1. Any stormwater management facility (i.e., detention basin) designed to store runoff and requiring a berm or earthen embankment required or regulated by this Chapter shall be designed to provide an emergency spillway to handle flow up to and including the 100-year post-development conditions. The height of the embankment must be set so as to provide a minimum 1 foot of freeboard above the maximum pool elevation computed when the facility functions for the 100-year post-development inflow. Should any stormwater management facility require a dam safety permit under DEP Chapter 105, the facility shall be designed in accordance with Chapter 105 and meet the regulations of Chapter 105 concerning dam safety which may be required to pass storms larger than the 100-year event.

2. Any facilities that constitute water obstructions (e.g., culverts, bridges, outfalls, or stream enclosures) and any work involving wetlands as directed in DEP Chapter 105 regulations (as amended or replaced from time to time by DEP) shall be designed in accordance with Chapter 105 and will require a permit from DEP. Any other drainage conveyance facility that does not fall under Chapter 105 regulations shall be designed to convey, without damage to the drainage structure or roadway, runoff from a minimum 25-year design storm. Municipalities may require design based on a larger storm event. Open channels shall be designed with a minimum of 1 foot of freeboard. Any facility that constitutes a dam as defined in DEP Chapter 105 Any facility located within a PennDOT right-of-way must meet PennDOT minimum design standards and permit submission requirements. If the primary drainage facilities do not have capacity for future flows, then a safe drainage path must be provided to convey up to the 100-year design storm (without impacting structures).

3. Storm sewers must be able to convey post-development runoff from a minimum 25 year design storm without surcharging inlets.

4. Adequate erosion protection shall be provided along all open channels and at all points of discharge.

5. The design of all stormwater management facilities shall incorporate sound engineering principles and practices. The Township shall reserve the right to disapprove any design that would result in the occurrence or continuation of an adverse hydrologic or hydraulic condition within the watershed.

6. Stormwater drainage systems shall be provided in order to permit unimpeded flow along natural watercourses, except as modified by stormwater management facilities or open channels consistent with this Chapter.

7. The existing points of concentrated drainage that discharge onto adjacent property shall not be altered without permission of the adjacent property owner(s) and shall be subject to any applicable discharge criteria specified in this Chapter.

8. Areas of existing diffused drainage discharge shall be subject to any applicable discharge criteria in the general direction of existing discharge, whether proposed to be concentrated or maintained as diffused drainage areas, except as otherwise provided by this Chapter. If diffused flow is proposed to be concentrated and discharged onto adjacent property, the applicant must document to the Township in accordance with §19-405 that adequate downstream conveyance exists to safely transport the concentrated discharge, or the applicant must obtain drainage easements from affected downstream property owners and provide the facilities to safely convey the flow.

9. Downstream Hydraulic Capacity Analysis . Any downstream capacity hydraulic analysis conducted in accordance with this Chapter shall use the following criteria for determining adequacy for accepting increased peak flow rates:

A. Natural or man-made channels or swales must be able to convey the increased runoff associated with a 2-year return period event within their banks at velocities consistent with protection of the channels from erosion. Acceptable velocities shall be based upon criteria included in the DEP Erosion and Sediment Pollution Control Program Manual.

B. Natural or man-made channels or swales must be able to convey the increased 25-year return period runoff without creating any hazard to persons or property.

C. Culverts, bridges, storm sewers, or any other facilities which must pass or convey flows from the tributary area must be designed in accordance with DEP, Chapter 105 regulations (if applicable) and, at a minimum, pass the increased 25-year return period runoff.

10. Where a development site is traversed by watercourses, riparian buffers shall be provided conforming to the line of such watercourses. The width of the buffers shall be determined as set forth in §19-404.1. Excavating, placing of fill, building structures, or making any alterations that may adversely affect the flow of stormwater within any portion of the riparian buffer shall be prohibited unless the proposed work is associated with a regulated wetlands mitigation program. The buffer must be defined through a deed covenant.

11. When it can be shown that, due to topographic conditions, natural drainageways on the site cannot adequately provide for drainage, open channels may be constructed conforming substantially to the line and grade of such natural drainageways. Work within natural drainageways shall be subject to approval by DEP through the joint permit application process, or, where deemed appropriate by DEP, through the general permit process.

12. Any stormwater management facilities regulated by this Chapter that would be located in or adjacent to waters of the Commonwealth or wetlands shall be subject to approval by DEP through the joint permit application process, or, where deemed appropriate by DEP, the general permit process. When there is a question as to whether wetlands may be involved, it is the responsibility of the applicant or his agent to show that the land in question cannot be classified as wetlands; otherwise, approval to work in the area must be obtained from DEP.

