Cowichan Valley drought concerns continue

Cowichan Valley drought will affect Crofton mill, salmon and more, so raising the weir is a good option

It has been an interesting, productive and even historic couple of weeks in the Cowichan Valley.  Our drought concerns continue and it is now projected that we will reach zero storage in the lake about Oct. 18 without significant rainfall.  At that point the river flow will slowly decay, dropping below four cubic meters per second (CMS) and continuing down until the rains come.  The Crofton mill may then be forced to shut down, putting almost 600 valley residents out of work and jeopardizing the arrangements with their customers overseas.  Climate predictions for this fall are not encouraging. We are expecting warmer and drier than normal conditions.

The Federal Department of Fisheries and Oceans has stepped up to the plate by assigning our only local conservation officer to take the lead in the chinook salmon trap and trucking operation.  With financial support from CVRD, Cowichan Tribes and other conservation groups we will work together to get as many salmon as possible up river to their preferred spawning grounds.  The operation is scheduled to begin in the next few weeks.

On Sept. 10, the CVRD board passed a resolution that endorses the entire Cowichan Basin Water Management Plan, which includes provisions for increasing summer water storage.  This has been in front of the board for the past seven years and with our community suffering through our second drought in the past three years it was finally passed with only one dissenting vote.

The CVRD will now move quickly to assess the best options for increasing water storage in the summer.  Raising the weir is the obvious answer, but that may be combined with pumping water from deep in the lake to augment summer river flows.  There is some urgency to formulate plans and get the engineering completed as soon as possible not only to save our fish but also to access time-sensitive federal funding of millions of dollars.  We want to be “shovel ready” early next year.

Raising the weir has always been a contentious issue in our community, particularly with a small group of lakeshore residents.  It is true that our lakeshore residents will be the only ones that will be making a sacrifice for the health of the watershed that we all benefit from.  Their concerns must be heard and addressed as we continue in this initiative to store more water in the summer.

The Cowichan Lake and River Stewardship Society’s Shoreline Stewardship Program (CSP) it a community resource that could be very helpful for any lakeshore residents who are concerned about erosion or flooding in front of their property.  The CSP offers expert riparian area planning and can implement natural plant restoration in riparian areas.

It is important to understand that we are increasing our water storage in the summer only.  The winter lake levels will not be affected by raising the weir.  The average winter high water mark is a full four-and-a-half feet above the top of our existing weir.  The weir has no effect on the winter high water because the lake outlet is actually at the Greendale Trestle, where the river narrows and goes through a bedrock canyon.  The elevation of the riverbed at Greendale is the same as it is at the weir, and this pinch point is the cause of high water during the rainy winter season.  This geological feature has been there for many thousands of years and has always been responsible for the natural lake levels in winter.

To give a more graphic description of the summer storage levels we are planning take a look at your kitchen counter.  If the level of your counter represents the natural average winter high water mark in Cowichan Lake, then your kitchen floor would be the level of the lake in summer if we raised the weir by 50 cm (18 inches).  Each centimetre stored in the lake equates to 24 hours of river flow at seven cms.  The actual amount of increased summer storage is yet to be determined.

Every drop of increased summer water storage increases the health of our watershed and our community.   In the coming decades water will become increasingly scarce and exponentially more valuable.  Think of this initiative as building a bigger safe deposit box to store the wealth of pure fresh water we receive each winter.  Water in the lake is money in the bank.

Why go to all this trouble and expense for fish?  It is not just about fish, but our fish are the canary in our coal mine.  It is almost certain now that we will lose a large percentage of our chinook salmon this fall as we did in 2012.  The river is too low for them to enter and they will be decimated by predators as they wait in the estuary.  If we had more water available we could do a pulse flow to simulate a rain event and encourage the fish to enter the river but that will not be possible this year.

If we were to lose the salmon in our river it would signal the beginning of the end of the health of our watershed ecosystems.  The consequences of this would be far reaching, affecting not only the plants and animals in and around the river, but the health of our community as well.

Food security is another good reason for us to increase water storage.  The historic drought that has been affecting the entire west coast of North America from Mexico to the Cowichan Valley will continue to severely curtail food production.  We import most of our food and should the ferries ever stop running we would start to see food shortages on the Island in only 72 hours.  Mexico and California are in serious trouble because they have no ability to increase the water available to them.  They are tapped out.


We are very fortunate to have the ability to increase our water storage and with this increased storage we will have many options for food security, healthy fish stocks and a healthier community now and into the future.