A geomorphic interfluve-"landshed" ordering system, a reciprocal to the Horton-Strahler stream-order network, was developed at the Calhoun Critical Zone Observatory (CCZO) in SC. Earth's critical zone (CZ) is the near-surface environment in which rock, soil, water, air, and living organisms interact to regulate habitat and determine the availability of life-sustaining resources. While the nature of stream networks and watersheds have been widely discussed, the patterning of the land's residual terrain has received less attention. In the ordered interfluve-landshed system, the narrowest and most highly dissected interfluves (ridges) and isolated hilltops are considered 1st order and increase in rank dendritically as interfluve branches join uphill and become more massive and voluminous up to 5th order within the 150km2 CCZO landscape. Interfluve-order is positively correlated to upland landshed elevation and area and negatively correlated to landshed slope. Considered more intricately, increased branching proximity of low-order interfluves to higher order interfluves has a strong positive control on elevation and negative control on slope. Slope, elevation, area, and other variables strongly related to interfluve-order are central parameters in many models and CZ processes. Understanding their distribution and patterns across landscapes will increase our ability to analyze and explain landscape environmental processes in the context of neighborhood geomorphology captured by hierarchical interfluve-ordering. Statistical analyses of landscape terrain as well as land cover, soil erosion potential, and modeled geochemical weathering depth are considered from an ordered-interfluve framework.
Brecheisen, Zachary, Seulgi Moon, Daniel Richter, Patrick Halpin (2017): Ordering interfluves: an analytical framework for hierarchical patterns in landscape structure and function. American Association of Geographers Annual Meeting, Boston, MA, 7 April 2017.
This Paper/Book acknowledges NSF CZO grant support.