The City of London Dyke System
The City of London’s flood protection dykes are barriers made of earth, built along stretches of the Thames River and the North Thames River in London. The dykes help to protect people and properties in areas that would otherwise be at significant risk of flooding.
When London was settled in the early 1800s, the Thames River provided water, a means of transportation and a power source for mills. First Nations and early settlers had used the low riverside land to the west of the Forks for farming. These nutrient-rich soils were deposited over thousands of years by spring floods.
By the late 1800s, the small settlements of London West and Kensington were growing on the banks of the Thames River from their beginnings surrounding water-powered mills. The communities experienced several floods, such as the catastrophic July 1883 flood that killed 17 people. However, rather than resettling away from the hazardous areas, the response was to build a formalized dyke system.
Construction of the West London Dyke began in the late 1800s. This 2.4 km-long dyke protects over 1000 structures. It has been raised and strengthened many times, and is the focus of major ongoing rehabilitation efforts. After the devastating April 1937 Flood, the City built additional dykes through some of the lowest lying riverside neighbourhoods.
Today, seven dykes totaling 5.1 km in length help to protect low lying areas in London from floodwaters of the Thames River. The dykes are named for local neighbourhoods or streets: Ada-Jacqueline, Broughdale, Byron, Coves, Clarence-Nelson, Riverview-Evergreen and West London.
The City of London and the UTRCA are undertaking a Vegetation Management Project on the earthen dykes.
Most of the London Dyke System is on public property, primarily owned by the City of London with some sections owned by the UTRCA. A few areas of the dykes are on private property.
Between 1950 and 1967, the UTRCA constructed three large flood control dams upstream of London. These structures reduce flood damage throughout the river system, and greatly enhance the protection provided by the London Dyke System.
The UTRCA is responsible for major maintenance of the London dykes through an agreement with the City of London, which owns most of the dykes. Monitoring and rehabilitation of the structures have been ongoing since the early 1980s.
Regular inspection of dykes and other flood control structures can identify structural instabilities that may impact performance, and leads to recommendations to correct those instabilities. Monitoring of the dykes will continue in the future and further tree management will be considered as conditions indicate, until major rehabilitation projects are planned for the same areas.
Every year, the City of London and UTRCA review studies and repairs based on the UTRCA’s 20 year flood control capital repair budget outlook, to plan priority projects and optimize funding opportunities. Ongoing studies of the dykes assist the UTRCA and City in planning future works for the structures.
The UTRCA’s regular operating and project management costs for the dykes for 2013 was provided by the City of London (75%) and Ministry of Natural Resources (25%). The current annual operating funding is $32,000. The MNR portion has been in decline since 1995. Between 2003 and 2013, the City of London and MNR shared equally the cost of capital repair studies and repairs for the dykes.