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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Hydrology and Remote Sensing Laboratory » Research » Publications at this Location » Publication #342301

Research Project: Integrating Remote Sensing, Measurements and Modeling for Multi-Scale Assessment of Water Availability, Use, and Quality in Agroecosystems

Location: Hydrology and Remote Sensing Laboratory

Title: Parsimonious mathematical characterization of channel shape and size

Author
item Moglen, Glenn

Submitted to: Journal Hydrologic Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2017
Publication Date: 12/1/2017
Citation: Moglen, G.E. 2017. Parsimonious mathematical characterization of channel shape and size. Journal Hydrologic Engineering. https://doi.org/10.1061/(ASCE)HE.1943-5584.0001588.
DOI: https://doi.org/10.1061/(ASCE)HE.1943-5584.0001588

Interpretive Summary: Stream channel size and shape varies considerably depending on the characteristics of the watershed drained. This work presents a concise mathematical characterization of channel shape and size that gives rise to analytical formulas for common channel properties including cross-sectional area, top width, average depth, critical energy, and bankfull discharge at critical conditions. The concept of channel asymmetry and a measure for its quantification is also presented. The robustness of the developed mathematics is demonstrated through application to several observed channels in Maryland and Delaware, spanning three distinct physiographic regions. This work has value from an analytical perspective and can also be applied to channel restoration design where consistency with existing channels is necessary for channel stability.

Technical Abstract: This work has two purposes: 1) using a Leopold and Maddock (1953) hydraulic geometry approach, present a mathematically parsimonious, two parameter, characterization of channel shape and size; and 2) analytically quantify cross-sectional area, top width, average depth, critical energy, and bankfull discharge at critical conditions as a function of these two parameters. The matter of channel asymmetry is examined and a metric for quantifying asymmetry is presented. The robustness of this characterization is demonstrated in an application to several observed channels in Maryland and Delaware across three physiographic regions: Allegheny plateau, Piedmont, and coastal plain. Values of the shape parameter, u, ranged from 1.6 to 4.3 and asymmetry measures ranged from 0.09 to 0.51 for the demonstration cross-sections. The channel characterization and set of channel property relationships have value for both analysis and design applications related to stream restoration where the consistency of a designed channel with existing field conditions is imperative for channel stability.