October 2, 2013

« All News

Geosyntec Studies LID Impacts for Future Design Techniques

BOSTON, Ma. — The Massachusetts Department of Conservation and Recreation (DCR) retained Geosyntec to monitor and evaluate the stormwater flow from the Partridgeberry Place subdivision, a recent residential development located in the Ipswich River Watershed. The immediate project goal was to help improve groundwater base flow and develop a scientifically-based, reliable stormwater model to aid in other future low impact development (LID) designs within the Ipswich River Watershed. This study is rare in that it uses actual field measurements from two land-use types in the same watershed to compare pre-development and post-development stormwater conditions. DCR is striving to understand, and possibly mitigate, observed reductions in water flow throughout the Ipswich River Watershed north of Boston.

Partridgeberry Place employs a variety of LID design features, including dry wells, vegetated swales, GrassPave, bioretention, as well as three raingardens on individual residential lots, reduced impervious area, narrow roads, and native drought-resistant vegetation. In fact, it has a compact site design, clustering 20 single-family homes on residential lots less than 0.20-acres in size, preserving 28 acres of the 38-acre site as undeveloped open space.

Through project implementation, Geosyntec was able to analyze, understand, and estimate the subdivision's stormwater runoff dynamics through on-site flow monitoring and modeling using the U.S. Environmental Protection Agency (EPA) Storm Water Management Model. Our staff engineers compared the post-development impacts of Partridgeberry Place to the pre-development (i.e., forested) watershed, providing an understanding of how closely LID design mimics pre-development watershed conditions. The results are expected to advance the state-of-the-practice in using models to design and implement LID stormwater management techniques in the years to come. This project was funded under a Targeted Watershed Grant from the U.S. EPA to the Massachusetts DCR.