The SWM site plan shall consist of all applicable calculations, maps, and plans. A note on the maps shall refer to the associated computations and erosion and sediment pollution control plan by title and date. The cover sheet of the computations and erosion and sediment pollution control plan shall refer to the associated maps by title and date. All SWM site plan materials shall be submitted to the Township in a format that is clear, concise, legible, neat, and well organized; otherwise, the SWM site plan shall be disapproved and returned to the applicant. Said plan shall be prepared by a registered professional land surveyor, qualified geologist, landscape architect, architect, or engineer licensed in the State of Pennsylvania, with said preparer's seal and registration number affixed to the plan. The following items shall be included in the SWM site plan:
A. Stormwater management report:
(1) General description of project.
(2) General description of permanent stormwater management techniques, including construction specifications and materials to be used for stormwater management facilities.
(3) Complete hydrologic, hydraulic, and structural computations for all stormwater management facilities.
(4) A written maintenance plan for all stormwater features, including detention facilities and other stormwater management elements.
(5) Identification of ownership and maintenance responsibility for all permanent stormwater management facilities.
(6) Required information.
(a) The stormwater management report must include a narrative which clearly discusses the project and summary tables which, at a minimum, provide the following information:
[1] Narrative:
[a] The overall stormwater management concept.
[b] The expected project schedule.
[d] Total site area, pre and post, which must be equal or have an explanation as to why it is not.
[e] Total site impervious area.
[g] Number of stormwater management facilities (ponds), if applicable.
[j] Whether site is underlain by carbonate geology.
[k] Whether site is a water quality sensitive (WQS) development.
[l] Whether site is in a defined sensitive area.
[m] Types of water quality and recharge systems used, if applicable.
[n] Other pertinent information, as required.
[2] Summary tables:
[a] Predevelopment:
[i] Hydrologic soil group (HSG) assumptions, curve numbers (CN).
[ii] Computation of average slope, hydraulic length, computed time of concentration.
[iii] Required peak rate of runoff.
[b] Post-development:
[i] Undetained areas, areas to ponds.
[ii] Land use for each subarea.
[iii] Hydrologic soil group (HSG) assumptions, curve numbers (CN).
[iv] Time of concentration computed for each subarea.
[v] Post-development peak rate of runoff routed to ponds and out.
[vi] Pond maximum return period design data, including: maximum water surface elevation, berm elevation, and emergency spillway elevation.
[vii] Water quality depth and volume requirements.
[viii] Recharge volume requirements.
[x] Capture volumes required.
(b) Reports that do not clearly indicate the above information may be rejected for review by the Township's Engineer or representative and will be returned to the applicant.
B. Plans for tracts of less than 20 acres shall be drawn at a scale of one inch equals no more than 50 feet; for tracts of 20 acres or more, plans shall be drawn at a scale of one inch equals no more than 100 feet. Plans shall be submitted on the following sheet sizes: 18 feet by 24 inches, 24 inches by 36 inches, or 36 inches by 42 inches. All lettering shall be drawn to a size to be legible if the plans are reduced to half size. All sheets comprising a submission shall be on one size. The following information, unless specifically exempted in writing by the Township Engineer, must be shown on the plans, prepared in a form which meets the requirements for recording in the office of the Recorder of Deeds of Centre County, Pennsylvania. The contents of the map(s) shall include, but not be limited to:
(1) The name of the development, the name and address of the owner of the property, and the name of the individual or firm preparing the plan.
(2) The date of submission and revision.
(3) The location of the project relative to highways, municipalities or other identifiable landmarks.
(4) Existing contours at intervals of two feet. In areas of steep slopes (greater than 15%), five-foot contour intervals may be used.
(5) Existing streams, lakes, ponds, or other bodies of water within the project area.
(6) Other physical features, including flood hazard boundaries, sinkholes, closed depressions, wetlands, streams, existing drainagecourses, areas of natural vegetation to be preserved, and the total extent of the upstream area draining through the site. In addition, any areas necessary to determine downstream impacts, where required for proposed stormwater management facilities, must be shown.
