35.40.050 Regulations – Wetland mitigation plans.
(1) The overall goal of a wetland mitigation plan shall be no net loss of wetland functions, acreage, and values.
(2) To achieve no net loss, wetland impacts shall be replaced according to the minimum area ratios shown in Table 8-1. The Administrator may increase the ratios by 25 percent when there is a high likelihood that the proposed mitigation will be unsuccessful in fully replacing the wetland functions and values lost at the impact site. The Administrator shall solicit input from the Department of Ecology and the U.S. Army Corps of Engineers when assessing the likelihood of mitigation success.
(3) Those persons proposing or required to compensate for wetland impacts shall show that the compensation project is associated with an activity or development otherwise permitted and that the restored, created, or enhanced wetland will be preserved in perpetuity by accomplishing the following:
(a) Demonstrate sufficient scientific expertise, supervisory capability, and financial resources to carry out the project;
(b) Demonstrate the capability for monitoring the site and to make corrections during this period if the project fails to meet projected goals; and
(c) Protect and manage or provide for the protection and management of the compensation area to avoid further development or degradation.
Category and Type of Wetland Impacts | Reestablishment or Creation | Rehabilitation Only1 | Enhancement Only1 |
|---|---|---|---|
All Category IV | 1.5:1 | 3:1 | 6:1 |
All Category III | 2:1 | 4:1 | 8:1 |
Category II Estuarine | Case-by-case | 4:1 | Case-by-case |
All Other Category II | 3:1 | 6:1 | 12:1 |
Category I Forested | 6:1 | 12:1 | 24:1 |
Category I Based on Score for Functions | 4:1 | 8:1 | 16:1 |
Category I Natural Heritage Site | Not considered possible2 | 6:1 | Case-by-case |
Category I Coastal Lagoon | Not considered possible2 | 6:1 | Case-by-case |
Category I Bog | Not considered possible2 | 6:1 | Case-by-case |
Category I Estuarine | Case-by-case | 6:1 | Case-by-case |
1These ratios are based on the assumption that the rehabilitation or enhancement actions implemented represent the average degree of improvement possible for the site. Proposals to implement more effective rehabilitation or enhancement actions may result in a lower ratio, while less effective actions may result in higher ratio. The distinction between rehabilitation and enhancement is not clear-cut. Instead, rehabilitation and enhancement actions span a continuum. Proposals that fall within the gray area between rehabilitation and enhancement will result in a ratio that lies between the ratios for rehabilitation and the ratios for enhancement.
2Natural heritage sites, coastal lagoons, and bogs are considered irreplaceable wetlands because they perform some functions that cannot be replaced through compensatory mitigation. Impacts to such wetlands would therefore result in a net loss of some functions no matter what kind of compensation is proposed. These ratios are based on the assumption that the rehabilitation or enhancement actions implemented represent the average.