For any of the regulated activities of this chapter, prior to the final approval of subdivision and/or land development plans, or the issuance of any permit, or the commencement of any regulated earth disturbance activity, the owner, subdivider, developer or his agent shall submit a drainage plan and receive municipal approval of the plan.
Exemptions from the drainage plan requirements are as specified in § 139-6.
The following items shall be included in the drainage plan:
Map(s) of the project area showing:
The location of the project relative to highways, municipalities or other identifiable landmarks.
Existing contours at intervals of two feet. In areas of steep slopes (greater than 15%), five-foot contour intervals may be used. Off-site drainage areas impacting the project including topographic detail.
Streams, lakes, ponds or other bodies of water within the project area.
Other features including flood hazard boundaries, existing drainage swales, wetlands, closed depressions, sinkholes and areas of natural vegetation to be preserved.
Locations of proposed underground utilities, sewers and waterlines; the locations of all existing and proposed utilities, sanitary sewers and waterlines within 50 feet of property lines of the project site.
An overlay showing soil types and boundaries based on the Lehigh or Northampton County Soil Survey, as applicable, latest edition. Any hydric soils present on the site should be identified as such.
An overlay showing geologic types, boundaries and any special geologic features present on the site.
Proposed changes to land surface and vegetative cover.
Proposed structures, roads, paved areas and buildings.
Final contours at intervals of two feet. In areas of steep slopes (greater than 15%), five-foot contour intervals may be used.
Stormwater management district boundaries applicable to the site.
Clear identification of the location and nature of permanent stormwater BMPs.
An adequate access easement around all stormwater BMPs that would provide municipal ingress to and egress from a public right-of-way.
A schematic showing all tributaries contributing flow to the site and all existing man-made features beyond the property boundary that would be affected by the project.
The location of all public water supply wells within 400 feet of the project and all private water supply wells within 100 feet of the project.
Stormwater management controls and BMPs.
All stormwater management controls and BMPs shall be shown on a map and described, including:
Groundwater recharge methods such as seepage pits, beds or trenches. When these structures are used, the locations of septic tank infiltration areas and wells shall be shown.
Other control devices or methods such as roof-top storage, semipervious paving materials, grass swales, parking lot ponding, vegetated strips, detention or retention ponds, storm sewers, etc.
All calculations, assumptions and criteria used in the design of the BMPs shall be shown.
All site testing data used to determine the feasibility of infiltration on a site.
All details and specifications for the construction of the stormwater management controls and BMPs.
The BMP operations and management plan, as required in Article VII, describing how each permanent stormwater BMP will be operated and maintained and the identity of the person(s) responsible for operations and maintenance. A statement must be included, signed by the landowner, acknowledging that the stormwater BMPs are fixtures that cannot be altered or removed without approval by the municipality.
Environmental resources site design assessment.
An environmental resources site design assessment that describes the following:
The extent to which the proposed grading and impervious cover avoid disturbance of significant environmental resources and preserve existing site hydrology.
An assessment of whether alternative grading and impervious cover site design could lessen the disturbance of significant environmental resources and/or make better use of the site hydrologic resources.
A description of how the proposed stormwater management controls and BMPs serve to mitigate any adverse impacts on environmental resources on the site.
Significant environmental resources considered in the site design assessment include, but are not limited to, steep slopes, ponds, lakes, streams, wetlands, hydric soils, floodplains, riparian vegetation, native vegetation and special geologic features.
The drainage plan shall be submitted by the developer to the municipal secretary (or other appropriate person) as part of the preliminary plan submission for the subdivision or land development.
Four copies of the drainage plan shall be submitted.
Drainage plans involving more than 10,000 square feet of additional impervious cover shall be submitted by the developer (possibly through the municipality) to the Lehigh Valley Planning Commission as part of the preliminary plan submission. The Lehigh Valley Planning Commission will conduct an advisory review of the drainage plan for consistency with the Trout/Bertsch Creeks Watershed and Hokendauqua Creek Stormwater Management Plans. The LVPC will not review details of the erosion and sedimentation plan or the BMP operations and maintenance plan.
Two copies of the drainage plan shall be submitted.
The LVPC will provide written comments to the developer and the municipality, within a time frame consistent with established procedures under the Municipalities Planning Code, as to whether the drainage plan has been found to be consistent with the stormwater management plan.
Editor's Note: See 53 P.S. 10101 et seq.
The drainage plan shall be submitted by the developer to the Lehigh Valley Planning Commission for coordination with the DEP permit application process under Chapter 105 (Dam Safety and Waterway Management), Chapter 106 (Flood Plain Management) of DEP's Rules and Regulations and the NPDES regulations.
Editor's Note: See 25 Pa. Code Chapters 105 and 106.
One copy of the drainage plan shall be submitted.
The municipality shall review the drainage plan, including the BMP operations and maintenance plan, for consistency with the adopted Trout/Bertsch Creeks Watershed and Hokendauqua Creek Watershed stormwater management plans as embodied by this chapter and with any permits issued by DEP. The municipality shall also review the drainage plan against any additional storm drainage provisions contained in the municipal subdivision and land development or zoning ordinance, as applicable.
The municipality shall notify the applicant in writing whether the drainage plan, including the BMP operations and maintenance plan, is approved.
The municipality may require an "as-built survey" of all stormwater BMPs and an explanation of any discrepancies with the drainage plan.
A modification to a submitted drainage plan for a proposed development site which involves a change in control methods or techniques, or which involves the relocation or redesign of control measures, or which is necessary because soil or other conditions are not as stated on the drainage plan (as determined by the municipality) shall require a resubmission of the modified drainage plan consistent with § 139-22 subject to review per § 139-23 of this chapter.
The municipality may hear requests for waivers where it is alleged that the provisions of this chapter inflict unnecessary hardship upon the applicant. The waiver request shall be in writing and accompanied by the requisite fee based upon a fee schedule adopted by the municipality. A copy of the waiver request shall be provided to each of the following: municipality, municipal engineer, municipal solicitor and Lehigh Valley Planning Commission. The request shall fully document the nature of the alleged hardship.
The municipality may grant a waiver provided that all of the following findings are made in a given case:
That there are unique physical circumstances or conditions, including irregularity of lot size or shape, or exceptional topographical or other physical conditions peculiar to the particular property, and that the unnecessary hardship is due to such conditions, and not the circumstances or conditions generally created by the provisions of this chapter in the stormwater management district in which the property is located;
That because of such physical circumstances or conditions, there is no possibility that the property can be developed in strict conformity with the provisions of this chapter, including the "no harm" provisions, and that the authorization of a waiver is therefore necessary to enable the reasonable use of the property;
That such unnecessary hardship has not been created by the applicant;
That the waiver, if authorized, will represent the minimum waiver that will afford relief and will represent the least modification possible of the regulation in issue; and
That financial hardship is not the criteria for granting of a hardship waiver.
In granting any waiver, the municipality may attach such conditions and safeguards as it may deem necessary to implement the purposes of this chapter. If a hardship waiver is granted, the applicant must still manage the quantity, velocity, direction and quality of resulting storm runoff as is necessary to prevent injury to health, safety or other property.
The municipality shall not waive the water quality provisions of this chapter.