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 Section 8
Links from this page are included to assist the reader, and are not part of the rule. Text amended effective December 27, 2006.
8. Submissions and pre-application meetings. The applicant shall use the application form provided by the department and include evidence that affirmatively demonstrates that the standards will be met, including information such as described in this section. A pre-application meeting between the applicant and the department is an opportunity for the applicant to determine the statutory and regulatory requirements that apply to a specific project, and to identify the department staff person who will serve as project manager for the application.
A. Pre-application meetings for Stormwater Management Law projects. A pre-application meeting is required for a project that does not qualify for a stormwater PBR, unless the requirement for such a meeting is waived by the department based on an initial review of project plans and scope. A written request for a stormwater pre-application meeting must include two copies of a preliminary site plan, brief project description, and a regional map with the site marked. Note: A Site Law application for a new development project requires a pre-application meeting pursuant to Chapter 2, Section 10(B).
B. Design requirements. A design for a stormwater management system that includes any form of conveyance structure must be prepared under the supervision of, and dated, signed and sealed by, a professional engineer registered in the State of Maine , who by education, training, or experience is knowledgeable in stormwater management.
C. Basic standards submissions. These submissions are required for all sites except those that qualify for stormwater PBR described in Section 7 above. An erosion and sedimentation control plan or an inspection and maintenance plan for a project that does not qualify for a stormwater PBR must be prepared by a professional engineer registered in the State of Maine , or a certified erosion and sedimentation control professional.
(1) Erosion and sedimentation control plan. Submit a plan showing designs for temporary and permanent stabilization measures for all disturbed areas within the project site and for all proposed stormwater management structures. Erosion and sedimentation control plan requirements are described in Appendix A of this chapter . At a minimum, the erosion and sedimentation control plan must include the following.
(a) Location plan. Submit a plan sheet or set of plans 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.
(b) Site details. Submit a plan sheet showing the following.
(1) Erosion and sedimentation control notes. Erosion and sedimentation control notes, must include, but not limited to, permanent stabilization measures, seeding and mulching rates, and a construction schedule with the proposed construction dates and timeframe for major earth moving and construction events.
(2) Construction and installation details. Construction and installation details for erosion and sedimentation control measure must include, but are not limited to, sedimentation barriers, ditch lining, rip rap, and culvert inlet and outlet designs.
NOTE: For guidance, see the Maine Erosion and Sediment Control BMP Manual.
(2) Inspection and maintenance plan. Submit a plan for the inspection and maintenance of the temporary and permanent erosion and sedimentation controls for the project site as described in Appendices A and B of this chapter. At a minimum, the inspection and maintenance plan must include the following:
(a) List of measures. Submit a list of the erosion control measure and stormwater management measures to be inspected and maintained (e.g., “parking lot catch basins”).
(b) Inspection and maintenance tasks. Submit a list of inspection and maintenance tasks specific to each erosion control measure or stormwater management measure (e.g., “remove accumulated sediment s 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”).
(c) Task frequency. Indicate the 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) Maintenance plan for detention basins or retention ponds. For each stormwater management pond or basin submit, at a minimum, an inspection and maintenance plan 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) Maintenance plan for infiltration structures. For each infiltration structure, submit, at a minimum, an inspection and maintenance plan 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) Maintenance plan for underdrained filters. For each underdrained filter, submit, at a minimum, an inspection and maintenance plan for the filter embankments, vegetation, 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) Maintenance plan for stormwater buffers. At a minimum, submit a plan for inspecting and maintaining 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 reestablishment of buffer vegetation destroyed by post-construction activities.
(i) Maintenance plan for manufactured stormwater treatment systems. For each manufactured system installed on the site, submit an inspection and maintenance plan 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) Maintenance plan for ditches, culverts, and storm drains. Provide an inspection and maintenance plan 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.
(3) Housekeeping. Submit a plan to address spill prevention, groundwater protection, fugitive sediment and dust, debris and other materials, trench or foundation de-watering, or non-stormwater charges, as applicable to the specific site. Housekeeping requirements are described in Appendix C of this chapter.
D. General standards submissions. A project required to meet general standards must provide the following information and design specifications.
(1) Narrative. A narrative describing site layout, and on-site and off-site watershed hydrology, including all new and existing buildings and facilities, which may be affected by the site runoff. Provide the total amount of impervious area, disturbed area, and developed area created by the project.
(2) Drainage Plans. All topographic features, such as buildings and other facilities, drainageways, cover type, roads, drainage easements and subcatchment boundaries for pre-construction and post-construction conditions must be shown on a plan. Show all hydrologic flow lines and hydrologic soil groups boundaries on a plan and identify each subcatchment, reach, and pond. For post-construction conditions, show all new stormwater management structures and changes to the hydrologic drainage patterns.
(3) Calculations. The stormwater runoff calculations for measures designed to meet general standards must be in accordance with acceptable engineering practice, including the following.
(a) Water volume. Calculations used to determine the water volume needed to be filtered, infiltrated, or detained based on the proposed site development must be provided.
(b) Buffer sizing. Buffers used for runoff control must be sized according to requirements described in Appendix F.
(4) Details, designs, and specifications. Submit designs, construction details, and technical specifications for each stormwater management measure that will be constructed, installed, or managed on the site.
