Spatial scale dependence of ecohydrologically mediated water balance partitioning: A synthesis framework for catchment ecohydrology
Abstract
The difficulties in predicting whole catchment water balance from observations at
patch scales motivate a search for theories that can account for the complexity of
interactions in catchments. In this paper we suggest that the spatial patterns of
vegetation may offer a lens through which to investigate scale dependence of hydrology
within catchments. Vegetation patterns are attractive because they are observable
drivers of evapotranspiration, often a dominant component in catchment water balance,
and because the spatial distribution of vegetation is often driven by patterns of
water availability. We propose that nontrivial, scale‐dependent spatial patterns in
both vegetation distribution and catchment water balance are generated by the presence
of a convergent network of flow paths and a two‐way feedback between vegetation as
a driver of evapotranspiration and vegetation distribution as a signature of water
availability. Implementing this hypothesis via a simple network model demonstrated
that such organization was controlled by catchment properties related to aridity,
the network topology, the sensitivity of the vegetation response to water availability,
and the point‐scale controls on partitioning between evapotranspiration and lateral
drainage. The resulting self‐organization generated spatial dependence in areally
averaged hydrologic variables, water balance, and parameters describing hydrological
partitioning. This spatial scale dependence provides a theoretical approach to connect
water balance at patch and catchment scales. Theoretical and empirical studies for
understanding the controls of vegetation spatial distribution, point‐scale hydrological
partitioning, and the implications of complex flow network topologies on the spatial
scale dependence of catchment water balance are proposed as a research agenda for
catchment ecohydrology.
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Journal articlePermalink
https://hdl.handle.net/10161/5111Published Version (Please cite this version)
10.1029/2010WR009998Citation
Thompson, S. E., C. J. Harman, P. A. Troch, P. D. Brooks, and M. Sivapalan (2011),
Spatial scale dependence of ecohydrologically mediated water balance partitioning:
A synthesis framework for catchment ecohydrology, Water Resour. Res., 47, W00J03,
doi:10.1029/2010WR009998.
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