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The science behind stream monitoring for water quality

Follow along as two SWCD employees sample stream water to see why you can trust the data collected in this monitoring project.

Tom J Bechman 1, Editor, Indiana Prairie Farmer

September 15, 2020

3 Min Read
Brooke Rudicel and Joelle Beals prepare to sample stream water from a bridge near New Haven, Ind.
PREPARE TO SAMPLE: Brooke Rudicel (left) and Joelle Beals prepare to sample a stream near New Haven, Ind. Rudicel will drop a tape to measure stream depth while Beals lowers collection tubes to pull water samples. Tom J. Bechman

Water-monitoring data collected since the mid-1990s in northeast Indiana and into Ohio is helping people who work with farmers and city utilities make more informed decisions about how to improve water quality in streams and drinking water. Those conclusions are only as good as the data collected, and the data is only valid if it’s collected and analyzed properly.

Currently, two employees with the Allen County Soil and Water Conservation District in Indiana conduct water sampling. They pull samples and measure stream depth once per week on 28 streams in watersheds that feed major rivers in the area. Samples are pulled from April through October.

“The goal is to monitor during the growing season, when we would expect potential runoff of nutrients and chemicals to occur during rain events,” explains Bob Gillespie, a retired professor with Purdue University Fort Wayne. He’s involved with both the Maumee Watershed Alliance and the St. Joseph River Initiative, and assists with data collection, storage and analysis using university resources.

Here’s how Brooke Rudicel and Joelle Beals, both with the Allen County SWCD, collected samples from the Trier Ditch near New Haven, Ind., on a collection day in early August.

First, Rudicel lowered a long tape measure from the bridge over the stream to water level. “We measure the distance to the water level each time,” she explained. “We do it from the same place on the bridge every week. Our goal is to both measure and pull samples from the middle of the stream.”

Related:What water-monitoring project reveals about water quality

Beals lowered twin plastic collection cylinders on a rope from her position on the bridge. She dipped them into the water and then pulled cylinders full of water back to the top.

containers gathering water samples hang below bridge

COLLECTING SAMPLES: The water level is relatively low in this stream in early August, but Joelle Beals is able to grab quality samples. Pulling samples from a bridge allows her to pull from the middle of the stream in a consistent location each time.

“Sampling from the same place each time is extremely important,” Beals said. “Once we have the water samples, we can do some quick testing, and package them for delivery to labs, where they will be analyzed for other things.”

At this location, Rudicel and Beals worked out of their vehicle, which was parked in a small park along the edge of the stream. They recorded water temperature, measured dissolved oxygen and pH, and observed and recorded turbidity, which relates to how clear the water is on any given day. Turbidity is affected by the amount of sediment and solids in the stream.

tool to read water samples

READ SAMPLES: Water samples are packaged in containers and sent to various labs for measurement. Some readings can be checked on-site shortly after water samples are pulled.

They placed samples in various sampling containers and delivered them to various labs that cooperate in the monitoring project. Each week, water from each stream is tested for E. coli bacteria levels to get a measure of fecal material in the water, atrazine, phosphorus, nitrates and total suspended solids.

“We’re careful to do things the same way each time to minimize experimental error in our results,” Rudicel concluded.

About the Author(s)

Tom J Bechman 1

Editor, Indiana Prairie Farmer

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