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Orographic Controls on Subdaily Rainfall Statistics and Flood Frequency in the Colorado Front Range, USA
Author(s) -
Rossi Matthew W.,
Anderson Robert S.,
Anderson Suzanne P.,
Tucker Gregory E.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl085086
Subject(s) - orographic lift , surface runoff , precipitation , environmental science , orography , flood myth , climatology , rain gauge , hydrology (agriculture) , range (aeronautics) , drainage basin , front (military) , geology , meteorology , geography , ecology , materials science , geotechnical engineering , cartography , archaeology , composite material , biology
Abstract Generalizable relationships for how subdaily rainfall statistics imprint into runoff statistics are lacking. We use the Colorado Front Range, known for destructive rainfall‐triggered floods and landslides, to assess whether orographic patterns in runoff generation are a direct consequence of rainstorm climatology. Climatological analysis relies on a dense network of tipping‐bucket rain gauges and gridded precipitation frequency estimates from the National Oceanic and Atmospheric Administration to evaluate relationships among subdaily rainfall statistics, topography, and flood frequency throughout the South Platte River basin. We find that event‐scale rainfall statistics only weakly depend on elevation, suggesting that orographic gradients in runoff “extremes” are not simply a consequence of rainfall patterns. In contrast, bedrock exposure strongly varies with elevation in a way that plausibly explains enhanced runoff generation at lower elevations via reduced water storage capacity. These findings are suggestive of feedbacks between bedrock river evolution and hillslope hydrology not typically included in models of landscape evolution.