Frequently Asked Questions
Here are some of the questions received by the Cowichan Watershed Board, with replies from Tom Rutherford (email@example.com). Last updated October 2020. Also check cowichanlakeweir.ca for current information.
1. Why do we need a new weir?
- The changing climate means that low flow conditions are occurring about 80% of the years now where they used to occur much less frequently. This means that years of poor reproductive success for salmon are common now instead of just occasional.
- Land use over the past 150 years has affected the resilience of the river’s ecosystems, including changes to the riverbed and gravel deposition. Pools important for fish to shelter in are fewer and more shallow. Riparian habitats have been logged, invasive species have moved in, other wetland and side-channel habitats have been lost to property developments in the flood plain and diking.
- This all means that habitat features that were capable of supporting fish at low flows 100 years ago are now diminished.
2. Properties around the lake flood every winter already. Will raising the weir make this worse?
- It is true that high winter levels have serious negative impacts on some lake front residences. The new weir is being carefully planned with this in mind and is not anticipated to cause measurable changes to the high water mark.
- Winter lake levels are not controlled by the existing weir – and will not be controlled by the new one. The lake levels in the winter are controlled by a natural channel restriction near the Greendale Trestle. Picture the river at the outflow of the lake being like a pipe draining a barrel. At high lake levels the “pipe’ that water has to pass through is smaller at the Greendale trestle than at the weir, so it is that natural constriction near the trestle that “backs up” the lake and causes flooding. You can see this at winter high flows because there is no elevation drop as water flows over the weir. The weir is not holding water back. It will be the same with the new weir at higher winter water levels.
- The weir only stores water when the lake levels drop from spring to fall.
3. This project is going to be expensive. Who is going to pay for this? Why should I pay if it’s not of any benefit to me?
- Yes, this project will be expensive, but the costs of not doing this project would be greater. The options, including doing nothing, were fully examined by a multi-party Steering Committee of the Cowichan Water Use Planning process form 2017-2018. The group concluded by consensus that the weir should be replaced. You can read about that here.
- Science projections show that the costs of not expanding the water storage for Cowichan River would likely include a significant impact to jobs throughout the region (including the closure of Crofton mill) as well as our culture and well-being. If you live in Cowichan Region, the health of the Cowichan River is a benefit to you.
- So far most funding has come from senior levels of government, which actually represents an injection of funds into our community:
- $500,000 for the Water Use Planning phase came from the BC Government and Catalyst Paper
- $4.3 million for the current phase of engineering and impact analysis came from the BC Salmon Restoration and Innovation Fund (Fed. and Prov.) with in-kind contributions of staff time by partners Cowichan Tribes, Catalyst Paper and Cowichan Watershed Board. All CVRD hours are funded by the grant. This will pay for planning and design work for decommissioning the old weir, and building the new one, along with the work to analyse any impacts on the shoreline and upstream property owners
- Construction costs are estimated to be another $15 million. We anticipate funding support from senior government again in recognition that the benefits from the Cowichan River include salmon, orca, and other benefits to the province and nation. However the greatest benefits will accrue locally and local taxpayers may need to contribute.
- These are normal costs for this type of work.
4. Who will be responsible for compensating lake front property owners for damage and loss of use of their property?
- Work is being done to assess the impact of raising the weir by 70cm on the shoreline around Cowichan Lake. This assessment will give the future water license holder an understanding of if and where there might be impact.
- The determination of whether compensation is due would be made by the BC Ministry of Forests, Lands, Natural Resource Operations and Rural Development water authorizations officer in Nanaimo, as informed by the shoreline assessment of potential impacts. It would happen during the process to apply for a conservation water license to store additional water.
- The water license holder(s) (yet to be determined) would be responsible for any compensation issues.
- Work is being done to assess the impact of raising the weir by 70cm on the shoreline around Cowichan Lake. This assessment will give the future water license holder an understanding whether and where there might be impact.
5. Can’t we just close the pulp mill? Would we still need a weir then?
- Yes a weir would still be required to ensure stable water flows in the summer and fall even if the mill closed.
- The out-take pipe for the mill is located 2/3 of the way down the river, near the hospital in Duncan, meaning that for the majority of the river’s length, the water licensed for the mill’s use is still in the river providing these benefits.
- Adequate flows provide great benefit to salmon, public health (sewage dilution, domestic water licenses) and the economy through recreational and tourism activities (paddling, tubing, fishing camping etc.)
- The mill provides over 500 local jobs and significant associated economic spin-off benefits to the community, and if the mill closes, taxpayers will need to cover the costs of maintaining and operating the weir. Currently all those costs, including pumping during dry years, are paid by the mill.
6. If we didn’t release so much water in the spring, or started to store water earlier, would that solve the problem? Can we just manage the existing weir better?
- This is a common question and so we addressed it specifically in the first 2 minutes of this video: Why Fish Need Water. https://www.youtube.com/watch?v=ZsD4X1zPmTw
- Basically, good flows are needed in April, May and June for salmon to thrive.
7. How can a new weir help without flooding out property owners?
- Modelling that was carried out as part of the Cowichan Water Use Plan (2018) demonstrated that beginning to store water March 1 rather than April 1 would result in no significant increased risk of flooding.
- This in itself will not result in enough stored water though because of the current and forecasted decrease in summer inflows. We also need a higher weir to ensure adequate summer flows.
8. Why don’t they dredge the weir on the Lake side to gain increased capacity and to clean up the turbidity when the lake levels are low?
- It would be impossible to remove enough material to make any significant difference to lake capacity, and any advantages would only be seen by pumping the lake down. As we began to witness in 2019, pumping the lake down can cause other negative impacts such as “stranded” docks, muddy beaches, endangering rare Lamprey habitats, and the costs of pumping.
- Dredging might create more turbidity than it prevents, and would have other environmental impacts.
9. What is in the shore line sediments that are being exposed at low water? Should we be concerned when they dry out and blow around?
- To the best of our knowledge, no one has done an analysis of shoreline sediments. Because there have never been any chemical or heavy industrial activities around the lake that would result in toxic waste or heavy metals, it is likely that the sediments are natural materials.
10. If the water is held higher than normal, will the waves damage my property and cause erosion? Will I lose property and trees?
- The higher water levels that would be made possible by a new weir will be in the spring and summer, and will be well below current high winter levels.