HR: 0800h
AN: H31G-0735    [Abstracts]
TI: Evolution, structure and function of hydrologic subsystems in hillslopes
AU: * Troch, P A
EM: patroch@hwr.arizona.edu
AF: Department of Hydrology and Water Resources, The University of Arizona, 1133 E James E Rogers way, Tucson, AZ 85721, United States
AU: Brooks, P
EM: brooks@hwr.arizona.edu
AF: Department of Hydrology and Water Resources, The University of Arizona, 1133 E James E Rogers way, Tucson, AZ 85721, United States
AU: Chorover, J
EM: chorover@cals.arizona.edu
AF: Department of Soil, Water and Environmental Science, The University of Arizona, P.O. Box 210038, Tucson, AZ 85721, United States
AU: Huxman, T
EM: huxman@email.arizona.edu
AF: Department of Ecology and Evolutionary Biology, The University of Arizona, P.O. Box 210088, Tucson, AZ 85721, United States
AU: McDonnell, J J
EM: jeffrey.mcdonnell@oregonstate.edu
AF: Department of Forest Engineering, Oregon State University, 204 Peavy Hall, Corvallis, OR 97331, United States
AU: Rasmussen, C
EM: crasmuss@Ag.arizona.edu
AF: Department of Soil, Water and Environmental Science, The University of Arizona, P.O. Box 210038, Tucson, AZ 85721, United States
AU: Sivapalan, M
EM: sivapala@uiuc.edu
AF: Department of Geography, University of Illinois at Urbana-Champaign, 607 South Mathews Avenue, Urbana-Champaign, IL 61801, United States
AB: Hillslopes offer a useful elementary scale to construct catchment hydrologic models, and to understand the role of water in the landscape. However, hillslopes exhibit enormous complexity and heterogeneity, much of which is not easily observable. The complexity is driven by the interactions between water, biogeochemistry, ecology and soils, within the constraints set by the climate and the geologic history of the system. These interactions create complex, non-random patterns and structures in space-time. Current models have difficulty accounting for these interactions and unobserved structural complexity. A new approach may ask: why do the complex structures exist at all? Taking the view that the hydrology of a landscape has evolved along with its soils, ecology and geomorphology, we may ask if the hydrologic subsystem of a hillslope has a functional role in the maintenance of the overall system. This functional role may be expressed as an organizing principle - a constraint on possible ways that the hydrologic flowpaths may be organized such that the functional role is met. If a relationship can be established between an organizing principle and the structure of hydrologic flow-paths and storages, it can form the basis for developing closure relations at the hillslope scale that have meaningful relationships to the underlying dynamics. In this way, heterogeneity and complexity of hillslopes are no longer problems to be overcome, but rather are keys to making meaningful predictions. Formulating and testing organizing principles will necessarily require the synthesis of knowledge from many disciplines. One approach is to construct artificial hillslopes in a controlled environment, and use them to ask, given a set of observable constraints (climate, soil, ecologic and biogeochemical parameters) which structures and responses are "behavioral" - in the sense that they fulfill the function set by the organizing principle. Such artificial hillslopes will be constructed at the newly established B2 Earthscience facility run by the University of Arizona. This effort is also part of one of the synthesis activities organized by an NSF funded hydrologic synthesis project, coordinated by the University of Illinois at Urbana- Champaign. Decisions about critical design parameters will be based on a series of consultations (in the form of workshops) engaging scientists from different Earth science disciplines.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 1851 Plant ecology (0476)
DE: 1866 Soil moisture
DE: 1878 Water/energy interactions (0495)
DE: 1886 Weathering (0790, 1625)
SC: Hydrology [H]
MN: 2007 Fall Meeting