HR: 0800h
AN: H51D-1170 [Abstracts]
TI: A Comparison of Runoff Pathways and Nutrient Export in Small Tropical Forest Catchments
AU: * Hamann, H B
EM: hhamann@coloradocollege.edu
AF: Colorado College, 14 E. Cache la Poudre Street, Colorado Springs, CO 80829
United States
AU: Stallard, R F
EM: stallard@colorado.edu
AF: USGS, 3215 Marine St E127, Boulder, CO 80303-1066
United States
AU: Stallard, R F
EM: stallard@colorado.edu
AF: Smithsonian Tropical Research Institute, Apartadao 2072, Balboa AncĒn, xxxxx
Panama
AU: Stallard, R F
EM: stallard@colorado.edu
AF: INSTAAR, University of Colorado
Campus Box 450, Boulder, CO 80309-0450
United States
AU: Pullen, N H
EM: hoalst@colorado.edu
AF: INSTAAR, University of Colorado
Campus Box 450, Boulder, CO 80309-0450
United States
AU: Pullen, N H
EM: hoalst@colorado.edu
AF: University of Colorado, Geography Department
Campus Box 260, Boulder, CO 80309-0260
United States
AB:
The Center for Tropical Forest Research (CTFS), a program of the Smithsonian Tropical Research Institute (STRI), has
coordinated a global network of 17 tropical forest dynamics plots of approximately 50 hectares in order to collect baseline
information and to monitor forest changes. Missing from most past studies of these plots is an integrated soil hydrology and
water chemistry component. To fill this gap, we have developed and are testing rapid assessment methods to measure soil and
hydrological properties for tropical forest catchments. This assessment includes gaging and sampling first to third order
headwater streams with high frequency over several storm events within a 2-4 week period. Detailed flow separations enable
us to test Elsenbeer's (2001) functional classification continuum for tropical soils and allow us to test the hypothesis that
forest sites with greater overland flow experience greater nutrient loss during storm events. Data from a storm event for
the steep Lutz Creek Catchment on Barro Colorado Island, Panama in September 1990 demonstrate that Na$^{+}$ and Si, typical
of most solutes, decrease in concentration with increasing discharge. In contrast, the nutrients, K$^{+}$ and NO$_{3}$$^{-}$
increase in concentration with increasing discharge. Results from a 20 ha catchment in Yasuni National Park, Ecuador from
November 2003 show a similar pattern during several small events on relatively impermeable soils. Data collected from a more
permeable 20 ha catchment in Lambir Hills National Park, Malaysia in July 2004 also show nutrient export, but suggest that
rainfall amount, intensity and duration may play a large role in the magnitude of nutrient concentrations.
Elsenbeer, H., 2001. Hydrological flowpaths in tropical rain forest soilscapes-a review. Hydrological Processes, 15:
1751-1759.
DE: 1806 Chemistry of fresh water
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
DE: 0400 Biogeosciences
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting