CCP 03-25-2008 - Laserfiche WebLink

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The quantity of unexpected and expensive waste items that may be encountered during dump excavations which require off-site trucking/disposal at landfill (asbestos materials, industrial wastes, etc.). 2. The potential need to upgrade to an active landfill gas collection system rather than a more affordable passive landfill gas collection system (this is an on-going point of discussion with MCPA). 3. The uncertain bid prices that may be obtained for the work depending on timing and market conditions. In 2007, the City obtained very favorable construction pricing for other NW Quadrant projects given the current slow market for earthwork contractors, but that could change depending on the actual schedule for the dump closure. 4. The required volume of off-site borrow soil is uncertain and will be impacted by the availability of existing stockpiled soil, the final development grades required, and whether basements will be included in the future buildings. 5. The sequencing of the work could affect the total price. It is anticipated that the overall cost will be more if it is conduced in phases rather than as a single construction project. The optimistic schedule for completing the east side cleanup is: • Obtain MPCA approval of the Feb. 2008 RAP in April • Seek DEED and Met Council Cleanup Grants on May 1, 2008 • Solicit bids for the work in July if funding for the project is available • Begin dump closure in August 2008, with a potential focus on clearing Block A to accommodate the Hotel development • Gain access to the PO and RR properties by Fall 2008 • Seek additional cleanup grant funding on Nov. 1, 2008 • Complete dump closure/pond construction in 2009 West Side The environmental issues for the west side of the NW Quadrant are largely concentrated in the 25 - acre portion of the site located north of the "Tract 1" line on the former MW Asphalt property. South of that area, the City and their development partners were able to advance development efforts over the past two years without significant environmental issues. Those developments included the APi development, the new stormwater pond, and public infrastructure for the previously planned residential development in Tract 1. A vapor survey of the Tract 1 area in 2007 identified very low levels of volatile organic compounds in the deep soil gas that are believed to be originating from contaminated areas located elsewhere on the NW Quadrant. MPCA has concurred that the low level vapors in Tract 1 can be addressed for future buildings with relatively low cost, sub -slab vapor barrier construction methods that are commonly used in new buildings. The significant environmental impacts on the MW Asphalt property are the results of two Superfund Sites (NW Refinery and Trio Solvent) and a petroleum release site. Prior to acquiring MW Asphalt, the City worked with the MPCA voluntary cleanup program to investigate the environmental conditions at MW Asphalt and gain approval for a preliminary cleanup plan to address shallow soil contamination located above the water table in support of the planned residential development. The City also obtained a "No Association" liability assurance letter from MPCA for the non -petroleum impacts at MW Asphalt in December 2006. The cleanup plan did not include groundwater remediation, which was consistent with previous MPCA decisions for the portions of the Superfund CADocuments and Settings\gferne\Local Settings\Temporary Internet Files\OLK18D\City Council Work Session March 2008.doc Page 2 of 4