Article III Stormwater Management and Erosion and Sediment Control

Lawn maintenance and landscaping of existing cultivated areas, including gardens.

Alteration to the interior of a building and alteration to the exterior of a building, provided that such exterior alteration does not increase land coverage by the building, pavement, walks, patio, tennis court, swimming pool, etc., and the alteration does not involve the demolition of a part or all of the exterior of an existing building.

Any land-disturbing activity that involves less than 500 square feet on lots greater than 7,500 square feet, or 200 square feet on lots 7,500 square feet or less. However, any land-disturbing activity of any area shall follow the applicable soil erosion BMPs provided by the Village.

Any emergency activity which is immediately necessary for the protection of life, property or natural resources, as determined by the Village Engineer.

Activities of the Village in regard to the permitting provisions.

Routine maintenance activities that are performed to maintain the original line and grade, hydraulic capacity or original purpose of a facility.

Repairs to any stormwater management practice or facility deemed necessary by the Village Engineer or designee.

Land development or redevelopment activities for which a building permit has been approved on or before the effective date of this chapter.

Excavation of burial plots.

(10)

The installation of fence, sign, telephone, and electric poles and other kinds of posts or poles.

(11)

The stripping of existing lawn areas followed by the immediate placement of sod where there are no proposed changes in grade.

§ 254-6 Waivers.

Upon written request from the applicant, the Village Engineer may grant a waiver, in writing, from any requirement of this chapter, specifically identifying the reasons therefor, using the following criteria:

Special circumstances applicable to the subject property, its intended use, or the scope of the project.

Any waiver issued by the Village Engineer shall not:

Result in an increase in the rate or volume of surface water runoff;

Result in an adverse impact on a wetland, watercourse or water body;

Result in degradation of water quality; or

§ 254-7 Activities requiring permit; permit requirements.

Otherwise impair the attainment of the objectives of this chapter.

No person shall commence or carry out any land-disturbing activity in the Village of Scarsdale that involves land disturbance of more than 500 square feet on lots greater than 7,500 square feet or more than 200 square feet on lots 7,500 square feet or less without first submitting a stormwater management plan and obtaining the proper stormwater management and erosion and sediment control permit from the Village Engineer and all other necessary local, state and federal permits and thereafter complying with the requirements of this chapter. All plans shall ensure that such development or land-disturbing activity shall not result in any increased water runoff or infiltration on or into any adjoining property and shall include measures to comply with this chapter and accommodate a twenty-five-year storm on a site up to two acres and a 100-year storm on a site of two acres or greater. All approvals and permits shall comply with the requirements of this chapter. Activities that involve the disturbance of an area of one acre or more also shall comply with all applicable New York State Department of Environmental Conservation (NYSDEC) requirements. The predevelopment calculations shall be based on an unimproved land area and the post-development calculations shall include all existing and proposed improvements for properties located in an SDA. Post-development calculations for all other properties shall be based upon the proposed improvements. Any land-disturbing activity within the adjoining property buffer as defined in § 254-4, is prohibited without Planning Board approval pursuant to § 254-10.1.

[Amended 1-10-2023 by L.L. No. 2-2023]

Applications for developed properties that otherwise comply with all requirements of this chapter shall not be denied approval on the basis of the requirement to retrofit the existing impervious surfaces if there is no proposed increase in the amount of impervious surface from that existing on March 24, 2009.

It is the responsibility of an applicant to include sufficient information in the stormwater management, erosion, sediment and pollution control plan in order to evaluate the environmental characteristics of the affected areas, the potential and predicted impacts of the proposed activity on watercourses and the effectiveness and acceptability of those measures proposed by the applicant for reducing or mitigating adverse impacts.

