CGRG Bibliography of Canadian Geomorphology
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Author : Cathcart, J.; and Alila, Y.
Date : 2000.
Title : Investigating the scaling behaviour of peak flows.
Publication : American Geophysical Union Fall Meeting, December 15-19, 2000. San Francisco, California.
Issue :
Page(s) :
Abstract
In British Columbia, the historical streamflow database is largely limited to basins with drainage areas of greater than 50 km2. However, in the majority of cases, peak flow estimates are required for basins with areas of less than 50 km2. The paucity of suitable data poses a real challenge to practitioners, who, due to a lack of appropriate guidance, often use the simple linear extrapolation of medium and large basin data to develop flow estimates for small basins. The validity of this practice was questioned, as the literature supports the idea that the scaling behaviours of small and large basins are significantly different, due to the varying relative roles played by various climatic and hydrologic mechanisms. Scaling linearity is generally believed to increase with increasing scale in humid regions, while in arid regions, the opposite is thought to be true. In an effort to address the validity of simple extrapolation, the scaling behaviour of peak flows was studied through an empirical analysis of USGS historical flow data for Oregon State. The Oregon data set was selected because Oregon has a similar climate and physiography to BC. In addition, the Oregon data is reasonably well distributed amongst small, medium and large basins, and it covers a large breadth of climatic conditions, thereby providing an ideal basis for exploring scaling patterns over a full range of scales and climates. Oregon was delineated into 12 hydrologically homogeneous regions, and regional regression plots against drainage area were developed for each of the primary L-moment statistics, namely the mean, L-standard deviation, L-coefficient of variation (L-Cv), L-skewness (L-Cs) and L-kurtosis (L-Ck). This discussion will present the key elements of the study and discuss the findings with regards to scaling of the mean of the annual peak instantaneous flows and the associated 100 year flood quantiles.
Bibliography of Canadian Geomorphology