Borough of West View, PA Article III Stormwater Plan Content

§ 240-11 Stormwater plan content.

A. No final subdivision or land development plan shall be approved, no permit authorizing construction issued, or any earthmoving or land disturbance activity initiated until the final stormwater management plan for the development site is approved in accordance with the provisions of this chapter.

B. A letter from the Allegheny County Conservation District (ACCD) approving the erosion and sedimentation control plan must also be received prior to the initiation of any grading. In the event that submission to the ACCD is not required by the Borough, an erosion and sedimentation control plan prepared in accordance with the most recent version of PADEP Chapter 102, Erosion and Sedimentation Control Program Manual, must be approved by the Borough.

C. Exemptions. The following activities are specifically exempt from this chapter:

(1) Use of land for gardening primarily for home consumption.

(2) Use of land for construction of landscaping improvements provided such improvements do not significantly alter the runoff characteristics for the land.

(3) Agricultural use of lands when operated in accordance with a farm conservation plan approved by the ACCD, or when it is determined by the ACCD that such use will not cause excessive erosion and sedimentation.

D. The stormwater management plan for all developments except small developments, as defined in § 240-13N, shall consist of the following four components:

(1) Narrative report. The narrative report shall consist of a general statement of the project giving the purpose and engineering assumptions and calculations for control measures and facilities. The following information shall be included.

(a) General description of the project.

(b) General description of accelerated runoff control plan.

(c) General description of erosion and sedimentation control plan.

(d) Expected project time schedule, including anticipated start and completion dates.

(e) Location and watershed characteristics.

(f) Hydraulic and hydrologic calculations, methodology and basis of design.

(g) Brief soils description.

(h) The name, address, and phone number of consultant who prepared the stormwater management plan.

(i) Stormwater management report date and date of the latest revision to the report.

(j) Typewritten narrative report that shall include sections describing the following items:

[1] Stormwater management plan objectives.

[2] Hydrologic procedures used to develop plan.

[3] Description(s) of predevelopment watershed conditions.

[4] Description(s) of postdevelopment watershed conditions.

[5] Description(s) of proposed plan and method(s) to handle postdevelopment runoff.

[6] Description(s) of proposed detention facility(s) and proposed outlet control.

[7] Summary tables for predevelopment and postdevelopment peak flows, detention facility(s) allowable release rates, stage-storage-outflow characteristics and storm-routing results.

(k) Watershed maps delineating predevelopment and postdevelopment watershed boundaries, as well as the flow path and segments used to determine time of concentrations for each watershed.

(l) Storm sewer calculations and watershed map delineating all subareas used to size and compute flow for storm sewer system.

(m) Operation and maintenance program. The report shall contain a proposed maintenance plan for all stormwater control facilities, in accordance with the following:

[1] Identify the proposed ownership entity (e.g., Borough, property owner, homeowners' association, other management entity).

[2] A maintenance program for all facilities, outlining the type of maintenance activities, probable frequencies, personnel and equipment requirements, and estimated annual maintenance costs.

(2) Preliminary plan. The preliminary plan shall provide, and be accompanied by, maps and other descriptive material indicating the feasibility of the plan and showing the following:

(a) A key map showing the development site's location within the designated watershed and watershed subsheds (consult watershed stormwater plans for boundaries). On all site drawings, show the boundaries of the watershed(s) and subarea(s) as they are located on the development site and identify the watershed names and/or subshed numbers.

(b) Location of the one-hundred-year floodplain on the development site based on West View Borough's Flood Insurance Study Maps or a determination by the applicant's engineer.

(c) An overlay showing soil types and boundaries within the development site.

(d) The streets, storm sewers and other storm drains to be built, the basis of their design, the outfall and outlet locations and elevations, the receiving stream or channel and its high water elevation and the functioning of the drains during high water conditions.

(e) The parts of the proposed parking area pavements, if any, which are planned to be depressed to provide stormwater storage or conveyance. A maximum of six inches depth of water may be ponded in a proposed parking area.

(f) Existing streams and watercourses to be maintained and new channels to be constructed, their locations, cross sections and profiles.

(g) Proposed culverts and bridges to be built, if any, their materials, elevations, waterway openings and basis of design.

(h) Existing detention ponds and basins to be maintained, enlarged or otherwise altered and new ponds or basins to be built and the basis of their design.

(i) The approximate location and percentage of the total land area in the development which will be covered by impervious surfaces after construction is completed.

(j) The slope, type and size of all proposed and existing storm sewers and other waterways.

(k) Existing contours at intervals of two feet except in areas with slopes greater than 15%, in which case five-foot contour intervals may be used.

(l) All natural features, including bodies of water (natural and artificial), watercourses (permanent and intermittent), swales, wetlands and other natural drainagecourses on the development site and those off site which will be affected by runoff from the development.

(m) Approximate depth, shape, size and storage of any proposed retention facility.

(n) Infiltration BMPs shall be spread out and shallow as much as practicable.

(o) One or more typical cross sections of all existing and proposed channels or other open drainage facilities, showing the elevation of the existing land and the proposed changes thereto, together with the high water elevations expected from the one-hundred-year storm under the controlled conditions called for by this chapter and the relationship of structures, streets and other utilities.

(p) A site plan showing the property lines, dimensions of the site and location of existing and proposed structures, sewers, waterlines, easements and rights-of-way.

(q) Certification of the registered Pennsylvania engineer responsible for preparation of the plan.

(r) A list of the permits and approvals relative to stormwater management that will be required from other governmental agencies and anticipated dates of submission and receipt. Copies of the applications may be requested by the Borough Engineer where they may be helpful for the stormwater plan review.

