Michigan LID Case Studies

Chapter 10 Michigan LID Case Studies This chapter highlights several developments that have Rain gardens and bioswales incorporated numerous LID best management practices The first phase, or neighborhood, of the development into their designs. These best management practices includes 17 homes. Each home has at least one rain help communities meet their land use planning goals of garden that accepts roof-top drainage. During the design protecting public health, safety, and welfare, as well as process, the native topography of the site was retained preserving community character, and making desirable as much as possible to preserve the natural drainage. places for people to live and work. Any stormwater runoff generated from the neighborhood is managed by the depressions where infiltration The following case studies showcase the implementa- capacities have been augmented by native vegetation to tion of numerous best management practices working create bioswales. together through integrated systems. Almost all compo- nents of the urban environment have the potential to serve as elements of an integrated stormwater management system. This includes using open space, as well as rooftops, streetscapes, parking lots, sidewalks, and medians. In addition, these case studies represent various size developments as well as a diverse range of land use types and property ownership. LID is a versatile approach that can be applied equally well to new development, urban redevelopment, and in limited space applications such as along transportation corridors. Pokagonek Edawat Housing Development Bioswale Source: Pokagon Band of Potawatomi Indians The Pokagonek Edawat Housing Development is located in Dowagiac, MI in Cass County. The Dowagiac River Watershed Management Plan was used as the basis for The rain gardens and bioswales required approxi- the design principles in this project, which led to inte- mately two growing seasons to become established. grating LID techniques into the development. The General Land Office survey notes indicate that the development location was a Mixed Oak Savanna circa The Pokagon Band of Potawatomi Indians Tribal 1800s. Thus, plant species associated with savanna Development used nine LID BMPs to arrive at an over- and prairie settings were selected. Initial maintenance all strategy that protects and uses natural flow pathways largely included watering and weeding, and infill plant- and preserves natural features in overall stormwater ing, as needed. Currently, periodic weeding is the main planning and design. This development also maximized maintenance activity related to this BMP. stormwater infiltration to ground water through: For the bioswales, a combination of plug placement and • Rain gardens and bioswales, seeding with a warm season grass drill was used, along • Sensitive area preservation, with an initial fertilizer application. A mixture of warm • Cluster development, and season grasses and forbs were selected for the bioswale vegetation. Initial maintenance largely included water- • Porous pavers. ing and weeding. Weed management during the first year included mowing. Current maintenance activities include prescribed burns and selective mowing. All maintenance is performed by the Pokagon Band Hous- LID Manual for Michigan – Chapter 10 Page 387 ing Department. Most maintenance costs involve the care of limited turf grass that surrounds each home. Watering of the rain gardens is conducted as needed during prolonged dry spells. Natural flow path and sensitive area preservation The site was formerly agricultural fields mixed with woodlots. The woodlots and native topography of the site was retained as much as possible to preserve the natural drainage, and the lots and streets were designed around these depressions. Land between these depressions that is not included as a lot and spared via clustered design is scheduled to remain as open space. Clustering homes Plant species associated with savanna and prairie settings Source: Pokagon Band of Potawatomi Indians were selected to mimic the presettlement ecosystem. Native vegetation was established by seeding the open space areas with a warm season grass and forb mixture. This was enhanced with selective placement of plugs. Turf grass was established in small, select locales within the open space to create social gathering areas. Addi- tionally, groomed walking trails were designed into the open spaces and woodlots. Walking trails will connect to subsequent phases of development to create a walk- able community. Annual maintenance costs are chiefly associated with prescribed burns, followed by lesser costs to maintain the limited areas of turf grass. However, the frequency of prescribed burns may be reduced in the future as the landscape matures. Reduced imperviousness Source: Pokagon Band of Potawatomi Indians Cluster development The housing units have been clustered in loops following ing surface. The street’s three-foot depth subbase is the site topography with 17 units in the first phase and 16 composed of a bottom layer of road-grade gravel and units scheduled for the second phase. Clustering reduced crushed concrete overlain by coarse grained sand to development costs by shortening roads and utility runs. help facilitate stormwater infiltration. The earth at the Smaller lots have reduced lawn and yard maintenance. bottom of the subbase is graded with a slight slope Clustering also allows for shared bioswales to be estab- toward the central bioswale to assist with drainage lished among the buildings, helping to manage runoff. during very heavy precipitation events. The footprints of the homes were minimized, through smaller hallway space and eliminating foyers, while still Additionally, the sidewalk was constructed using six providing for maximum usable space. inches of reinforced concrete and is actually part of the roadway. It is designed to accommodate the weight of Porous pavers heavier emergency vehicles and allow passage in the The street design for the first phase of the development presence of street traffic and parked vehicles, if needed. is 1,800 linear feet long with approximately 25,000 This approach also limits impermeable surfaces through square feet of interlocking pavers for the primary driv- the use of pavers and a narrower streetscape, encourag- LID Manual for Michigan – Chapter 10 Page 388 ing slower traffic flow while promoting the walkability ment, the Taubman Student Services Center uses the of the neighborhood. following best management practices: Curb and gutters were not used in the street design, • Vegetated roof, since the permeable nature of the pavers and subbase • Bioswale, and made it unnecessary to collect and divert stormwater. However, a concrete border was constructed to anchor • Soil restoration. the interlocking pavers into place at the outer edges of Vegetated roof the street. The building’s 10,000 square-foot living vegetated roof The tribal maintenance department is responsible for is created with layers of insulation, roof membrane, maintaining the streets. Placing sand between the pavers drainage fabric, and a four-inch granular composition is conducted as needed, along with periodic weeding. that supports nine different species of sedum ground cover. About nine inches thick, the roof offers more Additional information effective insulation than traditional roofs and expands The pre-existing use of the land was agricultural and and contracts with seasonal changes. It is expected to covered with large areas of wooded open space. Wood- last about 40 years, more than twice the lifespan of lots were maintained and treated with a tree management traditional materials. plan to open the canopy as well as to remove invasive tree species. Invasive underbrush was removed to assist The vegetated roof also controls and reduces stormwa- propagation of remnant native vegetation. Half of the ter runoff. With normal rainfall, about 60 percent of the Phase I development was integrated into a wooded water will be absorbed by the roof while the remainder portion of the parcel for aesthetics and variation. Soil drains into a 10,000-gallon underground cistern to be types within the property range from sandy loams to used as “gray” water for flushing toilets and for irrigat- gravelly sands. ing the campus quadrangle. The weight of the roof is estimated to be 10 to 12 pounds per square foot with a Additionally, the wooded areas have been identified as saturated weight of 15 pounds per square foot. potential conservation areas in a study conducted by the Michigan Natural Features Inventory for a regional green infrastructure project within Cass, Van Buren, and Berrien Counties. The restoration-based concept for the Pokagonek Edawat development demonstrates that conservation and development can be compatible. Lawrence Technological University – A. Alfred Taubman Student Services Center The 42,000 square-foot A. Alfred Taubman Student Services Center, located on the Lawrence Technologi- cal University Campus in Southfield, MI, in Oakland County not only meets the requirements of the impor- tant student services functions it is designed to house, but is also a “living laboratory” of sustainable design and engineering. Built to U.S. Green Building Coun- cil’s Leadership in Energy and Environmental Design (LEED) specifications, the Taubman Student Services Center addresses the criteria of sustainable site devel- Vegetated Roof at Lawrence Technological University opment and construction, recycled materials selection, Source: Lawrence

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