An application for a stormwater management, erosion, and sediment control permit shall be made on forms provided by the Village and shall include the name(s) and address of the owner, contract vendee or developer of the site and of any consulting firm retained by the applicant, together with the name and telephone number of the applicant's principal contact at such firm. Each application shall include a certification that any land clearing, construction or development involving the movement of earth shall be in accordance with the plans approved upon issuance of the permit. The permit shall be valid for the same period as the associated building or other municipal permit, or as may be specified by the Village Engineer. Where a building or other municipal permit is not issued, the stormwater management, erosion and sediment control permit shall expire within 180 days from the date of issuance, unless renewed by the Village Engineer.

For applications made pursuant to §§ 254-8 and 254-9, those properties located in an SDA shall retrofit to the maximum possible detention and retention for the entire site based upon calculations provided by the applicant as required under this chapter and subject to the approval of the Village Engineer, in connection with the construction of an addition to an existing structure or other land-disturbing activity so that stormwater management practices for the entire site (including retention of run-off and discharge into the public storm drain) is in full compliance with the provisions of this chapter.

The determination of the Village Engineer denying the grant of a permit for applications made pursuant to § 254-8 or 254-9 shall be in writing and set forth the basis for such decision, which decision may be appealed to the Planning Board.

§ 254-8 Application for land-disturbing activities of greater than 500 square feet and up to 5,000 square feet and those land-disturbing activities greater than 200 square feet on lots 7,500 square feet or less; land-disturbing activity of greater than 500 square feet or greater than 200 square feet on lots 7,500 square feet or less and up to 1,500 square feet located in SDA.

In addition to the requirements specified under § 254-7, each application shall be accompanied by the following and certified by a licensed/certified professional and shall include the following, unless specifically waived by the Village Engineer:

[Amended 1-10-2023 by L.L. No. 2-2023]

A vicinity map.

A stormwater management, erosion, sediment and pollution control plan for the site showing existing and proposed drainage patterns, existing and proposed grades, percolation rate, soil classification on-site stormwater appurtenances, wetlands, the 100-year floodplain, subdrainage basins and the proposed use of the site, including areas of excavation, grading and filling. The stormwater management, erosion, sediment and pollution control plan shall identify all adjoining property buffer areas including topography, spot elevations, natural and all developed features in the area.

A grading plan that is consistent with the preexisting topography and elevations of the surrounding terrain that includes tapered slopes back to preexisting grades within the adjoining property buffer area.

Stormwater management improvements for detention/retention and stormwater quality, including calculations, designs and special measures regarding safety and maintenance operations.

Proposed overflows to outlet through designed outlet control structures. Appropriate outlet control structure discharge calculations to be submitted to ensure a net zero increase in stormwater runoff from the site and into the public storm drain system.

Stormwater conveyance system, including plans, designs and materials to be used for improvements and erosion control in channel sections of stormwater conveyance systems and erosion control measures at culvert inlets and outfalls.

All stormwater management plans shall be designed or certified by a New York State licensed engineer specializing in drainage, hydrological and geotechnical sciences with expertise in soil erosion and sediment control and shall accommodate a twenty-five-year storm for sites of two acres or less or a 100-year storm for sites greater than two acres. All plans shall comply with the guidelines and specifications of the most recent editions of the New York State Stormwater Management Design Manual and the New York Standards and Specifications for Erosion and Sediment Control and shall include:

Temporary erosion and sediment control measures with an implementation and maintenance schedule.

Permanent post-construction erosion and sediment control improvements showing the location of improvements and an implementation and maintenance schedule.

The predevelopment calculations shall be based on an unimproved lot area, and the post-development calculations shall include all existing and proposed improvements for properties located in an SDA. Post-development calculations for all other properties shall be based upon the proposed improvements.

§ 254-9 Application for land-disturbing activities of greater than 5,000 square feet; land-disturbing activities of greater than 1,500 square feet on lands located in SDA.

Applications that involve retrofitting shall submit plans that accommodate storm intensities of 25 years, 10 years and two years.

(10)

Applications in an SDA shall comply with the requirements specified in § 254-7E, which requires the maximum detention/retention possible.

In addition to the requirements specified under § 254-7, each application shall be accompanied with plans certified by a licensed engineer specializing in drainage and hydrological and geotechnical sciences, unless specifically waived by the Village Engineer based on the scope of the project:

A map showing the FEMA floodplain, NYS and Village wetlands and local critical sub-drainage basin and any abutting drainage basins.

