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Controls on at‐a‐station hydraulic geometry in steep headwater streams, Colorado, USA
Author(s) -
David Gabrielle C. L.,
Wohl Ellen,
Yochum Steven E.,
Bledsoe Brian P.
Publication year - 2010
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.2023
Subject(s) - hydrology (agriculture) , geometry , streams , range (aeronautics) , geology , hydraulic roughness , hydraulic resistance , cascade , surface finish , geomorphology , geotechnical engineering , mathematics , physics , materials science , mechanics , chemistry , computer network , chromatography , computer science , composite material
Detailed hydraulic measurements were made in nine step‐pool, five cascade and one plane‐bed reach in Fraser Experimental Forest, Colorado to better understand at‐a‐station hydraulic geometry (AHG) relations in these channel types. Average values for AHG exponents, m (0·49), f (0·39), and b (0·16), were well within the range found by other researchers working in steep gradient channels. A principal component analysis (PCA) was used to compare the combined variations in all three exponents against five potential control variables: wood, D 84 , grain‐size distribution (σ), coefficient of variation of pool volume, average roughness‐area (projected wetted area) and bed gradient. The gradient and average roughness‐area were found to be significantly related to the PCA axis scores, indicating that both driving and resisting forces influence the rates of change of velocity, depth and width with discharge. Further analysis of the exponents showed that reaches with m > b + f are most likely dominated by grain resistance and reaches below this value ( m < b + f ) are dominated by form resistance. Copyright © 2010 John Wiley & Sons, Ltd.