01-16-1996 Planning Packet - Laserfiche WebLink

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of limited site area, while storm water treatment will require a small wet basin. Our solution will be to combine these two functions into a defined area that relates well to the drainage ditch adjacent to Old Crystal Bay Road. Connection to the ro?dway ditch will be by a culvert section that is sized to limit post development flow rate to the undeveloped condition for 1. lU and 100 year storms. Storm water treatment will settle out all particle greater than S micron size. Where access drives to the arena parking areas cross over the exisung ditch section, appropriately sized culverts will be installed to maintain the ditch drainage function. The site area is not presently sewered by municipal sanitary sewer; the nearest sewerage is located approximairly 1000’ south of the site near the high school. Because of relative ••levation difference between arena site and existing sanitary sewerage, a gravity connection is not possible. Accord ingly, a small lift station with force main connection to the municipal system would be possible and practical. However, because the site area is presently outside the Metro Urban Service Area (MUSA) limits, a connecUon to the municipal system cannot be made at this time. The City is expected to make application to the Met Council in Fanuary 1996 for an expansion of the MUSA limits that would include the arena site. If the City is unsuccessful in getting the arena site included in the MUS.\ limits at this time, the use of temporary sewage holding tanks would allow the project to go forward, but would require i variance for a new use. It seems likely that the MUSA line will be adjusted to include the arena site, either per Oronos January 1996 application or subsequent application. Based on data collected and site observauon b, C' IE Consultants, the area noted as basin #2 on the site drawing is a juris' .uonal wetland, i.e. Type I wetland per U S. Fish and Wildlife System. According to aerial photos, the area of basin #2 was extensively formed for many years up to at least 1990, and was sufficiently drained to allow farm machinery to traverse the basin and. therefore, was not a wetland dunng that peri* d. It appears that rela- uvely recent grading and drainage changes to the property south and adjacent to the arena property may have caused an increase of overland flow into the area of basin #2. unintenuonally creating wetland conditions. Exemption 10 per the Minnesota Wetland Conservation Act of 1991. states that ditches in upland areas which take on wetland characteristics over time may be filled or drained if they were created or overseen by a public enuty on property where the purpose was not to create a weUand. and the wetland has not existed for more than 20 years. On the basis of the CME report, there appears to be ample evidence that basin #2 is not a long term wetland, and that a Certificate of Exemption should be pursued with the local unit of government, ie. the W'atershed District. sanitary sewerage WETLAND Orono Ice Arena TRA/HSB/KA