All dams have some seepage as the retained water seeks the path of least resistance through the dam and its foundation. The quantity of seepage, the seepage path, and the velocity of seepage water is of great concern in analyzing the structural behaviour of a dam. Seepage becomes a concern if it is carrying material with it.
By capturing and analyzing soil particles suspended in or washed along with seepage flows, engineers can monitor a dam’s health over time. Changes in seepage flows or composition can be good leading indicators of issues internal to the dam structure. While changes in a dam’s health over time are important, the greatest risk of dam failure is during the first filling of the dam.
During this time, the leakage rate must be very closely monitored for abnormal leakage rate or composition. A large quantity of water moving through, around, or under a dam results in completely saturated soil and rock in the seepage areas, excessive hydrostatic uplift pressure, as well as softening and weakening of the soil and rock.
Moreover, an excessive quantity of seepage in extreme cases may compromise the storage capability of the reservoir. The location of seepage path is of great concern because high-velocity seepage confined only to a few discrete seepage paths may result in progressive erosion of soil particles, ultimately causing piping type failure of the dam. Seepage water in sufficient quantity in a few paths may result in concentrated dissolution in those areas.
Encardio Rite provides simple to use, comprehensive and cost-effective instrumentation scheme for seepage quantity and quality monitoring. Encardio Rite provides online data monitoring for all the instruments provided and installed at the site. Instruments used for measurements of seepage are as follows: