Article XII Stormwater and Erosion Control

New development or redevelopment on a parcel that is part of a subdivision previously approved under this chapter that has a compliant post-construction stormwater management plan with sufficient capacity to accept and treat increases in stormwater discharges associated with the project.

Smaller projects resulting in less than one acre of disturbed area but more than 10,000 square feet of new or redeveloped impervious area are exempt from § 230-1203 Stormwater quantity and quality control and § 230-1204, Post construction management, but shall comply with requirements of § 230-1205, Drainage plan.

§ 230-1203 Stormwater quantity and quality control.

All other projects are exempt from § 230-1203, Stormwater quantity and quality control, § 230-1204, Post construction management, and § 230-1205, Drainage plan but shall meet the general provisions in § 230-1201 to the maximum extent practicable.

[Amended 11-6-2023]

All projects subject to this section shall be designed to meet the requirements below:

To the extent possible, the design shall dispose of stormwater runoff on the land at the proposed development through the appropriate use of the natural features of the site. Stormwater runoff systems will infiltrate, detain, or retain stormwater falling on the site such that the rate of flow from the site does not exceed that which would occur in the undeveloped state for a storm of intensity equal to the two-, ten-, twenty-five-, and fifty-year storm events.

If the post-development peak runoff rate exceeds the predevelopment peak runoff rate, on-site mitigation measures, such as detention basins or flow restrictors, shall be required.

All natural drainageways shall be preserved at their natural gradients and shall not be filled or converted to a closed system except as approved by the City's reviewing authority and appropriate state agencies.

(4)

The design of the storm drain system shall fully incorporate the existing upstream runoff which must pass over or through the site to be developed. The system shall be designed to pass upstream flows without surcharging the system. Any special roadway culvert crossing designed to meet other applicable state regulations (i.e., fish passage) shall be specifically identified on the plans.

(5)

Proposed alterations in stormwater drainage paths shall not enable the crossing of runoff over a City street in order to enter a drainage system.

(6)

The drainage study shall meet the "urban impaired stream standard" when located within a watershed designated by the Maine Department of Environmental Protection as an urban impaired stream.

A waiver may be granted by the City of Saco Department of Public Works to discharge an insignificant increase in stormwater runoff to the municipal storm drain system when all of the following conditions are met:

A drainage study is prepared by a professional engineer licensed in the State of Maine, which demonstrates that the increase has no adverse impact to the downstream conditions, including impacts on abutting or City properties. Improvements may be required of the developer to prevent adverse downstream impacts caused by the project.

The increase in the peak flow from the site or in the peak flow of the receiving waters cannot be avoided by reasonable changes in project design or density.

§ 230-1204 Post-construction stormwater management plan.

Written authorization to discharge the increased peak flow rates has been provided by the Director of Public Works or their designee.

At the time of application, the applicant shall notify the Department of Public Works if its stormwater management system includes any stormwater BMP(s) that will discharge to the City's municipal storm drain system and shall include in this notification a listing of which stormwater BMP(s) will so discharge.

All projects subject to this section shall be designed to meet the requirements below:

The applicant may meet the quantity and quality standards listed in § 230-1203, Stormwater quantity and quality control either on site or off site; but where off-site facilities are used, the applicant shall submit documentation to Saco's Department of Public Works that the applicant has sufficient property interest where the off-site facilities are located, by perpetual easement or other appropriate legal instrument, to ensure that the facilities will be available to provide post-construction stormwater management for the project and that the property will not be altered in a way that interferes with the off-site facilities.

Where the applicant proposes to retain ownership of the stormwater management facilities shown in its post-construction stormwater management plan, and the stormwater management facilities will not be dedicated to the City, the applicant shall enter into a maintenance agreement with the City. A form for the maintenance agreement is contained in Article 3 of the City's TDCSM. The applicant shall be responsible for recording the maintenance agreement form at the York County Registry of Deeds within 30 days of the date of execution of the agreement. Failure to comply with the terms of the maintenance agreement shall constitute a violation of this chapter.

