Out on the boat, the Arundel Rivers’ water quality monitoring team has been watching summer melt into fall in the South, West, and Rhode watersheds. We are seeing the average water temperature across our rivers cool down. Temperatures dipped from an average of 86 degrees Fahrenheit in July to an average of 80 degrees Fahrenheit in August. Dissolved oxygen (DO) at the bottom of the rivers stayed low in August. At our deepest sites, located at the mouth of the rivers or mid-channel, on the West and Rhode rivers we observed readings as low as 2 to 3 mg/L of DO. For reference, 5 mg/L is the threshold considered healthy for aquatic life.
Using a secchi disk to measure water clarity, we saw that the average clarity on the South River was consistent from July to August. However, average clarity readings on the West and Rhode rivers improved in that period of time. Overall, the West and Rhode rivers’ August clarity readings were 3 to 5 inches higher than their July readings. Our mid-channel station on the West had the highest clarity reading at 31 inches! The mouths of the South, West, and Rhode rivers also saw clarity readings near 30 inches in August. Our lowest reading of 12 inches was on Beards Creek, a tributary of the South River. It is typical for tributaries and upstream stations to have lower clarity readings than stations located on open water since any sediment flowing into the river is more diluted at these sites.
Our bacteria monitoring season officially wrapped up on August 29th, and our team is busy working on a final report that summarizes our 2024 findings! Stay tuned for more information in October. Again, if you are interested in participating for our 2025 bacteria monitoring season, please reach out to riley@arundelrivers.org.
Stay tuned to see how our rivers transition from summer to fall!