Stormwater management pond
Encyclopedia
Stormwater management ponds collect and retain urban stormwater. They are frequently built into urban areas in North America to also retain sediments and other materials.
In urban areas, impervious surfaces (roofs, roads) reduce the time spent by rainfall before entering into the stormwater drainage system. If left unchecked, this will cause widespread flooding downstream. The function of a stormwater pond is to contain this surge and release it slowly. This slow release mitigates the size and intensity of storm-induced flooding on downstream receiving waters. Stormwater ponds also collect suspended sediments, which are often found in high concentrations in stormwater water due to upstream construction and sand applications to roadways.
For aesthetic and safety reasons, the system can be designed so that there is a permanent lake. A lake with an equivalent area of 1000 by 1000 metres rises by one metre will hold a million cubic metres of water. Typically such a lake would have an outer earth bank of 1 metre, then a leisure path, then a 10 cm inner bank to the steady state level.
In urban areas, impervious surfaces (roofs, roads) reduce the time spent by rainfall before entering into the stormwater drainage system. If left unchecked, this will cause widespread flooding downstream. The function of a stormwater pond is to contain this surge and release it slowly. This slow release mitigates the size and intensity of storm-induced flooding on downstream receiving waters. Stormwater ponds also collect suspended sediments, which are often found in high concentrations in stormwater water due to upstream construction and sand applications to roadways.
Engineering
At its simplest, a stormwater pond can be constructed by creating a dam across a drain or stream at a convenient valley, with a restricted diameter outlet pipe through the dam. Normal flows are carried through the pipe, but heavy flows back up and the water behind the dam is choked back. Over the following few days, the level subsides. If the lake fills to capacity, then it will begin to spill over. This is often enough for a small housing development.For aesthetic and safety reasons, the system can be designed so that there is a permanent lake. A lake with an equivalent area of 1000 by 1000 metres rises by one metre will hold a million cubic metres of water. Typically such a lake would have an outer earth bank of 1 metre, then a leisure path, then a 10 cm inner bank to the steady state level.
See also
- StormwaterStormwaterStormwater is water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system...
- Surface runoffSurface runoffSurface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...
- Urban runoffUrban runoffUrban runoff is surface runoff of rainwater created by urbanization. This runoff is a major source of water pollution in many parts of the United States and other urban communities worldwide.-Overview:...
- Sustainable urban drainage systemsSustainable urban drainage systemsSustainable Drainage Systems , sometimes known as Sustainable Urban Drainage Systems , are designed to reduce the potential impact of new and existing developments with respect to surface water drainage discharges.-Background:...