HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by Chamran, F. Articles by Chadwick, O. A. Search for Related Content PubMed Articles by Chamran, F. Articles by Chadwick, O. A. GeoRef GeoRef Citation Agricola Articles by Chamran, F. Articles by Chadwick, O. A. Related Collections Watershed and Landscape Processes Soil Geomorphology and Geography Spatial Distribution

DIVISION S-5—PEDOLOGY

Spatially Explicit Treatment of Soil-Water Dynamics along a Semiarid Catena

^a The RETEC Group Inc., Long Beach, CA 90815
^b Dep. of Forest Resources, Univ. of Idaho, Moscow, ID 83844-1133
^c Dep. of Geography, Univ. of California Santa Barbara, Santa Barbara, CA 93106

* Corresponding author (paulg{at}uidaho.edu)

Volumetric soil-water depth profiles at nine sample locations on a 2-ha hillslope were monitored throughout the 1997-1998 El Niño and the 1998-1999 La Niña cycles. A hydrological model integrating the soil-water measurements with digital terrain analysis and a one-dimensional water balance model was developed to map dominant hydrological patterns of soil-water storage and lateral flow redistribution. Statistical correlations between hydrologic behavior and the compound topographic index (CTI) generated from a digital elevation model (DEM) were used to generate spatially distributed input parameters of initial water storage and soil-controlled evapotranspiration utilized in the model. The results suggest that differences in water storage and availability are highly modified by climatic conditions and local topography. Nearly three times higher than normal rainfall in the El Niño year caused deeper infiltration of water and led to significant subsurface water redistribution into the concave hillslope positions which remained moist throughout the 1998 summer. Water infiltration and distribution was diminished considerably in the drier than normal La Niña, and led to a complete dry-down in 1999. Actual evapotranspiration was 87% of total precipitation during the El Niño, compared with 100% in the subsequent La Niña. The good correlation between modeled and measured water storage shows that even a simple one-dimensional model combined with the appropriate input parameters is a suitable tool for estimating changes in soil-water content on hillslopes where lateral flow is a significant functional component of the soil hydrology.

Abbreviations: DEM, digital elevation model • GIS, geographic information system • CTI, compound topographic index • TDR, time domain reflectometer • E_t, actual evapotranspiration • E_t,w, potential evapotranspiration • E_t,s, soil controlled evapotranspiration

This article has been cited by other articles:

				T. N. Williamson, P. E. Gessler, P. J. Shouse, and R. C. Graham Pedogenesis-Terrain Links in Zero-Order Watersheds after Chaparral to Grass Vegetation Conversion Soil Sci. Soc. Am. J., October 27, 2006; 70(6): 2065 - 2074. [Abstract] [Full Text] [PDF]