The current ‘Weir’ actually has several distinct and unique elements making it the WEIR as we commonly describe it today. From north to south it is a collection of a boat lock, a concrete dam, a concrete sill across the weir Island, a gate structure with 4 independent gates, a fish ladder and finally a concrete sill into the south abutment. Only the gates control the flow during the control period (from April to October). During the winter months (November to March) the gates are laid down and are considered fully open. The concrete dam and sills give us the elevated water supply for us to control but they do not control the flow volume.
As we design a new elevated weir one of the questions is whether or not any of the existing structures can be reused. We have determined that we cannot reuse the concrete dam, the concrete sills nor the fish ladder. They have deteriorated over the past 63 years but most importantly they are at the wrong elevation. It appears that both the boat lock foundation and the gate foundation can be reused and would save considerable costs of demolition and rebuilding new. The health of those concrete structures will be verified over the next couple of weeks.
The design is becoming clearer as we near our Preliminary Design deadline. We will share that information with you on December 10. Stay tuned.
Cowichan River Water Supply 