Detroit, blue city

Earlier this month, two years of intensive research, data collection, and community engagement culminated in the release of Detroit Future City, a strategic framework report that will serve as a roadmap toward a long term (50+ years) vision for the city of Detroit. One of its key recommendations is that "blue infrastructure" be developed on Detroit's vacant lands and along its roadways in order to promote water quality and decrease the burden stormwater places on Detroit's stressed sewer system.

Detroit's vacant land, says Detroit Future City, is both the city's greatest asset and its greatest liability. If this land is used strategically, the city can emerge as a national leader in blue infrastructure and water management. And if we continue with business as usual, well...

The report notes that "much of Detroit’s 19th and 20th infrastructure is nearing the end of its productive life." This is especially true of Detroit's sewer system, as was recently highlighted in an insightful and squalid report by PBS's NewsHour program. Repairing and expanding sewers and water treatment facilities to ensure continued compliance with the Clean Water Act of 1972 will be extremely costly for Detroit, requiring investments totalling hundreds of millions, if not billions, of dollars.

Detroit Future City introduces a concept that is likely foreign to most: that landscapes can serve as infrastructure for the 21st century. "Infrastructure in the 20th century was used to move, separate, and divide neighborhoods. Now infrastructure can connect them. Neighbors can access and interact with blue and green infrastructure in their own communities," says Dan Pitera, Director of the Detroit Collaborative Design Center at the University of Detroit Mercy and leader of the community engagement aspects of Detroit Future City.

Landscapes are also "less expensive to construct and maintain than conventional systems." One thing's for certain--Detroit has plenty of vacant land that can be transformed into landscape infrastructure. Because resources to maintain current systems, which are already woefully under-maintained, are limited, blue infrastructure is a sensible prescription for promoting a healthy future city.

"How do landscapes function as blue infrastructure?" you might ask. Landscapes can play a role in stormwater management by retaining and filtering runoff that would otherwise flow directly into sewers and natural bodies of water, thus relieving burdens placed on the existing sewer and water treatment system.

Specific types of blue infrastructure detailed in Detroit Future City include swales, stormwater boulevards (large roads that incorporate swales and retention ponds along adjacent lands), retention ponds, detention basins, and rubblized roads. That's right, some of Detroit's lesser-trafficked neighborhood roads could be rubblized and become permeable to rain water.

Detroit Future City divides the city into specific framework zones designated by their population densities and redevelopment potentials. Within each zone, the report details the appropriate land use typologies and development types to be implemented there. Because of weak market conditions and high vacancy rates, certain areas are not suited for traditional types of re-development, i.e. residential, commercial, or industrial uses; therefore, high vacancy areas have the most potential to be converted to blue infrastructure landscapes. Detroit Future City estimates that as much as 29 percent of Detroit's land could be converted landscape infrastructure in the next 50 years.

Dense areas, which happen to produce the most stormwater runoff, have the fewest opportunities for blue infrastructure because of their lack of open space. This does not mean, however, that blue infrastructure can't find its way into these areas. Conveyance mechanisms, such as swales can be installed along roads to carry stormwater to retention ponds and detention basins in lower vacancy areas, and buildings can be can be retrofitted with green roofs.

Detroit Future City urges its readers to reconsider complete streets to incorporate blue and green infrastructure. Unnecessary lanes on wide roads, e.g. Grand River Avenue, can be converted to landscapes that carry stormwater instead of cars, as well as bike lanes and wider sidewalks for pedestrians.

Why does Detroit need blue infrastructure? Detroit's sewer system is massive (consisting of roughly 3,500 miles of sewer lines) and under-maintained. Detroit's sewers are combined, meaning they collect rainwater runoff, domestic sewage, and industrial wastewater in the same pipe. This unholy mixture is routed to the water treatment facility in Southwest Detroit, where it is treated then discharged into the Detroit River. Seems fine, right? Well, sometimes the capacity of the system is exceeded when there is a heavy rainfall, resulting in a dreaded combined sewer overflow (CSO), an event that results in the discharge of untreated sewer water into the Detroit River. CSOs occurred 36 times in 2011.

In order for the current sewer system to prevent CSOs and comply with the tough regulations of the Clean Water Act, Detroit has essentially two options: build a holding tunnel for combined sewer waters at a cost of between $500 million and $1 billion, or gradually implement blue infrastructure elements that ease the burden placed on combined sewers by rainwater. Detroit Future City estimates that a realized blue infrastructure system could have prevented all but two of the CSOs that occurred in 2011.

Blue infrastructure has many benefits, some of them fiscal, some environmental, and others social. A blue infrastructure system can save the city hundreds of millions, if not billions of dollars in systems upkeep and vacant property maintenance costs, can contribute to the environmental health of the city, region, and Great Lakes Water Basin, can transform vacant lands from elements of blight to attractive and productive parcels, and can transform Detroit into a model American city for a new urban form based around sustainability.

Pilot blue infrastructure are already underway. "The Detroit Water and Sewerage Department is implementing small-scale blue infrastructure pilot projects in coordination with SEMCOG and Greening of Detroit in northwestern Detroit. Additional blue infrastructure projects should be aligned with their efforts," notes the Strategic Framework.

Of course, the ideas in Detroit Future City will amount to nothing more than science fiction without a general will towards implementation. Currently, as the framework points out, "state policy does not allow cities to use blue infrastructure to meet long-term control requirements; only hard infrastructure is seen as acceptable way to reduce overflows."

Detroit's zoning ordinance, which would require significant amendments to allow for implementation of many of Detroit Future City's recommendations, has no classifications for landscape infrastructure. Amending these laws and policies are critical first steps in reinventing the city.

Detroit Future City is explicit, saying, "The Master Plan of Policies and Zoning Ordinance should specifically permit all of the land uses identified and defined by the Strategic Framework, including the many landscape typologies defined in this Land Use Element. Doing so will expedite the process of vacant land renewal."

There is no monolithic entity that can single handedly tackle blue infrastructure implementation. The Detroit Water and Sewerage Department is responsible for maintaining and operating the current sewer system and wastewater treatment facility, but they cannot and should not be the only actor involved in promoting water quality in the city. Indeed, there is no monolithic system that can solve our stormwater problems, but rather layers of coordinated systems ranging from individual sites, to neighborhoods, to the city at large.

The realization of the vision of Detroit Future City will require actions by individuals, companies, neighborhood groups, and government agencies. Homeowners can disconnect the downspouts that lead from their gutters into sewers, companies can install green roofs on their office buildings and factories, and community groups can adopt and program blue infrastructure sites in their neighborhoods.