Program ID: Innovation Anthology #170
Program Date: 09/25/2008
Program Category: Energy, Engineering, Environment, Forests, Water
Instrumented Watersheds I: Oil Sands Reclamation Research
PROGRAM #170 INTERVIEW WITH CLARA QUALIZZA
MP3: 17.8 MB
CQ: An instrumented watershed is a piece of land, at Syncrude, is a piece of land we’ve reconstructed that’s a full watershed. Which means its an integrated landscape of uplands and wetlands and waterbodies that connect, that take the water off of a landform and lead it from the uplands, down through the wetlands, down to the streams that would feed a river.
And an instrumented watershed, at Syncrude, is one where we’re tracking all of moisture, all of the water, that is moving around that watershed, and all of the things that are moving around in the water, and the plants and the various organisms that are living in that landscape.
CC: WHY IS THAT A CONCERN FOR SYNCRUDE?
CQ: It’s really important for Syncrude because we reconstruct large areas of land. We reconstruct landscapes because our mining takes out landscapes, and we have put back a landscape that can function in a way that was very similar to what was there before.
And so, we reconstruct entire landforms, entire landscapes. And the watershed is the functional unit of the landscape.
CC: NOW YOU ARE DOING THIS IN THE BOREAL FOREST, OR WHAT WOULD HAVE BEEN THE BOREAL FOREST, BEFORE IT WAS MINED. WHAT ARE SOME OF THE CHALLENGES THAT YOU FACE WHEN DEALING WITH BOREAL LANDSCAPE AS OPPOSED TO SOMEWHERE ELSE IN ALBERTA?
CQ: Well the boreal landscape of course is dominantly treed landscape. We’re not putting this land back to an agricultural system. So you’re looking a very diverse landscape of mixed forest and wetlands. And so, we don’t, we have to put back a diverse landscape. So we can’t just focus on uplands or just focus on recreating a wetland It has to be an integrated functioning landscape that grows trees for centuries.
And supports all of the land uses that would be used in the boreal forest, which is varied land uses.
So that’s the challenge of recreating a landscape in the boreal forest.
CC: HOW DO YOU GO ABOUT RECONSTRUCTING IT?
CQ: It is really a very large team effort that involves research and technology and engineering to implement research, is how it goes, basically. And we have team of engineers and scientists at Syncrude who take the fundamentals of watershed function and convert it into landform design, soil placement and revegetation.
CC: WHEN YOU LOOK AT THE DIFFERENT LAYERS OF THE SOIL THEN, WHAT IT WAS LIKE BEFORE YOU TOOK IT OFF AND THEN YOU HAVE TO PUT IT BACK, ARE THERE ANY PREPARATIONS? DO YOU SAVE THE OVERBURDEN OR ANYTHING LIKE THAT?
CQ: Absolutely. We salvage all of our soil materials from in advance of the mining operation. And you used the right term. There is overburden, all the soil that sits on top of the oil sand, which varies, depending on which mine you are at. but the very top, the really critical layers are in the top, mostly in the top meter, but up to the 3 top three meters. And we selectively salvage the organic soil layers at the top, and then the mineral soil layers below.
And we reconstruct then in a way that is similar to what was there before. So we learn from the soil scientists what was there before we attempt to put that back by selective salvage and then selective placement back in the landscape.
CC: NOW YOU PUT INSTRUMENTS IN THAT RECONSTRUCTED LANDSCAPE. WHAT KIND OF INSTRUMENTS ARE YOU USING? HOW DO YOU PLACE THEM? HOW DOES IT WORK?
CQ: Well that’s really fun stuff, the instrument part. And we rely a great deal on our research partners to keep us abreast of the state of the art in how to monitor the fluxes in the landscape. A lot of our instruments are trying to water where is the water going
So we have numerous climate stations monitoring precipitation and wind speed and relative humidity. And the temperature flux off the surfaces of the reconstructed land forms and off the surfaces of the plants that are growing, because we have a very actively growing young forest. And every year changes. Every year it gets a meter higher, and change in species and those plants change the amount carbon they release, the amount of moisture they release to the atmosphere
So we use extensive waterwell networks. Shallow ones, deep ones. We monitor net radiation in the landscape. We use a very interesting instrument called an eddy co-variant system on various watersheds that monitors the carbon and the water fluxes in those landscapes.
Because that’s ultimately what its all about. Where is the water going? Where is the carbon going? Those are the functional processes in the landscape
So that type of thing. We also monitor, we use weirs that are automated to measure the water that is flowing into and out of wetlands. And we have various sensors that measure the salt content in the water bodies that we have
And things like neutron access tubes that we insert soil moisture monitoring devices into. Time domain reflectometry, which are soil moisture monitoring devices and it all depends on what the focus of the research we’re doing is. the type of instrument we use. But really looking a lot at water and carbon flux in the landscape.
