No activity regulated by this chapter may commence until the applicant has received written approval of a SWM site plan from Mahoning Township.
The SWM site plan and SWM site report shall consist of all applicable calculations, maps, and plans. All SWM site plan materials shall be submitted to Mahoning Township in a format that is clear, concise, legible, neat and well organized; otherwise, the SWM site plan shall be rejected. Appropriate sections from the Municipal Subdivision and Land Development Ordinance,[1] and other applicable local ordinances, shall be followed in preparing the SWM site plan.
A. 
A SWM site plan shall include, but not be limited to:
(1) 
Plans shall be of one size and in a form that meets the requirements for recording in the office of the Recorder of Deeds of Montour County.
(a) 
Scale:
[1] 
Plans for tracts of less than 20 acres: one inch equals 50 feet or less;
[2] 
Plans for tracts of 20 acres or more: no greater than one inch equals 100 feet;
(b) 
All lettering and details shall be drawn to a size to be legible if the plans are reduced to half size.
(2) 
The name of the development; name and location address of the property site; name, address, and telephone number of the applicant/owner of the property; and name, address, telephone number, email address, and the seal and signature of the qualified professional preparing the SWM site plan.
(3) 
The date of submission and dates of all revisions.
(4) 
A graphical and written scale on all drawings and maps.
(5) 
A North arrow on all drawings and maps.
(6) 
A location map at a minimum scale of one inch equals 1,000 feet and illustrates the project relative to highways, municipalities or other identifiable landmarks.
(7) 
Metes and bounds description of the entire tract perimeter.
(8) 
Existing and final contours at intervals:
(a) 
Slopes less than 5%: no greater than one foot;
(b) 
Slopes between 5% and 15%: no greater than two feet;
(c) 
Steep slopes (greater than 15%): five-foot contour intervals may be used.
(9) 
Perimeters of existing water bodies within the project area including stream banks, lakes, ponds, springs, field-delineated wetlands or other bodies of water, sinkholes, flood hazard boundaries (FEMA-delineated floodplains and floodways), areas of natural vegetation to be preserved, the total extent of the upstream area draining through the site, and overland drainage paths. In addition, any areas necessary to determine downstream impacts, where required for proposed stormwater management facilities, must be shown.
(10) 
The location of all existing and proposed utilities, on-lot wastewater facilities, water supply wells, sanitary sewers, and waterlines on and within 50 feet of property lines including inlets, manholes, valves, meters, poles, chambers, junction boxes, and other utility system components.
(11) 
A key map showing all existing man-made features beyond the property boundary that may be affected by the project.
(12) 
Soil names and boundaries with identification of the hydrologic soil group classification, including rock outcroppings.
(13) 
Proposed impervious surfaces (structures, roads, paved areas, and buildings), including plans and profiles of roads and paved areas and floor elevations of buildings.
(14) 
Existing and proposed land use(s).
(15) 
Horizontal alignment, vertical profiles, and cross sections of all open channels, pipes, swales and other BMPs.
(16) 
The location and clear identification of the nature of permanent stormwater BMPs.
(17) 
The location of all erosion and sedimentation control facilities, shown on a separate document from the SWM site plan (typically an E&S plan).
(18) 
The location of easements as requested by Mahoning Township or where required by this chapter. In lieu of providing an easement to the public right-of-way, a note may be added to the plan granting Mahoning Township or its designees access to all easements via the nearest public right-of-way.
(19) 
Construction details for all drainage and stormwater BMPs.
(20) 
Identification of short-term and long-term ownership, operations, and maintenance responsibilities.
(21) 
Notes and statements.
(a) 
A statement, signed by the landowner, acknowledging that the stormwater BMPs are fixtures that cannot be altered or removed without prior approval by Mahoning Township.
(b) 
A statement referencing the operation and maintenance (O&M) agreement and stating that the O&M agreement is part of the SWM site plan.
(c) 
A note indicating that record drawings will be provided for all stormwater facilities prior to occupancy, or the release of the surety bond.
(d) 
The following signature block for the qualified professional preparing the stormwater management plan:
"I, __________, hereby certify that the Stormwater Management Plan meets all design standards and criteria of the Mahoning Township's Stormwater Management Ordinance."
