No person shall commence or carry out any minor land development activity in the Town of Mamaroneck without first obtaining a surface water and erosion control permit from the Building Department and all other necessary municipal permits.
A. 
An application for a surface water and erosion control permit shall be made on forms provided by the Stormwater Management Officer. If the application is determined by the Stormwater Management Officer to be in accord with this chapter and if the application is accompanied by the appropriate fees, the Building Department shall issue the permit.
B. 
Each application shall include a surface water and erosion control plan and a certification by the applicant's expert that the minor land development activity shall be done in accordance with the approved plans.
C. 
Any modification of a plan shall be submitted to the Stormwater Management Officer and shall be processed and approved or disapproved in the same manner as the original plan. Modifications of a minor nature may be authorized by the Stormwater Management Officer without the submission of modified plans.
D. 
The Stormwater Management Officer may waive the requirement for the issuance of the surface water and erosion control permit when there is an application for a floodplain development permit, a wetlands and watercourses permit, subdivision approval, site plan approval or a building permit.
E. 
By accepting the permit, the applicant agrees to allow the Town to enter upon the property to inspect the work and to perform remedial measures when authorized by this chapter to do so.
The following information shall be shown on a surface water and erosion control plan unless otherwise noted:
A. 
The name of the development or identifying title. The name, address and telephone number of the owner and/or developer of the site and the consulting firm retained by the applicant for preparation of the plan. If the applicant is a corporation, it must list the name, home address and telephone number of at least two officers of the applicant. A phone number for an emergency contact must also be provided.
B. 
The plan shall show the date of its preparation and all revision dates, the approximate true North point and the scale, which shall be no greater than one inch equals 50 feet.
C. 
The proposed site layout shall include:
(1) 
The boundary line and acreage for the site.
(2) 
Existing zoning.
(3) 
A vicinity map that includes state and local wetlands.
(4) 
The location of existing buildings, structures, utilities, water bodies, floodplains, drainage facilities, vegetative cover, paved areas, watershed divides and other significant natural or man-made features on the site and land within 250 feet of the boundary.
(5) 
A schematic layout of the stormwater management practices proposed to control surface water runoff both during and after construction.
(6) 
A schematic layout of the proposed erosion and sediment control devices.
(7) 
Existing and proposed contours of the site and adjacent land within approximately 250 feet of the boundaries, drawn at no greater than two-foot contour intervals with critical spot elevations.
(8) 
Surface water control calculations using methods defined in "Technical Release-55," "Technical Release-20," the Rational Method, or other method approved by the Stormwater Management Officer, unless superseded by a comprehensive local watershed and/or stormwater model and plan.
(9) 
Base flood elevation data using the most current National Geodetic Vertical Datum.
(10) 
Construction schedule showing the sequencing of the installation of the required stormwater management practices, erosion and sediment control devices and other site construction activities, which shall be supplemented as directed by the Stormwater Management Officer to show required inspections.
(11) 
Signature block language, including the seal of a New York State licensed professional engineer, registered architect, or a New York State licensed landscape architect.
(12) 
The location of existing trees, including driplines, grassy areas and unique vegetation and detailed methods of tree protection.
(13) 
Identification and boundaries of the different soil types existing on the site.
(14) 
The dividing lines and direction of flow for different drainage areas.
(15) 
Areas with potentially significant erosion problems.
(16) 
Areas which are to be cleared and graded or used for storage.
(17) 
Detailed drawings that explain and illustrate any structural practices used that are not referenced to the design manuals.
D. 
In addition to complying with the requirements of Subsections A, B and C, a minor land development activity meeting Condition One below (other than for the construction of a one- or two-family house) shall also include water quality and water quantity controls (post-construction stormwater runoff controls) as set forth in § 95-10E.
(1) 
Condition One: disturbance of an area greater than 5,000 square feet but less than one acre or creating impervious surface area of 1,000 or more square feet, but less than one acre.
E. 
Surface water and erosion control plan for Condition One:
(1) 
Description of each post-construction stormwater management practice;
(2) 
Site map/construction drawing(s) showing the specific location(s) and size(s) of each post-construction stormwater management practice;
(3) 
Hydrologic and hydraulic analysis for all structural components of the stormwater management system for the applicable design storms;
(4) 
Comparison of post-development stormwater runoff conditions with pre-development conditions;
(5) 
Dimensions, material specifications and installation details for each post-construction stormwater management practice;
(6) 
Maintenance schedule to ensure continuous and effective operation of each post-construction stormwater management practice;
(7) 
Maintenance easements to ensure access to all stormwater management practices at the site for the purpose of inspection and repair, and such easements shall be recorded on the plan and shall remain in effect with transfer of title to the property; and
(8) 
Inspection and maintenance agreement binding on all subsequent landowners served by the on-site stormwater management measures in accordance with § 95-15.
A. 
The Stormwater Management Officer shall approve the issuance of a surface water and erosion control permit or authorize the release of a performance bond or authorize the issuance of a building permit or certificate of occupancy only if the following requirements are satisfied:
(1) 
Except in situations described in § 95-17B, there is a surface water and erosion control plan which demonstrates that the rate of stormwater runoff will not increase. Stormwater calculations certified by a New York State licensed professional engineer, landscape architect or registered architect shall be submitted demonstrating that stormwater management practices are designed to detain a twenty-five-year storm using those methods contained in the Natural Resources Conservation Service (NRCS) publication, "Urban Hydrology for Small Watersheds, Technical Release-55."