CC: NOW MY UNDERSTANDING IS THAT YOU ACTUALLY HAVE THREE DIFFERENT INSTRUMENTED WATERSHEDS, AND THEY ARE ALL LOOKING AT DIFFERENT TYPES OF SOILS OR SOIL CONDITIONS. WHAT ARE THOSE?
CQ: The three current watersheds that we have are build on three of the main types of materials that we will build landscapes out of at the end of the day. You referred to one of the types earlier that is called overburden. There’s the material sitting on top of the oil sand at Syncrude site is a cretaceous shale. And we call it overburden. And we’ve created land forms out of it. Because we have to remove that overburden to get at the oil sand. And it doesn’t go away. You have to turn it back into a landscape.
The other material type that we have a watershed on is on tailing sand. So after we’ve extracted the oil out of the oil sand layer, you end up with clean sand. And we create landforms out of tailing sand.
And the final watershed that we have constructed is on one of the by-products of our upgrading process which is coke. And coke is a carbonaceous sand that is basically left over after we’ve taken off all of the hydrocarbons we would use to create Syncrude sweet blend.
CC: TELL ME A BIT ABOUT COKE. WHAT HAPPENS TO THE COKE NOW?
CQ: Well coke is actually really neat stuff. At Syncrude, it’s a carbonaceous sand, so it’s essentially pure carbon. And because it’s carbon, the Energy and Utilities Board considers it and any body who is concerned about energy considers it a potential future resource for energy resource for the future.
And so we need to store it in such a way that it could be, if technology were developed to utilize it efficiently as an energy resource, and in a clean manner, that it could be used again in the future. So we store it in the landscape in such a way that it could be accessed in the future.
Right now we’re, the plan is to store it in discreet areas but then we would reclaim it because we don’t know when that technology would be developed and we don’t want to leave large open areas into the long term. So we would reclaim it just like we would any other landscape.
CC: NOW I UNDERSTAND THAT COKE HAS A LOT OF SULPHUR IN IT, SO IS THERE A CONCERN ABOUT THE SULPHUR LEACHING OUT INTO, INTO THE WATER IT ITS SAY BURIED UNDER TOPSOIL OR WHATEVER?
CQ: Sulphur is really, because of the way, because of the coking process, and the structure of coke, and I’m not a chemical engineer, but we have had to evaluate that, that aspect of the coke.
The sulphur, the issues of sulphur leaching are not the primary issues around coke storage, but we certainly have to keep track of, just like any material that you recreate the landscape with, you need to keep track of what’s flowing in and flowing out. It’s a watershed, again. And what’s flowing in and out.
So the sulphur actually turns out is not one of our, not one of the big issues with coke storage, per se.
CC: SO WHAT ARE YOU FINDING OUT WITH REGARD TO THE INSTRUMENTED WATERSHED ON THE COKE FIELDS? DOES IT REACT DIFFERENTLY THAN SAY THE OVERBURDEN WATERSHED OR THE TAILINGS WATERSHED?
CQ: Oh, most certainly. Yeah. Each of these watersheds behaves very uniquely because the material, each material is quite different. So primarily its about how those materials transmit water. And coke is actually like a sand, but its quite a bit different from tailing sand.
Tailing sand is a fine sand with lots of silt in it. So it actually holds more water than a coarser sand. So you could think of coke as a coarser sand, although its quite perfectly round little sand particles.
So it doesn’t hold water as well as tailing sand. And it certainly doesn’t hold water as well as overburden, which is clay. So water moves through it very quickly.
And so it’s quite a dry material. So we need to cap, to put a soil cover on it can hold enough moisture to keep the forest going. We don’t rely on the coke for moisture. So that’s the difference between these types of materials, is lots about how they hold moisture and transmit moisture.
Because the boreal forest and its interesting, its situated in an area that’s in a moisture deficit. And so moisture holding capacity in soils is a really critical concept and really rules our strategy in soil reconstruction. We try and enhance moisture holding capacity so that the trees will have plenty of water to keep them going.
CC: TELL ME ABOUT THE TAILINGS WATERSHED. WHAT IS UNIQUE ABOUT THAT?
CQ: The tailings watershed is on one of our sand storage areas. And un, the interesting thing about that watershed is it’s a large sand storage area that doesn’t have artificial drainage inserted in it.
So it’s got, when we place tailings sand, we pour it. It’s moved in a pipeline, and its carried in water. So it takes a while for the water to drain out of the tailings sands.