A vicinity map in sufficient detail to easily locate the site for which the permit is sought, including the boundary lines and approximate acreage for the site, the existing zoning, the date of the plan (to include the date of any revisions), North point, scale and legend.

A stormwater management, erosion, sediment and pollution control plan to accommodate a twenty-five-year storm for sites of two acres or less and a 100-year storm for sites greater than two acres. The plan shall include:

[Amended 1-10-2023 by L.L. No. 2-2023]

Existing topography of the site and adjacent land clearly portraying the drainage patterns of the area, including ditches, culverts, permanent or intermittent streams, wetlands or other water bodies, existing roads and size of existing culverts.

The location of existing buildings, structures, utilities, water bodies, floodplains, drainage facilities, vegetative cover, the size and species of trees with a trunk diameter of four inches or more at a point 4 1/2 feet above ground level, paved areas, watershed divides, and other significant natural or man-made features on the site, and adjacent land within approximately 50 feet of the boundary.

An analysis of site limitations and development constraints, including such factors as slope, soil type and erodibility, depth to bedrock, depth to seasonal high water, soil percolation, etc., in order to determine site suitability for proposed stormwater and erosion control facilities regarding the proposed development. Deep test pits and soil percolation to be conducted under the supervision of the licensed/certified professional and observed by the Village of Scarsdale Engineering or Building Department.

Wetlands boundaries and designated 100-year floodplain boundaries, including 100-year flood elevations and floodways where applicable. Such elevations should be based on the North American Vertical Datum of 1988. The plan shall also indicate the size of culverts downstream of the project, and existing easements for storm drains, sewers and other utilities.

The proposed use of the site, illustrating existing conditions and proposed development; areas of excavation, grading and filling; proposed contours, final grades and street profiles; provisions for stormwater management, including control of accelerated runoff, with a drainage area map and computations; kinds and locations of utilities; and areas and square feet proposed to be paved, covered, sodded or seeded, vegetatively stabilized, or left undisturbed.

The means and methods of preserving and protecting the adjoining property buffer area during construction.

Proposed overflows to the Village's storm drain system shall outlet through designed outlet control structures. Appropriate outlet control structure discharge calculations shall be submitted to ensure a net zero increase in stormwater runoff from the site and into the public storm drain system.

Comparison of predevelopment with post-development runoff, including:

A description of the methodology used to compare and evaluate predevelopment with post-development runoff conditions in terms of volumes, peak rates of runoff, routing and hydrographs.

Calculation of peak discharge rates and total runoff volumes from the project area for existing site conditions and post-development conditions. The relevant variables used in this determination, such as the curve number and time of concentration, shall be included. Downstream analysis, including peak discharge rates, total runoff volumes and evaluation of impacts to receiving water and/or wetlands, shall be evaluated. Storage volume and surface area requirements shall be calculated. Discharge provisions for the proposed control measures, including peak discharge rates, outlet design, discharge capacity for each stage, outlet channel design and a description of the point of discharge, shall be provided.

The predevelopment calculations shall be based on an unimproved lot area and the post-development calculations shall include all existing and proposed improvements for properties located in an SDA. Post-development calculations for all other properties shall be based upon the proposed improvements.

A description of the methodology used to compare and evaluate predevelopment with post-development pollutant loading. Contaminants to be compared include, when applicable, total suspended solids, total phosphorus, total nitrogen and biological oxygen demand and thermal pollution. Pollutant loading coefficients may be used. Water quality treatment improvements should be designed to meet the above specified stormwater management practice(s); compare pollutant loading between before and after conditions, with computations.

Calculation of the necessary storage volumes and the proposed stormwater management measure(s) described in detail, providing sufficient detail of the water quality control measures to ensure that the relevant design criteria will be met. Such detail may include surface area dimensions, depths, inlet designs, planting specifications for use of aquatic vegetation, percent solids removal expected, discharge rates and outlet design.

