The lifetime of a borrow pit converted into a water storage pond may be curtailed if it is filled with high sediment-rich water flows. To prolong its life, a number of measures are recommended:
- Locate borrow pits in areas with protected watersheds and low silt content in the runoff feeding the borrow pit. This may not always be possible, but the health of the catchment may be a consideration in siting the borrow pits.
- Seek vegetation in the most critical sediment runoff areas if well-protected watersheds are unavailable.
- Take measures to trap sediments before they reach the converted borrow pits. Install sediment traps or employ vegetative measures.
- Maintain sediment traps and vegetative measures that can fill up quickly. The sand in the sediment traps can sometimes be repurposed for use as building material or agricultural soil and may be harvested and sold.
7.4 Borrow pit management
Converted borrow pits need to be well managed to:
- Regulate use of the borrow pit, which is particularly important in times of scarcity.
- Avoid contamination that makes the water unfit for use.
- Undertake basic maintenance and protection, such as protecting vegetation, cleaning sand traps, controlling entrance by livestock, and undertaking periodic de-siltation (see above).
It is important to regulate the future ownership of the borrow pits in combination with storage facilities. The land used for digging the borrow pits may have been privately owned at one time. It is important that ownership of the borrow pit is settled and that the original landowner is compensated.
A local committee or local government should look after the water source and attend to its access, protection, and maintenance. To the extent possible, management committees should not be ad hoc but linked to a legitimate local government.
If a committee is in place, it can also mobilize the resources to conduct maintenance work. There are several possible arrangements for fundraising by a local committee, such as:
- Charging for use of the converted borrow pit, or
- Dividing the maintenance work among users who each take care of a section of the pond.