Shoreline Assessment Project October Update

With the weir design complete, there are many next steps including understanding the impact of raising the weir to the perimeter shoreline of the lake, agreeing on a Water License holder for the new Conservation License, and then going through the formal application and approval processes with the new water license holder. If approved, then construction funding would be finalized and contracts would be awarded. All of this will take a few years to get through before anything were to actually happen in the field.

The Shoreline Assessment project has been collecting data to help understand what types of impacts might be and where they would occur. The scope of this part of the project is primarily meant to understand potential impacts at the property level. The purpose of raising the weir is to help with aquatic habitat (particularly salmon) and vegetation which is why it will be considered a conservation license. The definition from the Water Sustainability Act – “conservation purpose”┬ámeans the diversion, retention or use of water for the purpose of conserving fish or wildlife and includes the construction of works for that purpose”. The current understanding is that the additional water storage will also benefit the unique Cowichan Lamprey which has been listed as endangered under SARA (Species At Risk Act).

One of the outcomes of our work is to create a publicly available ‘Property View Tool’ where an owner could zoom to their property and see the various lines or markers on their area – much like Google Maps but with lines that represent our work. We will have the low water mark, property title boundaries, existing weir elevation, new weir elevation, average high water mark, 1 in 200 year flood line, the present natural boundary and a modelled future natural boundary. We plan to share that tool with you on Wednesday NOVEMBER 17, 2021 at 7:00pm via a virtual meeting. More details on how to join will be coming in the mail and in the homepage TAB of this website.

The whole purpose of raising the weir is to store more water in early spring so it can be released throughout the dry summer and fall months. Therefore, more water will exist along the shoreline than it would be without the weir raise. Of course the water level will continually decline throughout the summer as the water is released. One additional benefit of storing more water is that we will see fewer extreme low water events and the probability of having to pump out of the lake to support the river will also be reduced. Low water scenarios has its own set of concerns such as riparian vegetation drying up, reduced fish habitat, tributaries sitting relatively higher impacting aquatic access, grounded docks, and navigational issues.

Water affects the shoreline in different ways and is highly dependent on wind/wave energy, the type of material the shoreline is made of, the slope of the beach and how long the water stays at different elevations. We are measuring and modelling this information to help determine impact upon raising the weir. This information is still being collected and calibrated and the work won’t be completed until February 2022. We plan to share a final update of our assessment work in March of 2022. Stay tuned.

Thanks for your attendance and questions. Q and A’s posted here.

For those of you who could attend the July 8th virtual meeting I appreciate your interest, your questions and most importantly spending your valuable time with us on this topic.

It was difficult to capture and hear all the questions and answers from that session so I’ll list them here.

Question: With concern regarding record breaking high water level in Feb 2020, how will future high water levels be affected? Answer: The current and the new weir will continue to be submerged during the high water flood events and do not control the flood levels. There is a downstream natural restriction near the Greendale Trestle that controls the high water lake levels. Therefore future high water levels will be unaffected by the new weir but may be affected by ongoing climate changes.

Question: Will the Canadian Government Data Graph 08HA009 for Cowichan Lake need to be adjusted to reflect the new datum? Answer: We have contacted the Government and they are planning to upgrade all their hydrographs to the new datum.

Question: If channels are excavated, is there a plan to incorporate archeologic studies, especially on the island. Answer: Yes, archeologic studies will be planned during the excavating work.

Question: Is the designed walkway structure earth quake safe? Answer: Yes, the walkway and supporting weir foundation is designed to meet all current earthquake requirements.

Question: Can the recreational paddlers provide input on the portage steps? The proposed design looks less than ideal. Answer: The portage you saw was an example photograph of one that uses steps. The design being considered does not have the haunches on the side you see in the photo. The current design for the portage use 0.5m by 1m wide and 3m long. If you would like to provide feedback there is opportunity.

Question: Will adaptive management be considered with respect to changes to design or features of the design as more information becomes available? Answer: With respect to adaptive management, the new weir design include as lot of flexibility for operations and there is flexibility in how the fishways can be operated.

Question: What improvements are being proposed for the boat lock? What price tag is associated with that? Answer: The only thing that will remain from the boat lock is the current concrete foundation which will need some enhancements to meet earthquake codes. All other components will be replaced with new parts and systems and should operate more quietly. Re-using the existing foundation and upgrading the boat lock is considerably less expensive than removing it and rebuilding altogether.

Question: Will the boat passage be dredged and cleared of logs? Answer: Yes, when the boat lock foundation is refurbished for reuse, the passage will be cleaned up.

Question: If there is a pinch point in the river, would the lake level be reduced to get as much water past before the lake crests the weir? Answer: When the weir is no longer being controlled (end of October) the gates and boat lock are left wide open to allow full flow through the weir. The lake level is then dependent on precipitation events and river pinch points.

Question: Have you received any comments from the downstream First Nation about potential impact to their rights and title interests? Any mitigation to your plans? Answer: As Cowichan Tribes in one of the partners and potentially an owner we are wanting to make sure that all steps are done properly at every stage.

Question: Where are the wind and wave data buoys located? Why were those locations chosen? Answer: One buoy is located in the South Arm near Woodland Shores and the second is located in the North Arm between Whittingham Point and Billy Goat Island. It was difficult to only choose two locations on such a large lake but we thought these locations would ‘catch’ a lot of the wind action and some boat wakes.

