06-20-11 Council Agenda - Laserfiche WebLink

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�1 �121N� Th O(IA11ES MK OM Memo TO: Honorable Mayor and City Council Members FROM: Lee Elfering, City Engineer DATE: June 17, 2011 RE: Jackson Railroad Storm Sewer Crossing Repair Background The City was informed of a sinkhole that had formed along the section of the Canadian Pacific (CP) Railroad adjacent to Jackson Street just north of Demont Avenue by a CP track inspector. The sinkhole is located on the top of the railroad bed and approximately 6 to 8 feet from the track. After investigation of the area the cause of the sinkhole has been determined to be a failed City storm sewer pipe crossing. The crossing provides a storm water outlet for a low area on the west side of the tracks. Drainage to this area includes back yard areas of the properties along the east side of Ruth Street and the railroad right -of -way west of the tracks between Demont Avenue and Old County Road C. As the cause of the sinkhole is the City storm sewer pipe crossing failure, the correction of the problem will be the responsibility of the City. Options The failure of the existing railroad crossing requires the abandonment of the old crossing. Regardless of the method used to serve the low area with storm sewer this cost will be incurred and is estimated at $3,000. The following three options were reviewed for providing a storm sewer outlet for the low area west of the tracks: 1. New railroad crossing directly adjacent to the old crossing. This option would be considered maintenance by the CP Railroad and therefore would not require a new railroad permit. However, the new storm sewer crossing would need to be jackbored under the tracks at a minimum cost of around $35,000. Adding the cost of connecting the storm sewer crossing to the existing system in the tight working area between the RR tracks and Jackson Street would increase this options cost to around $50,000. 2. Extension of the Ruth Storm sewer to the low area The option would extend the existing storm sewer system serving Ruth Street to the low area. Due to the limited depth of the Ruth storm sewer the pipe would need to run at a very shallow grade and cross an existing driveway. There also appears to be very little existing easement or right -of -way available for the pipe installation. The cost of this option is estimated at $14,500.00 and a new permit would most likely be required for grading within the RR right -of -way 10062 Flanders Court NE — Blaine, MN 55449 — Ph: (763) 780-0450 Fax (763) 780 -0452 Memo481711 -CC (Jackson RR Storm X -ing) 1