Drainage Maintenance Programs


Drainage Maintenance Programs

The City of Mission has various programs to ensure the continued effective operation of the drainage system:

Sewer Main Flushing

Where high-pressure water, via a hose and nozzle, are pulled through flat grade sewer mains to remove the build up of grease and debris. The frequency of flushing (from once every 45 days to once every 2 years) is determined by just how flat the sewer grade is and historical records on the build up of grease and debris.

Television Inspection

Where a small tractor mounted camera is driven through the sewer mains looking for defects and potential blockage problems. Each section of sewer main is inspected about every 6 years.

Maintenance Hole Inspection

Where municipal staff will open the lid and visually inspect the sewer line and the maintenance hole (often called manhole) for signs of debris accumulation or evidence of sewer backup. Maintenance hole inspection is performed annually and may require municipal staff to access private property when a sewer line runs through back or side yards. Part of the inspection is also to ensure the maintenance hole is visible and accessible to clear a potential sewer blockage.

Ditch Maintenance

Where municipal staff mow the grass during the growing season and when required, re-ditch to remove silt build-up and reduce the potential for blockages.

Ditch Cleaning

A priority schedule for cleaning is established. Most ditch cleaning will occur in January to April and October to December, however where the ditch has been identified as environmentally sensitive, based on the City of Mission Watercourse and Ditch Classification Database, approval from the Federal Department of Fisheries and Oceans (DFO) must be obtained before any cleaning work may occur. Under DFO regulations, unless an emergency exists, cleaning work in an environmental sensitive ditch can be only occur between August 1 and September 15 each year.

Culvert Maintenance

All cross culverts in the City of Mission are inspected on a three-year cycle. Planned paving projects reference these inspections so that drainage culverts can be replaced prior to all road paving projects.

Dyke Inspection and Maintenance

Where Municipal staff annually inspect and maintain the 8 kilometers of dykes, which protect the Mission and Silverdale flats areas.

Pump Station Inspection

Where Municipal staff perform a variety of tasks to ensure each of the 3 dyke pump stations work without service interruption. The tasks include regular inspections during Fraser River freshet, including testing of emergency generators (the two major pump stations have generators in case of power outage; for the third, the City owns a trailer mounted pump which can be transported to a station to replace a failed pump).