It is a kind of complicated geo-engineering surveying the weakness area of anti-seepage within surrounding rock masses of water-diversion system of a pumped storage power plant. In order to avoid the uncertainty involved only by one method

four methods

i.e. ?-ray radioactive determination

resistivity exploration

natural tracer and water quality analyzing method

were used in this case study. Essentially

the former two methods are based on geophysics

while the latter two ones are on geochemistry. According to the results

it is believed that some weakness areas of anti-seepage indeed exist within the domain. They were remarked with negative abnormal ?-ray density

lower resistivity

water chemistry mostly in coincidence with one as its recharge source

and others. As to the formation

it is resultant from the coupled action of multi-fields

in which hydro-dynamic and geochemical action are mostly active.