North Beach/ Parkview Canal study finds stormwater — and bird, dog and human markers — drive high bacteria; committee seeks short‑ and long‑term remedies

A University of Miami study presented to the Land Use and Sustainability Committee on March 11 found that stormwater runoff — not currently treated before entering the Parkview Canal — is the primary source of elevated enterococci counts in the canal, and that microbial‑source tracking identified birds as a dominant contributor alongside detectable human and dog signals.

Professor Helena Solo Gabriel, who led the analysis, told the committee the canal’s limited tidal flushing and direct drainage from a densely developed catchment help concentrate bacteria. “The stormwater… the levels are orders of magnitude higher,” she said, summarizing results that showed very large enterococci counts at stormwater collection points and especially high values near a school outfall.

Key findings - Stormwater is the largest immediate source. Street‑level samples collected during rainfall events had consistently higher enterococci counts — in many cases hundreds to hundreds of thousands of MPN/100 mL — than groundwater samples. - Birds are a major marker. Genetic microbial‑source tracking showed very high bird markers throughout the canal and in stormwater samples; human and dog markers were also present at multiple locations. The Biscayne Beach Elementary outfall registered among the highest single…