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.

2 thoughts on “Thanks for your attendance and questions. Q and A’s posted here.

  1. Hi Leroy yourself and Tom were good enough to come out and address my concerns on the increased height and potential flooding of my property. I still think any time you hold back more water with a dam. the lake will rise to a higher level before it flows downstream. And current control gates won’t flow enough water to mitigate a flood with changing winter weather patterns. Also we discussed why so much water is let go before control gates go into operation in the spring. info on July meeting says control is started in March but I see gates open wide and water well below weir in May as everything dries up. Apparently fisheries demands this. I feel your better to go into control mode earlier and save more water for exactly this kind of weather and time of year. From what I’m told they don’t want to hold back water in early spring as it might flood lake residents. We’ll the new weir height has that potential for sure. And if your going to hold back more water time to address Greendale restriction as you all feel this is the restriction not the dam. Many rivers are cleared to flow even the lower part of the Cowichan is a dredged out by excavator new channels created.

    1. The whole idea of a weir or dam is to store water to a certain elevation. We need to store additional water in the late winter/early spring to support flow throughout the summer and early fall. Therefore the lake will be higher as water is stored to the new weir elevation. If we have an excess rainfall event the water will flow over the weir and the the controlling feature for lake elevation then becomes the natural downstream restriction near Greendale Trestle. Because the lake is starting at a higher elevation when the rainfall event hits, we will see the effects of high water sooner (days) than we would have if the lake was not at a higher starting elevation. The high water mark should be no higher than it would have been otherwise, it will likely arrive sooner.
      The existing gates operate from the bottom upwards. When the gates are fully open it means they are laying fully flat on the bottom. When the gates are controlling flow they are pulled up from the bottom to control the flows as mandated by the Provincial rule curve. Sometimes they use all four gates, sometime just one. Measures have been taken to allow for earlier control if necessary, but it is never clear whether storing earlier is the right move as precipitation and snow melt are somewhat unpredictable.
      The Greendale Trestle area valley that the controls the winter flow and lake levels has naturally been in place for thousands of years. High water levels have been measured for over 70 years and recent development planning (past 30 years) has been planned around this history as well as looking forward due to climate change. Unfortunately older developments did not fully take into account the variability of the natural high water conditions. Lower parts of the river have been dredged due to excessive sedimentation and was done to support fish habitat. Blasting out the greendale valley is not practical nor environmentally helpful.

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