(2) 
Stormwater management practices shall be designed using a Type III, twenty-four-hour rainfall distribution.
(3) 
Detention facility maximum discharge rates shall not exceed pre-construction conditions for the twenty-five-, ten-, five- and two-year storms.
(4) 
The natural drainage features of the site, including natural drainageways and permanent and periodic ponding areas, shall be preserved, except for those reasonable alterations deemed necessary by the Stormwater Management Officer to allow for the development of the site in accordance with the provisions of Chapter 106, Fire Prevention and Building Construction, Chapter 110, Flood Damage Prevention, and Chapter 240, Zoning.
(5) 
Stormwater management practices shall be constructed so as not to discharge waters onto adjoining property or public ways in such a manner as to impair the permitted use or development of those properties or be detrimental to public safety.
(6) 
Temporary erosion and sediment control devices and stormwater management practices such as those identified in the design manuals, adequate to protect adjacent property, shall be installed at the commencement of the minor land development activity.
(7) 
Properties adjacent to the site of land disturbance shall be protected from sediment deposition at all times.
(8) 
Until a disturbed area is stabilized, sediment in the runoff water shall be trapped on site utilizing debris basins, sediment basins, silt traps or similar measures described in the design manuals.
(9) 
All storm drain inlets operable during construction shall be protected so that sediment-laden water will not enter the conveyance system without first being filtered or otherwise treated to remove sediment.
(10) 
Natural vegetation and trees shall be retained and protected wherever possible. The applicant shall be guided by the design manuals and the Town Tree Preservation Commission.
(11) 
Temporary vegetation and/or mulching shall be used to protect exposed land areas during construction. The applicant shall restore vegetative cover in disturbed areas as directed by the Stormwater Management Officer.
(12) 
Permanent or temporary soil stabilization must be applied to denuded areas within two days after final grade is reached on any portion of the site. Soil stabilization must also be applied to denuded areas which may not be at final grade but may remain dormant (undisturbed) for longer than two weeks.
(13) 
Permanent vegetation shall not be considered established until a ground cover is achieved which, in the opinion of the Stormwater Management Officer, is mature enough to survive severe weather conditions. Disturbed soils shall be stabilized as soon as possible, and properties adjacent to the site of land disturbance shall be protected from sediment deposition.
(14) 
Adequate barriers to prevent erosion and siltation shall be applied at the end of each day.
(15) 
Sediment basins and traps, perimeter dikes, sediment barriers and other measures intended to trap sediment on site must be constructed as a first step in grading and must be made functional before upslope land disturbance takes place. Earthen structures such as dams, dikes and diversions must be seeded and mulched within two days of installation and prior to any first step in the disturbance of upslope land, whichever comes first.
(16) 
All on-site stormwater conveyance channels shall be designed and constructed to withstand the expected velocity of flow from a ten-year-frequency storm without erosion or failure. Outlets of all pipes and paved channels must be stabilized to prevent erosion.
(17) 
Clearing or grading shall generally not occur on slopes in excess of 25%. Development shall preserve salient natural features, keep cut-and-fill operations to a minimum and ensure conformity with topography so as to create the least potential for erosion.
(18) 
In the design of cut-and-fill slopes, consideration must be given to the length and steepness of the slope, the soil type, upslope drainage area, groundwater conditions and other applicable factors. Slopes which are found to be eroding excessively must be provided with additional measures until the problem is corrected.
(19) 
Provisions shall be made to prevent surface water from damaging the cut face of excavations or the sloping surfaces of fills.
(20) 
All fills shall be compacted to provide stability of material and to prevent undesirable settlement in accordance with the design manuals.
(21) 
Fills shall not encroach on watercourses, channels, areas designated as wetlands or wetland buffers under Chapter 114, Wetlands and Watercourses, state or federal freshwater or tidal wetlands, or areas designated as critical environmental areas and/or significant fish and wildlife habitat under Ch. 92, Environmental Quality Review, unless undertaken under an appropriate permit issued under such regulations.
(22) 
Appropriate measures for dust control shall be exercised in accordance with the design manuals.
(23) 
Where no acceptable paved access exists for construction vehicles to enter the site, a stabilized construction entrance shall be created and shall be shown on the plans filed with the Stormwater Management Officer.
(24) 
All temporary erosion and sediment control devices shall be disposed of within 30 days after final site stabilization is achieved or after the temporary measures are no longer needed, unless otherwise authorized by the Stormwater Management Officer. Trapped sediment and other disturbed soil areas resulting from the disposition of temporary measures shall be removed from the site and disposed of in accordance with pertinent regulations or permanently stabilized to prevent further erosion and sedimentation.
(25) 
Road surfaces must be swept and kept free of sediment as needed. At the end of the project, catch basins, storm sewers and road surfaces must be cleaned to the satisfaction of the Town Engineer and the Stormwater Management Officer.
B. 
A copy of the approved surface water and erosion control plan shall be on file in the Building and Engineering Department and shall be maintained on site at all times for the duration of the project and shall be made available to the Stormwater Management Officer.