Section 096-501-3 - Mitigation through compensation fees or projectsThis Section applies to projects for which the applicant pays a compensation fee and/or undertakes mitigation through compensation projects in order to meet, or in lieu of meeting, certain stormwater standards. Mitigation projects eliminate off-site sources, or may reduce on-site sources as provided in this Section.
A. Projects required to meet the urban impaired stream standard(1) Compensation fees or mitigation credits used to meet the urban impaired stream standard. If a project is required to meet the urban impaired stream standard described in 06-096CMR ch. 500subsection (4)(D), compensation fees or mitigation credits used to meet the urban impaired standard are determined based on Table 1, whether or not the developed area will be receiving treatment to meet the general standards. Table 1
Compensation or Mitigation Based on Development Type
Type of surface | Compensation fee (per acre*) | Mitigation credits required (per acre*) |
Non-roof impervious area | $12,500 | 0.5 credits |
Roof | $5,000 | 0.2 credits |
Landscaped area | $2,500 | 0.1 credits |
*fees or credits for fractions of an acre are prorated.
(2) Compensation fees. Compensation fees may only be used in watersheds where a compensation fee utilization plan developed by a municipality or other entity has been approved by the Department. Acompensation fee utilization plan specifies how funds received from an applicant will be allocated to reduce the impact of stormwater pollution to an urban impaired stream. A plan must include provision to ensure that money will only be used for the intended purpose through establishment of a dedicated account. If a compensation fee utilization plan is proposed by an entity other than a municipality, the entity must demonstrate that the plan has been submitted to the municipality in which the project is located for review and adoption prior to submittal of an application to the Department.(3) Amount of mitigation credit. Table 2 indicates the amount of on-site or off-site mitigation credit earned by a project in the direct watershed of an urban impaired stream for a variety of allowed off-site and on-site pre-development mitigation activities. Table 2
Mitigation Credits Based on Type of Activity and Type of Development
Mitigation activity | Development type | Credit earned (per acre* treated) |
Retrofit with general standards at 1/3 required sizing or with approved flow through sedimentation device | Road or high use parking lot | 0.5 credit |
Medium use parking lot | 0.4 credit |
Other parking lot | 0.3 credit |
Roof or other impervious area | 0.2 credit |
Landscaped area | 0.1 credit |
Retrofit with general standards at 2/3 required sizing | Road or high use parking lot | 1.0 credit |
Medium use parking lot | 0.8credit |
Other parking lot | 0.6 credit |
Roof or other impervious area | 0.4 credit |
Landscaped area | 0.2 credit |
Retrofit with general standards at required sizing | Road or high use parking lot | 1.5 credit |
Medium use parking lot | 1.2credit |
Other parking lot | 0.9 credit |
Roof or other impervious area | 0.6 credit |
Landscaped area | 0.3 credit |
Eliminate impervious source area, replace with landscaped area | Road or high use parking lot | 1.0 credit |
Medium use parking lot | 0.7 credit |
Other parking lot | 0.4 credit |
Roof or other impervious area | 0.2 credit |
Eliminate impervious source area, replace with a designed planting and approved maintenance plan that will result in a forest | Road or high use parking lot | 2.0 credit |
Medium use parking lot | 1.5 credit |
Other parking lot | 1.0 credit |
Roof or other impervious area | 0.5 credit |
Retrofit detention with vegetated gravel under-drains | Impervious areas only | 0.5 credit |
*credits earned for fractions of an acreare prorated.
In addition to the use of on-site or off-site mitigation or compensation fees, the Department may approve other mitigation measures on a case-by-case basis. Other measures proposed by an applicant must provide at least equivalent protection as measures described in Table 2 above, as determined by the Department.
