H-O isotope characteristics and hydraulic connections of various waters in the Tai’an pumped storage power station reservoir, Shandong province, China

Reservoir leakage is typically a potential risk to reservoir operation in the world. However, due to the difference of climate, hydrology and geology conditions, the patterns and causes of water leakage in different reservoirs are quite different. This study took the Tai'an pumped storage power station reservoir in Shandong Province as an example to analyze the H-O isotope characteristics of various waters in detail. The results showed that the δ18O, δ17O and δ2H values in the reservoir water collected in July were significantly more positive than those in September and October, and other waters also had similar variations. The isotopic difference between September and October was not significant. Isotope analyses showed that water leakage varied with months: in October, well water and leakage water in the right bank gallery and bottom gallery drainage hole 005 did not come from the reservoir, while other waters were closely related to the leakage of reservoir water; in September, well water in the left bank did not originate from reservoir water leakage, while water in the measuring weir behind dam and the right bank gallery drainage hole were closely related to the reservoir water. In July, leakage water in the right bank gallery drainage hole and reservoir water had a close relationship. Our findings are expected to be helpful for guiding the treatment and control of reservoir water leakage.