Primary factors affecting water quality and quantity in four watersheds in Eastern Puerto Rico

By:  and 

Links

Abstract

As part of the U.S. Geological Survey (USGS) Water, Energy, and Biogeochemical Budgets (WEBB) program, four small watersheds in eastern Puerto Rico were monitored to identify and evaluate the effects of geology, landcover, atmospheric deposition, and other factors on stream water quality and quantity. Two catchments are located on coarse-grained granitic plutonic rocks, which weather to quartz- and clay-rich, sandy soils, and two are located on fine-grained volcanic rocks and volcaniclastic sediments, which weather to quartz-poor, fine-grained soils. These differing soil materials result in different hydrologic regimes. Soils on the granitic rocks have greater permeability than those developed on the volcaniclastic rocks, allowing more water infiltration and potentially greater landslide erosion rates. For each bedrock type, one catchment was covered with mature rainforest, and the other catchment was affected by agricultural practices typical of eastern Puerto Rico. These practices led to the erosion of much of the original surface soil in the agricultural watersheds, which introduced large quantities of sediment to stream channels. The agricultural watersheds are undergoing natural reforestation, like much of Puerto Rico. Eastern Puerto Rico receives large atmospheric inputs of marine salts, pollutants from the Northern Hemisphere, and Saharan Desert dust. Marine salts contribute over 80 percent of the ionic charge in precipitation, with peak inputs in January. Intense storms, mostly hurricanes, are associated with exceptionally high chloride concentrations in stream waters. Temperate pollution contributes nitrate, ammonia, and sulfate, with maximum inputs during northern cold fronts in January, April, and May. Pollution inputs have increased through time. Desert dust peaks in June and July, during times of maximum dust transport from the Saharan Desert across the Atlantic Ocean.

Study Area

Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title Primary factors affecting water quality and quantity in four watersheds in Eastern Puerto Rico
Year Published 2009
Language English
Publisher U.S Geological Survey
Publisher location Reston, VA
Contributing office(s) National Research Program - Central Branch
Description 6 p.
Larger Work Type Report
Larger Work Subtype USGS Numbered Series
Larger Work Title Planning for an uncertain future - Monitoring, integration, and adaptation (SIR 2009-5049)
First page 251
Last page 256
Conference Title Third interagency conference on research in the watersheds
Conference Location Estes Park, CO
Conference Date September 8-11, 2008
Country United States
State Puerto Rico
Online Only (Y/N) N
Additional Online Files (Y/N) N