A Day in the Life of a Water Quality Monitor – Step by Step Guide to Field Monitoring
Phillip Oswald, Monitoring and Education Specialist
A day in the life of a water quality monitor is a balance of planning and reacting. Under normal conditions, we sample every 10-14 days. However, I have to be ready to sample the very next day if there is a big rain event. The International Water Institute (IWI) has a few different projects that require sampling. As a local partner for the Minnesota Pollution Control Agency’s Watershed Pollutant Load Monitoring Network (WPLMN), IWI staff sample over 40 sites on the Minnesota side of the Red River Basin. IWI staff also collect samples for the Minnesota Department of Agriculture as a part of their pesticide monitoring and the Buffalo Red River Watershed District as a part of their annual sampling. Additionally, IWI staff sample at various impoundments and ditch systems in the Red River Basin for the Flood Damage Reduction Workgroup.
The International Water Institute (IWI) has a few different projects that require sampling. As a local partner for the Minnesota Pollution Control Agency’s Watershed Pollutant Load Monitoring Network (WPLMN), IWI staff sample over 40 sites on the Minnesota side of the Red River Basin. IWI staff also collect samples for the Minnesota Department of Agriculture as a part of their pesticide monitoring and the Buffalo Red River Watershed District as a part of their annual sampling. Additionally, IWI staff sample at various impoundments and ditch systems in the Red River Basin for the Flood Damage Reduction Workgroup.
Sometimes, I must sample for all three projects on the same day, which can lead to long days and a tired mind keeping everything straight! So, I would say the first step in water quality monitoring is setting a schedule. Everyday we check online hydrographs (Photo 1) to see if a river is rising or falling, and determine if sampling needs to take place. As the river is rising, I sample more frequently. Hopefully I time it right and sample at the peak, then I can space out sampling a little more as the river is falling back down to base flow. This year alone, some storms in the Basin have caused rivers to rise over 8 feet overnight! Pollutant concentrations differ at various stages of a river so it is important to collect samples at a wide range of flows and levels. We will try to plan a route to sample several sites in a day. If I’m sampling routinely I get sites close together, but if I’m reacting to a storm event, I may have to travel more depending on where the water is rising.
Once my route is set, the next step is to pack the car. I carry lots of equipment on a day out sampling. First and foremost, we bring a cooler or two with ice packs and sample bottles. A critical piece of equipment is a Van Dorn (Photo 2) and extendable rod with a sampling cup at the end. Depending on the site, we could use either the Van Dorn or the grab sample bottle to collect our water samples. Once I collect a sample, I place them on ice in the cooler to get them as cold as possible, hopefully down to 6° C before reaching the lab.
I also bring a sonde. What is a sonde, you ask? A sonde (Photo 3) is a tool to take field measurements of the river, such as temperature, conductivity, pH, and dissolved oxygen. These field parameters vary spatially throughout the basin, at different stages, and different times of year.
Additional gear I carry includes a Secchi tube to measure stream transparency, an empty jar for photographing the river water, a weighted tape measure to measure distance from the bridge to water, and safety equipment like traffic cones and a flashing light.
When I get to a bridge, there are several things that need to be done to complete our sampling routine. The first thing I do is take a stage reading if necessary using a wire weight, a staff gauge, or a tape-down depending on the site. Wire weights and tape-downs measure the distance from the bridge to the water, while a staff gauge acts as a ruler to measure river height. All three forms measuring are compared to reference elevation points. Once the stage reading is recorded, I take pictures. We take a photo capturing the upstream and downstream visuals (Photo 4). After the pictures, and making notes about how the river looks, I deploy the sonde. It usually takes a few minutes for the sonde readings to stabilize. While waiting, I tend to some other things, like labeling sample bottles and filling out the data sheet. We record observations such as: weather conditions, debris in the stream channel, recreational suitability, river stage and flow, and any additional info I think may be important such as water coming into the river from a ditch or culvert which could influence the readings.
Once the data sheet is filled out and the sonde readings are recorded, I collect the samples. At most sites, we use the Van Dorn to collect water, but we may use the rod and sample bottle if necessary. We collect one Van Dorn to fill up a Secchi tube to measure transparency, then fill up a jar for a picture. Next, we collect another Van Dorn for the sample bottles. Depending on the site, we fill two or three bottles that are sent for lab analysis including total suspended solids, total phosphorus, nitrates and nitrites, and total Kjeldahl nitrogen. The “outlet” site, or the site closest to the river’s confluence to the Red River, will also be tested for ortho-phosphorus (component of total phosphorus). I then clean out our equipment to ensure I don’t cross-contaminate between sites, and get back on the road to the next site.
This has been my first season in the field monitoring rivers in the Red River Basin. If I have learned anything it is to always be prepared. Just when you think you can take a breath and take some time to catch up on everything, a storm event comes through and the rivers start to rise again. When it comes to sampling, the only thing for certain is uncertainty!