2008 - 2017 Capital Improvement Program

Project #8003, Mpls/St Paul Interceptor Improvements

Description:

This project provides for the rehabilitation of the core wastewater conveyance facilities in Minneapolis and St. Paul. Ranging in size from 54” to 13’ – 10” in diameter, some of these sewers have been in service for 60 or more years. This core interceptor system conveys more than 200 MGD to the Metropolitan Treatment Plant. It is characterized by large size, high flows and difficult access. Access shafts are as deep as 193 feet, and a few are located in underground caves and in ravines.

Project Map

The facility planning will include a review of the inspection findings, and will recommend alternative means to improve and repair the core interceptor system. An interceptor for conveyance and in-line storage between Interceptor 1-MN-320 and the Minneapolis East Interceptor tunnel is planned as a means to eliminate combined sewer overflows in the downtown Minneapolis area. Another major project is relocation of the Oak Street Interceptor to accommodate the new Gophers Stadium and the Central Corridor LRT through the University of Minnesota. The project will also result in separating the existing sanitary sewer from being located inside the storm sewer.

Purpose and Justification:

The project will correct problems with the aged, existing interceptors to assure system integrity and function and to avoid potential very costly emergency repairs to correct failures when they occur. The project also provides in-line storage for the elimination of combined sewer overflows in downtown Minneapolis. The Oak Street Sewer Replacement project provides the opportunity to construct the sewer segments as part of the new Gopher Stadium work at a lower cost and in advance of the LRT project.

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Project Authorization:

	Project Schedule		Authorizations
	Start	End	Funding	Status
Prelim. Engr.	Jan-00	Dec-07	$3,000,000	Approved
Design	Jan-05	Dec-09	$7,000,000	Approved
Construction	Mar-06	Dec-15	$90,000,000	Approved
Prior Authorization:			$10,500,000
2008 Budget Adjustment:			$19,500,000
Total 2008 Authorization:			$30,000,000
Future Authorizations:			$70,000,000
Total Project Cost:			$100,000,000

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Projected Cash Flow:

	Authorized	Future	Total
Prior to 2008	$3,626,000	$0	$3,826,000
2008 Budget	5,000,000	0	5,000,000
2009	8,000,000	0	8,000,000
2010	8,000,000	0	8,000,000
2011	5,000,000	5,000,000	5,000,000
2012	0	10,000,000	10,000,000
2013	0	15,000,000	15,000,000
2014	0	15,000,000	15,000,000
2015	0	15,000,000	15,000,000
2016	0	10,000,000	10,000,000
2017	0	0	0
Post-2017	0	0	0
Contingency	174,000	0	174,000
Totals	$30,000,000	$70,000,000	$100,000,000

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Impact on O&M Costs:

The project will significantly reduce emergency repair costs over potential costs without the project.

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Current Projects

Project Number & Description

o Project #800310, Interceptor 1-MN-300 and 1-MN-320 Improvements - this project provides for color television inspection of the downstream 18,906 feet, or 63 per cent, of the Interceptor 1-MN-300 and the downstream 8500 feet, or 47 per cent, of Interceptor 1-MN-320. Last inspected in 1977, Interceptor 1-MN-300 is 60 to 92 feet deep and was constructed as concrete lined tunnel in 1936 to1938. The portion of Interceptor 1-MN-320 to be inspected was constructed in 1889, of brick stone and concrete. The inspection and report preparation was completed in 2006. The estimated cost of this inspection work is $78,000. (Location Map).

o Project #800330, Oak Street Sewer Replacement - the Metropolitan Council currently owns and operates a 100 year old 96” storm sewer with a 10 year old 26.5”x45” sanitary sewer imbedded in its invert. The sanitary sewer needs to be redirected to the Minneapolis East Interceptor (MEI), a 10 ft. diameter sewer, to allow for the construction of the Central Corridor LRT crossing Oak Street at Washington Avenue. The project will improve the system reliability by providing additional capacity for the redevelopment of the area and eliminate a segment of the “pipe in a pipe” construction. The estimated cost of this project is $24,000,000. (Location Map).

o Project #800320, 1-SP-255 and 1-SP-214 Interceptor Rehabilitation - this project will restore the structural integrity of these deteriorated interceptors. As the proposed method of rehabilitation, size of the pipes and general location is similar, the two projects have been merged together for both design and construction. Both of these facilities have been found to have structural defects. Due to factors such as traffic volumes on Como Avenue, the cost of bypass pumping and the disruption to adjacent businesses/residences the method of rehabilitation being proposed is slip lining. Preliminary engineering and design will be completed in 2008. The estimated cost of this project is $4,000,000. (Location Map).

Project #800390, Blue Lake Plant and Metropolitan Plant Service Area Planning - this project originated from the Interceptor Master Plan which identified a number of interceptor facilities requiring needed improvements to convey peak flows from different service areas. Since the development of that plan in 2002, significant growth has occurred faster than anticipated. A number of the projects need to be accelerated and moved from the Master Planning Level to the Facility Planning Level in a concerted, comprehensive and coordinated approach. The project utilizes a single contract and alternative procurement techniques for multiple projects to allow effective management of concurrent studies to take place with limited impact on Met Council Staffing. The estimated cost of this four year project is $10,000,000 of which $1,439,000 is being funded out of Mpls/St Paul Interceptor Improvements project.