[Amended 11-6-2023]

Whenever elements of the stormwater management facilities are not within the right-of-way of a public street and the facilities will not be offered to the City for acceptance as public facilities, the Planning Board may require that perpetual easements be provided to the City allowing access for maintenance, repair, replacement, and improvement of the stormwater management facilities in accordance with the approved drainage maintenance agreement. If an offer of dedication is proposed, the applicant shall be responsible for the maintenance of these stormwater management facilities until such time (if ever) as they are accepted by the City. Nothing in this chapter requires the City to accept any stormwater management facilities offered or dedicated by the applicant.

(4)

Any person, business, corporation, or other entity owning, leasing, or having control over stormwater management facilities required by a post-construction stormwater management plan shall demonstrate compliance with that plan as follows:

At least annually, inspect, clean, and maintain the stormwater management facilities, including, but not limited to, parking areas, catch basins, drainage swales, detention basins and ponds, pipes, and related structures, in accordance with all City and state inspection, cleaning and maintenance requirements of the approved post-construction stormwater management plan.

Deficiencies found during inspection of the stormwater management facilities shall be corrected within 60 days of identification and a record of the corrective action taken shall be provided to the City's Planning and Public Works Departments within the same sixty-day period. If it is not possible to correct the deficiency and notify the City within 60 days, the property owner shall coordinate with the City's Planning, Code Enforcement and Public Works Departments to establish an expeditious schedule to correct the deficiency and provide a record of the corrective actions taken. Enforcement action shall follow provisions of Saco City Ordinance, Chapter 1, Article 18 (Enforcement actions and civil penalties).

[Amended 11-6-2023]

(c)

On or by July 15 of each year, provide a completed and signed certification to the Department of Public Works certifying that the person has inspected, cleaned, and maintained the stormwater management facilities, describing any deficiencies found during inspection of the stormwater management facilities, and certifying that the person has repaired any deficiencies in the stormwater management facilities noted during the annual inspection. A form for the annual stormwater certification is available on the City's website.

(d)

The required inspection(s) must be conducted by a qualified inspector. The inspector shall perform an initial inspection to determine the status of the stormwater management facilities. If the initial inspection identifies any deficiencies with the facilities, the same inspector shall reinspect the facilities after they have been maintained or repaired to determine if they are performing as intended.

(e)

"Qualified inspector" means a person who conducts post-construction stormwater management facilities, best management practice ("BMP") inspections, and meets the following qualifications:

[1]

The inspector shall not have any ownership or financial interest in the property being inspected nor be an employee or partner of any entity having an ownership or financial interest in the property; and

[2]

The inspector shall have a working knowledge of Chapter 500, Stormwater Management Rules, and Maine's Stormwater BMP Manual; and

[3]

The qualified inspector must be on the DEP's list of approved post-construction stormwater BMP inspectors, or alternately, shall satisfy at least one of the criteria outlined below:

[a]

Nonproprietary stormwater management facilities.

Has a college degree in environmental science or civil engineering and is a professional engineer with at least three years of experience designing, evaluating or inspecting stormwater management facilities; or

[ii]

Has a college degree in an environmental science or civil engineering, or comparable expertise, and has demonstrated a practical knowledge of stormwater hydrology and stormwater management techniques, including the maintenance requirements for stormwater management facilities, and has the ability to determine if stormwater facilities are performing as intended. This qualification must be accompanied by two professional references to be valid; or

[iii]

Has successfully completed the requirements of a DEP training course on inspecting post-construction stormwater management facilities. Note: successful completion may require receiving a passing grade in an examination at the conclusion of the course.

[b]

Proprietary stormwater management facilities.

Proprietary stormwater management facilities must be inspected by a person approved by the manufacturer.

In order to determine compliance with this section and with the post-construction stormwater management plan, the Director of the Department of Public Works or their designee may enter upon a property at reasonable hours and after making a good-faith effort to contact the owner, occupant, or agent to inspect the stormwater management facilities. Entry into a building shall only be after notice is provided to the owner, occupant, or agent.

Submission requirements.

