Fraser River Water Management: Metro Vancouver Agriculture Water Forum will showcase results of salinity monitoring (Nov 3, 2016)
Note to Reader:
Food security, protection of agricultural lands and water use are issues facing BC. In December 2015, the Feast AND Famine Workshop addressed this question: How will water supply and agriculture be affected by rising sea levels and a changing climate in the Fraser Delta?
Drawing on the findings from his university research work at the University of BC, John ter Borg provided an overview of the potential issues and the impact of changes in river hydrology and salinity on fresh water irrigation intakes and the agricultural water supply in the Fraser Delta. He previewed a salinity modelling and monitoring program which has since been implemented.
Early findings will be presented by Albert Leung at the 2016 Metro Vancouver Agriculture Forum. To provide context, an overview of the 2015 presentation by John ter Borg is reproduced below.
How the salt wedge would move up the Fraser River if the channel is deepened for shipping after removal of the George Massey Tunnel
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:
Download a PDF copy of Fraser River Salinity Study, the PowerPoint presentation by John ter Borg at the 2015 Feast & Famine Workshop.
Download and read The Salt Wedge and Delta’s Agricultural Water Supply, an article by John ter Borg as published (on page 3) in the Delta Farmer’s Institute Newsletter published in October 2014.