Evaluation of the Health of the Lower Esopus Creek

Regular biological stream monitoring (bioassessment) is needed to assess water quality to determine whether a stream meets its classification for different uses. Water quality studies were conducted on the Lower Esopus Creek from June to October 2007. This study consisted of two components - evaluation of water quality using chemical parameters and biological assessment using Benthic Macro invertebrates (BMI). For the first component, thirteen sites along the Esopus Creek were selected. Environmental parameters including temperature, conductivity, pH and dissolved oxygen (DO) were measured onsite. Water samples were collected and analayzed in the lab for further chemical analysis utilizing sophisticated instruments. The chemical constituents analyzed included: bicarbonate, total organic carbon (TOC), copper, iron, total chorine, chloride, sodium, sulfate, magnesium, calcium, fluoride, ammonia, nitrate and nitrite. The turbidity of each of the thirteen sites was also analyzed. The BMI samples were collected along seven riffle zone sites in accordance with New York State Department of Environmental Conservation (NYSDEC) guidelines. The BMIs were identified to the family level. The Biological Assessment Profiles for the BMI studies ranged from non-impacted to moderately impacted categories. The biological and chemical data suggest that as one moves closer to more urbanized areas, the overall water quality of the stream appears to decrease. In urbanized area, the chemical parameters such as calcium, magnesium and bicarbonate appear to be lower and of natural occurrence, whereas higher levels of constituents such as total chlorine, total organic carbon and iron appear to be of anthropogenic nature. This may contribute to a decrease in water quality. Some sections of the stream may limit to fish propagation and may not meet their NYSDEC classification.