The post-construction stormwater management plan shall conform to the applicable submission requirements of Section 8 of DEP Chapter 500 Rules.

The applicant shall provide the Department of Public Works with an electronic copy of the post-construction stormwater management plan in a format that is compatible with the City's requirements. Following completion of construction, the applicant shall provide the City with an updated version of the plan showing the stormwater management facilities as actually constructed.

The Planning Board may modify or waive any of the submission requirements for a post-construction stormwater management plan if the Planning Board finds that, due to the unique physical characteristics of the site or the scale of the proposed activity, the information is not required to allow the Planning Board to determine if the applicable stormwater management standards are met.

As-built certification. Prior to the issuance of a certificate of occupancy for a project requiring a post-construction stormwater management plan under this chapter, the applicant shall submit evidence in the form of a letter with as-built survey plan prepared and stamped by a professional engineer who either prepared the post-construction stormwater management plan and its associated facilities or supervised the plan and facilities construction and implementation. The letter or plan shall certify that the stormwater management facilities have been installed in accordance with the approved post-construction stormwater management plan and that they will function as intended by said plan. The as-built survey plan shall be performed for all post-construction stormwater facilities to document general conformance with the approved plans.

§ 230-1205 Drainage plan.

A drainage plan is required for activities that result in the expansion or alteration of an existing building or structure that results in the creation or redevelopment of 10,000 square feet of impervious surface. New principal buildings that are located in a subdivision with an approved post-construction stormwater management plan are not required to comply with the requirement for a drainage plan if the approved stormwater management plan contains provisions that adequately address surface drainage related to the construction of the building, as determined by the CEO.

The drainage plan shall meet the "urban impaired stream standard" of DEP Chapter 500 Rules when located within a watershed designated by the Maine Department of Environmental Protection as an urban impaired stream.

The drainage plan shall demonstrate that the proposed improvements are designed to minimize the volume of stormwater leaving the site. This shall include consideration of the design and location of improvements to minimize the total area of impervious surface on the site and stormwater management techniques to minimize both the volume and rate of runoff from the lot. The drainage plan shall provide for the treatment of 0.5 inch of runoff from 90% of the new or redeveloped impervious area and 0.2 inch of runoff from 75% of the new or redeveloped nonimpervious surface area.

The drainage plan must also demonstrate that:

Stormwater draining onto or across the lot in its pre-development state will not be impeded or redirected so as to create ponding on or flooding of adjacent lots;

Any increase in volume or rate of stormwater draining from the lot onto an adjacent lot following the improvement can be handled on the adjacent lot without creating ponding, flooding, or other drainage problems and that the owner of the lot being improved has the legal right to increase the flow of stormwater onto the adjacent lot;

Any increase in volume or rate of stormwater draining from the lot onto City property following the improvement can be handled without creating ponding, flooding, or other drainage problems and that the owner of the lot being improved has the legal right to increase the flow of stormwater onto the City's property; and

(4)

Any increase in volume or rate of stormwater draining from the lot into the City's municipal storm drain system can be accommodated in the system without creating downstream problems or exceeding the capacity of the storm drain system.

Submission requirements.

A drainage plan must include a written statement demonstrating how the project has been designed to minimize the volume and rate of stormwater leaving the site, including provisions for minimizing the area of impervious surface or the use of LID practices, and a plan and supporting documentation with at least the following information:

The location and characteristics of streams or drainage courses existing on the parcel and/or abutting parcels.

The existing and proposed grading of the site using one-foot contours.

(c)

The location and area of existing and proposed buildings and impervious surfaces on the site.

(d)

The existing pattern of stormwater drainage on the site, including points of discharge to the City's municipal storm drain system or adjacent properties.

(e)

The proposed pattern of stormwater drainage after development, including the location and design of any stormwater facilities.

§ 230-1206 Standards for drainage easements and rights-of-way.

The City's reviewing authority may modify or waive any of the submission requirements for a drainage plan if the reviewing authority determines that the information is not required to determine if the drainage standard is met.

