Interpreting the landscape from above

This week, I finally saw copies of A Safe and Prosperous Future: 100 Years of Engineering and Geoscience Achievements in Saskatchewan, the book I spent a great deal of the last year or so working on for the Association of Professional Engineers and Geoscientists of Saskatchewan.

The book is full of (I hope) interesting stories about Saskatchewan achievements in engineering and geoscience. One of the people I most enjoyed talking to was Jack Mollard, one of the world’s leading experts in the use of aerial photographs to map and study the landscape and its resources.

Mollard (who studied with Professor Donald Belcher, an internationally recognized pioneer in the field of remote sensing, at Purdue and Cornell Universities) formed J.D. Mollard and Associates in 1956. Since then the Regina-based company has explored and evaluated natural resources and infrastructure routes and site on six continents, undertaking literally thousands of projects. In the mid 1990s Mollard was even sent 28 satellite images of Mars and asked to interpret some puzzling features.

One of the most important uses of aerial photography is in choosing road and pipeline routes. Once upon a time all road routes had to be picked out on the ground. During the Second World War, for instance, conscientious objectors were put to work locating the highway on the marshy east side of Montreal Lake. They’d walk in a straight line carrying a sharp stick. As long as they could feel bottom with this stick they would keep on that route. When they could no longer feel the bottom, they would back off a little bit and start probing a different direction until they found a tangent where there was bottom.

Working like that you can find a route, but you can never be certain you’ve found the best route. But by looking at a set of stereoscopic aerial photographs, Mollard can tell where there’s rough rock or muskeg with permafrost in it or other things to be avoided.

Aerial photographs can also be used to find gravel or aggregate, water, mineral resources, dam sites, old coal mines, hazards like potential landslides and contaminated land, and on and on and on. Mollard once calculated he had used the same set of aerial photographs for a relatively small area near Estevan for more than 20 different kinds of projects.

Mollard is often asked, “How can you possibly identify soil and rock formations from air photos?” His stock reply is “How do you recognize people? They’ve all got eyes, nose and mouth. You see them, you say, this is (someone I know)… There are typically fewer landforms in the world than one’s friends and acquaintances—maybe 100 or so basic landforms with recognizable minor variations. For me, the landforms I see almost daily in stereoscopic air photos are as easy to recognize as friends.”

Mollard prefers to work from black-and-white photographs. The subtle variations among the 256 grades from white to black are distinctive. For example, a glacier-deposited hilltop that’s been eroded by wind and water for 10,000 years usually has very little organic topsoil left and its surface looks whitish after being ploughed, while a nearby slough bottom looks darkish because it contains dark organic topsoil that’s been washed down from the eroded hilltop over 10,000 years, along with the added growth and decayed slough-bottom vegetation over the same time.

Nowadays, of course, satellite photography as well as aerial photography is available. Radar imagery, which can establish precise elevations even through tree cover, can be used to create a three-dimensional computer model of the landscape over which an air photo can be “draped” to create a detailed virtual version of the real world.

Although he’s worked all over the world, Mollard says that one of his most rewarding tasks has been searching for groundwater right here in Saskatchewan—maybe, he says, because he grew up on a combined wheat farm and purebred St. Bernard dog ranch outside Watrous, where “we hauled water in barrels when it was 40-below-zero weather.”

“In many of the Saskatchewan towns and villages where we discovered groundwater, the people there had no running water. They couldn’t turn a water tap, flush a toilet, run a washing machine, or flood a skating rink,” he said. “When you discovered a good drinking water supply for them, you’d think you’d found a gold mine.”

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    • Walrus on September 12, 2006 at 10:33 pm
    • Reply

    Had to ask. My father was the minefield supervisor for a good number of years.

    • Edward Willett on September 12, 2006 at 8:54 pm
    • Reply

    They’re mentioned, but just in the context of a much more detailed account of the conversion of the Patience Lake mine from a conventional mine to a solution mine, since that was a first.

    • Walrus on September 12, 2006 at 5:48 pm
    • Reply

    Out of curiosity, did the solution potash mines at Kalium Chemicals in Belle Plaine figure among the engineering accomplishments listed?

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