13. Any stormwater management facilities regulated by this Chapter that would be located on State highway rights-of-way shall be subject to approval by PennDOT.

14. Minimization of impervious surfaces and infiltration of runoff through seepage beds, infiltration trenches, etc. are required, where soil conditions permit, to reduce the size or eliminate the need for detention facilities.

15. In order to promote overland flow and infiltration/percolation of stormwater, roof drains must discharge into an accepted BMP providing infiltration and filtering of the stormwater.

(Ord. 4-2004, 6/2/2004, §406)

1. Whenever the vegetation and topography are to be disturbed, such activity must be in conformance with Chapter 102, Title 25, Rules and Regulations, Part I, Commonwealth of Pennsylvania, DEP, Subpart C, Protection of Natural Resources, Article II, Water Resources, Chapter 102, "Erosion Control," and in accordance with the Delaware County or Chester County Conservation Districts, as appropriate, and the standards and specifications of the appropriate municipal government.

2. Additional erosion and sedimentation control design standards and criteria that must be applied where infiltration BMPs are proposed include the following:

A. Areas proposed for infiltration BMPs shall be protected from sedimentation and compaction during the construction phase to maintain their maximum infiltration capacity.

B. In order to ensure compliance with Chapter 102, the timing of the installation and operation of the infiltration BMP shall be at the discretion of the Township Engineer.

(Ord. 4-2004, 6/2/2004, §407)

1. The Township Engineer or his municipal assignee shall inspect all phases of the installation of the permanent stormwater management and water quality facilities, including non-structural BMPs.

2. During any stage of the work, if the Township Engineer determines that the permanent stormwater management facilities, water quality facilities, or nonstructural BMPs are not being installed in accordance with the watershed's respective approved Stormwater Management Plan, the Township shall revoke any existing Township permits or issue a stop work order until a revised drainage plan is submitted and approved, as specified in this Chapter.

(Ord. 4-2004, 6/2/2004, §501)

The fee required by this Chapter is the Township review fee as set by the Board of Supervisors from time to time. The Township review fee shall be established by the Township to defray review costs incurred by the Township and the Township Engineer. All fees shall be paid by the applicant.

(Ord. 4-2004, 6/2/2004, §601)

The Township shall establish a review fee schedule by separate resolution of the Township Board of Supervisors based on the size of the regulated activity and based on the Township's costs for reviewing drainage plans. The Township may periodically update the review fee schedule to ensure that review costs are adequately reimbursed.

(Ord. 4-2004, 6/2/2004, §602)

The fees required by this Chapter shall, at a minimum, cover:

A. Administrative costs.

B. The review of the drainage plan by the Township and the Township Engineer.

C. The site inspections.

D. The inspection of stormwater management facilities and drainage improvements during construction.

E. The final inspection upon completion of the storm water management facilities and drainage improvements presented in the drainage plan.

(Ord. 4-2004, 6/2/2004, §603)

Applicant will be invoiced for any additional costs incurred by the Township in the course of reviewing the development plan. These costs may include, but are not limited to, special studies by qualified engineers or surveyors, field reconnaissance, and testing.

(Ord. 4-2004, 6/2/2004, §604)

The applicant shall provide a financial guarantee to the Township for the timely installation and proper construction of all stormwater management controls as required by the approved stormwater plan and this Chapter equal to the full construction cost of the required controls.

(Ord. 4-2004, 6/2/2004, §701)

1. The drainage plan for the development site shall contain an operation and maintenance plan prepared by the applicant and approved by the Township Engineer. The operation and maintenance plan shall outline required routine maintenance actions and schedules necessary to ensure proper operation of the facility(ies).

2. The drainage plan for the development site shall establish responsibilities for the continued operation and maintenance of all proposed stormwater control facilities, consistent with the following principles:

A. If a development consists of structures or lots that are to be separately owned and in which streets, sewers, and other public improvements are to be dedicated to the Township, stormwater control facilities may also be dedicated to and maintained by the Township.

B. If a development site is to be maintained in single ownership or if sewers and other public improvements are to be privately owned and maintained, then the ownership and maintenance of stormwater control facilities shall be the responsibility of the owner or private management entity.

3. The Township, upon recommendation of the Township Engineer, shall make the final determination on the continuing maintenance responsibilities prior to final approval of the drainage plan. The Township reserves the right to accept the ownership and operating responsibility for any or all of the stormwater management controls.

