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Les Henry: A pretty little slough, a picture story

Sloughs are affected by the underground as well as surface features

Be patient. This piece does have a punch line and it does relate to farming — but it comes at the end. Carry on and read. No peeking!

In 2007 I was involved in a hydrogeology study of a new subdivision in southeast Saskatoon. The real work was done by an engineering firm who hired a subcontractor to handle the hydrogeology part. I just helped a bit by showing what could be learned about the underground by being able to “read” what Mother Nature was telling us at the soil surface.

Elk Point Drilling of North Battleford was the drilling contractor and John Soloninko (1935 – 2017) himself was coming — a great thrill for me. I knew he would want good quality (low salt) water for drilling so I tested nearby sloughs with my trusty field electrical conductivity (EC) meter.

One pretty little slough (PLS) had very salty soil on the east end with nothing much growing. On that basis I expected it to be too salty for drilling but noted good poplar growth on all but east end. To my surprise the salt level was less than half that of the South Saskatchewan River at Saskatoon.

This PLS was a good learning experience for me. How could it have salty soil at one end and still have good fresh water in the slough? The land northwest of the slough had a very sharp drop in elevation.

Three shallow (15 foot) water table wells were installed to the northwest of the slough. The table below shows data from those wells.

Data from test wells northwest of the slough.
photo: File

The test wells started about 12 m west of the slough and were spaced about 22 m apart. In a distance of about 60 paces a lot was happening. The water level dropped by 10 feet from the slough to Well 3. The salts in the water went from 200 ppm in the slough to 2,300 ppm in Well 3. The water table had a large horizontal gradient that was the driving force allowing the water to move even in the clay soils at this site.

The slough had good water because it had an underground outlet to the northwest that allowed the water to get away and avoid buildup of salts by evaporation. When more water came in from snowmelt or rain, it quickly leaked away in the underground. Mother Nature is amazing when you understand how she works.

Why is the east end salty?

The salty soil at the east end of the slough is due to a glacial aquifer at a depth of about 100 feet that has pressure enough to push water near or above the soil surface. We knew that, so the east end salt was not the mystery. The mystery was why the slough had such good water. The aquifer ends just at the east end of PLS.

Hand-dug homesteader wells

Water was the first order of business on a homestead. Many used common sense and dug a well as near as possible to a slough. If that slough had a salt ring around it, the well was highly mineralized. Many of the salts were sulphates so no laxative required.

Well 1 had water with only 900 ppm minerals (see the table), about as good as a sand point well. Only about 45 steps away, Well 3 had 2,300 ppm. Well 3 water would be hard enough to make soap curdle and keep the stomach active. So, it is no mystery when wells almost side by each have very different water.

By June 25, 2009, the pretty little slough was almost gone.
photo: Source: Google Maps

By July 2009 the PLS was all but obliterated by the bulldozers (see above). The poplar trees are all gone and the slough seems to be filled with topsoil.

By June 2011 the PLS was dead and buried with no evidence that it ever existed (see below). Poor little PLS.

By June 9, 2011, the pretty little slough had been all but obliterated by bulldozers. Note the salty soils east of the PLS and the salt rings around sloughs to the west.
photo: Source: Google Maps

By July 2017 the PLS was the site of fancy homes for city slickers (see photo at bottom).

The punch line

We hear a lot these days about pretty little sloughs. I almost cried about such a PLS as this being obliterated forever. Could it not have been saved and used as an outdoor laboratory for education at all levels? Not really. People have to have a place to build houses.

If the PLS had been saved and houses built all around, it would no longer function as it did anyway. The soil surface and water is linked to the soil and water beneath it. They act as a unit. To understand the surface we must understand what is beneath it. The water moving underground outside the slough boundaries is important. Underground water movement pays no attention to surface boundaries.

City slickers call sloughs wetlands and crow about all the ecosystem services (buzzword) they provide and how we must protect them at all costs. All these little sloughs must be saved and we must try to farm around them. Just as city slickers must have a place to build their houses, farmers must have land to farm.

With that, I rest my case.

By July 8, 2017, the former site of the slough had become the site of fancy new homes.
photo: Source: Google Maps

About the author

Columnist

J.L.(Les) Henry is a former professor and extension specialist at the University of Saskatchewan. He farms at Dundurn, Sask. He recently finished a second printing of “Henry’s Handbook of Soil and Water,” a book that mixes the basics and practical aspects of soil, fertilizer and farming. Les will cover the shipping and GST for “Grainews” readers. Simply send a cheque for $50 to Henry Perspectives, 143 Tucker Cres., Saskatoon, Sask., S7H 3H7, and he will dispatch a signed book.

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