Assumptions and coefficient values used in the hydrologic calculations for making the above comparisons; evaluate the post-development effect of stormwater runoff in SDAs.

A stormwater management improvement plan, including:

A narrative of all proposed stormwater management improvements. A soil profile to at least five feet below the stormwater management improvements shall be provided.

Designs of proposed stormwater management improvements for peak flow attenuation and water quality management and an indication of which improvements will be used to attenuate peak flows, which will be used to enhance stormwater runoff quality and which improvements will serve a dual role; identification of the materials to be used in constructing these improvements.

Calculations for sizing stormwater improvements shall be provided.

Designs and calculations for siting and sizing such specialized measures and devices as filter strips, water quality inlets (oil/grit separator), forebays, etc., which will be used to remove sediment, oil-based products and other contaminants found in urban runoff.

Evaluation of the amount of treatment or level of pollutant reduction that can be expected from the proposed stormwater management improvement(s). Contaminants to be considered in this evaluation, when determined appropriate by the Village Engineer, include total suspended solids (TSS), total phosphorus (P), total nitrogen (N), biological oxygen demand (BOD) and thermal pollution. Evaluation of the effectiveness of stormwater management practices can be based on reports on the effectiveness of comparable stormwater improvements on similar sites.

Information on the design provisions that address safety considerations (e.g., gentle slopes and benches in ponds or streambanks) and accommodate maintenance needs (including access to conduct maintenance operations).

A stormwater conveyance system plan, including:

A narrative of the stormwater conveyance (drainage) system indicating which segments of the drainage system are open channels and which segments are piped (culverts) and which provide a rationale and justification for installing piped segments.

Plan view and cross-sectional designs of stormwater conveyance systems with hydrologic calculations for siting and sizing the stormwater conveyance system. The plan shall also identify materials to be used.

Plans and designs identifying materials to be used for preventing erosion in channel sections of stormwater conveyance systems and erosion control measures at culvert inlets and outfalls.

The above plans shall be designed or certified by a New York State licensed engineer specializing in drainage and hydrological and geotechnical sciences. Properties two acres or greater shall design to accommodate storm intensities of 100 years, 50 years, 25 years, 10 years, and two years For all properties less than two acres, the design shall be for a twenty-five-year, ten-year and two-year storm. All plans shall comply with the guidelines and specifications of the most recent editions of the New York State Stormwater Management Design Manual and the New York Standards and Specifications for Erosion and Sediment Control and include:

Temporary erosion and sediment control measures to be used during land clearing, land grading and the construction phases, including:

Temporary structural and vegetative measures to be used to control erosion and sedimentation.

Plans showing the location of temporary vegetative and structural erosion and sediment control measures.

(c)

Dimensional details of proposed erosion and sediment control measures identifying materials to be used in developing these measures with calculations used in siting and sizing sediment basins.

(d)

Temporary erosion and sediment control measures to be converted to permanent stormwater management measures.

(e)

An implementation schedule for the staging of temporary erosion and sediment control measures.

(f)

A maintenance schedule for soil erosion and sediment control measures.

Permanent erosion and sediment control improvements, including:

Permanent structural and vegetative practices to be used to provide long-term control of erosion and sedimentation when construction activities are completed and the project site is restored.

A plan showing the location of permanent erosion control improvements, including both structural and vegetative.

(c)

An implementation schedule for restoring the project site with permanent erosion and sediment control improvements.

An implementation schedule and maintenance, including:

An implementation schedule for the staging of all stormwater management improvements, coordinating the staging of erosion and sediment control facilities and construction activities.

§ 254-10 Review of stormwater management, erosion, sediment and pollution control plan and inspections.

A description of the arrangements, including deed restrictions, if applicable, that will be made for ensuring long-term maintenance of stormwater management and erosion control improvements with contingency plans identifying responsible parties for performing maintenance and the frequency of maintenance.

