Swales

Swales are one of the most commonly used stormwater management practices.  They slow down the rapid flow of stormwater runoff from highways and residential streets by ponding the water between two sloping sides. By letting the ponded water soak into the ground, swales reduce the volume of pollutants thereby improving the quality of the stormwater that reaches the river or the lagoon. Swales have been created along roadsides throughout the County.

The following are ways to maintain swales to maximize their effectiveness:

• Let water pond.  Runoff should temporarily pond in the swale for 24 to 36 hours.

• Mow the swale, but not too short.

• Remove leaves and grass clippings from swales.

• Minimize use of fertilizers, pesticides, and herbicides in swales and adjacent areas.

• Do not pile garbage, trash, leaves, tree limbs or garden debris in swales as this adds pollutants that can wash into downstream waters.

• Do not pave the swale as this will reduce the filtration and infiltration of runoff.

• Do not park vehicles in the swale, as this compacts the soil, reducing infiltration and increasing runoff.