MeetingOfInterest:Meeting-128

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AGU Chapman: Spatial organization and complex behavior of intermediate scale catchments – is there a connection?

Luxemburg City, Luxemburg
23 - 26 September 2014

Deadlines Abstract submission: The abstract submission deadline has passed Registration: Registration is now closed Official website http://chapman.agu.org/catchments Meeting contact Erwin Zehe Erwin.Zehe@kit.edu

The fact that persistent spatial organization in catchments exists inspired many scientists to speculate whether this is a manifestation of self-reinforcing co-development due to an underlying organizing principle. Spatial organization of catchments manifests through different fingerprints and affects different processes:

• Hillslope scale spatial organization of soil types manifests in a typical arrangement of soil types along the topographic gradient. This is of key importance for overland flow, sediment yields, water availability for evaporation and temporal stability of soil moisture patterns.
• Spatially organized variability at the pedon scale (within a soil type) is reflected in a spatial correlation of soil hydraulic properties, which translates into spatially correlated storage and recharge.
• Soils and unconsolidated rock are veined with connected networks of preferential flow paths either created by biota (worms, rodents, roots) or by abiotic processes (shrinkage cracks, pipes, rills). Activated preferential flow networks allow for high mass flows even at small driving gradients and thus dominate export and redistribution of water and matter across many scales.

Jim Dooge was to our knowledge the first hydrologist who realized that spatial organization alongside with stochastic heterogeneity leads to complex hydrological behavior at intermediate scales (5-250 km2). Dooge argued that these are systems of organized complexity; being already too large and heterogeneous to be treated in a reductionist deterministic manner, but yet too small for characterizing their behavior using first and second order statistics. The latter is possible at larger scales of organized simplicity. Despite great progress made since Dooge’s pioneering work in hillslope hydrology and the conceptualization of organized simplicity, we feel still pretty “naked” at the intermediate scale of organized complexity. There is little agreement neither on how fieldwork-based understanding should be reflected in catchment models to improve hydrological predictions, nor on how an appropriate model structure should look like, nor on what the controls are that determine the emergent behavior.