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� <br /> � Clarification of Cowardin Classification <br /> , and Circular 39 <br /> Wetland Types 1, 1L, 2, 3 and 7 <br /> � <br /> By <br /> Franklin J. Svoboda <br /> � Svoboda Ecological Resources <br /> 2477 Shadywood Road, Suite 100 <br /> Excelsior,MN 55331 <br /> � (952)471-1100 <br /> franksCa��psinnovations.com <br /> � Introduction <br /> The National Wetland Inventory (NWI) mapping process completed in Minnesota between 1979 <br /> � and 1982 developed a wetlands inventory map for the state of Minnesota utilizing remotely <br /> sensed color infrared photography that was visually interpreted. The interpretation process <br /> hierarchically classified wetlands using, at the time, the recently published Cowardin <br /> � classification system (Cowardin et al 1979). The wetland interpretation and classification process <br /> was ground verified using selective plots and locations but was field verified to only a limited <br /> extent. Consequently, the published NWI paper copies carry the disclaimer that these maps are to <br /> � be used for advisory purposes only and actual classifications are to be based on ground <br /> verification. Visual interpretation from remote sensed imagery has some limitations particularly <br /> with regard to the water regime modifier. Year to year variation in precipitation cycles along <br /> � with the occurrence of precipitation events at the time that the imagery was acquired, even if all <br /> acquisition occurred during the spring season, can result in variations in modifier categorization. <br /> � Accurate classification becomes critical when regulatory decisions are being made with regard to <br /> the wetland type and the amount of de minimum fill that is permissible. Also, it is a matter of <br /> scientifically accurate consistency with regard to adherence to the various technical publications <br /> � and regulatory guidance documents. <br /> Circular 39 was authored by Shaw and Fredine and published by the U. S. Fish and Wildlife <br /> � Service (USFWS) in 1956. The intended purpose of Circular 39 was an effort at classifying and <br /> inventorying wetlands on a national scale in order to assess the wetland base and related <br /> waterfowl production potential. The classification process was never intended to serve as a <br /> � classification system for wetland regulatory purposes. However, since it was the first national <br /> effort of its kind and as wetland regulatory intentions materialized, this was the only method <br /> available to differentiate between wetlands of different types. <br /> � The Board of Water and Soil Resources (BWSR) cross-reference table (8420.0549 subp. 2.) <br /> indicates that Circular 39 Type 3 wetlands have a "C" water regime modifier. This is an <br /> ' <br /> 1 <br /> ' <br />