Knowledge Base

The primary purpose of the ditch along the roadside is to collect and store stormwater runoff generated during a rainfall event when it flows from the impervious roadway surface. Once collected in the ditch the stormwater can dissipate naturally by evaporation and percolation. Many but not all of the roadside ditches are connected to larger stormwater receiving facilities designed to convey excess stormwater runoff to a downstream receiving area. This allows ditches full of stormwater to convey excess runoff away from the area, the secondary purpose of the road side ditch.