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<br />(x) Must provide at least one soil boring, test pit or infiltrometer test in the <br />location of the infiltration practice for determining infiltration rates; <br />(xi) For design purposes, divide field measured infiltration rates by 2 as a safety <br />factor or use soil-boring results with the infiltration rate chart in the Minnesota <br />Stormwater Manual to determine design infiltration rates. When soil borings <br />indicate type A soils, field measurements should be performed to verify the <br />rate is not above 8.3 inches per hour. <br />(xii) Must employ appropriate on-site testing to ensure a minimum of three (3) feet <br />of separation from the seasonally saturated soils(or from bedrock) and the <br />bottom of the proposed infiltration system; <br />(xiii) Must design a maintenance access ,typically eight (8) feet wide; <br />(xiv) Infiltration Systems are prohibited in the following areas (See "higher level of <br />engineering review" in the Minnesota Stormwater Manual for more <br />information): <br />i. Areas that that receive runoff from vehicle fueling and maintenance <br />areas; <br />ii. Areas where infiltrating stormwater may mobilize high levels of <br />contaminants in soil or groundwater; <br />iii. Areas where soil infiltration rates are field measured at more than 8.3 <br />inches per hour unless the soils are amended to slow the infiltration <br />rate below 8.3 inches per hour; <br />iv. Areas with less than three (3) feet of separation distance from the <br />bottom of the infiltration system to the elevation of the seasonally <br />saturated soils or the top of bedrock; <br />v. Areas of predominately Hydrologic Soil Group type D soils(clay); <br />vi. The following areas within a Drinking Water Supply Management <br />Area (DWSMA) as defined in Minn. R. 4720.5100, subp. 13: <br />1. In an Emergency Response Area (ERA) within a DWSMA <br />classified as having high or very high vulnerability as defined <br />by the Minnesota Department of Health; or <br />2. In an ERA within a DWSMA classified as moderate <br />vulnerability unless a higher level of engineering review <br />sufficient to provide a functioning treatment system and to <br />prevent adverse impacts to groundwater has been approved by <br />the City of Arden Hills; or <br />3. Outside of an ERA within a DWSMA classified as having high <br />or very high vulnerability unless a higher level of engineering <br />review sufficient to provide a functioning treatment system and