Stormwater

When designing and constructing a new building, one common issue is stormwater.

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Stormwater

Stormwater is the excess water that builds up on a site, usually from large storms, and can cause problems such as flooding. Buildings reduce the amount of ground available to naturally soak up this water; the goal, then, is to form a plan for dealing with this excess water within the site, so that it does not run off onto streets and other sites.

The Science Center approached this issue by installing two components: a wetland, and a dry basin. The runoff from most storms will be detained within the wetland portion, which is formed of highly permeable soils and serves as a natural habitat for wetland plants. Higher intensity storms will overflow into the dry basin, which also serves as the College’s softball field. With the addition of these two components, the volume of stormwater able to be held on the site was increased by 3.3 acre-feet, accounting for the 1.2 a.f. required for the Science Center as well as 2.1 a.f. banked for future campus projects.

While the quantity of stormwater retention is important, Wheaton also chose to address the quality of this water. Both the wetland basin and a 100-foot vegetated swale along the North side of the softball field were designed to filter the water that flows through them, reducing the total suspended solids by 80%. The entire site is tributary to the constructed wetland basin, meaning all water on the site flows into this area, so runoff from rainfall will be treated through this system.

Stormwater diagram

Download full-size Stormwater diagram

Stormwater is the excess water that builds up on a site, usually from large storms, and can cause problems such as flooding. Buildings reduce the amount of ground available to naturally soak up this water; the goal, then, is to form a plan for dealing with this excess water within the site, so that it does not run off onto streets and other sites.

The Science Center approached this issue by installing two components: a wetland, and a dry basin. The runoff from most storms will be detained within the wetland portion, which is formed of highly permeable soils and serves as a natural habitat for wetland plants. Higher intensity storms will overflow into the dry basin, which also serves as the College’s softball field. With the addition of these two components, the volume of stormwater able to be held on the site was increased by 3.3 acre-feet, accounting for the 1.2 a.f. required for the Science Center as well as 2.1 a.f. banked for future campus projects.

While the quantity of stormwater retention is important, Wheaton also chose to address the quality of this water. Both the wetland basin and a 100-foot vegetated swale along the North side of the softball field were designed to filter the water that flows through them, reducing the total suspended solids by 80%. The entire site is tributary to the constructed wetland basin, meaning all water on the site flows into this area, so runoff from rainfall will be treated through this system.

Stormwater diagram

Download full-size Stormwater diagram