Snow-covered ground and frozen lakes, swamps, and ponds no longer signal the termination of wetland delineation work. Although the optimal time for completing wetland delineations falls during the traditional growing season from April – November, work may continue during the winter months to keep a project on pace.

While a variety of factors — late fall or delayed project starts, funding, community project consensus — can cause the wetland delineation process to be delayed beyond the optimum season, work can continue, according to SEH Senior Biologist Brad Kovach.

Turning to off-site resources such as soil maps, wetland databases, and aerial photographs can help identify and map potential wetlands. This approach provides preliminary mapping of wetlands for planning purposes, and can be followed up with a formal wetland delineation in the field after the start of the spring growing season.

Project owners requiring a more refined and precise wetland boundary during the winter, can refer to a wetland specialist for help. The specialist can combine off-site resources with a winter field delineation of the wetland boundary using a Global Positioning System (GPS) and can employ special methods determined by USACE. A combined off-site/on-site approach to delineation may require a spring site visit to gather additional data. Under special circumstances, such as an unseasonably warm winter, the delineation can be completed entirely within the winter months.

Kovach stresses the uniqueness of each wetland project, the importance of planning, as well as contact and coordination with the regulating agencies, especially when there is a need for an out-of-season wetland delineation.

"Planning and integrating wetland services with other project tasks and coordinating with agencies and project engineers and planners, keeps projects on pace." However, Kovach does caution that, "although a winter wetland delineation may allow work to progress, it can take longer and add costs. The best approach is to plan for the wetland process earlier, rather than later."

Contact

Wisconsin, Illinois, Indiana
Gloria Chojnacki
gchojnacki@sehinc.com