A CAD3 million (USD2.3 million) riverbed dredging project will take place at Britannia Beach, a popular leisure site in Canada’s capital, Ottawa, from July to October this year.
The 110 m by 80 m section of the Ottawa River will see around 9000 m3 of sand removed, which the City of Ottawa’s Susan Johns, manager, Design & Construction – Facilities, said has been tested clear of contaminants.
When complete, the riverbed will slope out from the beach to a maximum of depth of 2.4 m.
Maintenance dredging at the sight, which last took place in 1988, is required approximately every 30 years primarily as a result of sedimentation due to the natural movement of the river, currents, waves and weather patterns. Johns also told DPC that new sand is brought in every year to freshen up the site for public use, which to a lesser extent adds to sediment accumulation.
A contractor to carry out the work will be announced towards the end of May following a pre-qualification process. Johns said that methods and equipment used will be decided by the awarded contractor, which will be selected based on the success of past projects amongst other criteria.
Johns anticipates that to reduce the weight of the dredged sand, it will be taken to a nearby allocated stretch of land where it will be laid out to drain. It will then be removed and transported in trucks to an environmentally safe disposal site, decided by the contractor. Johns said there were no plans to re-use the sediment.
The decision to carry out the work during Ottawa’s summer months is due to environmental constraints, such as the protection of aquatic species that use the river area as a mating site in spring. In-water work is banned is not permitted at these times, Johns explained.
The current shallow draft means that adults can’t really swim, only wade, said Johns, adding that a lot of attention is given to co-ordinating the work so that much of the land around the beach remains accessible for recreation during the summer months.