And what we’ve found in the tailings sand watersheds is, and so that water seeps out at the low points in the landscape where the wetlands would be. And what we’ve found from that watershed and the groundwater regimes is we’ve determined the type of configuration that you need to build tailing sand landforms with to create enough relief in the landscape to allow the reestablishment of groundwater regimes that allow for that water to drain in a quick fashion and support the wetlands you are trying to put in those watersheds.
So we had built an area that didn’t have much topographic relief and another area that had quite a lot, hills and valleys. And the one that had lots of hills in it had flushed and the water had drained out of those sands quicker. And so then we got this nice , diverse upland, wetland sequence of landscape. And a lot of that work came out of the groundwater research we did in that area.
CC: IS THERE A CONCERN OVER TOXICITY FROM THE TAILINGS?
CQ: The tailings water is salty and it carries residual napthenic acids which are natural in the oil sand formation. And so there is concern in the short term about the napthenic acids in the water as well as the salinity.
And so salinity management means then planning, designing the landscape so that the groundwater flushes and has time to naturally attenuate the napthenic acids and flush out the salts is a key feature of our landscape design and our research, is to figure how to optimize that in tailings based landscapes.
CC: SYNCRUDE HAS BEEN WORKING ON THESE INSTRUMENTED WATERSHEDS FOR ALMOST A DECADE NOW. WHAT ARE SOME OF THE THINGS THAT YOU’VE FOUND OUT?
CQ: We’ve had lots of graduate students come through the research programs in a decade.
Some of the things that stand out are we’ve definitely learned about, I spoke before about the importance of soil holding capacity in reconstructed soils. And how we can reconstruct soils using layering. The layers of the soil s we recreate are really important in enhancing moisture in soil profiles and enhancing tree growth.
We’ve also learned a lot about how these landscapes how we design the land form, the topographic relief enhances salt flushing. So we’ve got better advice on how to create the landform design based on, because we want to enhance salt flushing. We don’t want salt in any of the tree root zones because trees don’t enjoy salt very much.
We have learned very interesting things about the selective salvage of forest floor materials to enhance native species establishment, selective salvage and placement of the top layers of forest floors in the reclaimed areas, because there isn’t a lot of suppliers of all of the native plant species we want to see in the landscape. So if we can get that seed bank and place it properly, and we have shown that it does enhance native species establishment.
We have also shown that if you place the right type of material in the bottom of wetlands, you enhance the reestablishment of the benthic community that is in those wetlands that forms the basis of the food web.
We have certainly got one of the best long term data bases on how an evolving forest, the water and carbon fluxes of the forest, what those balances are. So it’s very important for developing models to project your expected long term success of these various soil prescriptions and landform prescriptions.
So it’s a whole suite of research that has led to changed in how we build landforms and has many of the guidelines that the entire industry uses for reclamation planning.
CC: DO YOU HAVE ANY INDICATION AT THIS POINT HOW LONG IT WOULD TAKE IT ACTUALLY REESTABLISH THE FOREST WHERE MINING AS TAKEN PLACE? THAT YOU’RE DOING THIS RESEARCH USING THE INSTRUMENTED WATERSHEDS. HOW LONG WILL IT TAKE TO REESTABLISH THE FOREST AND THE NECESSARY HYDROLOGY, BRINGING IT BACK TO WHAT IT MIGHT HAVE BEEN LIKE BEFORE?
CQ: Boreal forests, you don’t actually have a boreal forest for about 25 to 30 years, to have mature trees in a boreal forest. Its not an instantaneous process. And the interesting thing about the watershed studies is that it shows that as the forest develops, the forest influences how the hydrology develops.
And it’s a very dynamic system. The good thing about the watersheds is that we’re tracking that interaction from planting of the trees all the way to a mature forest. So we don’t expect to, we don’t claim to ever have a complete forest before 15 years even It might be even 20. And we’re going to study how that interaction evolves over time.
Because the hydrology does evolve as the trees evolve. It’s fundamentally linked. The processes in a watershed are all linked. The trees, the soil, ecosystem processes. The hydrology, they hydrogeology of those landscapes are intimately link.
So they influence each other. So until the boreal forest is actually, until you have mature trees, you can’t say the hydrology is finished evolving. Or the trees are done and that’s it.
So right now, 15 years is considered the trees have gotten a good toehold, they’re on a good trajectory and that’s when we would start to talk about the fact the forest is on a healthy path to a mature forest, which is anywhere between 30 and 50 years.
CC: THANK YOU VERY MUCH CLARA.
CQ: You’re welcome.
Clara Qualizza is an environmental scientist with Syncrude Canada