PUERTO RICO PROJECTS

• Major Projects
  • Hydrology and QW of Levittown Lake
  • Assessment of Hydrogeologic Conditions of the Punta de Cabullones Area
  • GW Quality/Agricultural Activities in Río Coamo
  • Synoptic Studies
  • Effects of forest cover on baseflow characteristics of streams
  • Water, Energy, and Biogeochemical Budgets in the Luquillo Mountains
  • Ground Water Site Inventory

• Recently Completed Projects
  • Laguna Grande Limnology

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Water, Energy, and Biogeochemical Budgets in the Luquillo Mountains, Puerto Rico

Project Number: 2516-AEU01
Project Chief: Heather L. Buss
Cooperators:
Period of Project:Continuous

Introduction

Problem

The study and assessment of geomorphic and biogeochemical processes controlling the movement and transformation of water, energy, bedrock weathering products, and nutrients in the earth-surface environment in a humid-tropical setting.

One of the concerns associated with the prospect of global warming is its potential consequences in the hydrologic regime. Changes in the amount and seasonality of precipitation may have far-reaching implications to the patterns of water and nutrient movement in terrestrial ecosystems. The current state of knowledge on the interrelations and transfers of water, energy, and chemical compounds is insufficient to adequately model these processes, thus hampering predictive efforts of the true environmental impacts of global warming. A better understanding of Water, Energy, and Biogeochemical Budgets (WEBB) is needed over a range of scales, in a representative cross section of global ecosystems.

Objectives

Evaluation and quantification of the elements listed in the PROBLEM section and the development of accurate budgets for the processes studied.

The Luquillo WEBB research project is presently calculating water, energy, carbon, nutrient, dissolved-constituent, and sediment (suspended and bed load) budgets in four watersheds located in eastern Puerto Rico. Two of the watersheds are in tropical rain forest in the Luquillo Experimental Forest (LEF), an 11,300 hectare forest preserve administered by the U.S. Forest Service. Two additional watersheds are located in the agriculturally-developed and partially urbanized Río Grande de Loíza basin.

The four watersheds are being compared and contrasted according to dominant land use (forested versus developed) and lithology (intrusive bedrock versus volcaniclastic bedrock) The sites are instrumented with streamflow, meteorological, soil, and ground-water monitoring and sampling equipment. Some of the principal study objectives are the comparison of chemical weathering, erosion, and mass wasting processes in an environment with a history of anthropogenic modification and periodic extreme hydrologic events associated with the passage of hurricanes. Luquillo WEBB publications describe a variety of topics including watershed-scale water and sediment budgets, surface runoff, hillslope processes and sources of fluvial sediment, slopewash, soil creep, tree throw, and landsliding. In addition, budgets of all aqueous constituents are being developed.

Strategy and Approach

The study will include the following field activities:

Benefits