Water can move mountains, one piece at a time. Fragments get carried downstream, often ending up in the sea and bringing with them minerals and organic material. Many of the tiniest coastal ocean creatures can trace their food sources back to these nutrients coming off the land.
To understand these intricate food webs that span land and sea, scientists first need to gauge how much nutrient-laden water enters the ocean. But there’s a logistical barrier.
For the full hydrological story, you can’t merely sample the water in fair weather. You also need to be taking measurements during the worst winter storms when the flows of water and nutrients are at their peak. Sideways rain and high winds aren’t only uncomfortable for fieldwork, the stormy conditions can also be unsafe, especially in remote areas.
“There’s always this dream of a hydrologist that you can get those high flows and get them over an extensive area,” says Bill Floyd, a research hydrologist with the province of British Columbia and an adjunct faculty member at Vancouver Island University.
Floyd and a handful of researchers and engineers came to Calvert Island to realize this dream of measuring water flow as it changes over the course of a day, a month, or a year, in all weather conditions.
A trickle can become a torrent in a flash in the Great Bear Rainforest. During a heavy storm, one stream’s flow increased by a factor of nine in just six hours. For perspective, that stream would take 14 minutes to fill an Olympic-sized swimming pool before the storm. After the storm, it could fill that same pool in only 90 seconds.
So the team set out to wire a small corner of this remote landscape with a clever system that can quantify the stream flow using a pinch of salt and basic chemistry principles.
A bucket of salty water is dumped into the stream, which consequently alters its concentration. The change to the concentration of the stream is equivalent to adding one sugar cube in 32 cups of coffee. Connectivity sensors downstream measure the wave of salty water when it passes and can calculate how much water is flowing. That information then gets sent back to scientists hundreds of kilometers away.
“When you’re working with Mother Nature’s infrastructure, you often have to improvise,” says Colby Owen, a designer-builder and electrician with Hakai Energy Solutions.
Watch our mini-documentary Go with the Flow to discover how Hakai scientists and engineers joined forces to quadruple their number of stream measurements without suffering through a single storm.
“You get the data as the storm is happening. It’s like you’re there, but you’re inside your office and you’re dry and warm,” says Floyd, as a wide grin comes across his face.
*** Correction: The blog and video initially stated that the concentration of the salt water in the bucket was equivalent to a sugar cube in 32 cups of coffee. This number actually represents the approximate concentration of the stream after the salty water has been dumped in.