10-29-07 Item 7C, Env Characterization Contractor for TCAAP Property

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Lost Lake Redevelopment City of Mound' Mound, Minnesota . Grant assistance Services provided: . Response action plan . Geotechnical evaluation and surcharge-load design . Plans and specifications . Construction oversight The old Lost Lake dump in Mound, Minnesota, was a marsh until the I 950s, when the city began using it as a disposal site. A significant portion of the filling at the site occurred in 1965 when tornado-derived wastes, including hundreds of tree stumps and limbs, were buried. The dump and waste materials have the potcntial to generate methane gas, and petroleum and other hazardous materials have been monitored in both the groundwater and soil. The city slopped using the dump in 1970 and began looking at redevelopment options in 1984. Throughout the I 990s, the city explored various redevelopment options on top of the existing dump. In 2004, it hired Barr, who recommended completely excavating thc dump materials and pursuing grant funds to help cover the costs. By agreeing to a total excavation, the city increased its chances of receiving state and local grant money and made it possible to mcetthc cleanup standard for a residential development, which will provide greater tax benefits to the city than a commercial development. In mid-2005, with application assistance from Barr, Mound was awarded a $1.47 million cleanup grant from the Minnesota Dep811ment of Employment and Economic Development (DEED) and $221,000 in additional funding from the Metropolitan Council. Working for the city and with the future property developer, Barr completed a pre-design investigation, developed plans and specifications for the site-restoration activities, and prepared a response action plan. Barr also conducted a limited geotechnical settlement evaluation of organic soil (peat) at the site. Some of the soil was to be left in place, and a surcharge load was designed to consolidate the soil in order to meet the developer's schedule for construction. An aggressive three-and-a-half-month cleanup schedule was developed, and Barr assisted in the contractor-bidding phase and provided field oversight during implementation. To prevent inflow from the adjacent wetland during excavation, 30,000 square feel of sheet pile were installed along the perimeter of Ihe site. In all, more than 100,000 cubic yards of waste materials and organic soil were removed from the site and replaced with clean backfill. In addition, a 20,000-cubic-yard surcharge pile was constructed, and 4.7 million gallons of water were treated. A groundbreaking event for construction of the Lost Lake redevelopment was held in November 2005. The project will feature 37 residentialtownhomes and a commercial building and is a key element in the city's "Downtown Mound" revitalization strategy. The development will also include a lighted walking trail and floating dock facilities with access to Cooks Bay and the rest of Lake Minnetonka. 246247v2 Barr E.nglneering Company