Agenda - Council - 10/27/1998 - Laserfiche WebLink

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Steve Jankowski Page 2 November 19, 1997 Location C, South of CR 116, in the Magnesium Pond area A stormwater system was constructed on the property line west of the First Team Sports Building and just west of the American Paper Shredders Building.The system extends from Lurid Blvd. to a point just south of County State Aid Highway 116 (Industry Avenue). At the north end of the system a 27 inch diameter R.C.P. storm pipe was extended northerly, intended solely for future use by the City of Ramsey or by Anoka County. The pipe is available either for direct area runoff or for pond outflow with a capacity of 10 cfs. The Anoka Stormweter System pr.o~fi.ded the three locations A, B, and C '¢,,ith the specific intention to make these 'pipes available for potential City of Ramsey use. Locations A & B are available for off peak stormwater pond depletion. Location C was intended for possible direct runoff from Anoka County Right of Way and for long time period flow associated with depletion of the potential high storage volume in Ramsey's Magnesium Pond. The City of Anoka was aware of future planning for CSAH 116 upgrading, and of past Magnesium Pond flooding. The pipe at Location C may help solve these problems. Combined, the outflow rate Location A, B and C from Ramsey to Anoka can be at least 25 cfs and as much as 40 cfs which is the outflow rate from Anoka's Phase 3 pond to the Thurston Avenue trunk system with the key factor being that the flow must be "off peak", i.e. detained by City of Ramsey storage. Just south of CR 116 and just east of The City of Ramsey there is a wetland located within Anoka labeled on the sketch as "Lot 3 Pond". At one time, prior to construction of CR 116, this wetland was likely contiguous with Magnesium Pond. There is a culvert under CR 116 that has a very significant south to north slope. The north end of the culvert is submerged. The invert of the south end is about 1-1/2 feet above the current water level in the Lot 3 pond. After construction by Anoka of the Enterprise Park Storm System as shown, there is no need for outflow of water flow from Anoka areas Sout|~' of CR ii6 ~o'~he'Magnesium Pond in Ramsey.' 'i'his CF( 1 'i ~ culvert is no longer necessary. The intent has been to plug and abandon 'the culvert. The south end of this culvert will be permanently plugged so no City of Anoka flow is conveyed north. The Lot 3 pond is a special situation in that it is not intended as a major stormwater retention facility. The Anoka pipe system design provided sufficient conveyance capacity in the storm pipe leading southerly from CR 116 to Lund Blvd. so that the Lot 3 pond does not have to accept impervious surface stormwater runoff from a future development on Lot 3. It is the intent to utilize and improve this pond as an amenity to the property and not as a high use stormwater basin. This is a fairly small pond. I--~ Hakanson Anderson Assoc., Inc.