About the author: Jacob Dorman is region regulatory manager for Contech Engineered Solutions. Dorman can be reached at [email protected].
Using green infrastructure (GI) practices to treat runoff at its source while delivering environmental, social and economic benefits makes sense as municipalities seek to achieve volume reduction and water quality improvements. GI practices not only aid in meeting storm water management goals, but also improve streetscapes, neighborhood livability and redevelopment opportunities. However, GI is not a silver bullet that works for all applications, and the development community needs a comprehensive set of tools, including innovative best management practices (BMPs), to help local governments achieve their compliance goals. Each jurisdiction should tailor guidance to its community priorities.
Comprehensive Plans
A locality’s comprehensive plan guides decision-making related to the built and natural environments. In that context, it provides a framework for how the locality chooses to grow and what it may look like in the future. Growth is a hot-button topic, and how a locality grows has a direct effect on its ability to effectively manage storm water runoff. Typically, high-density communities develop with greater residential densities and mixed-use commercial development to discourage sprawl. Low-density communities develop via low-density residential development, single-use commercial development and greenfield deforestation. Both patterns present storm water management challenges.
When adopting comprehensive plans, localities should encourage innovation and adaptation in addressing storm water management by recognizing the unique challenges posed by development and set policies that provide the development community with successful implementation tools.
An example of this would be creating broad policies that meet municipal separate storm sewer program requirements and total maximum daily load action plans via flexible strategies aimed at utilizing GI practices, while also identifying and incorporating additional BMPs that can either complement GI practices or be used when GI is not feasible. Additionally, manufactured and other BMPs often can be used on difficult sites where GI is not feasible.
Manuals & Zoning Ordinances
Many localities rely on local public facility manuals related to standard details, specifications and practices to guide development within public rights of way, on public property, and in some cases, private development projects. The manuals need to be flexible enough to select the most appropriate solutions for the given site conditions and constraints, regardless of who owns it. Examples include reducing vehicular travel lane widths to reduce imperviousness, enhancing pedestrian features and streetscapes via landscaped BMPs, and allowing combinations of structural and non-structural BMP treatment trains to be constructed for storm water management.
Zoning ordinances govern the type of land use allowed in a jurisdiction. Land use has a significant impact on local water quality. The uses permitted have a direct correlation to the quality and quantity of runoff that flows from a property. A suburban shopping mall, for instance, is a fairly intensive land use with significant swaths of impervious parking spaces that increase runoff volume and pollutant loads. Instituting parking maximums is one way to reduce overall imperviousness, create storm water management design flexibility and potentially reduce costs.
Redevelopment projects are not without their own sets of problems, such as poor soils, high imperviousness and constrained lot sizes. Zoning for redevelopment situations should ensure flexibility to use GI where feasible and other BMPs where GI is not realistic. An example of this is the use of flow-through treatment practices, combined with underground or surface detention facilities, as an equivalent to GI.
We should remember that GI practices are sound, but not always possible or practical. Local development guidance should encourage GI while providing flexibility to use all available BMPs capable of meeting water quality goals. Failing to do so can push development into unwanted areas and encourage sprawl. If the goal is to treat runoff at its source, GI tools, and those that complement them, should be considered a resource for the development community and be included in local guidance documents. The environment is the ultimate winner.