(a) Ponds. Submit a plan sheet having the following details and specifications for each stormwater management pond: a topographic plan view of the pond, a cross section of the pond embankment, a cross section and profile of the overflow spillway, test pit information, and specifications for constructing and stabilizing the pond's embankment. The peak storage depth required to meet the general standards must be shown on a cross section for each pond embankment. Submit a cross section of the gravel underdrain used to meet the standards. This cross section must specify the width and elevation of the pond bench, the thickness and gradation for the gravel drainage fill, and the diameter and material for the perforated underdrain pipe.
(b) Underdrained soil filters. Submit a plan sheet having the following details and specifications for each underdrained vegetated filter bed: a plan view of the filter area, a cross section of the embankment for the filter area at the overflow spillway, a cross section and profile of the overflow spillway, a cross section of the underdrain filter, the thickness and composition of the soil filter media, the thickness and gradation of the gravel drainage fill, thelayout for the perforated underdrain pipe and the stabilization of the filter bed.
(c) Infiltration. Submit a plan sheet showing the following details and specifications for each infiltration measure: a plan view of the infiltration structure, a cross section of the infiltration measure's runoff storage area, a cross section and profile of the structure's overflow spillway, and details and specifications for permanently stabilizing the infiltration area. The following information must be included, if required, as determined by the department and described below.
(i) Locations of any monitoring wells necessary for assessing the infiltration measure's performance or stormwater infiltration impacts on groundwater, surface irrigation sites, or subsurface wastewater disposal systems must be shown on the site plan.
(ii) Location of an existing or proposed surface irrigation site, waste disposal site, subsurface wastewater disposal system, or other facility that could be impacted by operation of the infiltration system must be shown on the site plan.
(iii) Location of any soil borings, test pits, or other explorations used to determine depth to groundwater, separation from bedrock, or other design information must be shown on the site plan.
(iv) Location of any water supply wells on-site or within 300 feet of the infiltration areas, zones of contribution for public water supply wells must be shown on the plan sheet.
(v) Location of storage for any petroleum products, pesticides, fertilizers, road salt, hazardous materials, or other materials with the potential to contaminate groundwater must be shown on the site plan.
(vi) Plans for management of any potential contaminants and soil sample analyses, such as a spill prevention, control, and countermeasure plan, must be submitted with appropriate supporting information.
(vii)Depth to the seasonal high groundwater table, depth to bedrock, and the thickness and composition of any liner used for restricting infiltration rates must be shown on the cross section view of the infiltration structure.
(d) Buffers. Submit a topographic site plan showing the location of each buffer on the site, showing the layout of any berm level spreaders used to spread flows into each buffer, identifying the soil type and cover type within each buffer, and showing the land use and impervious and developed area draining to each buffer area. Provide a typical cross section for the berm level spreaders showing the geometry of the berm, the geometry of the upstream storage area, and the specifications for the berm material. Submit information demonstrating that the inslope fill material will have slopes no steeper than 3:1. Submit documentation, in the form of draft convenants and restrictions, demonstrating that buffer area(s) will be maintained as buffer.
(5) Phosphorus export calculations. An application for a project using the phosphorus standards must include phosphorus export calculations.
NOTE: For guidance in determining phosphorus export see "Phosphorus Control in Lake Watersheds ", Maine Department of Environmental Protection.
(6) Maintenance contract. Submit an executable contract with a third-party for the removal of accumulated sediments, oils, and debris within any proprietary devices and the replacement of any absorptive filters if these measures are part of a project's proposed stormwater management system. An applicant that has the personnel and equipment necessary to perform maintenance on any proprietary devices may submit a demonstration of capability in lieu of an executable contract with a third party. The frequency of sediment clean-out and filter replacements must be consistent with the unit's storage capacity and the estimated pollutant load from the contributing drainage area. This clean-out frequency is usually established by the manufacturer of the proprietary system when sizing the device for the project. The contract must state that a qualified professional will perform maintenance on stormwater management systems to maintain pollutant removal levels.
E. Flooding standard submissions
(1) Control of peak flows. If a project must meet the flooding standard, the project must be designed to control the peak flows from the 2-, 10- and 25-year, 24-hour storms. This is in addition to the submittal requirements listed in Section 8(C) and (D) above.
(2) Details, designs, and specifications. Provide runoff curve number computations and time of concentration calculations for each subcatchment . Areas may qualify as subcatchment s based on the characteristics of the site or the model used. The department will review all methods of determining subcatchment s on a case-by-case basis. Provide a reach description and reach routing analysis for each drainage structure and provide pond descriptions and storage routing calculation for any stormwater management structure, detention pond and culvert backwater areas.
Acceptable stormwater methodologies and models include, but are not limited to, “TR-20 - Computer Program for Project Formulation - Hydrology,” Second Edition, U.S. Department of Agriculture, Soil Conservation Service (March 1986); and “TR-55 - Urban Hydrology for Small Watersheds,” Second Edition, U.S. Department of Agriculture, Soil Conservation Service (June 1986); “WIN TR-55 2003.00.24 Microcomputer Program,” (January 12, 2003); and “HEC-HMS Flood Hydrology Package,” U.S. Army Corps of Engineers (January 2001). Any methodology or model other than those listed must have prior approval from the department.
F. Transfer. An applicant may apply for a transfer of an individual Stormwater Management Law project pursuant to Section 10(A)(4). If the project was approved under stormwater PBR, the transferee of the property shall file a new stormwater PBR notification.
G. Modification. An applicant may apply for a modification of an individual Stormwater Management Law permit. If a stormwater PBR needs to be modified, the applicant shall file a new stormwater PBR notification.
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