(4) Reduction of compensation fees or mitigation credit for projects in watersheds with an approved watershed management plan. The Department may waive or reduce compensation fees or mitigation credit if a municipality, or quasi-municipal entity having jurisdiction over the area in which the project is located has developed and is implementing a watershed management plan for the watershed in which the project is located. The watershed management plan must be approved by the Department as meeting the purpose of restoring water quality. Within a designated growth area of a municipality with an adopted comprehensive plan that the Maine Department of Agriculture, Conservation & Forestry has found to be consistent with the Planning and Land Use Regulation Act, or within a watershed located in a Service Center Community identified pursuant to 30-A M.R.S.§4301(14-A), implementation of the watershed management plan may be deferred for up to five years from the date of Department approval, or until state or federal financial assistance is available, whichever comes first.B. A project required to meet the general standards that is not in the direct watershed of an urban impaired stream. If a project is required to meet the general standards described in 06-096 CMR ch. 500subsection (4)(C) and it is not in the direct watershed of an urban impaired stream, the Department may allow the portion of a project's impervious or developed acreage that must be treated to be reduced through mitigation by eliminating or reducing an off-site or an on-site pre-development impervious stormwater source. For Site Law projects, the amount of reduction in treatment allowed is limited to 50%.(1) Source reduction or elimination. A source is considered to be eliminated if impervious area is removed, the underlying soil is aerated, and the area revegetated and returned to a wooded condition. A source is considered to be reduced if the impervious area is removed, the underlying soil is aerated and the area revegetated and maintained as a lawn or other non-forested area. The amount of reduction in the project's treated acreage allowed will be determined on a case-by-case basis by the Department, based on the existing and future uses of the project site, the existing and future use of the eliminated or reduced off-site or on-site pre-development impervious area, and the equivalency of these uses. In determining whether to approve a mitigation proposal, the Department will determine whether the expected reduction in stormwater pollutant export and stormwater flows can reasonably be expected to exceed the stormwater pollutant export and stormwater flow resulting from the untreated acreage at the project site.(2) When the amount of roof or non-impervious developed acreage that must be treated may be reduced. The Department may reduce the portion of a project's roof or non-impervious developed acreage that must be treated by an equivalent area of on-site, pre-development roof, parking or road surfaces for which the applicant agrees to incorporate and maintain stormwater treatment structures.C. A project in the direct watershed of a lake that is required to meet the phosphorus standards. If a project is required to meet the phosphorus standards described in 06-096 CMR ch.500 subsection (4)(D), a compensation fee may be paid, or an off-site mitigation credit may be allowed as follows: (1) Elimination or reduction of off-site sources of phosphorus. A source is considered to be eliminated if impervious area is removed, and the area is revegetated and returned to a wooded condition. A source is considered to be reduced if the impervious area is removed, and the area is revegetated and maintained as lawn or other non-forested area. For every two pounds of estimated off-site phosphorus export that is removed from the watershed, estimated on-site phosphorus export may be reduced by one pound. If the applicant can demonstrate, based on type of impervious area and intensity of use, that the level of phosphorus export from the eliminated or reduced off-site area is equivalent to or greater than that expected from the proposed impervious area, then a credit may be allowed at a ratio of 1 to 1.(2) Treatment of certain off-site sources of phosphorus(a) Paving of a road to eliminate erosion of the road surface if the Department determines it is a significant source of phosphorus. The amount of credit will be established based on modeling to determine the amount of phosphorus that will be removed.(b) Repairing a chronic erosion site if the Department determines it is a significant source of phosphorus. The amount of credit will be based on the Department's determination of the life expectancy of the erosion repair. The ratio of the life expectancy to a 50 year period will determine the percent credit given; e.g., an erosion site that is expected to need repair every 10 years will be given 20% credit for the actual amount of phosphorus that will be removed from the source.(c) Credit for other treated phosphorus sources will be determined on a case-by-case basis.(d) A Department-approved inspector may be required to conduct weekly inspections during the period of construction as a condition of approval.(3) A compensation feeper pound of phosphorous export as described in 38 M.R.S. §420-D(11)(A), or off-site mitigation is allowed at the Department's discretion, depending on the availability of suitable compensation projects. This option, which permits an applicant to pay a compensation fee in lieu of reducing phosphorous export beyond a project's allotment, is only allowed for sites where the phosphorous export from the proposed development site has already been reduced by at least 60%. This compensation fee option is not available for projects or portions of projects that are residential subdivisions or roads within residential subdivisions, unless the project is using only wooded or meadow buffers and associated level spreaders and ditch turnouts as described in 06-096 CMR ch. 500 Appendix F to address the remaining phosphorus export reduction required to meet the projects phosphorus allocation, or unless a mitigation project is identified and approved by the Department in the same watershed. The compensation fee per pound of phosphorous export shall be determined based on Table 3. Table 3
Compensation Fee Per Pound of Phosphorus Export
Percentage of Project's Phosphorous Export | Additional Phosphorous Compensation Fee (dollars per pound)* |
60% | $25,000 |
75% | $12,500 |
100% | $0 |
* feesare prorated.
D. Location. The mitigation activity must be located in the same watershed as the project to off-set the impact of the pollutant export from the project. More than one mitigation activity may be applied to a project.E. Protection from alteration. Areas in which an off-site or on-site pre-development stormwater source has been reduced or eliminated as described in subsections 3(A), 3(B), and 3(C) above, must be protected from alteration through deed restrictions, a conservation easement to which the Department is a party, or similar measures. These covenants must specify that they may only be modified with Department approval. See Appendix A of this Chapter.F. Maintenance and transfer. Areas revegetated to off-set project impacts must be maintained and any transfer of these areas must be made subject to deed restrictions that require such maintenance and are enforceable by the Department. These deed restrictions must specify that they may only be modified with Department approval.06- 096 C.M.R. ch. 501, § 3