Arn Canal Drainage Improvements Study

Project Highlights

The Arn Canal is a man-made channel that drains agricultural lowlands and a mountainous area behind the Lillooet River and Pemberton Creek dykes.  It discharges to Pemberton Creek via a floodbox.  Flooding of the agricultural lands occurs approximately four times a year during the fall and winter.  Some flooding occurs when water levels on the Lillooet River are high.

The Pemberton Valley Dyking District retained KWL to characterize the existing hydraulic capacity of Arn Canal and develop recommendations for future analysis and improvement works to address flooding issues.

The study included review of existing data and reports, a comprehensive field inspection of pertinent areas and drainage facilities, and an hydraulic analysis of the Arn Canal and characterization of the existing drainage conditions using MIKE11 modelling software.

The interaction of water levels between the Arn Canal, Pemberton River and Lillooet River, and the existing Arn Canal channel constraints made this a complex hydraulic study.  It required significant investigation and careful modelling of the mechanisms that control the flows and water levels in the connected canal-river system.  The study identified areas of the system requiring further analysis, and recommended dredging at a potentials immediate improvement.