HR: 0800h
AN: H51D-0745    [Abstracts]
TI: A Long Island Sound-Specific Water Quality Index Based on Cluster Analysis and Discriminant Analysis
AU: * Zhang, P
EM: pzhang@sci.ccny.cuny.edu
AF: City College of New York, Department of Earth and Atmospheric Sciences Convent Ave at 138th Street 106 Marshak Science Building, New York, NY 10031, United States
AU: Dathe, A
EM: adathe@sci.ccny.cuny.edu
AF: City College of New York, Department of Earth and Atmospheric Sciences Convent Ave at 138th Street 106 Marshak Science Building, New York, NY 10031, United States
AU: Ponce, F
EM: freda.ponce@gmail.com
AF: City College of New York, Department of Earth and Atmospheric Sciences Convent Ave at 138th Street 106 Marshak Science Building, New York, NY 10031, United States
AB: A new water quality index (WQI) is computed using multivariate cluster analysis and discriminant analysis of a set of individual water quality indicators (e.g., chlorophyll-a, total dissolved nitrogen, total dissolved phosphorus, and dissolved oxygen) collected at different sampling stations. A numerical value (-1 to 1) results, with a value close to 1 indicating good water quality (oligotrophic), a value close to -1 indicating poor water quality (eutrophic), and a slight negative value representing mesotrophic conditions. This new water quality index provides a simple framework that overcomes several shortcomings of the traditional water quality index rating. The method is applied to Long Island Sound (LIS) water quality data (past 15 years at about 20 stations) collected by the Connecticut Department of Environmental Protection. There is a general trend of increasing WQI (increasing water quality) from west-LIS to east-LIS. For instance, the WQI values for station A4 (the most west station in LIS) are typically between -0.5 and -1 (indicating eutrophic conditions), whereas the WQI values for stations J2, K2, M3, N3 (east-LIS) are mostly between 0.5 and 1 (indicating oligotrophic conditions). These WQI values are consistent with the fact that west-LIS is more polluted (water quality more degraded) than mid- and east-LIS. There are some seasonal trends in the averaged WQI values. For instance, the WQI values increase from April to September for the east LIS stations, indicating that the water quality at these stations improves over this period. In contrast, the WQI values for the west to mid LIS stations generally decrease from June to August, indicating that the water quality degrades during this period.
DE: 1894 Instruments and techniques: modeling
DE: 4235 Estuarine processes (0442)
DE: 4271 Physical and chemical properties of seawater
SC: Hydrology [H]
MN: 2007 Fall Meeting