Split-Flow Stormwater Demonstration and Feasibility Study

The management of stormwater runoff from impermeable surfaces in highly developed urban areas is a major environmental challenge. Impervious surfaces such as roads, roofs, and parking
lots convey considerable volumes of runoff to sewer systems, bypassing the normal detention and infiltration processes. Federal regulations require municipal governments to develop, adopt, and
implement stormwater management strategies to reduce non-point source pollution directly related to new development. Despite these regulations, current stormwater management strategies have shown only limited success in protecting aquatic environments. To address this issue, a new stormwater management strategy is proposed that regards runoff as a valuable resource, emulates the natural hydrology system, fulfills our environmental goals, and
satisfies local flood control regulations.

The Split-Flow Stormwater Management Strategy is a newly developed method for managing
stormwater on-site by replicating the natural processes of evapo-transpiration, soil infiltration and stream flow. The design feasibility and construction costs of the split-flow system have been compared to other stormwater management methods with promising results. However, development of the strategy is at a standstill due to a lack of in-ground testing.

The study will be the first in-ground test to assess the system’s ability to replicate natural discharge flow rates, volumes, frequency and duration. This will be done by comparing runoff discharges from parking lots equipped with Split-Flow systems to runoff discharges from
undeveloped adjacent analogous land. The knowledge gained from in-ground testing will offer practical evidence of the strategy’s usefulness and reveal areas in need of further refinement. Additionally, the site will serve as a sustainable stormwater management demonstration
and education facility.

This project supports research by a new faculty member in Landscape Architecture at the Penn State-University Park campus.