Testing a near-infrared Lidar mounted with a large incidence angle to monitor the water level of turbid reservoirs
It is sometimes difficult to monitor the water level of reservoirs with a sloping bank  such as many lakes and earth-dam embankment  using terrestrial techniques or airborne instruments. A proposed alternative is a new technique using a terrestrial near-infrared Lidar mounted with a large incidence angle (at least between 40 and 70). This technique assumes that the Lidar can detect the (sub-)surface of a water body provided that it contains enough suspended particles to backscatter the light emitted by the instrument to its detector. Tests performed with a commercial Lidar show that the technique can be used to estimate the water level of a reservoir with moderate accuracy (within 0.05m [p=0.95]) when the water is very turbid (Secchi depth<0.5m). The versatility and accuracy of the technique is expected to improve in the future with the use of current Lidar that are more sophisticated than the tested one.
lake terrestrial lidar off-nadir angle tyndall effect stage monitoring earthdam embankment