Question: If the operations in March would change water levels, the goal of raising the weir, why has that not been a priority in recent years? Answer: The current weir is typically at full storage in March. Analysis is done each spring to determine if early control is viable based on snow pack and weather forecast and lake levels. A higher weir would allow for earlier control of the increased storage.

Question: You reference the 200 year flood line. What year was that established? Answer: 1984. CVRD Document Risk-Assessment-of-Floodplains-and-Coastal-Sea-Level-Rise. Recent analysis also supports this flood line.

Question: I think that your 3 meter swing between low water and high water is a little low. I’m thinking it is more like 15 feet or 5 meters. Although I have never measured it. Answer: The average high water mark over the past 60 years is 164.2m. The low water mark is 161.0m. So a 3.2m difference.

Question: As a WSP objective in the future, can we ensure that there will be maintains connections between cold water refugia and riffle habitat? Presumably the weir can help meet that objective. Answer: Cold water refugia exists in both the river and the lake. The weir will not affect those natural refugia. The new weir fish passages will provide for more opportunity for fish to move back and forth from river and lake, allowing them to better find refugia. Also, by storing more water for release throughout the summer, the minimum flow rate will be achieved more frequently and allow for more fish survival.

Question: Will this video be posted online for review? Answer: Yes it will.

Getting Close to a Final Weir Design

The design of the new weir is reaching it’s final stages and will be shared at a virtual public meeting on July 8 at 6:00pm.

The final engineered design and drawings will be wrapped up shortly by Stantec Engineering. We’ve incorporated the Preliminary Design efforts that were shared in December 2020 and have brought the design to a state of being fully engineered, costed and with construction quality drawings. Even though we will have this work completed, it does not mean we are moving into construction right away. This work is meant to inform the future water license holder, the public, and the approval bodies of what is possible, how it would operate and how it would impact the surroundings and yet still support the objective of creating enough storage to support environmental flows throughout the summer.

In parallel, work is well underway in our Shoreline Assessment Project. This project will look at today’s ‘as-is’ landscape (shoreline and natural boundaries) and project forward the impacts of raising the weir and the impacts of ongoing climate changes. We will also provide an update of this work on July 8th. One exciting feature coming out of this work will be something called a ‘Property View Tool’ where a homeowner can type in their address and have a plan view of their property and waterfront. The plan view will show many different elements such as the high water mark, current weir elevation, new weir elevation, present and future natural boundaries, etc. Note that this Shoreline Assessment Project will take into account the new weir design, new climate projection data, historical data, landscape data and many other factors to understand the potential changes going forward if the weir were to proceed. This assessment work is expected to wrap up in March of 2022 and will also help to inform future discussions and decisions.

Lake Levels – High Water Mark

One of the biggest concerns I hear are to do with lake levels, particularly in the winter at peak water levels or often referred to as the High Water Mark (HWM).

As is turns out the Government of Canada has been recording lake levels and river flows for decades. This can be found on their website at and look for station 08HA009 where it will show you current water levels and you can search historical data as well. The graph is referenced as: Real-Time Hydrometric Data Graph for COWICHAN LAKE NEAR LAKE COWICHAN (08HA009) [BC]

This data shows us that before the existing weir was constructed in 1957 the HWM averaged 164.16m from 1953 to 1956 and has since averaged 164.01m for the 61 years from 1957 to 2018. The lowest HWM was 162.33m in 1978 and the highest HWM was 165.39m in 1968.

The current weir crest height is at 162.37m. With an average HWM of 164.01m you can see that the weir is actually submerged (by 1.6 meters or 5 feet) during the high water season. I took a few photos a couple of weeks ago and the flow over the weir is hardly noticeable as the water flows completely over it, across the weir island and around the south side. The flow control shifts downstream to the natural river valley close to the Greendale Trestle and it is the river valley that then controls the HWM as the valley narrows and the river bottom rises. Similarly the new weir (at 163.07m) will be submerged during the high water season and shouldn’t impact annual High Water levels.

With longer, hotter and dryer summers becoming the new norm it will be important to hold back some more of these winter waters for release through the summer months.

Whitewater Recreation

There has been a lot of interest and questions regarding paddling, kayaking, surfing and general whitewater types of recreation in connection with this project. I did not answer each of the questions that have come through individually – instead I thought I would address it here. Although not a paddler of any sort I can certainly understand the attraction of using this heritage river and all of it’s surrounding beauty and to want to ‘play’ in it.

This project and the associated grant from the BC Salmon Restoration and Innovation Fund (BCSRIF) is targeted towards the improvement of environmental/fish flows and doesn’t have the mandate to design integrated whitewater recreational features. This work is to inform the eventual water license holder who would also become the owner and operator of the new weir. This ownership entity is still unknown. Quite frankly, we are not even sure an integrated water feature would be feasible given the hydraulics, landforms and land ownership issues in this immediate area. Having said that, a feasibility study could be taken on (by others) and could take into consideration our current preliminary design and it’s hydraulic outputs. Perhaps there is opportunity to consider something immediately downstream of the weir or even further downstream throughout the entire reach of the river. People with expertise in this area of study would need to evaluate those different scenarios.

The whole notion of another form of recreation is important in my estimation, however it needs to be brought forward in a planful way and start fitting into strategic plans for local communities such as the CVRD and the Town of Lake Cowichan. Strategic plans usually look ahead 5 or more years and these new ideas need to be integrated into those systems for long term support and success.

I certainly appreciate your energy and enthusiasm and coming forward with such a strong and cohesive voice. I suggest keep your agenda moving forward by integrating your ideas into the local governments planning processes.

Skutz Falls – Nov 2020