EVALUATING THE IMPACT OF HYDROLOGY AND COMBINED-SEWER OVERFLOWS ON URBAN BEACH CLOSURES

Closures due to high E. coli are a frequent occurrence at Woodlawn Beach, a state park located just outside of Buffalo, NY. Combined-sewer overflow into nearby Rush and Blasdell Creeks – as well as into Lake Erie – during times of high precipitation contribute to elevated bacteria levels at Woodlawn. A study was conducted to evaluate Rush Creek’s impact on Woodlawn Beach water quality. Weekly discharge measurements were made in Rush Creek, and water quality monitoring was done in Rush Creek, Blasdell Creek, their combined outlet, and Lake Erie. Field data were compared with local precipitation rates and official E. coli measurements at Woodlawn. High flow rates in Rush Creek were not found to relate to high beach E. coli levels; however, E. coli levels at the two sites tended to rise and fall together. Our findings also show that as Rush and Blasdell Creeks enter Lake Erie through the same outlet, their respective E. coli levels mix into an intermediate level, which is then diluted further into the lake. The same was found for the specific conductance and pH for each creek. This indicates that the two creeks need to be viewed as a system, rather than two individual point sources, when evaluating their impact on Woodlawn Beach water quality.