Campus Construction

Stormwater Management

Site Work July 2007

Any built environment - buildings, parking lots, sidewalks, tennis courts, playgrounds, etc. - replaces water-absorbing soil with non-porous surfaces. The discharge of rainwater and snowmelt from the paved and built surfaces onto adjacent non-paved areas can increase the potential for soil erosion, which further deteriorates the ground's ability to absorb run-off. The waters that cannot be retained and absorbed on the site continue to travel through the watershed or into storm sewers. Pollutants and debris, such as rock salt and gravel from parking lots, travel with the flow. Proper retention of stormwaters enables the soil to naturally filter the water on site, before discharging to the watershed or the regional sewage treatment system.

While it has not always been a concern of developers or landowners to compensate for the loss of absorbent surfaces, it is now recognized as necessary to the success of a building project. An effective stormwater retention strategy will plan, design, and implement solutions to runoff and erosion. Potential stormwater loads are defined as "ten-year", "fifty-year", or "hundred-year" storms. The retention strategy for a particular stormwater load must retain and control the discharge of the volume of water that such a storm deposits over a specified time period. Common retention solutions are storm swales, run-off ditches, and the ubiquitous "retention pond".

After one hundred years of development, the WMU campus is heavily-built. Even moderate run-off volumes far exceed the absorptive capacity of available unpaved surfaces. The situation is further complicated by the sloping terrain that contributes to the Arcadia Creek and the Goldsworth Valley watersheds. In the area of the Miller Plaza and the Miller Parking Ramp, stormwater run-off has caused significant problems for many years. When the project to construct the Richmond Center and renovate South Kohrman came into play, the university seized the opportunity to solve the stormwater problems within the construction project.

The stormwater retention solution for the South Kohrman / Miller Plaza area was to construct underground structures on prepared gravel beds. These collect the run-off and allow the water to slowly seep into the ground below.

Preparing
Site for
Overflow
Piping
July 6

Installing
Overflow
Piping
July 6

Site Work
for
Overflow
Piping
July 13

Installing
Dry Well
July 13

Installing
Separator
Tanks
July 25

Installing
Separator
Tanks
July 25