Section 6

Links from this page are included to assist the reader, and are not part of the rule. Text amended effective December 27, 2006.

6. Compensation fees and mitigation credit. The following applies to projects required to provide mitigation, pursuant to Section 4(D), or where the Department has allowed the applicant to reduce the acreage treated or lower the phosphorus export reduction required to meet the phosphorus standards in Section 4(C) through mitigation. Mitigation eliminates or reduces other off-site sources or pre-development on-site sources, in accordance with the requirements of Sections 6(A) through (F) below. The project must still meet the basic standards, general standards, phosphorus standards and the flooding standard described in Sections 4(A), (B), (C) and (D), respectively, if applicable.

A. A project required to meet the urban impaired stream standard.

(1) Determining compensation fees or mitigation credits. If a project is required to meet the urban impaired stream standard described in Section 4(D), compensation fees or mitigation credits are determined as follows.

Type of surface with or without required treatment	*Required compensation fee (per acre)**	*Required mitigation credit (per acre)**
Non-roof impervious area	$5,000.00	0.5 credits
Roof	$2,000.00	0.2 credits
Landscaped area	$1,000.00	0.1 credits

*per acre fees are based on whole acreages of impervious or disturbed area. Fees for partial acreages are prorated.

Compensation fees may only be used in watersheds where a compensation fee utilization plan has been approved by the department. If a compensation fee utilization plan is proposed by an applicant who is not a municipality, the applicant must demonstrate that the plan has been submitted to the municipality in which the project is located for review prior to submittal of an application to the department.

NOTE: If a project is located in the watershed of a public drinking water supply, the municipality is required by 30-A M.R.S.A. § 4358-A(5) to notify the water district of the application as an abutter.

(2) Amount of credit. The following table indicates the amount of credit earned for a variety of allowed off-site mitigation activities.

Mitigation activity	Source 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
Low use parking lot	0.3 credit
Roof or other impervious area	0.2 credit
Lawn	0.1 credit
Retrofit with general standards at 2/3 required sizing	Road or high use parking lot	1.0 credit
Low use parking lot	0.6 credit
Roof or other impervious area	0.4 credit
Lawn	0.2 credit
Retrofit with general standards at required sizing	Road or high use parking lot	1.5 credits
Low use parking lot	0.9 credit
Roof or other impervious area	0.6 credit
Lawn	0.3 credit
Eliminate impervious source area, replace with lawn	Road or high use parking lot	1.0 credit
Low use parking lot	0.5 credit
Eliminate impervious source area, replace with forest	Road or high use parking lot	2.0 credits
Low use parking lot	1.0 credit
Retrofit detention with vegetated gravel under-drains	Impervious areas only	0.5 credit

*credits earned are based on whole acreages of impervious or disturbed area. Fees for partial acreages are prorated.

In addition to the use of 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 the table above, as determined by the department.

(3) Reduction of compensation fee or mitigation requirements for projects in watersheds with an approved watershed management plan. The department may waive or reduce requirements for 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 State Planning Office 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 MRSA § 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 general standards that is not in an urban impaired stream watershed.

(1) Reducing acreage that must be treated by eliminating or reducing an off-site or on-site pre-development impervious stormwater source. If a project is required to meet the general standards described in Section 4(B) and it is not in an urban impaired stream watershed, 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 on-site pre-development impervious stormwater source.

(a). 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 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 pre-development on-site 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.

(b) 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 roof, pre-development parking or road surfaces for which the applicant agrees to incorporate and maintain stormwater treatment structures.

C. A project in a lake watershed that is required to meet the phosphorus standards. If a project is required to meet the phosphorus standards described in Section 4(C), an off-site mitigation credit may be allowed, but only to eliminate or reduce 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 eliminated or reduced, 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. As an alternative, a compensation fee may be paid to off-set no more than 50% of the required reduction in export at a rate of $10,000 per pound of phosphorus export, as described in 38 M.R.S.A. § 420(D)(11)(A).

NOTE: For guidance in determining phosphorus export see "Phosphorus Control in Lake Watersheds ", Maine Department of Environmental Protection.

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 Section 6(A), (B), and (C) 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 G.

F. Maintenance and transfer . Areas revegetated to off-set project impacts must be maintained as required by the permit, and any transfer of these areas must be made subject to deed restrictions that require such maintenance and are enforceable by the department. These covenants must specify that they may only be modified with department approval.

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