// CODE SNIPPET

# 1114.3.1.1 Storage Volume

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The storage volume of an onsite stormwater disposal system shall be measured 3 feet (610 mm) above the level of the water table. The location of the water table shall be verified at the time of the field investigation conducted in accordance with Section 1114.2.1. Unless otherwise approved by the New York City Department of Environmental Protection, the storage volume of the onsite stormwater disposal system shall accommodate the total stormwater volume calculated in this section. The stormwater volume shall be calculated as follows:

Where:

Where:

Where:

Where:

- Compute the runoff rate using Equations 11-1 and 11-2.
- Calculate the outflow rate due to infiltration, in cubic feet per second, using Equation 11-3.
- Calculate the outflow rate, in cubic feet per second per acre, of imperviousness using Equation 11-4.
- Calculate the duration of the design storm in minutes using Equation 11-5.
- Calculate the maximum required detention volume using Equation 11-6.

Where:

Q_{inf} | = | outflow rate due to infiltration in cubic feet per second |

FA_{min} | = | minimum footprint or surface area of the stormwater disposal system |

i _{soil} | = | soil infiltration rate in inches per hour |

Where:

Q _{o } | = | restricted flow rate in cubic feet per second per acre of imperviousness |

Q _{inf } | = | outflow rate due to infiltration cubic feet per second |

C _{w} | = | weighted runoff coefficient for the area tributary to the stormwater system |

Where:

t | = | duration of the storm in minutes |

Q_{o} | = | restricted flow rate in cubic feet per second per acre of imperviousness |

Where:

v | = | maximum required detention volume |

t | = | duration of the storm in minutes |

Q_{o} | = | restricted flow rate in cubic feet per second per acre of imperviousness |

A | = | Area tributary to the detention facility in acres |

C_{w} | = | weighted runoff coefficient for the area of tributary to the stormwater system |