If components of the stormwater runoff system lie outside of the public right-of-way, the applicant shall convey a stormwater easement that conforms to the following standards.

The minimum width of the easement shall be 30 feet, provided that where a watercourse or retention area is wider than 30 feet, the City's reviewing authority may require a drainage easement of adequate width to conform substantially to the lines of such watercourse or retention area, including additional width to provide access. The City's reviewing authority may reduce the width of the easement upon a positive recommendation from the Director of Public Works or their designee if the narrower easement will allow the stormwater facilities to be maintained or if the unique characteristics of the site make the creation of a wider easement impractical.

Where a drainage easement would include an open channel, stream or drainageway, the easement shall be designed and landscaped to further the objectives of the stormwater management plan. The natural landscape shall be retained to the extent practical, as determined by the Planning Board.

Where a drainage easement would include a closed conduit, the easement shall be centered along the conduit.

A public stormwater management system that will be offered to the City for acceptance as a public facility shall be located on a separate parcel of land deeded to the City.

§ 230-1207 General erosion and sediment control provisions.

The Erosion and Sedimentation Control Law (Title 38 M.R.S.A § 420-C) applies to all activities in Maine's organized territories that will cause the filling, displacement or exposure of all earthen materials. The Erosion and Sedimentation Control Law requires that appropriate measures prevent unreasonable soil erosion and sedimentation beyond the site or into a protected natural resource (such as a river, stream, brook, lake, pond, or wetland). Erosion control measures must be installed before the activity begins and must be maintained until the site is permanently stabilized.

An erosion control plan is required for all new development or redevelopment projects that result in one or more acres of disturbed area or more than 10,000 square feet of new or redeveloped impervious area. This provision also applies to projects disturbing less than one acre if the construction activity is part of a larger common plan or development or sale that would disturb one or more acres.

Erosion control plan. The plan shall include comprehensive erosion and sediment control provisions as summarized below:

The plan shall show the use of erosion and sediment control best management practices (BMPs) at construction sites consistent with the minimum standards outlined in the Maine DEP Stormwater Rule Chapter 500 Appendix A - Erosion and Sediment Control, Appendix B - Inspections and Maintenance, Appendix C - Housekeeping. Erosion and Sedimentation Control BMPs shall be designed, installed and maintained in accordance with the standards contained in the latest revisions of the following Maine DEP documents:

Maine Erosion and Sediment Control Best Management Practices (BMPs) Manual for Designers and Engineers.

Maine Erosion and Sediment Control Practices Field Guide for Contractors.

An erosion control plan prepared by a registered Maine professional engineer shall be submitted. The plan shall include the following:

Narrative. Provide a narrative describing the site's erosion potential and the measures to be employed to control erosion and sedimentation during construction and after completion of the development. Describe the temporary and permanent erosion control methods to be employed on the site.

Give the expected date by which final stabilization of the site will be complete.

(c)

Show the locations of all roads, lot boundaries, buildings, parking lots, material stockpiles, existing and proposed culverts, drainage channels, catch basins, subsurface drainage pipes and storm drain outfalls.

(d)

Show the location of all temporary and permanent erosion controls to be installed on the site.

(e)

Show the limits of the areas disturbed by construction.

(f)

Provide design drawings and specifications for the temporary and permanent erosion and sedimentation control measures to be used on the site. The drawings and details must be sufficiently detailed to allow a contractor unfamiliar with the controls to install and maintain them.

(g)

Provide calculations for sizing, spacing or stabilizing each erosion and sedimentation control measure in accordance with the latest revision of the Maine DEP "Erosion and Sediment Control Handbook for Construction: Best Management Practices." These calculations must include analyses for determining the peak runoff flow to a control, its storage volume and its outlet design. At a minimum, the erosion and sedimentation control plan must include the following:

[1]

Location plan(s) showing, at a minimum, the location of structures, disturbed land, pre-construction site topography, post-construction site topography, on-site or adjacent water resources, and all erosion and sediment control measures.

[2]

Detail plan(s) showing the following:

[a]

Erosion and sedimentation control notes including, but not limited to, permanent stabilization measures, seeding and mulching rates, and a construction schedule with the proposed construction dates and time frame for major earth moving and construction events.

