From the Greenway to the Gulf (Part 1)
So I had this idea, what if we drove from Sioux Falls SD to the Gulf of Mexico, following the river the whole way? It seemed simple enough. Oh, and let’s take water samples all of the way down to see what we can learn. Oh, and let’s take a videographer and a driver so we can document the whole thing. Nuts right? Pointless, you say. Not so fast.
We left Sioux Falls SD just after 3 pm on a Thursday. Our small team picked up my daughter, the girl in the photos, from High School, and immediately headed south to catch as much daylight as possible. Our first stop, where the Big Sioux meets the Missouri River.
Honestly, we aren’t scientists. We are probably wannabe citizen scientists at best. We had spoken with three different local biologists about what we needed to sample the health of the river in a way children would understand. There are so many things you can test in a river like bacteria levels, turbidity, ammonia levels, etc. We kept it simple; we tested Phosphates, Ammonia, Nitrates, Temperature, and Turbidity.
So we pulled over at the first spot. Now from the bird’s eye view of Google Maps, it looked like we could quickly get off the highway, which we did, park, which we did, and walk down to the river to take a sample, not so much. The first hurdle was a 6-foot high chainlink fence at the bottom of nan embankment, not an ideal barrier in sub-zero temperatures with water testing equipment, a shovel, a Secchi disc, and a videographer with expensive equipment.
Finally, we made it to the “river’s edge” only to realize that the water level was a good 15 below us, and there was a nearly vertical mud wall down to the water. If we had slid down it, we would have never gotten out. We ended up dragging over an old tree and tipping it down the river bank and climbing down it to take our first water sample. Here is what we found.
Ammonia (NH3) 0 mg/L
Phosphates 0.5 mg/L
Nitrates 10 mg/L
Temperature 32.1 F
Okay, that was easy enough minus the shoes covered in mud, frozen hands, and fence hopping. Let me contextualize the numbers for you.
Ammonia — At higher levels (>0.1 mg/liter NH3), even relatively short exposures can lead to skin, eye, and gills damage on fish.
Phosphates — We are looking for less than 0.1 mg/L. Safe is 0.005 to 0.05 mg/L. Phosphates enter waterways from human and animal waste, phosphorus-rich bedrock, laundry, cleaning, industrial effluents, and fertilizer runoff. These phosphates become detrimental when they over fertilize aquatic plants and cause stepped up eutrophication.
0.01–0.03 mg/L — the level in uncontaminated lakes
0.025–0.1 mg/L — level at which plant growth is stimulated
0.1 mg/L — maximum acceptable to avoid accelerated eutrophication
> 0.1 mg/L — accelerated growth and consequent problems
Nitrates — We were looking for 1 mg/L with 10 mg/L being the absolute maximum with anything above 3 mg/L indicating human-made pollution.
Nitrate-nitrogen (NO3-N) in groundwater may result from point sources such as sewage disposal systems and livestock facilities, non-point sources such as fertilized cropland, parks, golf courses, lawns, and gardens, or naturally occurring sources of nitrogen.
So for test number 1, we had safe levels of Ammonia, five times as much Phosphates as it should be, and ten times as much Nitrates. On a random Thursday in February at a random spot on our river, it was at the toxic tipping point. Not encouraging.
Here is the exact spot where we recorded our data.
https://goo.gl/maps/H3ScY2mmnCHkz9G56
Let me make sure something is clear here. River health is a complex issue. There are so many factors that are interdependent and respond to each other in even more interdependent ways. At the most fundamental level, all life needs clean water. The health of the river is both the result of other environmental factors and the cause of them. It is part of a cycle. We are only trying to understand one tiny piece of a massive ecological cycle with this trip. You are welcome to draw your own conclusions. We’ll draw some ourselves on our way to the gulf. Join us for the journey.
Questions at the point:
Is the Big Sioux River higher or lower than the rest of the river?
How are the numbers so high before spring runoff?
If the Big Sioux River is higher, why?
Are there things we can do to bring it back to safe levels?
Source: https://www.water-research.net/
