Environmental Engineering Reference
In-Depth Information
high seepage will be detected as a low temperature anomaly. The temperature is measured
in a number of ways:
(a) Infra-red imaging of the downstream face of the dam and foundations. Tedd and Hart
(1988) report on trials on two dams. These showed that factors other than seepage
also influence the temperature and the method would seem to be of limited usefulness;
(b) Thermotic sensors in stand pipes in the dam. Dornstader (1996), Johansson (1996,
1997) give examples and report that the method is quite successful and able to detect
small variations in temperature. The main disadvantage is that stand-pipes have to be
inserted into the dam;
(c) Optical fibres embedded in the dam. USEPA (2000), Aufleger et al. (2000) and
Johansson et al. (2000) give examples which show the method is useful. However the
optical fibres have to be built into the dam, so the method is of limited applicability
for existing dams.
