Village of Oyster Bay Cove, NY Site Drainage

Site development may have impacts on the land's ability to absorb water, regional and site hydrology, natural resources, the natural hydrologic regime, drainage patterns and surface water flow conditions. Stormwater runoff may cause erosion, excess pollution in the form of sediment and chemicals, and may negatively impact water quality and it may increase flooding. Residential runoff may cause pollution, as it has the potential to transport sediment, nutrients, pesticides, metals, bacteria, debris and trash to property and waterways. The provisions of this chapter are in addition to those standards found in Chapter 274 of the Village Code.

A drainage plan is required for all subdivisions, new houses, and for site plans where there are changes in coverage types and amounts or increases in impervious coverage and for all site plans that would require site plan review pursuant to Chapter 264 of the Village Code.

A.

Land development plans should consider the following as part of the design of a project:

(1)

Avoiding stormwater impacts by reducing the amount of stormwater runoff by preserving natural features, including the reduction or minimization of land disturbance.

(2)

Reducing the impacts of stormwater runoff by decreasing or minimizing impervious coverage.

(3)

Managing the impacts of stormwater impacts by incorporating infiltration and green infrastructure techniques as part of the project design. Green infrastructure techniques include the use of bioswales, permeable pavements, rainwater collection or harvesting, planter boxes, rain gardens, native plants, and land conservation.

(4)

Site drainage should be directed to storm drains, stormwater collection systems and/or storage facilities to help minimize adverse impacts of runoff.

B.

Drainage plan requirements. The storm drainage plan must include details of stormwater structures and facilities. The drainage plan must be prepared by an appropriate licensed professional in conformance with New York State approved design standards. The storm drainage plan must include the following, as applicable:

(1)

Storm sewer sizes, materials, gradients and invert elevations, and profiles.

(2)

Type and size of manholes.

(3)

Catch basin types, size, and contributing areas.

(4)

Surface drainage structures, such as valley gutters, including grades and construction details.

(5)

Stormwater headwalls, including details.

(6)

Special structures, as designed for specific projects or applications.

(7)

Stormwater recharge basins or stormwater detention basins.

C.

Drainage plan design criteria. The following design criteria shall be used for storm drainage plan designs:

(1)

Runoff peak flow rates shall be calculated by using the rational method, TR-55, or an alternate engineering method acceptable by the Village Engineer.

(2)

Manholes shall be placed at a change of direction or change in slope and shall be at a maximum distance of 350 feet.

(3)

Stormwater pipes shall be in a straight line between structures.

(4)

Gutter flow shall be limited to that flow which does not exceed five inches in depth at the curb based on the tributary area, runoff factors, road grade, rainfall intensity and system inlet capacity.

(5)

Stormwater storage structures and facilities shall be designed with a storage capacity of runoff from a five-inch rainfall, given applicable tributary area and runoff factors. The Building Inspector and/or the Village Engineer may require additional or less storage based on site conditions, including site topography, steep slopes, or other conditions which warrant the protection of critical features such as flood-prone areas, public roads, adjacent property, building foundations and other circumstances which may be determined by the Building Inspector or Village Engineer.

(6)

Soil information must be provided, and soils must be ratable for a minimum depth of six feet below the bottom elevation of a leaching structure. All stormwater retention, detention or storage facilities or structures shall be located at least two feet above the highest water table or more if other jurisdictions require a greater distance.

In addition to the penalties enumerated in Article X of Chapter 320, Zoning, the Building Inspector shall stop all work and construction activity on any premises where a violation of this chapter has occurred and is prohibited from issuing any certification of occupancy or additional permits for construction at the property or permitting work to resume unless and until the provisions of this chapter have been satisfied.