* Water can be abstracted by a well a short distance upstream of the dam, or by a drain system which collects water from the upstream base of the dam and leads it to the downstream side to a well or gravity-pipe system.
* Where possible, a flushing valve is installed to facilitate cleaning of the subsurface reservoir.
* To prevent seepage through the dam, plastic canvas can be used. Plastering mud and water on the downstream side of a trench is recommended to smooth the slope cut and to prevent sharp stones and roots from puncturing the fabric.
====Maintenance====
* After each large flood, any damage to the dam should be repaired and the dam protected with large stones if necessary.
* For big repairs, such as when a dam has been undermined by infiltration, or damaged by a flood, many people and heavy machinery may be needed, and specialist technicians should be consulted.
* If the groundwater shows increased salinity during the dry season, a discharge pipe could be placed at the bottom of the dam, to allow annual drainage of dissolved salts.
Maintenance can normally be carried out by the users of the system or by a caretaker or watchman. Larger repairs may require skilled labour, which can usually be provided by local craftsmen. In some cases, unskilled labour may be required on a large scale (e.g. for repairing a leaking subsurface dam). The labour may be provided by the users (with or without pay), or by other people who are hired for the purpose.
