Photographs provide invaluable records of seepage. The inspector should always look for increases in flow and evidence of flow carrying soil particles. The control methods described previously are often designed to facilitate observation of flows. At some locations, v-notch weirs can be used to measure flow rates. Regular surveillance and maintenance of internal embankment and foundation drainage outlets is also required.
Normal maintenance consists of removing any soil or other material that obstructs flow.
Internal repair is complicated and often impractical and should not be attempted without professional advice. The rate and content of flow emerging from these outlets should be monitored regularly.