Utah State University Extension
Irrigation canals placed in native soil or lined with earth can have seepage water losses varying from 20 percent to more than 50 percent. Well designed, new compacted earth lined canals can have reduced seepage losses similar to concrete lined channels. However, consistent and regular maintenance is required to keep seepage losses low. Older concrete lined canals with deteriorated joints and frost heave or settled sections may also have high seepage losses and require rehabilitating.
Hill, Robert, "How Well Does Your Irrigation Canal Hold Water?" (2000). All Current Publications. Paper 1330.