| Volumes and Issues Contents of Issue 3 |
www.hydrol-earth-syst-sci-discuss.net/6/4411/2009/
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Hillslope hydrology under glass: confronting fundamental questions of soil-water-biota co-evolution at Biosphere 2
1Department of Forest Engineering, Resources and Management, Oregon State University, Corvallis, USA
2Department of Geography, University of Illinois at Urbana-Champaign, USA
3Department of Hydrology and Water Resources, The University of Arizona, Tucson, USA
4Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, USA
Abstract. Recent studies have called for a new unifying hydrological theory at the hillslope and watershed scale, emphasizing the importance of coupled process understanding of the interactions between hydrology, ecology, pedology, geochemistry and geomorphology. The Biosphere 2 Hillslope Experiment aims at exploring how climate, soil and vegetation interact and drive the evolution of the hydrologic hillslope behavior using a set of three large-scale hillslopes (18 m by 33 m each) that will be built in the climate-controlled experimental biome of the Biosphere 2 facility near Tucson, Arizona, USA. By minimizing the initial physical complexity of these hillslopes, the spontaneous formation of flow pathways, soil spatial heterogeneity, surface morphology and vegetation patterns can be observed over time. This paper documents the hydrologic design process for the Biosphere 2 Hillslope Experiment, which was based on design principles agreed upon among the Biosphere 2 science community. Main design principles were that the hillslopes should promote spatiotemporal variability of hydrological states and fluxes, facilitate transient lateral subsurface flow without inducing overland flow and be capable of supporting vegetation. Hydrologic modeling was used to identify a hillslope configuration (geometry, soil texture, soil depth) that meets the design objectives. The recommended design for the hillslopes consists of a zero-order basin shape with a 10 degree overall slope, a uniform soil depth of 1 m and a loamy sand soil texture. The sensitivity of the hydrologic response of this design to different semi-arid climate scenarios was subsequently tested. Modeling results show that the timing of rainfall in relation to the timing of radiation input controls the spatiotemporal variability of moisture within the hillslope and the generation of lateral subsurface flow. The Biosphere 2 Hillslope Experiment will provide an excellent opportunity to test hypotheses, observe emergent patterns and advance the understanding of interactions.
Discussion Paper (PDF, 896 KB) Interactive Discussion (Closed, 6 Comments)Final Revised Paper (HESS)
Citation: Hopp, L., Harman, C., Desilets, S., Graham, C., McDonnell, J., and Troch, P.: Hillslope hydrology under glass: confronting fundamental questions of soil-water-biota co-evolution at Biosphere 2, Hydrol. Earth Syst. Sci. Discuss., 6, 4411-4448, 2009. Bibtex EndNote Reference Manager
