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Suspended-sediment rating curve response to urbanization and wildfire, Santa Ana River, California

Journal of Geophysical Research F: Earth Surface

By:
and
DOI: 10.1029/2006JF000662

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Abstract

River suspended-sediment concentrations provide insights to the erosion and transport of materials from a landscape, and changes in concentrations with time may result from landscape processes or human disturbance. Here we show that suspended-sediment concentrations in the Santa Ana River, California, decreased 20-fold with respect to discharge during a 34-year period (1968−2001). These decreases cannot be attributed to changes in sampling technique or timing, nor to event or seasonal hysteresis. Annual peak and total discharge, however, reveal sixfold increases over the 34-year record, which largely explain the decreases in sediment concentration by a nonlinear dilution process. The hydrological changes were related to the widespread urbanization of the watershed, which resulted in increases in storm water discharge without detectable alteration of sediment discharge, thus reducing suspended-sediment concentrations. Periodic upland wildfire significantly increased water discharge, sediment discharge, and suspended-sediment concentrations and thus further altered the rating curve with time. Our results suggest that previous inventories of southern California sediment flux, which assume time-constant rating curves and extend these curves beyond the sampling history, may have substantially overestimated loads during the most recent decades.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Suspended-sediment rating curve response to urbanization and wildfire, Santa Ana River, California
Series title:
Journal of Geophysical Research F: Earth Surface
DOI:
10.1029/2006JF000662
Volume
112
Issue:
F2
Year Published:
2007
Language:
English
Publisher:
Wiley
Contributing office(s):
Coastal and Marine Geology Program
Description:
F02018; 15 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Geophysical Research F: Earth Surface
Number of Pages:
15
Country:
United States
State:
California
Other Geospatial:
Santa Ana River