Ford Allen Park Clay Mine Landfill - Fairlane Green Redevelopment
From clay mine to pay dirt
John G. Kozuh, City Engineer, City of Allen Park, Michigan
Patrick B. Podges, JM Olson Corporation, St. Clair Shores, Michigan
A very significant vote was taken in December 2002 by the City of Allen Park, Michigan, City Council; a vote that may result in the most significant economic impact in the City's history. The council voted unanimously for the redevelopment of Fairlane Green, a one million square foot retail center on what had previously been considered unusable land by many in the area.
The reason it was considered unusable was because since the mid-1950s Ford Motor Company, which owned the 243-acre site, used part of the property to mine clay reserves for the brick and cement industries. Cognizant that the site had the ideal geologic formation for a secure landfill, the clay excavations were subsequently backfilled with non-putrescrible waste generated from the nearby Ford Rouge Center.
The Council also voted in December 2002 to designate the land a brownfield site. Brownfields are environmentally challenged sites that often require additional measures to develop. Designating the Allen Park Clay Mine Landfill a brownfield allows Ford to capture new real property taxes generated by the project for up to 30 years to recoup as much as $30 million of extraordinary costs to clean up and redevelop the site. In the meantime, any new personal property taxes generated by the site will be collected by the City and other taxing jurisdictions.
From the Michigan Department of Environmental Quality's perspective this brownfield redevelopment project is a unique opportunity. This high-profile project to redevelop the landfill site with over one million square feet of retail shopping space is the largest of its kind in this state. The proposed redevelopment will return a significant piece of property that would otherwise remain vacant to productive use, providing jobs, services and tax base to the local community.
The challenge, in accordance with the brownfield designation, was to ensure that all the regulatory requirements of Parts 111 (Hazardous Waste Management) and 115 (Solid Waste Management) of Michigan's Natural Resources and Environmental Protection Act, Act 451, as amended were addressed. To do this entailed looking at innovative approaches to addressing the unique regulatory and technical issues associated with constructing this type of development on a site subject to both Parts 111 and 115. To resolve these issues required internal coordination among MDEQ staff responsible for Part 111, Part 115, and enforcement, then coordination with the legal staff for Ford and their partner developer to put together a post-closure plan that addressed all the regulatory requirements. The post-closure plan was approved by the MDEQ and establishes procedures to be used in the event construction requires intruding into the landfill or landfill cover.
|Fairlane Green Redevelopment rendering|
Since the development sits on top of the landfill, several hundred thousand yards of clay were trucked to the site to provide a "buffer" between the existing landfill cap and the proposed development surface. One of the greatest challenges has been determining the proposed surface elevations to balance the cost of importing and placing fill material versus the cost of intruding into the landfill cap.
JM Olson Corporation, located in St. Clair Shores, Michigan, the Construction Manager on the site work package, contracted with Angelo Iafrate Construction Company for the Fairlane Green Phase I development project. As the site work contractor, Iafrate is responsible for all earthwork, building pad development, grading, utility installation and general site development to convert the once-Clay Mine Landfill into a viable retail development.
Initial earthwork operations included the mass balancing of more than 750,000 cubic yards of onsite and imported clay fill, surcharging of the existing landfill surface with more than 300,000 cubic yards of clay fill, construction and maintenance of temporary roadways, grading of over 4,000,000 square feet of subgrade and construction of 900,000 square feet of HDPE lined detention basins.
Utility operations include the excavation and installation of sanitary sewer (8,300 feet), storm sewer (13,000 feet) and water main (16,000 feet). Approximately 17,000 feet of site utilities were installed in specially constructed utility corridor trenches. These trenches were lined with a combination geosynthetic clay liner and HDPE liner to prevent potential exfiltration and/or leakage from the site utilities from draining into the landfill to reduce the impact of settlement on utilities. Both the sanitary sewer and water main piping are HDPE piping so that there is enough movement in the system if needed; all the while the system is heat-fused together resulting in a jointless sanitary and water main network. In addition, pipe slopes were increased to reduce the potential for reversal of pipe slopes.
NTH Consultants, Ltd. provided environmental and geotechnical engineering services for Fairlane Green. This project faced several challenges, including reducing post-construction settlement, managing methane gas, and managing utility intrusions into an existing engineered landfill cap. Because construction activities were required to be limited to areas above the engineered cap, the conflicting nature of the need for extensive fill and requirements for minimal long-term settlement created a need for a carefully managed approach to final construction details.
To minimize the potential for intruding into the existing engineered landfill cap, the utilities and foundations were to be placed generally above the landfill cap in an engineered fill layer. This required the placement of 5 to 14 feet of fill across the cap area to raise the landfill grades and provide subgrade for the proposed development. The placement of these fills and proposed structures may induce significant deformations within the underlying wastes and foundation soils, resulting in settlements at the development surface. To reduce post-construction settlements to acceptable limits, the project team designed a preloading program and used lightweight fill at selected areas.
The building areas were preloaded with soil fills that exceed the anticipated final loads. Settlement plates were installed and monitored during and after surcharging operations. The surcharge fills were removed after the rate of settlement dropped to an acceptable level. In addition, to reduce post-construction settlements in areas with large fills, approximately 50,000 cubic yards of lightweight geofoam blocks were used to replace soil fills within the footprints of the proposed buildings. The typical geofoam block is 2'-0"h x 3'-0"w x 8'-0"l and is placed in alternating layers based on a pre-engineered design. The geofoam ranges in overall depths below finished floor from 2'-0" to 8'-0".
