ABSTRACT

Stratigraphic Analysis of Corte Madera Creek Flood Control Channel Deposits   [open pdf - 7MB]

From the Abstract: "Sedimentation in a channel can reduce flood conveyance capability and potentially place nearby property and life at risk from flooding. In 1998, Marin County Public Works dredged the concrete-lined segment of Corte Madera Creek, which drains a hilly and largely urbanized watershed that terminates in San Francisco Bay, California. From then through 2015, approximately 4,100 cubic meters of sand and gravel infilled the concrete-lined segment. Determining when and under what conditions this material was deposited informs dredging operations for the Corte Madera Creek Flood Control Project and increases understanding of sediment delivery timing and mechanisms from this and other San Francisco Bay tributaries. Two hypothesized scenarios were investigated: (1) complete flushing during high flows and re-deposition of channel fill afterward and (2) more steady, gradual channel infilling. Stratigraphic analysis of eight sediment cores collected from the flood-control channel deposits in August 2017 was used to identify the most likely scenario. In addition, sediment elevation profiles, grain-size data, and a one-dimensional hydrodynamic model were used to assess the potential for longitudinal-channel scour and deposition following the wet winter of water year 2017 in the intertidal reach of the concrete channel in Corte Madera Creek."

Report Number:
Scientific Investigations Report 2019-5070
Author:
Publisher:
Date:
2019
Copyright:
Public Domain
Retrieved From:
U.S. Geological Survey: https://www.usgs.gov/
Format:
pdf
Media Type:
application/pdf
URL:
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