[b]

Construction and installation details for erosion and sedimentation control measures including, but are not limited to, sedimentation barriers, ditch lining, rip rap, and culvert inlet and outlet designs.

[c]

Inspection and maintenance requirements for the temporary and permanent erosion and sedimentation controls for the project site shall be specified for each BMP in accordance with Maine DEP Stormwater Rule Chapter 500 Appendices A and B. At a minimum, the inspection and maintenance plan must include the following:

List of the erosion control measure and stormwater management measures to be inspected and maintained (e.g., "parking lot catch basins").

[ii]

Inspection and maintenance tasks specific to each erosion control measure or stormwater management measure (e.g., "remove accumulated sediments in basin sumps"). Submit the specific qualifications of the person performing each task (e.g., "a professional engineer registered in the State of Maine will inspect the retention pond embankment").

[iii]

Specify required frequency of each inspection and maintenance task (e.g., "accumulated sediments will be removed from all catch basins annually in early spring").

[d]

Responsible parties. Submit the name, job title, employer, employer address, phone number, and current email contact information for the person responsible for ensuring that inspection and maintenance tasks are completed. Submit the names, job titles, employer addresses, phone number, and any current email contact information of the engineers or other design professionals who designed the erosion control measures and stormwater management measures for the site. Include suppliers of proprietary erosion control measures or proprietary stormwater management measures used on the site.

[e]

For stormwater management pond(s) or basin(s) include a maintenance plan that specifies, at a minimum, the inspection and maintenance requirements for the pond's embankments, outlet structure, and emergency spillway. Include as part of this plan provisions for the removal and disposal of accumulated sediments in the pond and the control of woody vegetation on the pond's embankments.

[f]

For infiltration structure(s) or basin(s) include a maintenance plan that specifies, at a minimum, the inspection and maintenance requirements for the structure's pretreatment measures, embankments, surface lining, and overflow spillway. Include as part of this plan provisions for the removal and disposal of accumulated sediments in the structure and for the rehabilitation of clogged surface linings.

[g]

For vegetated underdrained filter basins include a maintenance plan that specifies, at a minimum, the inspection and maintenance requirements for the filter embankments, surface lining, underdrain piping, and overflow spillway. Include as part of this plan provisions for the removal and disposal of accumulated sediments in the structure, the rehabilitation of clogged surface linings, and the flushing of underdrain piping.

[h]

For stormwater buffer(s) include a maintenance plan that specifies, at a minimum, the inspection and maintenance requirements to ensure the integrity and function of the project's stormwater buffers. As part of this plan, include provisions for the inspection, maintenance, and, if necessary, reconstruction of any level spreaders or ditch turnouts used to spread runoff into the buffers. Include as part of this plan provisions for the frequent removal and disposal of accumulated sediments and debris in the level spreader and turnout bays, provisions for the inspection and repair of any eroded areas within the buffer, and provisions for the re-establishment of buffer vegetation destroyed by post-construction activities.

For manufactured stormwater treatment system(s) include a maintenance plan that specifies, at a minimum, the inspection and maintenance requirements for the system's inlet, treatment chamber(s), and outlet. The plan shall conform to the inspection and maintenance guidelines recommended by the manufacturer based on the estimated runoff and pollutant load expected to the system from the project. As part of this plan, include provisions for the frequent removal of accumulated sediments, debris, and contaminated waters from the system and, if applicable, provisions for the removal, disposal, and replacement of any clogged or spent filter media.

[j]

For ditches, culverts, and storm drains include a maintenance plan that specifies, at a minimum, the inspection and maintenance requirements for all stormwater conveyances to be built or installed on the site, including, but not limited to, ditches, swales, culverts, catch basins, and storm drain piping. As part of this plan, include provisions for the repair of eroded areas at the inlet, within, and at the outlet of each conveyance and include provisions for the frequent removal and disposal of accumulated sediments and debris at the inlet, within, and at the outlet of each conveyance.