Across the United States, education institutions are building classrooms, research facilities, stadiums and residence halls. These facilities have one thing in common—impervious surfaces. Hard surfaces such as rooftops and pavement prevent rainfall from soaking into the ground and force water to flow quickly overland into local waterways.
As schools look to expand, stormwater management master planning can help institutions cost-effectively adhere to complex regulations while harnessing stormwater to improve aesthetics, reduce water consumption, enhance pedestrian safety, and lower landscape maintenance costs.
The Science of Stormwater
Scientists’ understanding of the effects of urban stormwater runoff has changed significantly over the past 30 to 40 years. Once thought to be primarily a source of flooding, scientists now recognize that stormwater runoff harms waterways by carrying with it a battery of pollutants. The physical force of increased stormwater runoff also erodes stream channels, disrupting habitats and causing infrastructure damage.
Along with the progress in stormwater science, stormwater regulation, once focused on flood avoidance, also has evolved. Regulations now incorporate a range of requirements designed to remove pollutants, slow down stormwater, and, most of all, soak it into the ground. These requirements can be met through the use of sustainaable stormwater practices such as green roofs, rain gardens, and porous pavement. Although new regulations have proved challenging for institutions, they also have changed how stormwater is viewed: from a waste product to a resource.
The benefits of this new stormwater management paradigm can be seen on school and college campuses. Cisterns can be used to capture rainwater, and schools do not have to use costly potable water for non-potable uses such as landscape irrigation. Rain gardens can double as low-maintenance landscape features; larger features, such as constructed wetlands, can provide wildlife habitat and passive recreation benefits. Adopting new stormwater practices also can ease persistent erosion or flooding problems. In other locations, rain gardens can double as traffic calming features or frame pedestrian pathways to discourage shortcuts through quads.
Stormwater master planning outlines investments in stormwater infrastructure that meets regulatory requirements and accrues other social, environmental and economic benefits. Typically, a stormwater master plan will build on an existing campus master plan or expansion plan, outlining the stormwater best management practices (BMPs) needed to meet regulatory requirements for each campus expansion project, but also considering how stormwater investments within existing built areas could be beneficial.
Stormwater master planning provides important benefits for campus expansion programs. For instance, developing an integrated stormwater plan (as opposed to individual plans for each campus expansion project) can help streamline the regulatory process, provide cost savings and offer flexibility in meeting regulatory requirements through trading or offsets. Stormwater master planning also can help campuses earn campuswide stormwater-related LEED credits.
Charting the Course
Stormwater master planning starts with goal setting and a simple question—what do we want our stormwater systems to do? In many cases, the answer might start with getting through regulatory requirements or preventing flooding, but it doesn’t need to end there. In the new paradigm of stormwater management, goals are diverse, innovative and sometimes untraditional. For instance, placing rain gardens in existing turf areas can eliminate landscape trouble spots, while reducing energy and water usage associated with mowing and watering. Regardless of the goals chosen, goal setting should be collaborative and inclusive, and involve a diverse stakeholder group that includes architects, public-works staff, administrators, faculty and students.
Goal setting involves linking stormwater investments with campus sustainability initiatives, such as reducing water or energy use. Goal setting also can involve looking beyond campus borders to find connections with municipal, watershed and regional plans. Looking for ways to address goals articulated in these wider planning efforts can help contextualize a plan, build relationships and leverage grant funding to help build stormwater projects.
Following the goal setting, a stormwater master planning team works together to set measurable targets for each goal. If a sustainability plan has been developed, stormwater-related targets may relate directly to campus sustainability targets. Setting targets requires both an assessment of the opportunities and constraints present on campus and a consensus on appropriate investment levels.
Understanding Regulatory Requirements
Concurrent with goal and target setting, the planning process involves meeting with regulators to discuss regulatory requirements. During this initial dialogue, administrators should make certain they know whether regulatory agencies have an official process for approving stormwater master plans. If so, it is important to understand the benefits of the master plan approval vs. individual project-specific approvals. For instance, does the master plan approval substitute for individual concept or preliminary approvals? What happens if projects proposed in the master plan significantly change during project development? Does the master plan process offer a pathway to meeting regulatory requirements on a campuswide basis vs. project by project?
In addition, it is important to clarify the technical regulatory requirements, including hydrologic modeling, design and monitoring/maintenance requirements.
Optimization Through Iterative Design
The next phase in the stormwater master planning process involves moving from goals and targets to selecting the right mix of BMPs that add up to a feasible, cost-effective and achievable plan. This process can be aided by a GIS-based cost/benefit tool. GIS-based cost/benefit tools score BMPs according to their respective costs and benefits, enabling planners to quantify tradeoffs among competing design alternatives. For instance, a green roof on a new building will have a different cost/benefit profile than replacing an existing parking lot with porous pavement. Each choice presents tradeoffs, pluses and minuses.
Using the GIS-based tool, designers lay out an initial set of BMP based on site assessment data and stakeholder preferences. The tool then is used to rate each BMP and, subsequently, to compute costs and performance metrics for the entire plan. Designers refine, add or delete BMPs to improve the plan’s performance. This iterative optimization process ensures that designers hone in on the right combination of investments.
Carrying out the Plan
Beyond establishing goals, targets, and outlining the BMP that will best achieve the plan’s goals and targets, several issues related to carrying out the plan are best addressed as part of the stormwater master planning process. For instance, a comprehensive plan will address reporting, verification and tracking procedures. These procedures will involve, among other aspects, collecting appropriate stormwater-related as-built data for campus expansion projects.
BMP maintenance and monitoring procedures and data management protocols also are important components of a comprehensive plan. Finally, the stormwater master plan provides design guidance to ensure that project design teams incorporate master plan requirements into their designs.
Sidebar: Managing stormwater at Johns Hopkins University
Johns Hopkins University (JHU), Baltimore, Md., recently used a stormwater management master planning process to streamline regulatory approvals for the continued development of its 150-acre main Homewood Campus and for linking long-term stormwater investments with campus sustainability initiatives.
The master plan approach offered a number of regulatory advantages compared with a more traditional approach. By developing a master plan and having the city’s Department of Public Works approve it, JHU may forgo individual preliminary stormwater concept-level approval for campus development projects within the master plan. The plan also enables JHU to address peak flow requirements campuswide, rather than project by project. In this way, increases in peak flow associated with one project can be offset by a commensurate decrease in peak flows for other projects, providing more flexibility in meeting peak flow requirements.
In addition to streamlining the regulatory approvals for campus expansion projects, the master planning process also enabled JHU staff to explore opportunities for incorporating green stormwater practices into its existing campus to reduce potable water usage and landscape-associated energy consumption. For instance, the plan proposes the construction of a network of rainwater cisterns that will reduce reliance on potable water for landscape irrigation by some 3 million gallons per year. The plan also proposes converting several existing turf areas to meadow or forest cover, reducing peak flows and the need for irrigation and mowing.
Although the core of the plan focused on identifying specific stormwater projects, JHU staff made sure that the plan also addressed operations and maintenance, design and administrative aspects of plan. It incorporated project design, maintenance and monitoring, and reporting and tracking guidance into the final plan.
To track the plan once it is put into place, JHU also created a stormwater GIS geodatabase that maps the campus’s entire existing stormwater system, including pipe networks and stormwater management practices. As stormwater projects are carried out, the GIS system will be updated with survey data for newly built projects. Custom queries and reports then enable JHU staff to generate updated statistics for internal and external reporting purposes.