(7) The locations of all existing and proposed utilities, sanitary sewers, and waterlines within 20 feet of property lines.
(8) An overlay showing soil names and boundaries, including rock outcrops.
(9) Total area of impervious surfaces proposed.
(10) Proposed structures, roads, paved areas, and buildings.
(11) Final contours at intervals of two feet. In areas of steep slopes (greater than 15%), five-foot contour intervals may be used.
(12) A graphic and written scale.
(14) The total tract boundary and size with distances marked to the nearest foot and bearings to the nearest degree.
(15) Existing and proposed land use(s).
(16) A key map showing all existing man-made features beyond the property boundary that would be affected by the project and the extent of the watershed or subarea that drains through the project site.
(17) Horizontal and vertical profiles of all open channels, including hydraulic capacity.
(19) Access easements around all stormwater management facilities that would provide ingress to and egress from a public right-of-way.
(20) A note on the plan indicating the location and responsibility for maintenance of stormwater management facilities that would be located off site. All off-site facilities shall meet the performance standards and design criteria specified in this chapter.
(21) A construction detail of any improvements made to sinkholes and the location of all notes to be posted, as specified in this chapter.
(22) Complete drainage systems for the site, including details for construction. All existing drainage features, which are to be incorporated in the design, shall be so identified. If the site is to be developed in stages, a general SWM site plan for the entire site shall be presented with the first stage, and appropriate development stages for the drainage system shall be indicated.
(23) Location and selected plan material used for vegetative filter paths to sinkholes, and the location of all notices to be posted.
(24) A statement, signed by the landowner, acknowledging the stormwater management system to be a permanent fixture that can be altered or removed only after approval of a revised plan by the Township.
(25) A note indicating that as-built drawings will be provided by the developer for all stormwater facilities prior to occupancy or the release of the surety bond.
(26) The following signature block for the registered professional preparing the stormwater management site plan:
| "I, _________________________, hereby certify that the stormwater management site plan meets all design standards and criteria of the Harris Township Stormwater Management Ordinance." |
(27) The following signature block for the Township Engineer reviewing the stormwater management site plan:
| "I, _________________________, have reviewed this stormwater management site plan in accordance with the design standards and criteria of the Harris Township Stormwater Management Ordinance. |
(28) The location of all erosion and sedimentation control facilities.
C. Supplemental information:
(1) A soil erosion and sediment pollution control plan, where applicable, including all reviews and approvals, as required by PA DEP.
(2) Soils investigation report, including boring logs, compaction requirements, and recommendations for construction of detention basins.
(3) Karst features identification and analysis reports and a hydrogeologic assessment of the effects of runoff on sinkholes.
(4) The effect of the project (in terms of runoff volumes and peak flows) on adjacent properties and on any existing municipal stormwater collection system that may receive runoff from the project site.
(5) A declaration of adequacy and highway occupancy permit from the PA DOT district office when utilization of a PA DOT storm drainage system is proposed.
(6) All permits required by the Pennsylvania Department of Environmental Protection and Army Corps of Engineers and other regulatory agencies.
D. Stormwater management facilities.
(1) All stormwater management facilities must be located on a plan and described in detail.
(2) When groundwater recharge methods such as seepage pits, beds or trenches are used, the locations of existing and proposed septic tank infiltration areas and wells must be shown.
(3) All calculations, assumptions, and criteria used in the design of the stormwater management facilities must be shown.
(a) A sketch 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.
(b) Design computations for the pipe barrel and riser.
(c) A plot or table of the stage-storage (acre-feet vs. elevation) and all supporting computations.
(d) Flood routing computations.
(e) A detailed plan of the trash rack and anti-vortex device.
(4) Record set (as-built) plans. At the completion of the project, and as a prerequisite for the release of the guarantee or issuance of an occupancy permit, the owner or his representative shall:
(a) Provide certification of completion from a registered professional verifying that all permanent facilities have been constructed according to the plans and specifications and approved revisions thereto; and
(b) Provide a set of approved stormwater management site plan drawings showing all approved revisions and elevations and inverts to all manholes, inlets, pipes, and stormwater control facilities.