Ditches and flooding

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Ditches are a form of stormwater infrastructure designed to direct surface runoff flow to acceptable locations for the purpose of minimizing flooding and erosion risk to surrounding properties.

Ditches rely on gravity to move stormwater towards catch basins and culverts, which carry the stormwater to a stormwater management pond or other receiving location. Ditches provide no water quality improvement, however, the addition of plant life can increase the infiltration rate.

There are no mechanical or chemical components related to the operation of ditches within the stormwater collection system. Ditches function through natural physical processes.


There is a lot of water in my ditch, should I be concerned?

If water is in the ditch after a rain event, that is normal but the water should not be still. It should be slightly moving or flowing at a minimum. Ditches are designed to capture runoff and convey it to a natural outlet.

Ditches can capture and/or hold water up to 48 hours after a significant rainfall. Water continues to enter the ditch from the adjacent land for a period after rainfall/snowfall and it can give the appearance the water level is not lowering.

After 48 hours there should be a difference in water depth, but it does take time to flow out and/or infiltrate, and is very dependent on how much rainfall there has been, or the amount of snow that has melted due to sudden increased temperature. 

Some of the questions, staff may ask you:

  1. Is the water flowing in the ditch?
  2. Is there something blocking your culvert?
  3. Is there vegetation in the ditch?
  4. How often is water in your ditch? (is there water in it in the drier months?)
  5. Has there been a consistent increase/change in water level?
  6. Where is your proximity to the lake? (understanding of high water mark relative to Lake Simcoe)
  7. Is the water also present in your neighbours ditch?
If the ditch is overflowing and there is personal property damage due to flooding
  • Contact your insurance company
  • Contact Customer Service and they will create a PSR ticket for the Roads Division to attend the property to relieve the flooding
If the ditch is not overflowing and there is no personal property damage but the culvert is blocked

Contact Customer Service and staff will create a public service request ticket for the Roads Division to attend the property to relieve the blockage.

There is stagnant water in my ditch it is not moving

A good way to tell if the water is moving is to throw a leaf in the ditch and see if it starts to slowly travel indicating the water is moving or not.

If the water is not flowing or flowing very slowly

Call customer service and an associate will create a PSR ticket to have staff from the Roads Division to attend the property to evaluate the situation.

There is always water in my ditch
  • In some locations, the ditches carry water from large upstream areas. Water may continue to flow in the ditches for several days after a rainfall.
  • In locations near Lake Simcoe or adjacent to wetlands, the water level in the lake or wetland may back up into the nearby ditches.
  • The ditches will not drain out until the lake level is lowered. Lake levels are controlled seasonally as part of the Trent-Severn Waterway system.
What about mosquitoes?

If water is moving, then the mosquitoes will not breed in moving water. It takes up to five days on average for mosquitoes to start to breed. If you do the leaf test and it doesn’t move, call customer service at 905-476-4301 and staff will create a public service request ticket.

I have been cutting the vegetation in my ditch, however, I am now unable to cut or mow the vegetation. Whose responsibility is it to keep the ditch cut?
  • The Town’s current service level is to cut ditches in rural areas two times a year. The Town will not mow grass in ditches in urban areas in front of residential properties.
  • It is common for rural areas to have vegetation in the ditches. This is acceptable unless the vegetation impedes the flow of water.
  • The Town’s Road Patrol identifies these locations and prioritizes the locations for vegetation removal.
  • If your ditch is blocked, contact customer service and they will create a PSR ticket for investigation of ditch blockages and flooding.
Can I add river rock to my ditch or any other decorative material?

Residents are not permitted to add river rock or any other decorative material in ditches.

Residents are not permitted to fill in or cover up a roadside ditch. This is a contravention of By-Law 2002-0046 (TR-1)

When a ditch is filled or altered, stormwater management benefits will be compromised for the entire system. Additionally, when the ditch is filled in the road base will not drain properly leading to damage to the road.

What are some of the reasons they cut one ditch but not another, outside of the two seasonal cutting programs?

Sightline: At times vegetation is removed to improve driver sightlines at intersections. This may occur separately from the seasonal cutting.

Does the Town spray weeds in ditches?

The Town only applies herbicide spray on invasive weed species and harmful weeds such as Giant Hogweed, poison ivy and the European common reed (Phragmites).

The Town sprays once a year in late summer and if someone calls Customer Service then we will put them on a list (map) to spray. We ask residents not to cut as this leads to growth and spread.

The European common reed (Phragmites australis) is an invasive weed species which is an aggressive plant that spreads quickly and out competes native species for water and nutrients. It releases toxins from its roots into the soil to hinder the growth of and kill surrounding plants. While it prefers areas of standing water, its roots can grow to extreme lengths, allowing it to survive in relatively dry areas.

The European common reed is different from the native North American reed. Although these plants look very similar, staff will generally not cut the native phragmites. So you may see staff cutting reeds in some ditches but not others.