Vassar College
OP-23: Rainwater Management

For construction disturbances of greater than one acre, the state Department of Environmental Conservation requires planning and monitoring of stormwater mitigation. The college hires an engineer to design a stormwater mitigation pan, and to inspect the implementation of that plan at regular intervals. For construction disturbances less than one acre, the college is not required to mitigate stormwater runoff, but it does so anyway by requiring the contractor to install stormwater protection (silt fencing, hay bales, check dams, filter fabric, storm catch basin protection, etc.) which the college inspects at regular intervals. The College was awarded in Summer 2016 a NY DEC Stormwater Planning grant to develop comprehensive rainwater management policies for the campus. The Campus Green Stormwater Management plan was published in March 2018.

The grant project team reviewed relevant green stormwater research and collaborated with the grant’s NYSDEC Project Manager to develop the following overarching goals for integration of GSI on Vassar Campus over time: • Minimize impervious surfaces on campus, especially close to waterways and in areas that drain directly to waterways through buried pipes. • Promote low-cost practices to treat stormwater close to its source rather than at stream outfall. • Improve decision-making on maintenance projects, retrofit projects and capital projects to explicitly consider inclusion of GSI design elements. • Reveal underground hydrology of the campus landscape and thereby enhance visitor, staff and student quality of life and experience. • Improve water quality by filtering/infiltrating stormwater, rather than directing stormwater directly to water bodies. • Avoid over-design and over-sizing of conventional grey infrastructure systems. • Maintain and expand tree canopy on campus, to provide both water uptake and cooling. • Match or improve on the cost of traditional piped stormwater strategies. • Reduce flood pulse intensities and frequencies in the Casperkill per Casperkill Assessment. • Enhance riparian buffers and edges of existing waterways and wetlands. • Anticipate the need for and cost of training to properly maintain GI elements well before projects are conceptualized and designed. • Maximize ecosystem services and benefits of maintenance practices, infrastructure investments and capital projects with an eye toward improving the overall health of waterways and watersheds. • Leverage educational programming to connect students, faculty, staff, administrators, the community and other stakeholders with unique learning opportunities related to GI and watershed health. • Meet relevant state and municipal stormwater management requirements. • Develop monitoring and performance metrics, such as tracking the percentage of campus rooftops and impervious coverage captured and treated and quantifying total runoff reduction as GI practices are implemented over time. • Consider establishing a campus-wide mitigation bank and performance metrics for stormwater runoff; for example, in exchange for a new building footprint or impervious coverage, create wetland or implement other GI practices to offset new impacts.