Scuba Diving Campbell River - Tides & Currents Explained
The waters around Campbell River are some of the most beautiful and productive in the world. However, the geography creates special challenges. Constrictive passages create tidal currents that can reach upwards of 16 knots (30km/hr). These currents are a serious consideration when planning dives, and dive times are different each day, at each dive site.
THE TIDES AND CURRENTS
As the tides rise and fall as a result of complex lunar and solar gravitational forces, currents are created. As the tidal height of an outer basin rises, the water flows into the inside passages (flood tide). Once the highest tidal height is reached, the currents slack momentarily. As the tidal height of the outer basin falls, the water flows from the inside passages into the outer basin (ebb tide). Once the lowest tidal height is reached, the currents slack again. The bigger the tidal exchange, the stronger the currents.
On the west coast of North America, we experience mixed semidiurnal tides, meaning there are two high and two low tides of different sizes every day.
Depending on the time of year and month, we can have tides as high as 5m (16ft) and as low as 0m (0ft) - twice a day! That is a massive amount of water movement!
On Vancouver Island, the tides flow in from both the north and the south. Halfway down Vancouver Island at Mitlenatch Island (just south of Campbell River), the tidal current direction switches. In Discovery Passage, the ebb currents flow North, while the flood currents flow South. In Courtenay, just 30 minutes south, the ebb currents flow South, and the flood currents flow North.
Any narrow, constrictive passage creates stronger tidal currents. Discovery Passage is a prime example of a constrictive passage - and the basins surrounding the passage are much larger and deeper. With maximum depths of 100m (330ft) and a maximum width of 2km (1.2 mi), water flows through the passage at speeds upwards of 16 knots (30km/hr, 17mph).
Of course, shorelines are rarely straight or smooth. Often times, the topography you see above water is indicative to what’s happening underwater. There are obstacles such as shelves, walls, canyons, and hills that create eddies, whirlpools, and upwellings.
Seymour Narrows is a narrow channel north of Campbell River with regular currents of 16 knots (30km/hr, 17mph). During large tidal exchanges, eddies, whirlpools, and standing waves are common.
The dive sites in Discovery Passage are, at most, a 30 minute boat ride away from Campbell River.
The currents in Discovery Passage are a substantial consideration when planning a dive. You need a boat captain with local area knowledge of tides and currents, and the expertise to deliver you to a dive site at the safest time. The only way to accurately determine slack is to look at tidal current predictions. High or low tide and slack current don’t always match up.
Most dive sites in Discovery Passage are best accessed at slack current. However, there are some sites that can be accessed on a backeddy, or some that are hardly affected by the main current at all.
- Outside Walls
Whiskey Point's dive sites (End of the Road, Middle of the Road, and The Rock) are examples of outside walls. When diving these sites, the captain puts you in the water at or just before slack. During the dive, divers slowly drift through the site as the current pushes, and the boat is there to pick up divers wherever they surface.
Some dive sites can be accessed on a backeddy. Argonaut Wharf is a great example. When the main current picks up to higher speeds, the water is pushed around a shelf or wall, creating a backeddy at the dive site where currents are much slower and in a different direction than the main current.
- Minimal Current
There are a number of sites hardly effected by current. Inside Grouse Island, Lone Tree Island, and the HMCS Columbia are in protected bays and less effected by the main current in the passage. These sites are often used for training - by both recreational and commercial divers.
Drift diving is arguably the most relaxing type of diving, and the closest to flying you can get - but can be intimidating to new divers. Our boat captains, instructors, and divemasters are very experienced with local tides and currents and will go out of their way to make your diving experience a safe and fun one.
Not certified or looking to expand your diving knowledge? All of our courses teach you how to safely dive in mild to moderate currents. There's even a PADI Drift Diving Specialty course that we can teach upon request!
Certified and wanting to dive Campbell River for the first time? Join us on a charter and request a divemaster. They'll teach you everything you need to know about drift diving, and show you just how amazing Campbell River diving is.
A surface marker buoy (SMB) is an essential when drift diving. Carry an SMB and spool, and learn how to deploy it from depth. While ascending or making a safety stop, deploy your SMB so your captain (and other boaters) know exactly where you are.
An audible surface signalling device, such as a whistle or air horn, are also recommended.
Brightly coloured gear ensures you can be easily spotted on the surface by your captain.