{"id":7305,"date":"2019-02-06T13:13:35","date_gmt":"2019-02-06T19:13:35","guid":{"rendered":"https:\/\/www.iisd.org\/ela\/?p=7305"},"modified":"2024-01-25T16:41:38","modified_gmt":"2024-01-25T22:41:38","slug":"nine-years-manipulating-lakes-watershed-mimic-climate-change-just-diversion","status":"publish","type":"blog","link":"https:\/\/www.iisd.org\/ela\/blog\/nine-years-manipulating-lakes-watershed-mimic-climate-change-just-diversion\/","title":{"rendered":"LONG READ: Nine Years of Manipulating a Lake\u2019s Watershed to Mimic Climate Change: More than just a diversion?"},"content":{"rendered":"

From creating algal blooms to spilling crude oil and building reservoirs, IISD Experimental Lakes Area is known for big, in-your-face experiments that are highly visible and impactful. The benefit of having visual evidence of the effects of an environmental stressor are undeniable\u2014it\u2019s easier to demonstrate a concept or result when it\u2019s staring you in the face.<\/p>\n

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Left: Lake 226 eutrophication experiment<\/a>.\u00a0 Middle: Experimental Lakes Area Reservoir Project (ELARP) at Lake 979<\/a>. Right: Freshwater Oil spill Remediation Study (FOReSt).<\/a><\/em><\/h5>\n

\u201cSee, it never even got a snazzy acronym\u2026\u201d.<\/h2>\n

But what about those projects that are not so easy to see\u2014the ones whose results are more nuanced and take time to develop?<\/p>\n

IISD-ELA\u2019s Water Diversion Project<\/a> (see, it never got a snazzy acronym) involves intentionally manipulating the amount of water flowing into a lake to mimic the impact of climate change and explore the results. Unlike some IISD-ELA experiments that involve chemical additions to a lake, this project was based around a physical manipulation of the landscape. In terms of visual impact, the project is both striking and subtle\u2014the water diversion stream that was created is itself impressive to see (and was even more impressive to create!), but the actual effects on the lake are much less visible.<\/p>\n

Given that it is an experiment on climate change, it also relies on long-term study (possibly lasting decades), making it much less visual and immediate than past ELA whole-ecosystem studies.<\/p>\n

This project acted as an important bridge between our research under Fisheries and Oceans Canada and research under IISD-ELA, and it is still going strong. The Water Diversion Project has been with me through almost every step of my career, and as we move into the ninth year of the project, I wanted to take some time to reflect on what we set out to do, what we have found, and where we plan on going.<\/p>\n

At its core, the Water Diversion Project aims to mimic a drought scenario in which lake levels have dropped and connectivity between lakes on the landscape is eliminated. When the water level in a lake is higher than the lowest point of land along the lake shore (called the \u201csill\u201d), water naturally flows out of the lake at this point, typically (in the boreal shield, where IISD-ELA is located) into a stream and then into another lake. If the water level drops below the sill (because of decreased precipitation, for example) the flow out of the lake will stop and the water will remain in the lake, sort of like water in a bowl. The water in the lake may still be lost to evaporation, and the lake still receives inputs of water from precipitation and runoff from the surrounding landscape, but it no longer contributes water (and any substances dissolved therein) to water bodies downstream.<\/p>\n

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Our Water Diversion Project aimed to mimic a drought scenario to find out what would happen to a lake when it stops receiving water from upstream water bodies\u2014all in an effort to understand what might happen to boreal shield lakes in Canada as climate change progresses. The predictions for this project are well-described in a previous blog post<\/a>, so I have just briefly summarized them below.<\/p>\n

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\u201cI\u2019ve said it before, and I\u2019ll say it again\u2014you don\u2019t need a workout program when you work at IISD-ELA!\u201d<\/h2>\n

Lake 626 was chosen as the site of the experiment, and to mimic the loss of connectivity between lakes we needed water from the upstream lake (Lake 627) to flow around Lake 626 instead of into it. In doing so, Lake 626 went from being a 4th<\/sup> order lake (with three lakes upstream) to a 1st<\/sup> order lake (which only receives inputs of water as runoff from the land around it).<\/p>\n

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To create the water diversion stream, our hydrologist (ELA living legend Ken Beaty) surveyed the route of the new stream and then brought in the heavy machinery to blast the channel with dynamite. Although my history working at the world\u2019s freshwater laboratory extends back to 2005 when I started on the fish crew as an undergraduate research assistant, one of the first field-based tasks I had when I began my permanent job as biologist was to help create the dike that stops water from flowing from Lake 627 into Lake 626, and then to open the water diversion channel, thereby creating a new outflow for Lake 627 that bypassed Lake 626.<\/p>\n

I\u2019ve said it before, and I\u2019ll say it again\u2014you don\u2019t need a workout program when you work at IISD-ELA! After a few days of heavy lifting, the diversion channel was officially opened on November 26, 2010 and has been flowing ever since.<\/p>\n

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Left: Researchers<\/em> took two days to create the dike which prevents water from flowing from Lake 627 into Lake 626. Right: Water flows through the diversion channel for the first time on November 26, 2010.<\/em><\/h5>\n

Once the channel was open, we focused on monitoring activities (we had spent three years monitoring before the experiment to establish baseline data), including looking at the thermal structure of the lake, water clarity, water flow, water chemistry, and fish abundance and behaviour, among many other parameters. As with all whole-ecosystem experiments, the sampling for this project involves a lot of teamwork to ensure all parts of the ecosystem are covered. This project has been a collaboration between IISD-ELA researchers and scientists and graduate students from Fisheries and Oceans Canada, Environment Canada, University of Waterloo, Milne Technologies, and University of Toronto.<\/p>\n

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Left: A Secchi disk is used to measure water clarity. Right: IISD-ELA researchers Paul Fafard (left) and Ken Sandilands measure water temperature and oxygen and collect water samples in winter.<\/em><\/h5>\n

\u201cYes, even in the winter!\u201d<\/h2>\n

As a fish biologist, my involvement in the project has always focused on fish, and particularly on fish behaviour. If the thermocline<\/a> was going to become deeper, this would in turn reduce the available habitat for cold-water fish (in this case lake trout).\u00a0 In fact, the main reason Lake 626 was selected for this study was because it was a fairly shallow lake (13 m deep) that contained lake trout (who require cold water) and would therefore be on the \u201cedge\u201d of acceptable lake trout habitat in the face of climate change.<\/p>\n

In order to study their behaviour and habitat choices we implanted tracking tags into the fish<\/a> and monitored their movements both spatially (latitude\/longitude) and in terms of depth. These tags send out acoustic signals every two to five minutes that are detected by receivers deployed in the lake.<\/p>\n