(c)

Property owners of stormwater management systems constructed after March 24, 2009, shall submit to the Village Engineer certification from a licensed/certified professional, at five-year intervals, certifying that the stormwater management system is operating as provided in the approved design.

Applications in an SDA shall comply with the requirements specified in § 254-7E, which requires the maximum retention/detention possible.

[Amended 1-10-2023 by L.L. No. 2-2023]

The Village Engineer or designee shall review the plan for compliance with the requirements of this chapter. A stormwater management permit shall not be issued unless all aspects of an application and submitted plan are in full compliance with all requirements of this chapter. The applicant shall promptly correct any portion of the plan that does not comply.

Compliance required; site inspections.

Prior to the issuance of a permit, the Village Engineer or designee may conduct random site inspections to ensure that all provisions of this chapter and aspects of any approved application are complied with.

The party responsible for the land development or redevelopment activity, or his or her representative, shall at all times properly operate and maintain all facilities and systems of treatment and control (and related appurtenances) which are installed or used by the applicant or developer to achieve compliance with the conditions of this code. Sediment shall be removed from sediment traps or sediment ponds.

For land development or redevelopment activities defined in § 254-4 of this chapter and subject to the requirements set forth in §§ 254-8 and 254-9 of this chapter, or as determined by the Village Engineer, the applicant shall have a licensed/certified professional conduct site inspections and document the effectiveness of all erosion and sediment control practices every seven days and within 24 hours of any storm event producing 0.5 inch of precipitation or more. Inspection reports shall be maintained in a site logbook.

The applicant, developer or his or her representative(s) shall be on site at all times when construction or grading activity takes place and shall inspect and document the effectiveness of all erosion and sediment control practices.

Right to inspect.

Prior to the issuance of a certificate of occupancy required under Chapter 132 of this code, property owners of stormwater management facilities that need to be maintained by the property owner or developer shall provide access to the Village. Access to the facility must be provided at reasonable times for periodic inspection by the Village to ensure that the facility is maintained in accordance with BMPs and that it performs to meet the approved and certified design standards.

The applicant, developer, property owner or party responsible for the ongoing maintenance of permanent stormwater management facilities installed and approved shall ensure that said facilities are operated and maintained in accordance with BMPs and performs at the design standards certified by a licensed/certified professional and approved by the Village Engineer under terms of this chapter. The responsible party may be required to provide a performance bond or other security instrument pursuant to § 254-11 of this chapter guaranteeing the operation and maintenance of any facilities installed. The Village, at its sole discretion, may accept dedication of any existing or future stormwater management facility, provided that such facility meets all the requirements of this chapter and includes adequate perpetual access and sufficient area, by easement or otherwise, for maintenance.

The Village may require erosion and sediment control inspections as necessary to determine compliance with this Code and may approve a portion of the work completed, or notify the applicant wherein the work fails to comply with the requirements of this Code chapter. If any violations are found, the applicant and developer shall be notified in writing of the nature of the violation and the required corrective actions. No further work shall be conducted, except for site stabilization, until all violations are corrected and all work previously completed has received approval.

Inspections shall be conducted as frequently as necessary as determined by the Village Engineer, including, but not limited to, routine or random inspections or inspections based upon complaints or other notice of possible violation; inspection of drainage basins or areas identified as higher-than-typical sources of sediment or other contaminants or pollutants; inspections of businesses or industries of a type associated with higher-than-usual discharges of contaminants or pollutants or with discharges of a type which are more likely than the typical discharge to cause violations of state or federal water or sediment quality standards of the NYSDEC SPDES general stormwater permit and joint inspections with other agencies inspecting under environmental or safety laws. Inspections may include, but are not limited to, reviewing maintenance and repair records, sampling discharges, surface water, groundwater and material or water in drainage control facilities; and evaluating the condition of drainage control facilities and other stormwater management practices. Typically, inspections include the following:

An initial inspection prior to plan approval.

An erosion and sediment control inspection to ensure that erosion and sediment control practices are in accord with the approved plan.

An inspection prior to backfilling any underground drainage or stormwater conveyance structures.