(3) Final plan. Upon approval of the preliminary plan, the final plan shall be submitted to the Borough. The final plan shall provide all descriptive material and maps previously submitted and required prior to the final plan, in addition to the following items:

(a) All calculations, assumptions and criteria used in the design of the storm sewer system, detention facilities and sediment and erosion control operations. Hydraulic and energy grade lines shall be provided for proposed storm sewers if, in the opinion of the Borough Engineer, they are required to evaluate the storm system.

(b) All plans and profiles of proposed storm sewers and open channels, including horizontal and vertical controls, elevations, sizes, slopes and materials.

(c) Locations, dimensions and design details required for the construction of all facilities.

(d) For all detention basins, a plot or tabulation of storage volumes with corresponding water surface elevations and basin outflow rates for those water surface elevations.

(e) For all detention basins, design hydrographs of inflow and outflow for the peak design flows from the site under natural and developed conditions.

(f) A description of operation for all detention basins.

(g) Contours of the finished project site at intervals of two feet, except in areas with slopes greater than 15%, in which case, five-foot contour intervals may be used.

(h) The staging of earthmoving activities and program of operation, including a schedule for the installation of all temporary and permanent stormwater control measures and devices.

(i) All information relative to the design and operation of emergency spillways.

(j) Emergency routing of outfall for stormwater runoff in the event of failure of off-site drainage structures.

(k) When major control facilities, such as retention basins, requiring a PADEP permit, are planned, soil structures and characteristics shall be investigated. Plans and data prepared by a licensed professional engineer or geologist with experience and education in soil mechanics shall be submitted. These submissions should consider and offer design solutions for frost heave potential, shrink/swell potential, soil bearing strength, water infiltration, soil settling characteristics, fill and backfilling procedures and soil treatment techniques as required to protect the improvements or structures.

(l) All erosion and sedimentation control measures, temporary, as well as permanent, in sufficient detail to clearly indicate the effectiveness of the plan.

(m) Project specifications relative to stormwater control, erosion and sedimentation.

(n) Evidence that all on-site and off-site easements required to convey runoff flow to an existing public drainage facility or a permanent stream have been granted to the operating entity.

(o) Provide the information to conform with the requirements noted in Articles V and VI.

(p) Provide a list of adjacent property owners within 200 feet of the subject property and documentation that the adjacent property owners have been notified of the proposed project.

(q) A note shall be placed on the recorded plan: "As per the approved stormwater management plan, the Borough shall have right of access to the on-site detention facility for the right of maintenance in the event the owner, assigns or heirs do not adequately maintain the facility. The owner, assigns or heirs shall reimburse the Borough for all costs associated with said maintenance. The aforementioned rights granted the Borough in no way diminish the responsibility of the owner, assigns or heirs of said maintenance, and no liability will be assumed by the Borough associated with required access for maintenance purposes."

(4) Maintenance plan and agreement. A maintenance plan establishing ownership and maintenance responsibilities for all stormwater control facilities (identifying the specific person or entity responsible) and detailing financial requirements and sources of funding shall be submitted with the final plan. Any legal agreements or covenants required to implement the maintenance program shall be submitted (See Appendix 1).[1] A maintenance schedule shall be submitted in accordance with the Standardized Maintenance Schedule in Appendix 1.

[1] Editor's Note: Appendix 1 is included as an attachment to this chapter.

§ 240-12 General standards.

A. The following provisions shall be considered the overriding performance standards against which all proposed stormwater control measures shall be evaluated:

(1) Any landowner and any person engaged in the alteration or development of land which may affect stormwater runoff characteristics shall implement such measures as are reasonably necessary to prevent injury to health, safety and other property. Such measures shall include, but not be limited to, such actions as are required to:

(a) Assure that the maximum rate of stormwater runoff is no greater after development than prior to development activities.

(b) Manage the quantity, velocity and direction of resulting stormwater runoff in a manner which will not adversely impact the health on, or value of, any affected properties.

(c) No discharge of toxic materials into any stormwater management system will be permitted.

(d) Where applicable stormwater management facilities shall comply with the requirements of Chapter 105 (Dam Safety and Waterway Management) of Title 25, Environmental Protection, of the Pennsylvania Department of Environmental Protection (PADEP) and Section 404 of the Clean Water Act as authorized by the United States Corps of Engineers.

(e) Stormwater management facilities that involve a state highway shall be subject to the approval of the Pennsylvania Department of Transportation.

(f) Stormwater runoff from a project site shall flow directly into a natural watercourse or into an existing storm sewer system, or onto adjacent properties in a manner similar to the runoff characteristics of the predevelopment flow.

(g) Stormwater runoff shall not be transferred from one watershed to another unless the watersheds are subareas of a larger watershed that are tributary to a common point of interest within or near the perimeter of the property. Transfer of runoff from one watershed to another under any other circumstances shall only be approved at the discretion of the Borough. Documentation shall be provided that peak flow rates are not increased following development and there will be no detrimental impact in downstream areas.

(h) All stormwater runoff flowing over the project site shall be considered in the design of the stormwater management facilities.

(i) For any stormwater management facility requiring a permit to be issued by PADEP, said permit along with supporting report and plans used to secure the permit shall also be submitted.

(2) Fees and expenses.

(a) The Borough may charge a reasonable fee for review of BMP operations and maintenance plans to defray review costs incurred by the Borough. The applicant shall pay all such fees.

(b) The fees required by this chapter may cover:

[1] Administrative/clerical costs of 5%.

[2] The review of the BMP operations and maintenance plan by the Borough Engineer.

[3] The site inspections including, but not limited to, preconstruction meetings, inspections during construction of stormwater BMPs, and final inspection upon completion of the stormwater BMPs.

[4] Any additional work required to monitor and enforce any provisions of this chapter, correct violations, and assure proper completion of stipulated remedial actions.