Minnesota River Interviews - Dave Craigmile - Lac qui Parle River

"We sample for clarity, for nitrates, for bacteria, and we also sample it for phosphorous."

Video Text: "We’re sitting here at a road crossing on this county ditch, of course, a township road crossing and it’s a perfect place to monitor the water that flows into this 48-inch culvert right here. I don’t have my T-tubes or our other monitoring gear with us today, but we take a sample of that water and we sample it for clarity, for nitrates, for bacteria, and we also sample it for phosphorous. What we normally find very low counts of bacteria, in the order of 3 or 4. Nowadays instead of fecal coliform its E. coli that we’re searching for. It will be well under the standards.  When we look at the phosphorous, it’s normally in the range or under 1/10th of a milligram per liter here. So that’s reasonably good. That’s plenty enough to grow algae. You can actually grow algae with, you know, 3/100ths. It doesn’t take very much, but that is reasonably good when we compare that to the discharge from a modern wastewater treatment plant, which is 1 milligram per liter. So we’re talking about less than 1/10th or in the range of 1/10th.

Nitrates
The primary problem we would have here would be with the nitrates. The nitrates can run from 15-25 parts per million (ppm.) We don’t like to see that, but a lot of studies are showing that in a normal cropping situation, it’s very hard to get less than 15 ppm, because it’s just going to leech through the soil profile and get into the water. So there is, what I would say very judicious use of nutrients in this watershed here. I mean most of the farmers (well there’s only like three farmers in this watershed, myself and two others), in this part here that feed in here, but they’re pretty careful, especially now days, because the cost of these nutrients is exorbitant. It’s very foolish to let them get away.

Turbidity
The other thing you would notice here is, looking at it today, most of the time it’s very clear. You can see right to the bottom. It generally is not turbid at all or does not become turbid unless you have a substantial, very substantial rain, where it’s washing across the soil surface and then it will be turbid for a time and then it will clear up quite quickly. The other thing you’ll notice in this ditch is that [the ditch] is highly vegetated in here and actually this time of the year over the late spring, we’ve had, it’s less vegetated than it normally would be. It’s generally extremely vegetated and quite stable."

This page was last updated 7/11