September Riverkeeper Report

Summer is wrapping up here on the South, West, and Rhode with the start of cooler evenings and longer nights, and the end of the 2026 Arundel Rivers Bacteria Monitoring Season!

First, we’d like to thank all of our dedicated volunteers for your commitment to helping us understand the health of our waterways. This year we had almost 30 volunteers participate in our bacteria monitoring program, doubling our volunteer cohort from 2025! You volunteers made this season possible, and we are so grateful to each of you. Thanks to your support, we were able to expand our bacteria monitoring program to include 33 sites, giving YOU the important information you need to make safe swimming choices in our rivers.

We care about getting you accurate and timely information about bacterial contamination in our waterways, so this year, we hosted a Lunch & Learn with our partners at Anne Arundel Community College to dive deeper into our program and the lab analysis. If you missed the live event, no need to worry! Check out https://www.arundelrivers.org/copy-of-bacteria-monitoring to see the recorded discussion. We also had representatives from our team, Riley Kuehn and Rachel Beall, present at the National Marine Educators Association conference in Cambridge, MD. They shared our program logistics, data analysis, and an exploratory case study activity to educators and scientists across the country. Talk about Community Science in action!

Throughout the summer, more than 500 bacteria samples were collected, including samples that will be used by our partners at the Smithsonian Environmental Research Center (SERC) to further investigate the sources of bacterial pollution in the waterways. When we receive the results of those tests, we will be sure to share them, so be on the lookout.

This year, we found that across all 33 sites this season, 17% of samples failed and 83% of samples passed. Last year, we saw 38% of samples fail and 62% of samples pass.

Our Monitoring Team is hard at work looking at how rainfall, tides, and even wind are impacting if a sample passes or fails. We will be sharing our 2026 and multi-year trend analysis with you soon, but in the meantime, our 2025 results and analysis are always available to you on our website. 

Excitingly, eight sites passed 100% of the time this year! That’s 24% of our sites, meaning more sites passed all summer this year than in 2024 or 2025! Check out the maps below to see the sites that passed all summer this year, highlighted in green.

Based on the data now, we are seeing that of the samples that failed (17% of all samples), ~70% of them failed after a rain event within 48 hours before testing.

Curious to learn more about what we found this year? If this program or our data is of interest to you, please reach out to Riley Kuehn, our Monitoring Programs Coordinator (riley@arundelrivers.org), or Rachel Beall, our Programs Assistant (rachel@arundelrivers.org), for more information. Stay tuned for more analysis and discussion of our results and the health of our rivers, coming soon!

Finally, we would love to keep growing our volunteer cohort so we can continue to monitor the places you care about most. If you or someone you know would like to volunteer with us, or sponsor a site for our 2027 Bacteria Monitoring season, please let us know! We’d love to have you. 

Enjoy these last few days of summer, and as always, we’ll see you out there!

The Arundel Rivers Monitoring Team

Elle Bassett (elle@arundelrivers.org)

Riley Kuehn (riley@arundelrivers.org)

Rachel Beall (rachel@arundelrivers.org)