[[Image:InfiltrationBasin.jpg|thumb|right|400px350px| An infiltration basin in Omdel, Namibia. The aquifer provides water to the coastal towns of Walvis Bay, Swakopmund and Henties Bay, and a large open pit mine at Rössing.]]
Infiltration ponds (also called infiltration basins or percolation ponds) are large open water ponds that are either excavated or in an area of land surrounded by a bank, and normally will not exceed 15,000 m3. They store rainwater but with the main aim of infiltrating the water to aquifers where it can be extracted using boreholes, hand-dug wells, or nearby springs. They are constructed in areas where the base of the pond is permeable and where the aquifer to be recharged is at or near the surface.
==Construction, operations and maintenance==
[[Image:InfiltrationPond_diagram.gif|thumb|right|400px350px| Cross section diagram of a SUDS infiltration basin <br> Source: Environment Agency (2006)]]
The main issue is to minimize silting, as this will reduce infiltration capacity through the base and sides. There are several techniques to minimize this:
* Any diversion and intake structures should be made so as to minimize input of silt to the ponds. Sedimentation basins can reduce silt load before water enters infiltration pond. What might work better is to keep a good cover of indigenous grasses in the run-off area. Kambiti Farm in Kitui District provides a good example of previously degraded land being managed and where open dams did not silt up due to pasture management. Contour lines with trees or grasses in the runoff area also work. If the inflow channel is defined, silt traps can be tried out to reduce silt load as is done with Charco dams in Tanzania. In this case, stones laid across the channel form mini dams and perennial vegetation can be grown between these mini dams to reduce the flow velocity of water, thereby encouraging silt deposits.