§ 254-10.1 Site plan for land-disturbing activities in adjoining property buffer.

A final inspection when all work, including construction of stormwater management facilities and permanent soil stabilization, has been completed.

The Village maintains the right to enter a property at any time, if necessary, without notice when a new stormwater management facility is installed on private property or when any new connection is made between private property and the public storm sewer system. The Village will endeavor to enter all properties at reasonable times and in a reasonable manner for the purpose of inspection as specified above.

No building permit may be issued until a stormwater management and erosion and sediment control permit has been issued for those activities controlled under this chapter.

Activities that involve the disturbance of one acre or more shall comply with all applicable New York State Department of Environmental Conservation (NYSDEC) requirements.

[Added 1-10-2023 by L.L. No. 2-2023]

Whenever any land-disturbing activity within the adjoining property buffer area, as defined in § 254-4, is proposed, a site plan shall be submitted to the Planning Board pursuant to this section. No building permit shall be issued except in conformity with a site plan approved by the Planning Board.

A written application shall be submitted to the Planning Board, together with maps and plans, prepared by and bearing the seal of a land surveyor or professional engineer licensed to practice in the State of New York. An application for approval of a site plan pursuant to this section shall be submitted with eight copies and shall contain the following information:

A written statement describing the land-disturbing activity.

The adjoining property buffer area.

The area to be excavated or graded.

A narrative describing the amount of soil to be excavated from the adjoining property buffer area and where the soil will be disposed.

Existing and proposed drainage on the premises.

Existing state or federally regulated wetlands, rivers, streams or watercourses on or adjacent to the premises.

Adjoining properties and streets.

Existing and proposed contours showing elevations based on Scarsdale datum, at intervals of not more than two feet.

The size and species of trees with a trunk diameter of four inches or more at breast height.

(10)

Such other information as the Planning Board may require.

A public hearing shall be held by the Planning Board on the site plan application.

Public notice of any such hearing shall be published by the Clerk in the official newspaper of the Village of Scarsdale at least once and at least five days preceding the date of the hearing.

[Amended 3-26-2024 by L.L. No. 5-2024]

Applicant to mail public notice of the hearing to proximate property owners. Each applicant seeking approval of a site plan pursuant this section shall serve the public notice setting forth the location of the property, the nature of the application and the time and place of the hearing upon all owners of property, any part of which is within 200 feet of any point on the boundary of the lot, or lots, involved in the application. As an exception, for properties larger than 15 acres in area, notice shall be sent to all owners of property within 200 feet of the activity covered by the application. Such notice shall be served by certified mail not less than 10 days, or by personal service not less than seven days, prior to the date of the hearing thereon. If service has been effected by mail, a receipt from the post office of such mailing shall constitute proof. Each such notice shall be in a form as prescribed by the Board.

Further notice shall not be required in the event of a continuance unless the Board shall direct the giving of such notice.

At least two days prior to the hearing, the applicant shall file with the Clerk proof, in affidavit form, that such required notice in satisfactory form and substance has been served.

In the case of each application for land-disturbing activity within the adjoining property buffer area on any lot in a Residence A District, in considering whether to approve, approve with conditions, or disapprove the application the Planning Board shall consider:

Whether the proposed land-disturbing activity will aggravate drainage conditions, soil erosion, or lead to significant adverse runoff patterns on the subject property and/or across property lines.

Whether there is a unique physical or environmental condition that necessitates activities within the adjoining property buffer.

Whether the proposed activity within the adjoining property buffer will create an undesirable change in the character of the neighborhood or will be a detriment to nearby properties.

Whether the size and location of the proposed activities are appropriate for the natural and built of the property.

Whether there is some alternative method to achieve the same benefit other than disturbing, altering or developing within adjoining property buffer.

Whether the extent of regrading or alteration of preexisting terrain is necessary and unavoidable.

Whether there are adequate sediment and erosion control measures proposed.

Whether the proposed action is for construction staging purposes and is temporary in nature and poses no detriment to nearby properties.