basing on ArcGIS, a SWAT model of reservoir watershed is established. And watershed runoff conditions in 36 years are simulated, and a diel scale runoff is extract. The calculated Annual average runoff is more than 27 million m3.(2) According to the water balance equation, the Ming Tombs Reservoir leakage is calculate. During the simulation years, the annual average leakage is 30.8 million m3, which is more than the annual reservoir inflow. Therefore, the reservoir water levels is maintained by other water supply conducts.(3) The main factors of Ming Tombs Reservoir leakage are explored and quantified. Inflow(or basin runoff) is the most important factor in deciding reservoir leakage. And the amount of water lost through leakage exceeds 92% of total basin runoff. The reservoir leakage is also closely related to reservoir water level. When the reservoir water level is higher than 86 m, leakage through ancient rivers increases rapidly, which becomes an important factor in augmenting reservoir leakage.