Water Retention Pond Design

A retention basin sometimes called a wet pond wet detention basin or stormwater management pond swmp is an artificial pond with vegetation around the perimeter and includes a permanent pool of water in its design it is used to manage stormwater runoff to prevent flooding and downstream erosion and improve water quality in an adjacent river stream lake or bay.

Water retention pond design. The critical time is the time during which a waterway and or location will be impacted the most during a rainfall event. Design of storm water detention pond a. Congress st 3rd floor tucson az 85701 1791 520 724 4600 june 2014 design standards for stormwater detention and retention for pima county i revisions. Wet retention ponds are a stormwater control structure that provides retention and treatment of contaminated stormwater runoff.

Retention ponds should be surrounded by natural vegetation to improve bank stability and improve aesthetic benefits. Retention ponds are ponds or pools designed with additional storage capacity to attenuate surface runoff during rainfall events. Design standards for stormwater detention and retention supplement to title 16 chapter 16 48 runoff detention systems. A successful water retention landscape can be created using basic principles and well established parameters.

Pima county regional flood control district 97 e. Due to rapid and unbalanced urbanization key. During the critical hours post development runoff volume should be less than or equal to the pre development runoff volume from hour 11 to hour 18 of the 24 hour design storm for the 2 10 25 and 100 year return periods. Retention basin karen setty bren school of environmental science and management university of california santa barbara description.

In simple terms assure that the local soil has at least 40 percent clay all earth dam walls can be less than 20 feet 6 meters high and still meet minimum volume end use. They consist of a permanent pond area with landscaped banks and surroundings to provide additional storage capacity during rainfall events. Essentially water is detained in the basin while pollutants are treated by natural processes and water exits the basin slowly over time or during the next. Retention basins are a best management practice intended to mitigate storm water runoff.

Paved surfaces buildings etc increase the volume of surface runoff in a watershed because they prevent rain water from infiltrating into the soil. Floodplain and erosion hazard management ordinance. The climate condition in chuxiong prefecture is categorized as subtropical climate with short winter and summer and long spring and autumns. Stormwater retention ponds are designed to minimize the adverse effects that impervious surfaces have on watersheds.

These ponds are designed to efficiently collect water from a wide swath of land and then as the name suggests retain it indefinitely. Building a successful retention pond is much the same as building any pond but more care must be given to the feeder streams. Chuxiong yi autonomous prefecture chuxiong prefecture is located at about 160 kilometer km west of kunming the provincial capital of yunnan province. By capturing and retaining stormwater runoff wet retention ponds control stormwater quantity and quality.

Additionally you ll want to work more closely with your county or city land management office to ensure you don t adversely affect the surrounding water table. On some landscapes sediment traps diversion drains and swales make sense. At a minimum a water retention landscape is comprised of earth dams embankment ponds spillways and erosion control interventions. The ponds natural processes then work to remove pollutants.

Also pollutants that collect on impervious surfaces are not filtered by the soil or plants and are conveyed directly to rivers and beaches without treatment. They are created by using an existing natural depression by excavating a new depression or by constructing embankments.