244 Int. J. Environment and Pollution, Vol. 31, Nos. 3/4, 2007 Copyright © 2007 Inderscience Enterprises Ltd. Effect of non-point source runoff and urban sewage on Yaque del Norte River in Dominican Republic Peter Phillips* Department of Biology, Winthrop University, Rock Hill, South Carolina 29733, USA Fax: 803 323 3448 E-mail: phillipsp@winthrop.edu *Corresponding author F. Arturo Russell Pontificia Universidad Católica Madre y Maestra, Santiago de los Caballeros, República Dominicana Fax: 809 582 2947 E-mail: arussell@pucmmsti.edu.do John Turner Department of Biology, Winthrop University, Rock Hill, South Carolina 29733, USA Fax: 803 323 3448 E-mail: turnerj2@winthrop.edu Abstract: A Yaque del Norte, Dominican Republic watershed survey monitored dissolved oxygen, eutrophication from point and non-point sources, and high conductivity resulting from agricultural runoff. The upper mainly forested watershed had good water quality except for untreated sewage from the city of Jarabacoa. The mid-watershed had a deforested landscape, mixed agriculture and the city of Santiago contributing nitrogen and phosphorus. The lower watershed had extensively-irrigated agriculture resulting in appreciably higher conductivity, as well as high nitrogen and phosphorus. Sedimentation from erosion is evident throughout the watershed. Managing the river’s land and water resources for all stakeholders is critical. Keywords: surface water quality; nitrogen; phosphorus; dissolved oxygen; turbidity; non-point source runoff; point sources; irrigation; Yaque del Norte River; Dominican Republic. Reference to this paper should be made as follows: Phillips, P., Russell, F.A. and Turner, J. (2007) ‘Effect of non-point source runoff and urban sewage on Yaque del Norte River in Dominican Republic’, Int. J. Environment and Pollution, Vol. 31, Nos. 3/4, pp.244–266. Biographical notes: P. Phillips is an Associate Professor of Biology in the Department of Biology, Winthrop University, Rock Hill, South Carolina, USA, since 1999. He conducts water quality research on the Catawba River basin in North and South Carolina. He was the recipient of a Fulbright Scholar Award in the summer of 2004; this funded the research effort in the Dominican Republic. He was previously a Research Scientist at Clark Atlanta University, Atlanta, Georgia, USA, conducting research on bioremediation of contaminated water using a microbial mat based technology.