An initial abstraction and constant loss model, and methods for estimating unit hydrographs, peak streamflows, and flood volumes for urban basins in Missouri

Abstract

The author gratefully acknowledges the assistance of Jeff Shiner at Metropolitan Sewer District of St. Louis, who provided rain gage information and interpretation that was useful in the verification of the values obtained from next generation weather radar data. Several people at the National Oceanic and Atmospheric Administration provided valuable insight on the usefulness and applicability of the various next generation weather radar products; most notable are Daniel Berkowitz and David Kitzmiller.

Measurements of the initiation of post‐wildfire runoff during rainstorms using in situ overland flow detectors

“…Initial abstraction, I a , and maximum infiltrability, f c When travel time is zero, I a equals measured values of R p at T r . These values are usually much lower than typical threshold values published for unburned low-relief areas (2·5 to 50 mm; Carey and DeBeer, 2008;Huizinga, 2014) and for mountainous areas (98·6 mm; Cydzik and Hogue, 2009). Differences in I a between the upper and lower groups of OFDs for each storm cell were not significantly (two-tail, p = 0·33).…”

“…for runoff initiation at this burned site. These values are usually much lower than typical threshold values published for unburned low-relief areas (2·5 to 50 mm; Carey and DeBeer, 2008;Huizinga, 2014) and for mountainous areas (98·6 mm; Cydzik and Hogue, 2009). Few measurements of I a exist for burned areas, but for comparison, a 'conservative' lower limit of 1·0 mm was assumed by Elliott et al (2005) to model runoff using the curve number method for the 2002 Hayman fire (also in the Front Range Mountains of Colorado).…”

“…Runoff models need to predict the time varying infiltration and the initial abstraction. For low-relief, unburned basins typical values of I a range from 2.5 to 50 mm (Carey and DeBeer, 2008;Huizinga, 2014) depending upon the environment. Julien et al, 1995;Hydrologic Engineering Center Hydrologic Modeling System [HEC-HMS], 2000;CASC2D, 2014;KINEROS2, 2014;Water Erosion Prediction Project [WEPP], 2014; WRF-Hydro, 2014) are calculated using either Green and Ampt (1911), Mein-Larson (1973), or Parlange et al (1982) infiltration models.…”

“…Another method is to estimate I a by calibrating the model using optimization and measured runoff (Cydzik and Hogue, 2009;Alonistioti et al, 2011;Yuan et al, 2014). For low-relief, unburned basins typical values of I a range from 2.5 to 50 mm (Carey and DeBeer, 2008;Huizinga, 2014) depending upon the environment. For an unburned, forested basin in the southern California mountains, typical calibrated values of I a ranged from 50·5 to 210 mm (Cydzik and Hogue, 2009).…”