Floodplain Functions

Floodplains in our City serve a beneficial purpose to our quality of life. These low areas are where rainfall goes to drain, andDiagram of water on roadway and swales - Cross Section of Typical Roadway when the rainfall drains into the ground, this helps reduce flooding, and recharges our drinking water supply. These floodplains also serve as filters of stormwater runoff as it seeps through the ground and into our aquifer. This aquifer is our only source of drinking water, and this filtering helps contain pollution before it reaches our aquifer! It is important that we appreciate our floodplains, and try to maintain, preserve and restore these areas whenever possible.


A swale is a long narrow depression of land in front of your home adjacent to the street, which varies in depth and is typically wider than it is deep. Swales provide an area for stormwater runoff from roads and other impervious areas to accumulate or pond. Normal time for ponding in swales is typically 24 to 48 hours. Water in swales will eventually evaporate or infiltrate into the soil. Swales filter the stormwater and allow percolation of the water into the soil below.


Swales should have grass, a form of cover that allows percolation into the soil below. Rock or pebbles are not allowed due to compaction of the material, and it does not allow the rainwater to percolate back into the ground. This condition floods your driveway and your neighbor.

Benefits of Swales

  • Improve the look of the neighborhood
  • Provide filtering of runoff Reduce pollutants entering water bodies (canals, rivers, lakes, etc.)
  • Reduce flooding, allow water to pond and protect properties

Maintenance of Swales

  • Clear the swales of any debris including leaves, branches and other vegetation. Allow water to pond.
  • Do not park in swale which causes compaction of the soil and reduces infiltration.
  • Do not pave swales which will reduce the filtration and infiltration of the runoff.
  • Minimize use of fertilizers, pesticides and herbicides.
  • Mow swales, but allow good grass growth.

Management Plan