Green Parking Lots in Cold Climates - APWA Award

City of Southfield Economic, Innovative and Green Civic Center Municipal Parking Lot APWA Project of the Year Award Mayor - Brenda L. Lawrence DPW Director - Gary Mekjian DPW Deputy Director - Mike Habowski City Administrator - James Scharret

Project Details Project: Civic Center Municipal Parking Lot Client: City of Southfield 26000 Evergreen Road P.O. Box 2055 Southfield, MI 48037-2055 Project Cost: $1.1 Million Design Cost: $90,000 Construction Cost: $1 Million Design Completion: Summer 2007 Construction Completion: Spring 2008 Consulting Engineers: OHM (Orchard, Hiltz & McCliment, Inc.) Contractor: Asphalt Specialists, Inc. Geotechnical Analysis: Schleede Hampton Associates, Inc.

Project Site: 26000 Evergreen Rd., Southfield, MI, 48076

Project Background Come to the City of Southfield, and according to its tag line, you are at The Center of it All™. So it was a problem for City officials to invite the public to the City’s municipal complex where the roads surrounding the complex had badly deteriorated. In addition, the original configuration of the parking lot posed safety issues for pedestrians and the path to the building was not truly ADA compliant. The overall condition of the parking lot was poor. Concrete thickness was substandard, base failure was evident in over 50% of the parking lot causing pavement settlement and drainage problems. The existing topography of the parking lot directed storm water run-off to sheet flow to the south and collect in a series of catch basins. Storm sewers conveyed run-off directly to the Evans Ditch, a tributary of the Rouge River. The deteriorated condition of the pavement caused debris to be carried to the catch basins and made it impossible for the lot to drain effectively after storm events; ponding water remained for several days until it evaporated. The City of Southfield contacted OHM to determine the best repair option. The project goals were to improve the parking lot condition, reduce its environmental impact and enhance safety and usability. Based on the existing conditions, OHM recommended the lot be reconstructed rather than rehabilitated to achieve a satisfactory service life and meet the City’s goals. This was also the most cost effective option. M-1 0 I-696 I-696 TELEGRAPH RD. SOUTHFIELD RD. SOUTHFIELD CIVIC CENTER DRIVE CIVIC CENTER TEN MILE EVERGREEN RD. M -1 0 NINE MILE

Reconstruction Improves Environmental Impact The City’s administration took the lead in environmental stewardship. An environmentally sensitive way to manage parking lot storm water run-off is to incorporate porous asphalt pavement into the design. Porous pavement is a permeable pavement surface and was used for one-third of the City’s parking lot. Under the pavement, a reservoir temporarily stores surface run-off before infiltrating it into the subsoil. This process provides some water quality treatment. It also reduces the amount of storm water run off into the drainage system and provides for groundwater recharge. When the City decided to incorporate innovative design solutions to improve the site’s sustainability they didn’t stop at porous pavement. Another design element was reconfiguring the drainage to route storm water through a bioswale before it outlets to the Evans Ditch. A bioswale is a shallow depression created in the earth to accept and convey storm water run-off. It uses natural means, including vegetation and soil, to treat storm water by filtering out contaminants in the water. This feature collects up to 80% of the run off from the parking lot, further reducing the direct discharge of contaminants to the drains.

Safety and Accessibility Benefit the Community Safety improvements were another major motivator for redesigning the parking lot’s traffic flow. In the existing lot, an access road separated the parking area from the municipal buildings, creating potential for conflicts between visitors to city hall and emergency personnel responding to calls. Traffic volume within the municipal complex has increased significantly since the complex opened in 1964. Today vehicles accessing the site are rerouted to the outside limits of the parking area, reducing potential conflicts between pedestrians and vehicles. Meeting ADA requirements for accessibility was another important project goal. All pedestrian facilities were updated to meet ADA requirements. This required slight shifts in pedestrian traffic patterns to ensure that grades and walk alignments worked in relation to the accessible parking and the building. A fuel station located in the middle of the parking lot added complexity to the design and construction planning, as it had to remain in service and in the current location. While the City hoped to have the project completed in a single construction year, the schedule proved to be too aggressive. The project design finished in July 2007 and construction concluded in the spring of 2008.

