This image depicts what can occur when a tributary carrying elevated E. coli levels flows into a larger body of water. In this example on May 25, 2022, the E. coli level measured in Manassas Run was 1553.1. Downstream of the confluence with the Shenandoah River, the E. coli levels remained elevated, 648.8, along the bank. During the same sample collection visit the E. coli levels measured in the middle of the River was 23.1.
(E. coli results reported as MPN colony forming units per 100mL of water samples)