Detection and Quantification of Dam Leakages Based on Tracer Tests: A Field Case Study

Abstract

Leakage is a common phenomenon in dams, and its early detection is critical for dam safety. In the present study, a new method based on tracer tests is applied to detect and quantify leakage in the Wanyao Dam, Jiangshan City, China. The objective is to detect the leakage zone of a dam wall by combining the natural tracer test and the artificial tracer test. Temperature, electrical well-logging tests with nature tracers, and the artificial tracer test with salt (NaCl) were conducted using 48 and 5 pre-existing boreholes, respectively. Using natural tracer tests, the 48 boreholes are categorized into 4 leakage classes: (1) Class 1, high connectivity within whole borehole; (2) Class 2 high connectivity at lower depths; (3) Class 3, weaken connectivity; and (4) Class 4, safe boreholes with no connectivity. Using the proposed method, specific leakage rates of some boreholes were estimated. The results of the new method are validated by comparison with those from natural tracer tests, site-investigation, and historical observation data. Overall, the new tracer test has the following merits: (1) low cost, (2) environment friendliness, and (3) is simple to apply. Moreover, the proposed method improves the accuracy of traditional tracer tests for detecting leakage zones.