Above Ground Cistern

Storm Water Management

Storm Water Design Components

Landscape Design Components

Picture Gallery

References & Resources

Circular Depression

Planted Storm Water Buffer

Infiltration Trench

Above Ground Cistern

Underground Storm Water Chamber

Preserved Wetland

Tree Protection Area

Habitat Protection Area

Riparian Buffer

Constructed Wetland

Parking Lot Detention

Vegetated Ditch

Above Ground Cistern

A disconnected roof top is one in which storm water falling on a building roof is captured and prevented from being added to the amount of storm water run off from a construction site. Since this water is relatively clean it can be reused for certain domestic used or recycled through an irrigation system for evaporative disposal or to feed moisture to landscape beds, lawns, and tree stands.

Disconnecting the rooftop storm water can reduce storm water amounts by a huge percentage, perhaps up to forty percent of the water volume falling on any development site as well as decrease the storm water coefficient of the development site.

There are various ways to disconnect the roof top. Perhaps the easiest is to convey the water through an eave and downspout system directly into above ground cisterns. Storm water captured in this way can also be stored in underground storm water cisterns.

Calculations

Watershed Area

The one (1) inch design storm watershed area includes the roof top surface of the building.

Square Feet x One Twelfth (1/12) Foot = Cubic Feet

9605 Sq Ft x 1/12 Foot = 800 Cubic Ft

Cubic Feet ÷ Twenty-seven (27) = Cubic Yards

800 Cubic Ft ÷ 27 = 29.6 Cubic Yards

Cubic Yards x Two Hundred Two (202) = Gallons

29.6 Cubic Yards x 202 = 5988.3 Gallons

Watershed Area = 5988.3 Gallons in a 1” Design Storm

Above Ground Cistern (BMP) Capacity

Area = πr² π (4.25’)² = 439.7 Sq FT x 2 Tanks

Square Feet x One (1) Foot = Cubic Feet

879.5 Sq Ft x 1 FT = 879.5 Cubic Feet

Cubic Feet ÷ Twenty-seven (27) = Cubic Yards

879.5 Cubic Ft ÷ 27 = 32.57 Cubic Yards

Cubic Yards x Two Hundred Two (202) = Gallons

32.57 Cubic Yards x 202 = 6579 Gallons

Above Ground Cistern Capacity = 6579 Gallons

BMP Capacity ÷ Watershed Area = BMP Percentage

6579 ÷ 5988.3 = 110% BMP Capacity for 1” Design Storm

1” BMP watershed design storm Gal ÷ 1” storm total property =

5988 ÷ 40736 = 14.7% BMP Management Factor

General Design Standards for Above Ground Cisterns

Above Ground Cisterns can be used to collect storm water. They may be specially designed from stainless steel, galvanized metal, lightweight reinforced concrete or bondable synthetic compounds or any pre-manufactured water vessels.

This facility shall be calculated based upon the size of the drainage basin in which water is collected to be stored or filtered prior to use or disposal. Individual storage vessels must be provided to allow collection of the design storm volume. Collect storm water for this facility from rooftops, parking lots, or other areas that can supply storm water that can be filtered to be used for landscape irrigation. Attached irrigation lines through an electronic valve and operate with a computer commanded irrigation controller. Building gray water may also flow through this system. Check local codes and standards.

Maintain facility from time to time by removing particulate matter, salts and other storm water debris that may collect within the individual storm water chambers. Replace filters and pumps as necessary.

Click Here for more Technical Standards

Buck Abbey

309 Design Building

Baton Rouge, LA 70803

(O) 225.578.1475

(F) 225.578.1445

LSUGreenLaws@aol.com