Celebrating 10 years of water quality monitoring

Celebrating 10 years of water quality monitoring

For ten years, local volunteer citizen scientists have been leaning over the sides of their kayaks, canoes, or boats to either look at a black and white secchi disk or to haul up a clear tube full of lake water. Curious passersby might wonder what they are doing or what that odd device is. The short answer is that they are collecting water quality samples that help determine the health of Lake Pend Oreille. The long answer is that for a decade, Lake Pend Oreille Waterkeeper staff and volunteers have been collecting water quality samples at over 13 locations around the lake and the Pend Oreille River. These samples are then tested for 11 different physical, chemical, and biological parameters which establish a baseline for the lake’s health and help identify potential pollution problems. The answer you get likely depends on how busy the volunteer is trying not to drop their sample bottles into the water or upset their watercraft.

LPOW Board Member and WQMP volunteer Gray Henderson checks the temperature of the lake water using his vertical water sampler

After returning to shore, volunteers bring their bottles back to the LPOW office so we can send them off to a chemical analysis lab for testing. Once we receive our final data reports from the lab, I add the results to our master data sheet and update the 200+ graphs on our website. With graphs, it’s easy to see how this year’s data compares to previous years. We can determine if nutrient levels have changed, how the lake changes over the course of the summer, and how abnormal weather conditions (such as this summer’s heat wave) may have affected water quality.

Started in 2012, our water quality monitoring program (WQMP) was the first consistent, long-term monitoring effort for local waterways. Each year we have collected between 800 and 1000 data points that characterize conditions at key areas around our lake and rivers. Having more data increases confidence in our estimates and water quality predictions. Reliable and consistent data collection also makes it easier to identify patterns and determine what is considered “normal” for a particular site. Over the years, we can see if nutrient levels at our sites are increasing, decreasing, or staying the same. We can also compare different sites to see if their nutrient levels are different, and if so, try to figure out why.

Boyer Slough in early summer

We are also able to see what types of habitat our sample sites may host based on the water quality indicators we measure and observe. For example, our sloughs generally have higher nutrient levels, warmer water temperatures, higher dissolved oxygen levels, are more turbid (or have murkier water), and have more bacteria present. This is because sloughs, or backwater areas, have less water flushing through them – allowing for more plant growth, higher biodiversity, and higher productivity. This also leads to warmer temperatures and more dissolved oxygen available for the organisms that live in the water. In contrast, our deep water bays and river stations typically have lower levels of nutrients, colder and clearer water, and less bacteria present. 

One of the first major outcomes of this program was identifying the abnormally high nutrient levels in Boyer Slough. Boyer Slough sits at the top of Kootenai Bay and is home to turtles, moose, otters, waterbirds, and native fish. However, it is also highly developed and surrounded by fertilized lawns and agricultural fields. In addition, effluent from the Kootenai-Ponderay Sewer District flows into the slough, allowing for high levels of nutrients to accumulate and leading to terrible algae blooms every year

Boyer Slough in late summer; an active harmful algae bloom turned the water bright green

With the data we collected, we were able to notify the Idaho Department of Environmental Quality (DEQ) about the high nutrient levels in Boyer Slough. Thanks to our Quality Assurance Project Plan (QAPP) that assures the reliability of our data, DEQ initiated their own monitoring of Boyer Slough. As a result, Boyer Slough was added to the state’s list of impaired waterways due to nutrient pollution. Although it is still impaired for nutrient levels, consistent and reliable monitoring will provide valuable information as we work alongside state and local agencies to protect it from further pollution and prevent degradation of its important aquatic habitat.

We are incredibly proud of our WQMP and are beyond thankful for the efforts of our volunteers to collect data all around our watershed. This program wouldn’t be possible without their dedication and the monetary support we receive from our community. Each year, this program costs LPOW thousands of dollars to train volunteers, analyze samples, compile data, and write reports. Your donations help us continue this program and provide critical data to DEQ. If you’re interested in protecting our precious waterways and keeping our lake swimmable, fishable, and drinkable for years to come, please consider donating at www.LPOW.org/membership.

If you’re interested in learning more about what our data tells us, we would like to invite you to our monthly Keeping Up with the Waterkeeper event on December 2nd at 5:30PM. We are hosting this event via Zoom to prevent the spread of COVID (we are scientists after all). This free event is open to all and we would love to answer any questions you may have about the quality of our water and the health of our lake!