wetland delineation

The identification and delineation of wetlands is an essential component of the Minnesota Wetland Conservation Act (WCA) regulatory program as well as Section 404 of the Clean Water Act as administered by the St. Paul District Army Corps of Engineers (Corps) in Minnesota. Both WCA and Corps regulatory programs in Minnesota utilize the same standards, resources and methodologies for identifying and delineating wetlands.

The basis for wetland identification and delineation starts with the 1987 Army Corps of Engineers Wetland Delineation Manual (87 Manual). Regional Supplements to the 87 Manual have been developed for specific Land Resource Regions (LRRs). Minnesota contains portions of 3 different LRRs each with its own regional supplement. Wetland determinations/delineations conducted in Minnesota for regulatory purposes must use the regional supplement associated with the LRR where the determination/delineation is conducted. For ease in implementation, Minnesota has developed an LRR map where regional boundaries follow the closest fit township boundaries.

Land Resource Region Boundaries by Township (pdf)

In addition to the delineation manuals, this page of the website includes numerous technical guidance and resource documents related to wetland delineation and determinations including vegetation, hydrology and soils (Delineation Guidance & Resources). You can find information on lateral effect and drainage setbacks as well as hydrology monitoring, antecedent precipitation analysis (Hydrology & Antecedent Precipitation)and many other related topics.


Ken Powell
Wetland Conservation Act Operations Supervisor