|
These maps present preliminary assessments of the probability of debris-flow
activity and estimates of peak discharges that can potentially be generated
by debris flows issuing from basins burned by the Cedar and Paradise
Fires of October 2003 in southern California in response to 25-year,
10-year, and 2-year recurrence, 1-hour duration rain storms. The probability
maps are based on the application of a logistic multiple regression model
that describes the percent chance of debris-flow production from an individual
basin as a function of burned extent, soil properties, basin gradients,
and storm rainfall. The peak-discharge maps are based on application
of a multiple-regression model that can be used to estimate debris-flow
peak discharge at a basin outlet as a function of basin gradient, burn
extent, and storm rainfall. Probabilities of debris-flow occurrence for
the Cedar Fire range between 0 and 98% and estimates of debris-flow peak discharges range between 893 and 5,987
ft3/s (25 to 170 m3/s). Basins burned by the Paradise Fire show probabilities
for debris-flow occurrence between 2 and 98%, and peak discharge estimates
between 1,814 and 5,980 ft3/s (51 and 169 m3/s). These maps are intended
to identify those basins that are most prone to the largest debris-flow
events and provide critical information for the preliminary design of
mitigation measures and for the planning of evacuation timing and route
|
|
Part or all of this report is presented in Portable Document Format. The latest
version of Adobe Acrobat Reader or similar software is required
to view it. If you wish to download the latest version of Acrobat
Reader free of charge, click here.
|
Downloading Suggestion:
It is best to download a large PDF file to your hard drive rather than open it
inside your browser. (A standard click may automatically open the PDF
file inside the browser but doing so will result in a very slow load.)
For guidance on how to do this, go to [http://cpg.cr.usgs.gov/toolbox/download_advice.html]. Downloading the PDF file may take several moments but will be worth the wait.
Once it is downloaded, open the PDF from your hard drive using Adobe
Acrobat—it will open in a fraction of the time it would take to open the PDF over the
Internet.
|
