The key recommendation of the 2018 Water Use Plan for Cowichan Lake and Cowichan River is to construct a new weir with an increase of 70 cm of elevation above the existing weir. In July 2021, the final design of the new weir was completed. A condition of the key recommendation is that an assessment be done of the potential impacts to the Cowichan Lake shoreline due to storing water earlier and at a higher level than has been done historically. The Property View Tool helps to visualize the various lake elevation information at a property level. It is a Geographic Information System (GIS) online tool in which we can compare the information gathered to date on top of aerial photography.
1. Watch the video below to learn how to use the Property View Tool. Click on the image to play the video.
2. Click the link below to access the Property View Tool, using any lakeshore address.
For a refresher on the terms used in the Property View Tool, see the infographic or video below.
Watch the video below of a section from the July 8 2021 Project Update in which we presented the terms. Click on the image to play the video.
Need help?
Cowichan Watershed Board staff are available to set up an appointment (no cost) to walk you through the tool for your address. Fill in the contact us field here and someone will email or phone you back.
Hi. Sorry for the delayed response.
Boat wakes are a concern regardless of the water level and would likely be of higher concern when the lake is extra low or pumped down as this would create energy where the beaches have not ‘felt’ that energy before. The new weir water levels are within the same ranges as previous water levels albeit a slightly different time of year. Our 9 month wave buoy analysis shows that boat waves are relatively minor in the whole picture of wave energy. Having high waves due to high winds that last for many hours and even days provides more wave energy than relatively few boat waves. Having said that, I realize that it also depends and where you are on the lake, the type of shoreline and the type of vegetation one has. Our project and study was focused on the the potential impact of raising the weir and therefore doesn’t make any recommendations towards recreational boating. That is a discussion that could be raised with others like Area I and Area F directors.
I’m impressed that the preparation for a new weir has involved such thorough study which should minimize any “surprises” when the new structure is actually built.
I have concerns though, about the possible impact of boat wakes during summer …. with the water at a higher level for a longer period of time, the erosion factor could become more significant. Presently wakes tend to impact mostly exposed beach (and (unfortunately) floating dock structures) more than vegetated areas but this dynamic will change with higher summer water levels. With this in mind, is it now time to consider restricting operation of wake surfing boats to offshore areas in the main arm of the lake as is done in some other jurisdictions?
Flooding is defined as when the water first touches the foundation of the primary residence. A shoreline protection structure is typically a retaining wall or wave break of some sort (wooden, concrete, rocks, vertical or sloped). Modelling shows that the duration of flooding is similar to historical durations. Inundation duration will be longer as a result of the new water storage due to raising of the weir and will vary from property to property. I’m not sure on the question ‘what does the impact assessment of 5yrs mean?’ – perhaps you could clarify.
RE: Property Impact Tool
How is flooding defined? Our property currently floods to some degree every year. What does the impact assessment of 5yrs mean?
Shoreline Protection Structure: does this include a retaining wall?
What do the models show for duration of flooding/inundation?
There is no definitive number as the lake drops in elevation every day as the water flows out into the river. The flow rates through the weir and into the river will be roughly the same as they are with the existing weir but now we will have an additional 70 centimeters of water to release. The 70 cm will be stored behind the weir starting in March or April (depending on climactic conditions) and then released throughout the control period from March/April to end of October. The daily release volume is authorized by the Province using a strict set of guidelines or ‘rule curve’. Throughout the summer the goal is to release water at 7 cubic meters per second. At this rate the lake lowers by approximately 1 centimeter per day.
The alternative to a new weir will be to have much lower lake levels than we have had in the past.
What increase in lake water height can we expect over the course of the summer?
The property view tool is meant to represent the various boundaries as accurately as possible, however it does nor replace title documents, field pins and surveys. When you open the Tool, it says “This map is for information purposes only. It is not intended for design, analysis or construction.” To be sure to get the answer to your question you would need to obtain a proper survey of actual conditions.
Just by observation, I don’t think the levels are correct for our place east of Saseenos point. The actual water levels fall well below where the existing weir crest is indicated by the light blue line. In March before the melt starts, there is considerably more beach showing.
The legal parcel lines show my neighbors cabin over the property line . Is this accurate ?
All ok, I found by just entering Walton Rd then moving the map to my property.