(Ord. 4-2004, 6/2/2004, §702)

1. Prior to final approval of the site's stormwater management plan, the property owner shall sign and record a maintenance agreement covering all stormwater control facilities that are to be privately owned. Said agreement, designated as Appendix E, is attached and made a part hereto.

2. Other items may be included in the agreement where determined necessary to guarantee the satisfactory maintenance of all facilities. The maintenance agreement shall be subject to the review and approval of the Township Solicitor and Township.

(Ord. 4-2004, 6/2/2004, §703)

1. Stormwater detention and retention basins or facilities shall be inspected by, or under the direction of, a registered professional engineer on behalf of the applicant or responsible entity (including the Township Engineer for dedicated facilities) on the following basis:

A. At the request of the Township.

B. During or immediately after the cessation of a 100-year or greater storm event.

2. The entity conducting the inspection shall be required to submit a report to the Township within 1 month following completion of the inspection. The report will present documentation regarding the condition of the facility and recommend necessary repairs, if needed. Any needed repairs shall be implemented by the owner within 1 month of the report issuance date.

(Ord. 4-2004, 6/2/2004, §704)

Upon presentation of proper credentials, duly authorized representatives of the Township may enter at reasonable times upon any property within the Township to inspect the condition of the stormwater structures and facilities in regard to any aspect regulated by this Chapter.

(Ord. 4-2004, 6/2/2004, §801)

In the event that a person fails to comply with the requirements of this Chapter or fails to conform to the requirements of any permit issued hereunder, the Township shall provide written notification of the violation. Such notification shall set forth the nature of the violation(s) and establish a time limit for correction of these violations(s). Failure to comply within the time specified shall subject such person to the penalty provision of this Chapter. All such penalties shall be deemed cumulative and shall not prevent the Township from pursuing any and all other remedies. It shall be the responsibility of the owner of the real property on which any regulated activity is proposed to occur, is occurring, or has occurred, to comply with the terms and conditions of this Chapter.

(Ord. 4-2004, 6/2/2004, §802)

The Township is hereby authorized and directed to enforce all of the provisions of this Chapter. All inspections regarding compliance with the drainage plan shall be the responsibility of the Township Engineer or other qualified persons designated by the Township.

A. A set of design plans approved by the Township shall be on file at the site throughout the duration of the construction activity. Periodic inspections may be made by the Township or designee during construction.

B. It shall be unlawful for any person, firm, or corporation to undertake any regulated activity under §19-104 on any property except as provided for in the approved drainage plan and pursuant to the requirements of this Chapter. It shall be unlawful to alter or remove any control structure required by the drainage plan pursuant to this Chapter or to allow the property to remain in a condition that does not conform to the approved drainage plan.

C. At the completion of the project, and as a prerequisite for the release of the performance guarantee, the owner or his representatives shall:

(1) Provide a certification of completion from an engineer, architect, surveyor, or other qualified person verifying that all permanent facilities have been constructed according to the plans and specifications and approved revisions thereto.

(2) Provide a printed set of as-built drawings to the Township.

(3) Provide a set of as-built drawings to the County Conservation District. Such plans shall be prepared in accordance with established criteria and procedures and in a format (electronic or otherwise) as required by the Conservation District for long-term storage.

D. After receipt of the certification by the Township, a final inspection shall be conducted by the Board of Supervisors or its designee to certify compliance with this Chapter.

E. Suspension and Revocation of Permits.

(1) Any Township permit issued under this Chapter may be suspended or revoked or a stop work order may be issued by the Township for:

a) Noncompliance with or failure to implement any provision of the permit.

b) A violation of any provision of this Chapter or any other applicable law, ordinance, rule, or regulation relating to the project.

c) The creation of any condition or the commission of any act during construction or development which constitutes or creates a hazard or nuisance, or which endangers the life or property of others.

(2) A suspended permit shall be reinstated by the Township when:

a) The Township Engineer or his designee has inspected and approved the corrections to the stormwater management and erosion and sediment pollution control measure(s).

b) The Township is satisfied that the violation of this Chapter, law, or rule and regulation has been corrected.

c) A permit that has been revoked by the Township cannot be reinstated. The applicant may apply for a new permit under the proce- dures outlined in this Chapter.

F. Occupancy Permit. An occupancy permit shall not be issued by the Township unless all requirements of this Chapter have been met. The occupancy permit shall be required for each lot owner and/or applicant for all subdivisions and land development in the Township.

(Ord. 4-2004, 6/2/2004, §803)