The author's research and experience suggest a number of additional geotechnical monitoring applications for TDR. For example, foam or air filled coaxial cables can be used to monitor groundwater levels. The presence of water in the dielectric produces a characteristic change in cable impedance. Horizontal cables buried in shallow trenches can be used to monitor potentially unstable slopes and embankments. With the addition of some computer software, the remotely accessed TDR equipment could be used as a landslide warning system. Finally rockfall barriers could be remotely monitored with TDR for rock impacts and damage.