Ensemble and master plan
Retention pond
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A depression or pond that receives rain from the roofs, streets and hard areas of a development, holds it for hours or days and releases it little by little.
What it solves
It keeps a tropical downpour from rushing out to the street and the river downstream. It can hold water all year or stay dry and be used as a park between storms.
Today
Design the pond as landscape with gentle edges, native plants and a controlled outlet with a safe overflow. Place it on the low part of the site and bring water to it through green swales instead of pipes.
Common mistake
Digging a hole with concrete walls, fenced with mesh, that no one sees or looks after and that fills with trash.
Tomorrow
Ponds can become parks that flood on purpose, with birds, shade and paths that the neighborhood uses in the dry season. With heavier downpours, several ponds in a chain will share out the water as the ancient reservoirs did.
Fact A wet pond always keeps a sheet of water, while a dry pond only holds the storm’s rain and empties at a controlled rate.
Where it comes from
- 1Island kingdoms dry zone of Sri Lanka, since the 3rd century BC
Cascading chains of rain reservoirs store water, use it and pass it on to the next through sluices in their earth dams.
Masters
- Kongjian Yu Benjakitti Forest Park, Bangkok, Thailand, 2022
It turned a paved site into wetlands with islets that can hold up to 200,000 m³ of rain during the monsoon. It teaches that a retention pond can be the green heart of a neighborhood.
Appears in the routes
See also
Also in Ensemble and master plan
Diagrams and texts by LDB Arquitectura. They are shared under the CC BY 4.0 license, which allows them to be used and adapted with credit to the source.