Drainage swales are shallow-sided, sloped channels intended for the conveyance of surface runoff towards the nearest street, lane, dry pond or stormwater management lake.

Shared drainage swales are located on common property lines and graded to meet the requirement of the approved Lot Grading Plan.

The following diagrams and pictures illustrate how the swales help drain the runoff away during the rain:

For lots that drain from rear to front, a swale is located in the back yard where the forward slope of the lot meets the rearward slope of the foundation grading. The rear internal swale directs surface drainage to one, or both, of the side lot swales.


This Rear to Front Surface Drainage diagram shows how the swales direct water away from the properties.

For Split Lots, common shared swales are necessary to direct surface drainage from the highest points to the nearest street or lane.

This Split Surface Drainage diagram shows how the swales convey water to the front and back.

Swales on common property line must provide a minimum of 15 cm of unobstructed width within each property.
 

This is an example of Swale on the common property line which maintains at least 15 cm of unobstructed width from the driveway.

Improper grading generates

a chance for ponding.

Lot-to-lot drainage may be approved due to the topographic conditions of the developing areas.

On some lots, an easement or right-of-way is registered to allow a concrete or grass drainage swale construction. Easements or rights-of-way shown on approved Lot Grading Plan must be displayed on Lot Grading Certificate.

Note: There is a 1.5% of minimum slope requirement for grass drainage swales, and a 0.75% for concrete drainage swale.