Wetland report/Svoboda - Laserfiche WebLink

Home Browse Search

� � Modifier "U" Unknown (No comparable Cowardin cate�ory� � The water regime is not known (Santos and Gauster 1993, pg 32). � Discussion Type 1/1L The description provided for Type 1 wetlands and the reference to the absence of wetland vegetation � in basins that are only flooded very temporarily raises a regulatary question. One of the criteria for a jurisdictional wetland is the presence of hydrophytic vegetation (1987 Manual pp 16 - 26). Type 1 wetlands often are found in agricultural fields and often are determined to be jurisdictional on the � basis of an aerial 35mm slide review; the quality of the slides is poor under the very best of circumstances. .The determination of regulatory jurisdiction is based on normal circumstances or as defined by the COE, being agriculturally cropped 51 out of 100 years (i.e. by inference lacking � sufficient hydrology for either 5 or 12.5 percent of the growing season). The Wetland Conservation Act(WCA)determines narmalcy as a�ricultural cropping for 6 out of 10 � years (MnRules 8420.0110, Subp 53; 8420.0122 Subp.l, A and B j. Typically, normalcy on agricultural lands is determined by the review of the aforementioned low quality 35mm aerial slides and judgments are made as to whether an area is cropped or if the crops are subject to hydrological � stresses. The process is highly subjective and can be biased by excessive precipitation that may occur early in the crop growth cycle. � Field examination of these areas may indicate the presence of smartweed and some of th� other indicated species in seasonally abnormally wet years whereas in normal years, hydrophytic � vegetation is absent. It is highly probable that the process of determination of Type 1 wetlands as jurisdictional in many cases is extending beyond the legitimate detinition of Type 1 wetlands and the intent of the 1987 Manual. Does a Type 1 basin need to be flooded for 5 percent of the growing � season (the lower definitional bound for jurisdictional hydrology) or 12.5 pereent (the upper definitional bound for jurisdictional hydrology)in order for hydrophytic vegetation to develop?In practice, the St. Paul District of the Corps of Engineers (COE) (also applied in praetice under the � Wetland Conservation Act) applies the 5 percent hydrological definition but if that is too short to allow the development of hydrophytic vegetation under normal conditions than the absence of hydrophytic vegetation would make those Type ] wetlands non-jurisdictional. � Type 1L— bottomland hardwoods — poses an equally difficult regulatory question. Tools for the evaluation of hydrology for non-cropped areas are much more data intensive and are also subject to � precipitation event variability.Measurement tools for the determination of precipitation normalcy are a combination of evaluating annual precipitation and comparison to a 30-year rolling average along with extensive near ground surface early season hydrological monitoring. If the water levels are � within 12"of the surface for less than 8.5 days in the general latitude of the Twin Cities(5 percent of the growing seasonj, than the area is not wetland. If water levels are within l2" of the surface � between 5 percent and ]2.5 percent of the growing season (21 days in the general ]atitude of the Twin Cities) according to the 1987 Manual (Table 5 pg. 36), the area may be wetland but usually is � Svoboda Ecological Resources 744 Brown Road North Project No.: 2007-081-03 37 Ted Schultze �