Baltimore Ecosystem Study Institute of Ecosystem Studies

2010 BES Annual Meeting Presentation and Poster Abstracts

The contribution of outfalls with dry weather perennial flow to coliform bacteria counts and nutrient concentrations in the Lower Jones Falls
Kemp, Stanley
Co-Authors: Stanley Kemp Vishal Lalwani Timothy Kaub

Abstract: One intractable obstacle in improving water quality in urban waterways is the presence of storm drain outfalls along the length of those waterways, often connected during periods of heavy rainfall with sanitary sewer lines. In Baltimore, the Jones Falls continues to be impacted by these outfalls. Remediation will involve identifying and quantifying impacts of individual outfalls in order to trace problems inherent in the system. This study represents a survey of perennial outfalls along the Lower Jones Falls and the mainstem Jones Falls for coliform bacteria concentrations, conducted during Summer 2010. In addition, nitrate, ammonia and phosphate levels were monitored at sites along the mainstem Jones Falls during 2009 and 2010. Dry weather coliform bacteria counts measured at various perennial outfalls ranged from 0 MPN/ ml to 410 MPN/ml, and there was significant variation between outfalls over time. Mainstem Jones Falls coliform bacterial counts above and below two contaminated outfalls were compared using a Type I ANOVA with nested design, with counts downstream of the outfalls significantly higher. Conversely, none of the nutrient levels measured on the mainstem Jones Falls were significantly elevated downstream of the same two outfalls. Nutrient levels at all monitored sites fluctuated over time, particularly following rainfall. Though nutrient and bacterial levels were not quantified during periods of heavy rainfall, anecdotal information suggests large inputs of raw sewage into the Jones Falls System during brief pulse events via combined sewage outfalls. The pulse nature of nutrient input presents a challenge for water quality monitoring efforts.