* Fill the remaining volume with sand.
* Add a coarse mesh after the silt trap before inlet to prevent large debris from entering the tank.
====Water extraction====
For open water catchments, like from rock surfaces or stored behind earth dams, direct abstraction (pump or pipe taking water off) works well. Abstraction method should minimize disturbance of the settled water, thus reducing treatment requirements later.
* Direct abstraction is one option, via a bank-mounted pump ([[Small and efficient motor pumps]] or [[Handpumps]]) which uses a floating intake to reduce sediment intake. An outlet pipe and strainer through the dam wall to the downstream side is another option, but these have potential problems of weakening the dam wall. In addition, piping will have to be secured externally when traversing rocks, so care has to be taken to secure pipes with anchor posts.
* With preventive methods to reduce turbidity (silt trap, extraction method) the water is still turbid & contaminated and will require treatment.
* For direct abstraction, promotion of household water treatment is advocated. Choice of household water treatment technology should be based on efficiency of removing contaminants present in the water. For open water that may be prone to cyanobacterial blooms, a [[Concrete Biosand Filter]] is a good choice due to its ability to remove cyanobacterial toxins. Other technologies however may be more suitable for mobile communities (e.g. [[Sodis]] or a [[Ceramic pot filter]], depending on turbidity levels). For reservoirs near urban environments or where the runoff area has intensive agriculture practised in its vicinity, diversification of water resources is a good idea to provide alternatives for direct drinking purposes. Strengthening controls and restrictions on use of illegal substances will also help.
====Tank modifications and maintenance====