(e) 
The following signature block for the Municipal Engineer reviewing the stormwater management plan:
"I, __________, have reviewed this Stormwater Management Plan in accordance with the Design Standards and Criteria of the Mahoning Township's Stormwater Management Ordinance."
B. 
A SWM site report shall include, but not be limited to:
(1) 
General data including:
(a) 
Project name;
(b) 
Project location — address of the property site;
(c) 
Name, address, and telephone number of the applicant/owner of the property;
(d) 
Name, address, telephone number, email address, and engineering seal of the individual preparing the SWM site report;
(e) 
Date of submission and revisions.
(2) 
Project description narrative that clearly discusses the project and provides the following information:
(a) 
Narrative.
[1] 
Statement of the regulated activity describing what is being proposed. Overall stormwater management concept with description of permanent stormwater management techniques, including construction specifications and materials to be used for stormwater management facilities.
[2] 
Expected project schedule.
[3] 
Location map showing the project site and its location relative to release rate districts.
[4] 
Detailed description of the existing site conditions including a site evaluation completed for projects proposed in areas of carbonate geology or karst topography, and other environmentally sensitive areas such as brownfields.
[5] 
Total site area, pre and post, which must be equal or have an explanation as to why it is not.
[6] 
Total site impervious area.
[7] 
Total off-site areas.
[8] 
Number and description of stormwater management facilities.
[9] 
Type of development.
[10] 
Predevelopment land use.
[11] 
Whether site is a water quality sensitive (WQS) development.
[12] 
Whether site is in a defined sensitive area.
[13] 
Types of water quality and recharge systems used, if applicable.
[14] 
Complete hydrologic, hydraulic, and structural computations for all stormwater management facilities.
[15] 
A written maintenance plan for all stormwater features, including detention facilities and other stormwater management elements.
[16] 
Identification of ownership and maintenance responsibility for all permanent stormwater management facilities.
[17] 
Other pertinent information, as required.
(b) 
Summary tables.
[1] 
Predevelopment hydrologic soil group (HSG) assumptions, curve numbers (CN), computation of average slope, hydraulic length, computed time of concentration.
[2] 
Existing conditions runoff volume and peak rate of runoff.
[3] 
Postdevelopment runoff volume and peak rate of runoff.
[4] 
Undetained areas, areas to ponds.
[5] 
Land use for each subarea.
[6] 
Hydrologic soil group (HSG) assumptions, curve numbers (CN).
[7] 
Time of concentration computed for each subarea.
[8] 
Postdevelopment peak rate of runoff routed to ponds and out.
[9] 
Pond maximum return period design data including maximum water surface elevation, berm elevation, and emergency spillway elevation.
[10] 
Water quality depth and volume requirements.
(c) 
Calculations.
[1] 
Complete hydrologic, hydraulic and structural computations, calculations, assumptions, and criteria for the design of all stormwater BMPs.
[2] 
Details of the berm embankment and outlet structure indicating the embankment top elevation, embankment side slopes, top width of embankment, emergency spillway elevation, perforated riser dimensions, pipe barrel dimensions and dimensions and spacing of antiseep collars.
[3] 
Design computations for the control structures (pipe barrel and riser, etc).
[4] 
A plot or table of the stage-storage (volume vs. elevation) and all supporting computations.
[5] 
Routing computations.
(d) 
Drawings.
[1] 
Drainage area maps for all watersheds and inlets depicting the time of concentration path for both existing conditions and postdeveloped condition.
[2] 
All stormwater management facilities must be located on a plan and described in detail including easements and buffer boundaries.
(3) 
Reports that do not clearly indicate the above information may be rejected for review by Mahoning Township and will be returned to the applicant.
(4) 
Description of, justification, and actual field results for infiltration testing with respect to the type of test and test location for the design of infiltration BMPs.
(5) 
The effect of the project (in terms of runoff volumes, water quality, and peak flows) on surrounding properties and aquatic features and on any existing municipal stormwater collection system that may receive runoff from the project site.
(6) 
Description of the proposed changes to the land surface and vegetative cover including the type and amount of impervious area to be added.
(7) 
Identification of short-term and long-term ownership, operation, and maintenance responsibilities as well as schedules and costs for inspection and maintenance activities for each permanent stormwater or drainage BMP, including provisions for permanent access or maintenance easements.
C. 
