In support of its stormwater and street management plan, the City of Lafayette has chosen to integrate Green Infrastructure Best Management Practices (GI BMPs) as part of a “complete project” approach for the implementation of more sustainable urban streetscapes. The North Street Reconstruction and Integrated Stormwater Management project is the first of the City’s historic brick street improvements to utilize GI BMPs to minimize short and long term infrastructure costs while creating an aesthetically pleasing urban greenway through the use of functional integrated stormwater management practices.
Results from the Green Infrastructure Feasibility and Prioritization Study, completed in 2010, identified the North Street corridor as providing the best opportunity among the twelve historic brick streets studied to minimize wet weather flows to the combined sewer system through source control. The recommendation was based on several factors including the existing condition of the roadway, planned capital improvements within the area, and the project’s ability to cost effectively eliminate stormwater runoff to the City’s combined sewer system.
The 2,700 lineal foot project extends along North Street from 3rd Street to Erie Street and serves residential and commercial neighborhoods in the core of the City. It includes replacement of approximately 11,000 square yards of existing impervious brick roadway surface with permeable pavers and subsurface stormwater storage and infiltration and incorporates rain gardens, bioswales, tree planters, and native vegetation to improve water quality and enhance the neighborhood streetscape. The purpose of the design is the detention and treatment of post development runoff through the use of pervious concrete and permeable paver systems along with curb turnouts, sidewalk runnels, and distributed subsurface stone storage and infiltration linked by underdrains. The combinations of integrated GI BMPs serve to filter, store, infiltrate and convey runoff to the overflow connection points at the combined sewer system.
The integrated system has the potential to prevent up to 80% of the project area’s annual stormwater runoff from entering the combined sewer system, providing additional capacity within the system downstream of North Street and reducing the number of overflow events into the Wabash River.
In addition to integrated stormwater management, other elements include deconstruction and material salvage, street surface reconstruction, new sidewalk and ADA ramps, replacement of existing sewer laterals and existing water services, and downspout disconnection.
The opportunity exists for public education and outreach related to green infrastructure and development of data showing potential benefits for inclusion of green infrastructure integrated stormwater management in future Long Term Control Plan and infrastructure rehabilitation projects.
As a sustainability-based approach to project design and management, Triple Bottom Line (TBL) analysis investigates and presents the expected economic, environmental and social benefits and costs associated with a prospective project. TBL analysis can be used as a tool to compare different project options, and to select a project option that is most likely to provide the desired short and long term effects. It is generally understood that to achieve sustainability in project design and implementation, the relationship between social, environmental and economic impacts (both positive and negative, short and long term) must be considered and managed, to meet the degree of sustainability desired. The economic portion of TBL analysis focuses on the impact of the project on the local, regional or larger economy, and concerns the economic impacts of the project on stakeholders. The environmental portion of TBL analysis focuses on the impact of the project on ecosystems, land, air, water and other natural resources. Environmental indicators relate to inputs and outputs of materials, energy, pollution or waste products. The social portion of TBL analysis focuses on the impact of the project on stakeholders, communities and social institutions. Social indicators relate to the impacts of the project on the communities in which it takes place.