New Technology can Create Adverse Conditions • Porous pavement has received some criticism as not being effective in cold-weather climates. OHM’s design team researched applications in Innovative design elements sometimes mean construction challenges. climates similar to Michigan’s and determined that evidence supported Since porous pavement is a relatively new process, success depended the use of porous pavements in cold climates, as long as the pavements in part on the contractor’s determination, creativity and resourcefulness were properly maintained. Porous pavements should be plowed, just during installation. Key lessons learned included: like traditional pavements. However, if de-icing agents are used, “dirty” • Porous pavement design mix (which is manufactured without fine rock-salt with significant sediment should not be applied, as it will clog materials) is meant to be loose and moveable, at least until the the pavement, filling the voids that allow water to filtrate. Many owners surface hardens. This is contrary to traditional pavement designs. have found that snow melts much more quickly from the porous pavement and de-icing agents are needed less frequently. This project • The design cross-section for the pavement included a base will contribute to a better understanding of porous asphalt’s long-term course or filter course of MDOT 6AA stone. This acts as a stable performance in cold weather climates. surface on which to place the porous pavement, and protects the filter fabric placed on top of the reservoir course. On this project, Porous pavement requires more frequent maintenance than traditional during construction, the contractor had a difficult time obtaining the impervious paved surfaces. Over time, the voids that encourage infiltration specified 6AA stone, and substituted a 6A natural stone. Although fill with dirt and debris, reducing its effectiveness. The Michigan Asphalt the gradation is similar, the 6AA stone is a crushed limestone that Paving Association recommends that porous pavement be cleaned with a would provide aggregate interlock for a stabilized base. The natural vacuum sweeper at least twice a year to maintain proper function. Adding round shape of the substituted 6A material allowed the stones to slip more routine maintenance projects to an already overtaxed maintenance and slide against one another and made paving a difficult task. One crew is challenging for any municipality. construction worker likened it to “driving on a bed of marbles.” While The site’s bioswale also requires periodic maintenance including weeding applying the asphalt, the paving equipment created deep ruts in the and replanting to keep the vegetation healthy and functional. The bioswale shifting base stones. To place the first lift of asphalt, the contractor was populated with nearly 2,000 plants. turned to lighter equipment and manual raking. • Foundations for the parking lot lights were difficult to secure in the looser base material during construction. The parking light foundations were changed to a foundation with a larger surface area after a pole was toppled by a construction vehicle.

Social, Economic, and Sustainable Design Bolster Community Relations Parking lot improvements addressed the City’s desire to make the municipal complex accessible and safe for all citizens. One of the project’s primary goals was to allow disabled persons to traverse a barrier-free path from a vehicle or the bus stop to all of the municipal facilities within the complex. By rerouting the vehicle access road outside the parking areas, potential conflicts between people and vehicles were greatly reduced. After installing the porous pavement, municipal workers demonstrated the porous surface’s ability to absorb water by spraying 1,000 GPM from a fire-hose. The water quickly disappeared with no trace of ponding. Ecological improvements at the site are substantial. Since the parking area serves the Police Station, large amounts of salt are regularly deposited to keep the driving surface ice free at all times. Other types of vehicle run- off also affect the water quality in the immediate area. A typical bio-swale however, provides up to 80% pollutant removal, including decreases in petroleum products, excess nutrients, metals and sediments found in storm water.

Complexity Reconfiguring the lot’s traffic flow was complex because the area hosted a number of municipal functions: city hall, Meeting ADA requirements for accessibility was an the police station, a golf course and a new library. Traffic important project goal. The site was bound by existing volume had increased significantly since it was originally buildings. There were also new guidelines to interpret and built. The area surrounding the Civic Center Municipal meet through the design. During the project a retaining complex is distinctly urban, with high traffic counts and wall/ramp adjacent to one of the buildings was removed close proximity to heavily traveled freeways. and regarded to meet slope requirements. It was a significant challenge during both design and Pervious asphalt pavements are not yet commonly used in construction to meet the project’s aggressive schedule. Michigan. The differing nature and function of the materials The parking lot serves an entire municipal complex, so it had a significant impact on the pavement design, the was important to the City to minimize the disruption as lighting system design and the construction of the project. much as possible. A fuel station located in the middle of the parking lot had to remain in service and unmoved. This impediment added complexity to design and construction planning.

Engineering to Advance a Community World Class City The Southfield Civic Center Parking Lot reconstruction clearly Throughout the planning, design and construction phases of improves the quality of life for residents and visitors. Thanks to this project, OHM worked with the community and its leaders to the foresight of community leaders, the City was able to: provide ideas and various methods to reach the city’s goals. OHM created several options for redesigning the parking lot, detailing • Install porous pavement which reduces pollutants in storm the benefits and negative aspects of each approach. water run-off • Help alleviate flooding and contamination to streams OHM used its expertise in ADA compliant design to deliver a project • Increase groundwater recharge that conformed both to FHWA’s standards and the City’s stricter • Establish a bioswale to collect much of the remaining run- building code. Most satisfyingly, a local citizen who is wheel-chair off and further decontaminate the storm water bound tested accessibility of the parking lot, its features and the • Remove much untreated storm water to the nearby Rouge building approaches with success. River. • Improve the aesthetics and functionality of the Civic Center City of Southfield employs an engineering staff. Although OHM Complex. designed the entire parking lot project, the City wanted to provide • Smooth vehicular and pedestrian traffic flow and create as much of the construction engineering services as possible. safer access for all users. OHM assisted on an as-needed basis for construction engineering and inspection, but performed all of the construction staking. The new parking lot and surrounding area now demonstrate Interweaving these responsibilities with City staffers often meant the best of this world-class City and its administration: socially responding to requests within short timeframes, and being flexible responsible, forward thinking and environmentally conscious. A in the roles on the project. City at The Center of it All™.

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Green Parking Lots in Cold Climates - APWA Award

by OHM Advancing Communities on Apr 13, 2010

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Green Parking Lots in Cold Climates - APWA Award — Presentation Transcript