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' <br /> � Modifier"U" <br /> Unknown (No comparable Cowardin category) <br /> � The water regime is not known (Santos and Gauster 1993, pg 32). <br /> Discussion <br /> ' Type 1/1L <br /> The description provided for Type 1 wetlands and the reference to the absence of wetland <br /> vegetation in basins that are only flooded very temporarily raises a regulatory question. One of <br /> � the criteria for a jurisdictional wetland is the presence of hydrophytic vegetation (1987 Manual <br /> pp 16 - 26). Type 1 wetlands often are found in agricultural fields and often are determined to be <br /> jurisdictional on the basis of an aerial 35mm slide review; the quality of the slides is poor under <br /> � the very best of circumstances. . The determination of regulatory jurisdiction is based on normal <br /> circumstances or as defined by the COE, being agriculturally cropped 51 out of 100 years (i.e. by <br /> inference lacking sufficient hydrology for either 5 or 12.5 percent of the growing season). <br /> � The Wetland Conservation Act (WCA) determines normalcy as agricultural cropping for 6 out of <br /> 10 years (MnRules 8420.01 10, Subp 53; 8420.0122 Subp.l, A and B). Typically, normalcy on <br /> � agricultural lands is determined by the review of the aforementioned low quality 35mm aerial <br /> slides and judgments are made as to whether an area is cropped or if the crops are subject to <br /> hydrological stresses. The process is highly subjective and can be biased by excessive <br /> � precipitation that may occur early in the crop growth cycle. <br /> Field examination of these areas may indicate the presence of smartweed and some of the other <br /> � indicated species in seasonally abnormally wet years whereas in normal years, hydrophytic <br /> vegetation is absent. It is highly probable that the process of determination of Type 1 wetlands as <br /> jurisdictional in many cases is extending beyond the legitimate definition of Type 1 wetlands and <br /> � the intent of the 1987 Manual. <br /> Does a Type 1 basin need to be flooded for 5 percent of the growing season (the lower <br /> � definitional bound for jurisdictional hydrology) or 12.5 percent (the upper definitional bound for <br /> jurisdictional hydrology) in order for hydrophytic vegetation to develop? In pracCice, the St. Paul <br /> I District of the Corps of Engineers (COE) (also applied in practice under the Wetland <br /> Conservation Act) applies the 5 percent hydrological definition but if that is too short to allow <br /> the development of hydrophytic vegetation under normal conditions than the absence of <br /> � hydrophytic vegetation would make those Type 1 wetlands non-jurisdictional. <br /> Type 1 L — bottomland hardwoods — poses an equally difficult reg��latory question. Tools for the <br /> � evaluation of hydrology for non-cropped areas are much more data intensive and are also subject <br /> to precipitation event variability. Measurement tools for the determination of precipitation <br /> normalcy are a combination of evaluating annual precipitation and comparison to a 30-year <br /> � rolling average along with extensive near ground surface early season hydrological monitoring. <br /> If the water levels are within 12" of the surface for less than 8.5 days in the general latitude of <br /> the Twin Cities (5 percent of the growing season), Chan the area is not wetland. If water levels are <br /> � within 12" of the surface between 5 percent and 12.5 percent of the growing season (21 days in <br /> � <br /> ' <br />