VIDEO: The salinity study will assess how the salt wedge would move up the Fraser River if the channel is deepened for shipping after removal of the George Massey Tunnel, reports John ter Borg
Solutions and Tools for Building Water-Resilient Communities
The weather in 2015 has impacted on how the public views the BC climate and their understanding of how it is changing. There is now growing awareness that the summer dry season has extended on both ends. Annual volumes of water entering and exiting regions are not necessarily changing. Instead, what is changing is how and when water arrives – it is flood and drought!
Adaptation to a Changing Climate
Held in Richmond in December 2015, and co-hosted by the Partnership for Water Sustainability and Irrigation Industry Association, the Feast AND Famine Workshop showcased solutions and tools.
The program comprised four modules that were cascading – from high-level visioning to ground-level applications. Adaptation to a changing climate was a unifying theme. Both the urban and agricultural perspectives were represented.
How Will Salt Wedge Move Up the Fraser River as Climate Changes and River Channel is Deepened?
Each module was delivered by a team of two presenters who elaborated on an aspect of the workshop theme and engaged the audience in a conversation.
In Module C, Ted van der Gulik and John ter Borg explained the complexities of water supply for agricultural lands in the Fraser River delta, what impacts sea level rise may have, and how climate change will affect water demand to grow our food.
A Combination of Impacts
Many local governments draw water from the Fraser and distribute it to farmers through a network of channels and ditches. For agricultural lands near the estuary, however, this water supply may be jeopardized by a combination of two factors: sea level rise which extends the reach of the salinity wedge upriver; and lower flows in the Fraser during the summer months.
“The ‘salt wedge’ is a phenomenon that occurs in all tidal estuaries of the world. Salty and dense ocean water entering the river mouth forms an underlying wedge beneath the lighter fresh water that is exiting,” states John ter Borg. “Replacement of the George Massey Tunnel (with a bridge crossing) will allow for dredging of the river channel to accommodate deeper draft ships, which will result in movement of the salinity wedge during lower river flow and impact agricultural water supply.”
“The pending study will assess the sensitivity of the Fraser River to salinity changes. A range of channel dredging scenarios will be simulated, recognizing that there may be practical limitations on the depth to which the Fraser River can be deepened. Ports around the world typically have navigation channels that are 16 m to 18 m. We don’t as yet know what is realistic for the Fraser River.”
To Learn More:
To download a PDF copy of the PowerPoint presentation by John ter Borg, click on Fraser River Salinity Study.
To download and read an article by John ter Borg as published (on page 3) in the Delta Farmer’s Institute Newsletter published in October 2014, click on The Salt Wedge and Delta’s Agricultural Water Supply.