Critical Areas Mitigation

What is Mitigation?

In terms of impacts to critical areas, mitigation is the restoration, enhancement, and/or creation of critical areas to make up for losses due to land disturbance and development. Disturbance of critical areas is avoided and minimized when possible, but in some instances it is unavoidable. In these cases, mitigation is required for impacts using established mitigation ratios, which vary depending on the critical area.

Mitigation involves the planting of native vegetation within a designated area of a critical area and/or buffer. Common mitigation types include wetland creation, wetland enhancement, wetland buffer enhancement, stream buffer enhancement, and vegetation management plans for shoreline buffers. Other mitigation types provide slope stability in geologically hazardous areas and improve the function of frequently flooded areas. Sometimes signage and/or fencing are required as extra protective measures of the critical area.

Mitigation site

Mitigation Plan Development

If mitigation is necessary, a mitigation plan will be required through the critical areas review of the permit application. A mitigation plan identifies critical areas impacts, prescribes planting and protective measures, and lists performance standards to be met. Performance standards often include meeting a set planting survival and controlling invasive species.

For single family development impacts to critical area buffers that are 1,000 sq ft or less, landowners may complete the Mitigation Plan Worksheet as determined by Natural Resources staff.

In addition to a mitigation plan, several other documents are often required:
  • An Agreement to Maintain Form
  • Establish an Assignment of Saving (AOS) account or Bond as a monetary assurance for the completion of the mitigation requirements. The amount is based off of the estimated costs to complete the mitigation, multiplied by 125%. The Bond Quantity Worksheet can be used to calculate this amount.
  • A Notice on Title or Conservation Easement (to be determined by Natural Resources staff) as a protective measure filed at Whatcom County’s Auditor’s Office. It notifies future owners of the presence of critical areas on the property.


As-built Report

Once all planting, installation of protective measures, and any additional requirements are complete, an as-built report is to be submitted to Whatcom County PDS. Landowners of small, non-complex sites, may complete the As-built Documentation Form, and submit a copy with photos and receipts. Large or complex sites, such as wetland creation areas, require the submittal of an as-built report prepared by a qualified professional. The report should detail the plant species, locations, mitigation area size, and any deviations from the mitigation plan. Check with PDS Natural Resources staff to determine if you are eligible to use the landowner As-built Documentation Form.

After submitting the As-built Documentation Form or As-built Report, call the inspection hotline to schedule an inspection. The inspection is conducted by Whatcom County staff to ensure the construction has been completed according to the mitigation plan or as revised per as-built form or as-built report. Staff will determine if the as-built can be approved and provide next steps.

Yearly Monitoring Report

The spring growing season of the next calendar year following the approval of the as-built constitutes the first year of the monitoring period. Each monitoring year (typically Years 1, 2, 3, & 5), the applicant submits a monitoring report, including photographs and a record of any dead plants, new plantings, receipts of plant purchases, alterations to the mitigation area, and relevant issues specific to the site. Landowners of small, non-complex sites, may complete the Mitigation Monitoring Report Form, and submit a copy with photos. Large or complex sites, such as wetland creation areas, require the submittal of a monitoring report prepared by a qualified professional. Some large or complex sites are monitored for 10 years, with additional reports being due for Years 7 & 10.

After receiving the monitoring report, Whatcom County staff will complete an inspection to determine if the performance standards listed in the mitigation plan are being met. Inspections are completed from April through October, in the order of received reports. The owner may inform Whatcom County PDS if they wish to receive notice prior to the inspection. Once the inspection is completed, staff will notify the owner of the determination and any additional requirements needed, such as weeding or additional planting.

Once all performance standards have been completed and the monitoring period is over, the mitigation area is left to grow naturally.

Shoreline mitigation site

Assignment of Savings Release Schedule

Upon successful completion of the as-built, the estimated cost of vegetation, installation labor, installation monitoring, mulch, signage, fencing, and as-built report is released from the Assignment of Savings (AOS). Upon successful completion of the yearly monitoring reports and inspections, the estimated cost of monitoring and maintenance is released.

When the mitigation plan is determined to be complete, the remaining AOS amount is released. If a site fails to meet performance standards or objectives during monitoring years, Whatcom County reserves the right to withhold release amounts, or use the AOS to complete mitigation.

Bonds are released when the mitigation is determined complete. Due to the nature of bonds, there are no partial releases like there are for an AOS.

Selling a Property with Mitigation

In the event that the property is sold or the responsible party of the mitigation project has changed, it is the responsibility of the seller to transfer the mitigation responsibilities to the new owner. A new Assignment of Savings (AOS) or Bond shall be established by the new owner and a new Agreement to Maintain Form shall be signed and submitted. The new AOS balance must reflect the remaining balance at the time of sale. Once the new AOS or bond form is submitted to Whatcom County, the old AOS is released in full. An Assignment of Savings Form Example is available to assist in completing the AOS form.