Swarthmore College Science Center Stormwater Management Techniques


The renovation of Swarthmore College’s Science facilities was recommended by the college’s long-range planning study, completed in 1999. During the expansion project, the College installed several best management practices to reduce runoff from the site and to improve water quality through the use of vegetated areas and infiltration. Strategies included: porous paving on pathways, surface infiltration planting beds, underground vault for reuse of stormwater in the irrigation system, and a BioStream infiltration bed.

The BioStream Garden is planted with vegetation to allow stormwater to seep into the ground along the length of the “stream.” During gentle rains or snow melt, most of the collected storm water will infiltrate, but heavier rains allow a reduced amount of water to flow past the BioStream and enter the underground storm water system. The plantings along the BioStream are tolerant of periods of wetness.

The renovated Science Center, which is LEED certified, uses infiltration beds planted with prairie dropseed, Sporobolus heterolepis, a native grass. Stormwater is captured and channeled into the beds, which are composed of a 2-foot deep porous planting mix allowing for free drainage and infiltration into the local water table. The porous mix is 60% lightweight aggregate soil, 25% loam topsoil, and 15% organic matter. Porous pavement used throughout the walkways surrounding the Science Center also permit rain water to penetrate the surface and re-supply groundwater.

Roof runoff is also channeled into the Water Wall and Water Stairway structures, which operate as fountains during a storm. These innovative displays work to retain runoff on the site, reducing soil erosion impacting the Crum Woods slope and Crum Creek. In the first display, water flows from the roof down a building wall to be captured, thus creating a “water wall.” In the second location, piped stormwater is directed to the head of a water stair, where it is exposed in its descent to the Glade Garden, 13.5 feet below. Stormwater ultimately feeds the underground irrigation system.


County: Delaware
Watershed: Crum Creek


Einhorn, Yaffe & Prescott
Gladnick Wright Salameda
Swarthmore College


Swarthmore College funded thecost of the Science Center project, totaling $40 million.


Michael J. Gladnick
Gladnick Wright Salameda
106 Lakeview Drive
Chadds Ford, PA 19317

Swarthmore Site Plan

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