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Modifier"U" � <br /> Unknown.CNo comparable Cowatdin categor}� <br /> The water regime is not l:nown (Santos and Gauster 1993,pg 32). <br /> Discussion <br /> Type U1L � � � �• <br /> The descripfion provided for Type;._1 wetla�ds 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 /> tlie criteria for a jurisdictionai wetland is tlie presenee of hydrophytic vebetation (19$7 1Vlanval <br /> pp,16 - 26). Type I wetlands often are found in agricultural fields and often are determined to be <br /> jurisdictional on the basis of an aerial 3Smm slide review;the quality of the slides is Poor under <br /> . the very best of circumstances... The determinanon of regulatory jurisdiction is based on normal <br /> circumstances or as defined by the COE,being agriculturalIy cropped 5.1 out of 100 years (i.e.by <br /> inference lacking sufficient I�ydrology for eitherS or 12.�percent of the growing season). <br /> The Wetland Conservation Act (WCA) determines normalcy as agricultural aropping for 6 out of <br /> FO years (IVInRules 8420.01'10, Subp 53; 84?0:0122 Subp.l, :A and B): Typically, normalcy on <br /> agriculfural lands is determined by the review of the aforemenfioned low quaTity 3�mm aerial <br /> sli.des and judgments are made as to whether an area is cropped or if.fhe crops are subject to <br /> .bydrological stresses; The. .process is highly subjective and can be biased by excessive <br /> piecipitation that may occur early in the crop acowth cycle. . . <br /> Field exarnination of these areas may indicate the presence of smartweed a�d soine of the other <br /> indicated species in seasonally abnormally wet yeaxs wheTeas in normal years., .hydropt�ytic <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 iegitimate definition of Type l wetiands and <br /> the intent of the 1987,Manual. : <br /> Does a Type I basin need to, be flooded for 5 percent of the growing season (the lo.wer <br /> definitional bound.for jurisdictional hydrology) or 12.�percent{the ugper definitional bound for <br /> jurisdietional hydrology) in order for hydrophytic vegetation to develop? In practics,`rhe�t. Paul <br /> District of the .Corps -of Engineers (COE) (also applied in gractice under tihe VJe�land <br /> Conservataon Act) applies Che 5 percent hydrological definition tiut if that is too short to allow <br /> the development of hydrophytic vegetation under normal conditions than the absence of <br /> hydrophytic vebetation v�=ould make fhose Type 1 �vetlands non jUrisdictional.. <br /> Type 1L—:bottomland hazdwoods —poses an equally diff'icult regulatory question. Tools for the <br /> evaluation of h,y�ology for.non-cropped area"s are mvch more data intensi,�e and are also subject <br /> to precipitation event variability. 1Vleasurement tools for the determination of precipitation • <br /> normalcy are a combination of evaluating annual precipitation and comparison to a 30-year <br /> roI:ling average along with extensive near b ound surface early�season hydrological monitoring. <br /> If the wates le�lels are within :12" of the surface for less than 8.5 days in the genecal latitude o� <br /> the Twin Cities(5 percenf of the arowing season), fhan the area is not w.etland. If water levels are <br /> within 12" of the surface between 5 percent and 12.5 percent of the b owing season (21 da}�s in <br />