Respectively, Graduate Student, Department of Civil Engineering, Texas A&M University, College Station, Texas 77843; Associate Professor, Department of Natural Resources Management and Engineering, University of Connecticut, 1376 Storrs Road, Unit 4087 WBY Room 308, Storrs, Connecticut 06269–4087; and Research Hydrologist, U.S. Department of Agriculture Forest Service, International Institute of Tropical Forestry, Call Box 25000, Rio Pederast, Puerto Rico 00928–2500 (E-Mail/Warner: email@example.com).
MULTIVARIATE ANALYSIS OF WATER QUALITY AND PHYSICAL CHARACTERISTICS OF SELECTED WATERSHEDS IN PUERTO RICO1
Article first published online: 8 JUN 2007
JAWRA Journal of the American Water Resources Association
Volume 39, Issue 4, pages 829–839, August 2003
How to Cite
Santos-Román, D. M., Warner, G. S. and Scatena, F. (2003), MULTIVARIATE ANALYSIS OF WATER QUALITY AND PHYSICAL CHARACTERISTICS OF SELECTED WATERSHEDS IN PUERTO RICO. JAWRA Journal of the American Water Resources Association, 39: 829–839. doi: 10.1111/j.1752-1688.2003.tb04408.x
Paper No. 01039 of the Journal of the American Water Resources Association.
- Issue published online: 8 JUN 2007
- Article first published online: 8 JUN 2007
- water quality;
- multivariate analysis;
- factor analysis;
- cluster analysis;
- discriminant analysis;
- Puerto Rico
ABSTRACT: Multivariate analyses were used to develop equations that could predict certain water quality (WQ) conditions for unmonitored watersheds in Puerto Rico based on their physical characteristics. Long term WQ data were used to represent the WQ of 15 watersheds in Puerto Rico. A factor analysis (FA) was performed to reduce the number of chemical constituents. Cluster analysis (CA) was used to group watersheds with similar WQ characteristics. Finally, a discriminant analysis (DA) was performed to relate the WQ clusters to different physical parameters and generate predicting equations. The FA identified six factors (77 percent of variation explained): nutrients, dissolved ions, sodium and chloride, silicacious geology, red ox conditions, and discharge. From the FA, specific conductance, sodium, phosphorous, silica, and dissolved oxygen were selected to represent the WQ characteristics in the CA. The CA determined five groups of watersheds (forested, urban polluted, mixed urban/rural, forested plutonic, and limestone) with similar WQ properties. From the five WQ clusters, two categories can be observed: forested and urban watersheds. The DA found that changes in forest cover, percent of limestone, mean annual rainfall, and watershed shape factor were the most important physical features affecting the WQ of watersheds in Puerto Rico.