Supplemental information to be provided prior to recording of the SWM site plan, as applicable:
(1) 
Signed and executed operations and maintenance agreement (Appendix A[2]).
[2]
Editor's Note: Said Appendix is included at the end of this chapter.
(2) 
Signed and executed easements, as required for all on-site and off-site work.
(3) 
An E&S control plan and approval letter from the Montour County Conservation District.
(4) 
A NPDES permit.
(5) 
Permits from PADEP and ACOE.
(6) 
Geologic assessment.
(7) 
Soils investigation report, including boring logs, compaction requirements, and recommendations for construction of detention basins.
(8) 
A highway occupancy permit from PennDOT when utilization of a PennDOT storm drainage system is proposed or when proposed facilities would encroach onto a PennDOT right-of-way.
[1]
Editor's Note: See Ch. 211, Subdivision and Land Development.
A. 
The applicant shall submit the SWM site plan and report for the regulated activity.
B. 
Five copies of the SWM site plan and report shall be submitted and be distributed as follows:
(1) 
Two copies to Mahoning Township accompanied by the requisite executed review fee reimbursement agreement, as specified in this chapter.
(2) 
One copy to the Municipal Engineer.
(3) 
One copy to the Montour County Planning Department.
(4) 
One copy to the Montour County Conservation District.
C. 
Additional copies shall be submitted as requested by Mahoning Township or PADEP.
A. 
Mahoning Township shall require receipt of a complete SWM site plan and report as specified in this chapter. Mahoning Township shall review the SWM site plan and report for consistency with the purposes, requirements, and intent of this chapter.
B. 
Mahoning Township shall not approve any SWM site plan and report that is deficient in meeting the requirements of this chapter. At its sole discretion and in accordance with this article, when a SWM site plan and report is found to be deficient, Mahoning Township may disapprove the submission and require a resubmission, or, in the case of minor deficiencies, Mahoning Township may accept submission of modifications.
C. 
Mahoning Township shall notify the applicant in writing within 45 calendar days whether the SWM site plan and report is approved or disapproved if the SWM site plan and report is not part of a subdivision or land development plan. If the SWM site plan and report involves a subdivision or land development plan, the timing shall follow the subdivision and land development process according to the Municipalities Planning Code.[1]
[1]
Editor's Note: See 53 P.S. § 10101 et seq.
D. 
The Municipal Building Permit office shall not issue a building permit for any regulated activity if the SWM site plan and report has been found to be inconsistent with this chapter, as determined by Mahoning Township. All required permits from PADEP must be obtained prior to issuance of a building permit.
A modification to a submitted SWM site plan and report for a development site that involves a change in stormwater management facilities or techniques, or that involves the relocation or redesign of stormwater management facilities, or that is necessary because soil or other conditions are not as stated on the SWM site plan as determined by Mahoning Township, shall require a resubmission of the modified SWM site plan in accordance with this chapter.
A disapproved SWM site plan and report may be resubmitted with the revisions addressing Mahoning Township's concerns documented in writing to Mahoning Township in accordance with this chapter. The applicable municipal review fee must accompany a resubmission of a disapproved SWM site plan and report.
Mahoning Township's approval of a SWM site plan and report authorizes the regulated activities contained in the SWM site plan for a maximum term of validity of five years following the date of approval. Mahoning Township may specify a term of validity shorter than five years in the approval for any specific SWM site plan. Terms of validity shall commence on the date Mahoning Township signs the approval for a SWM site plan. If stormwater management facilities included in the approved SWM site plan have not been constructed, or if a record drawing of these facilities has not been approved within this time, then Mahoning Township may consider the SWM site plan disapproved and may revoke any and all permits or approvals.
A. 
The applicant shall be responsible for providing record drawings of all stormwater BMPs included in the approved SWM site plan. The record drawing and an explanation of any discrepancies with the approved SWM site plan shall be submitted to Mahoning Township as a prerequisite for the release of the guarantee or issuance of an occupancy permit.
B. 
The record drawing shall include a certification of completion signed by a qualified professional verifying that all permanent stormwater BMPs have been constructed according to the approved SWM site plan and report.
(1) 
Drawings shall show all approved revisions and elevations and inverts to all manholes, inlets, pipes, and stormwater control facilities.
C. 
After receipt of the record drawing and certification of completion by Mahoning Township, Mahoning Township may conduct a final inspection.