By Richard Peterson
I’ve heard it asked a hundred times: "Why don’t they just build a water treatment plant on the east end of Devils Lake and send treated water into the Sheyenne that can be used by Valley City, Fargo and other towns along the Sheyenne?"
I suspected that cost was prohibitive, but I hadn’t seen anything in print about this issue until the September 2009 issue of North Dakota Water arrived on my desk.
Here’s the answer submitted by the ND State Water Commission:
As Devils Lake continues its relentless rise, there’s a common question posed everywhere from local cafes to radio call-in shows. And that question is — why can’t the state or federal government just treat Devils Lake water so more can be released from the swelling lake via an outlet to the Sheyenne River?
Before this question is answered, perhaps a little bit of background on Devils Lake water quality issues is in order. Devils Lake is a terminal lake, meaning water will only leave the lake through evaporation, plant uptake, ground infiltration or unless the lake elevation gets high enough for an overflow. Thus, because there is no natural outlet to the basin at current lake levels, soil particles, organic material and other elements (often expressed as Total Dissolved Solids or TDS) borne by runoff water, continually collect in Devils Lake. As most people familiar with Devils Lake water issues know, sulfate concentrations in the water have been a particularly important issue.
With this in mind, the state has been required to limit outlet operations so water released from Devils Lake does not negatively impact water quality in the receiving Sheyenne River. And thus far, sulfate levels in the Sheyenne downstream of the outlet have been kept within limits deemed appropriate by the US Environmental Protection Agency and the ND Department of Health.
The other issue that has been brought up, particularly by Canada and the Province of Manitoba, involves the potential transfer of unwanted biota from Devils Lake to the Sheyenne River via an outlet. However, extensive monitoring and studies conducted downstream of the outlet have not found a single species of concern. In addition, water-to-water transfers are already common between the Devils Lake and Red/Sheyenne River basins.
Regardless of these facts, the debate rages on, which brings us back to our original question of why can’t the state or federal government just treat Devils Lake water before it’s released via an outlet? After all, it is often cited that a reverse osmosis filter for Devils Lake water would only cost about $15 million (which is far from accurate).
A preliminary assessment of treatment options for Devils Lake water was recently sponsored by the State Water Commission. Three treatment methods, including Reverse Osmosis (RO), Ion Exchange and Electrodialysis Reversal were considered. RO is generally more cost effective at the flow rates and the mineral levels expected with a Devils Lake facility, so RO became the focus.
Two locations were considered for the treatment plants; a west end facility on the west end of Devils Lake and a Stump Lake facility on Stump Lake. The sulfate concentration of the west end of Devils Lake was assumed to be 700 mg/L and 2,600 mg/L for Stump Lake. A total discharge of 250 cubic feet per second was also assumed, with a finished sulfate concentration of 400 mg/L after treatment.
For the west end water treatment plant using RO, the construction cost was estimated to be $266 million, with an operation and maintenance cost estimated at $13.8 million per year. For a Stump Lake treatment plant, the construction cost was estimated to be $525 million, with an operation and maintenance cost estimated at $27.4 million per year.
Beyond these prohibitive costs, the other issue would be the disposal of wastewater from the plant. For proper disposal, an evaporation pond of 14,000 acres would be required for the west end site and 28,000 acres for the Stump Lake location. As a comparison, the present surface area of Stump Lake is 16,000 acres.
As one can see, full treatment is not an option.
This past summer was one for the record books. It was unusually cold and summer didn’t arrive until September, which was gorgeous for 27 of its 30 days. There was very little wind all summer (can you believe that?) and we didn’t have one major storm, only relatively gentle rains. There were no threats of tornadoes.
The small grains crop was fantastic. Sixty to 80 bushel crops were the norm, not the exception. It appears the corn and beans didn’t do very well, but we don’t know for certain because the harvest of these crops has only just begun. Because of a beautiful September, there might be a surprise.
Last year my garden was a total failure. We only got a few tomatoes and only a five gallon bucket of potatoes. I had to dust the potatoes almost every week because of potato bugs. This year my garden yielded a bumper crop of tomatoes and potatoes. I didn’t have one potato bug.
What a difference a year can make!