Building construction of the Fairlane Green retail complex on a former landfill has also resulted in some rather unique construction approaches. These approaches include the placement of lightweight geofoam block for subgrade stabilization, installation of a gas management system and construction of utility intrusion trenches.
An HDPE liner and gas collection piping system is being installed in the buildings. This system is located between the lightweight backfill and clay fill materials and the building's concrete slab. The 4" collection piping is placed in an 8" sand layer and is used to gather any potential landfill gases that may permeate through the landfill cap to the surface. The HDPE liner serves as the separation barrier between the concrete slabs and fill materials. The liner is fusion-welded along the entire building perimeter to HDPE inserts in the concrete foundations in order to seal the entire area.
While the material disposed at the site is primarily non-putrescible waste, the project team elected to install a gas management system to manage limited methane gases that were measured at several locations across the site. The system consists of the following main components:
While every effort has been made to avoid intrusions into the landfill cap, there were areas where intrusions were inevitable without the placement of significant additional fills. For these areas, special details were developed to place the utilities inside specially constructed utility corridors that intruded through the cap. These intrusions required the excavation of limited volumes of existing wastes and the reconstruction of an upgraded cap.
Landscape site plan
In addition, innovative landscape design and sustainable systems included in the site development sets Fairlane Green apart from other power centers. The use of unique bioswales for stormwater management, and the sustainable, low-maintenance landscape environment, provide an interesting shopping experience with an environmental character.
Stormwater from the roads, parking lots and rooftops is captured and treated to improve water quality, reduce potential pollutants and slow the rate of runoff to reduce downstream flooding. A portion of the runoff is filtered through a bioswale along Fairlane Boulevard. The bioswale is landscaped with native shrubs and wildflowers that are adapted to wet soils and even periodic flooding. Once established the plantings, such as Michigan Holly, Blue Flag Iris and Joe Pye Weed, will provide habitat for many small birds, mammals and insects. Sidewalks and walking paths will provide an easy way for shoppers to get a firsthand glimpse of this unique environment.
Prairies of native grasses and wildflowers, such as Little Bluestem, Gray Coneflower and New England Asters, will surround the shopping areas, again providing habitat and reducing the need for weekly maintenance such as mowing, irrigation and fertilizers. Native trees and shrubs line the hedgerows, which are strategically located throughout the parking lots. The hedgerows are broad, linear green spaces that are large enough to provide a healthy growing environment, and also break up the parking fields into smaller spaces. A special blend of fescue grasses will provide a green edge to planting beds, but need little mowing.
Planters are strategically located throughout the retail areas and feature native and sustainable plants, including living walls of vine-covered trellises such as Virginia Creeper and a native Clematis.
Initially the plantings will be irrigated with an automatic irrigation system, supplied with water from the detention ponds. The unique selection of plants and the absence of traditional turf-grass lawns significantly reduce the need for long-term irrigation and eliminate the need for daily watering. In fact, no potable water will be used in the irrigation system.
The landscape at Fairlane Green is a careful balance of plantings that will do well in the unique environment of the former landfill, high above the surrounding region, as well as provide a positive shopping experience, visibility of the stores and meet the requirements of the City, local county and state permitting agencies.
To assist in monitoring the work on the site, the City of Allen Park contracted with Ken P. Buccilli, LLC of Farmington Hills, Michigan to oversee all of the inspection of the infrastructure, pavement, landscaping and the Michigan Department of Environmental Quality (MDEQ) soil erosion items on the project. A structured documentation program was designed and implemented by Buccilli. Minimum daily requirements for each inspector included a construction report, stationing and verification of pipe invert elevations, in-place materials, separate daily log in a job site master book for each underground crew, logging of production, unit footages, special notes and any approved changes. Upon completion of each inspector's daily reporting, this information was then documented on a master set of drawings which upon completion will be turned over to the City for future reference. This critical daily record-keeping process was necessary due to the uniqueness of this project.
The idea behind Fairlane Green, beyond being a retail destination, is to be a multi-environment experience. The site environment has been designed to be ecologically friendly by incorporating bioswales and ponds for retaining, filtering and reusing rainwater for landscape irrigation. The building environment has been designed with a prairie-style theme. This style has human scale proportions, and uses natural stones, bricks and colors that have a comfortable but stimulating presence. Many of the building materials have also been recycled or produced locally to reduce environmental impact. As such, the buildings will seek LEED certification under the Core and Shell criteria for developments. The LEED (Leadership in Energy and Environmental Design) Green Building Rating System is a voluntary, consensus-based national standard for developing high-performance sustainable buildings. Moreover, the landscape environment has been skillfully incorporated using native, low water-use plant materials in creative designs and in close association with the buildings.
The integration of all these environments into one destination was a challenging and optimistic approach which will produce an experience that is pleasant, enjoyable and memorable for years to come. "The City of Allen Park is fortunate to partner with a world-class developer at a time when we face tax revenue shortfalls," said Mayor Richard Huebler. "The Fairlane Green Project, by Ford Land Development, provides the largest known shopping complex located on a landfill. The City worked with Ford Land to establish the Brownfield Authority and continues to assist with their development. I am very proud of this reuse of land, which will provide new shopping opportunities for our City and create additional employment opportunities."