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Development and Evaluation of Bankfull Hydraulic Geometry Relationships for the Physiographic Regions of the United States
Author(s) -
Bieger Katrin,
Rathjens Hendrik,
Allen Peter M.,
Arnold Jeffrey G.
Publication year - 2015
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/jawr.12282
Subject(s) - streamflow , regression , regression analysis , division (mathematics) , population , hydrology (agriculture) , sample (material) , statistics , channel (broadcasting) , hydraulic structure , mathematics , environmental science , geometry , geology , geography , drainage basin , cartography , computer science , geotechnical engineering , demography , physics , computer network , arithmetic , sociology , thermodynamics
Bankfull hydraulic geometry relationships are used to estimate channel dimensions for streamflow simulation models, which require channel geometry data as input parameters. Often, one nationwide curve is used across the entire United States ( U.S. ) (e.g., in Soil and Water Assessment Tool), even though studies have shown that the use of regional curves can improve the reliability of predictions considerably. In this study, regional regression equations predicting bankfull width, depth, and cross‐sectional area as a function of drainage area are developed for the Physiographic Divisions and Provinces of the U.S. and compared to a nationwide equation. Results show that the regional curves at division level are more reliable than the nationwide curve. Reliability of the curves depends largely on the number of observations per region and how well the sample represents the population. Regional regression equations at province level yield even better results than the division‐level models, but because of small sample sizes, the development of meaningful regression models is not possible in some provinces. Results also show that drainage area is a less reliable predictor of bankfull channel dimensions than bankfull discharge. It is likely that the regional curves can be improved using multiple regression models to incorporate additional explanatory variables.