The unique surroundings and location presented some challenges to the design of the bridge and underpass trail. Raising the elevation of the trail and ensuring adequate clearance would require significant changes to the elevation of Marine Drive, which in turn would impact the Fell Ave. intersection and access to local businesses due to the grade change required.
To allow for the underpass trail, design features were implemented to accommodate periods of high streamflows, including:
- designing the tunnel to accommodate water flow, to retain and improve flood capacity under the bridge, limiting the chance of flooding Marine Drive;
- implementing drainage features on the tunnel path, to ensure water recedes quickly when streamflow levels are reduced;
- building the surrounding infrastructure, including the retaining wall, bridge and path to withstand being submerged, to ensure no long term damage after flood events;
- installing fencing at the top of the bank near Mosquito Creek and lighting to help illuminate the path to improve safety; and
- extending the multi-use pathway curb to the north to further reduce flooding.
Improvements Since Construction Completion
The City has undertaken several safety improvements to the trail in response to increased frequency of intense rain events as experienced in the fall of 2021. The extraordinary rain storms changed the creek bed profile resulting in sediment movement reduced flow capacity and increased inundation of water during intense rain events.
The improvements include:
- Wooden gates and a fence to easily close the trail during times of high flow and to limit access to the riparian area near the site.
- Signage advising the trail is designed to have water on it at times.
- A flow monitoring system to collect data on creek levels and improve forecasting for trail closures related to high flows.
- Signage with warning lights advising of high water if the trail is unsafe to use.
- Upgraded underpass electrical system.
- Redesign of the stream profile to improve flow capacity.
The increased safety measures and planned remediation of the channel will allow people to use the trail throughout most of the year.
The Mosquito Creek Bridge was the first pre-stressed concrete bridge constructed in Canada in 1952. It was widened in 1973 and 1981 to accommodate the growth of the North Shore community. In 2015, an inspection of the bridge’s condition recommended replacement due to corrosion.
The City contributed $6.55 million with additional support from TransLink ($1.65 million) and the Federal and Provincial Government ($3.87 million) through the Build Canada’s Small Communities Fund.
Mosquito Creek Bridge in 1952. Photo: Henry R. M. Murray, “Design and Construction of Mosquito Creek Bridge” (thesis submission), February 15, 1953. (British Columbia Historical Federation)