Maquoketa River WMA releases water quality results

     Last week, members of the Maquoketa River (MR) Watershed Management Authority (WMA) shared the results of four years of not only monitoring the water quality of the river itself, but the streams and tributaries that flow into the river as well.

   The river has been monitored in 2019, 2020, 2021, and 2022. Samples are taken three times a year: May, June and August. In 2020, due to the August derecho, the WMA had to postpone their August sample until September.

   “We’re trying to control variables such as climate conditions by all sampling at the same point,” said Lynette Seigley, a lead volunteer for the WMA.

   Volunteers throughout the watershed collect the various samples, which are then tested at Coe College. They test for chloride, sulfate, dissolved reactive phosphorus, nitrate-N (nitrate nitrogen) and E. coli bacteria.

   Seigley shared some final observations following this four-year cycle.

   “Chloride and sulfate concentrations for the Maquoketa tended to be low and really didn’t show much variability and concentration,” she said. “Turbidity levels tended to be higher for tributaries feeding into the North Fork and southern portion of the South Fork. The phosphorus concentrations were higher for tributaries in the upper portion of the North Fork. For nitrate concentrations, we were seeing higher values occurring in both the upper portions of the North Fork and South Fork. E. coli high levels were really scattered throughout the watershed. There wasn’t a particular area that was consistently showing the highest bacteria levels.

   “When we compare the Maquoketa data to streams statewide, the Maquoketa tended to have higher nitrate-N, E. coli bacteria, and phosphorus concentrations. The Maquoketa was lower in chloride and sulfate levels. Their turbidity levels were similar.

   “One thing I always like to point out is the way we designed the monitoring for the MRW; we only sample three times each year. There’s no way to really say anything about trends for particular sites in terms of is the water quality getting better or not. You really need more frequent monitoring probably on a monthly basis, maybe even more frequently, to really determine is water quality improving. With our design, what we were trying to do was to be able to look at a special area and identify where there may be higher values occurring and where some of the low values were occurring,” concluded Seigley.

   The Maquoketa is comprised of 1,870 square miles.

   “So it’s a very large watershed,” said Seigley. “We could monitor right where the MR enters the Mississippi River; that would tell us what’s leaving the entire watershed. But what we know is, that throughout the watershed, land use really varies. There are a number of other factors that impact water quality. So to really understand what’s going on throughout the entire watershed, we decided to break the watershed into smaller, sub-watersheds.”

   In 2019, the WMA started monitoring 34 sites in the watershed. That increased to 36 in 2020. For 2021 and 2022, they drastically increased it to 45 sites both years.

   “In 2021, we decided to add two additional sites down near the outlet of both the North Fork of the MR and the South Fork of the MR down by the City of Maquoketa,” noted Seigley. “Lake Delhi was interested in having seven sites in and around the lake to get an idea of what the water quality was flowing into Lake Delhi and the tributaries into the lake as well.”

   In Jones County, the WMA monitors a total of five sites.

   Turbidity measures how difficult it is to see through the water.

   “If the water is clear, it’s going to have a low turbidity; if it’s cloudy because of sediment or algae, it’s going to have a very high turbidity,” explained Seigley. “The upper portion of the watershed is where we were seeing our lowest turbidity values. Farther down in the watershed, both of the south branch as well as the north branch, is where we were seeing some of our higher turbidity values.”

   Chloride is a component of salt. The chloride levels were pretty low for streams in the watershed. The higher values tended to occur with some of the sub-watersheds in the North Fork.

   Sulfate is naturally occurring in minerals, soils, and rocks. Overall, the sulfate levels for the MR were quite low compared to statewide.

   Phosphorus is necessary for plants and animals.

   “The concern with phosphorus is if there is too much in streams, it can result in increased plant growth and cause algae blooms,” said Seigley.

   She noted that the levels of phosphorus in the MR are above the state average.

   “Compare the MR data with what we see in streams statewide, during the time we were doing our monitoring, the Iowa DNR was monitoring 60 rivers across Iowa,” offered Seigley.

   Nitrogen is essential for plant growth.

   “We typically see higher levels late spring/early summer. That has to do with the timing of when fertilizers are being applied and timely rains.”

   The lower end of the MR and the North Fork are where they saw lower concentrations of nitrate. The higher concentrations occur more up in the headwater areas and in a number of the sub-watersheds along the South Fork.

   E. coli bacteria indicates that there’s a relatively fresh source of fecal matter from a warm-blooded organism in the water.

   “So we had some sites that had some pretty high levels (of E. coli),” said Seigley. “So there wasn’t any real distinct pattern of where the high values were occurring.”

   So what are the WMA next steps?

   Seigley said they could prioritize and focus their efforts more on certain areas of the watershed or monitor more frequently.

   “It’s really a decision the MR WMA board needs to make,” she urged.