HomeMy WebLinkAboutWQ_Comm_Hydrodynamic Modeling_Flood Hazards on the San Jaoquion MarshHydrodynamic Modeling of Flood Hazards on the
San Diego Creek Floodplain at the San Joaquin Marsh
UCI Flood Lab
Jochen (Jo) Schubert, Research Specialist, UC Irvine
Brett Sanders, Professor, UC Irvine
Graduate Students in UCI ENGRCEE 270 (Flood Risk and Modeling) – Winter 2019-2020
Jeremiah Blackburn, Aishwarya Borate, Emily Dailey, Chufan Feng, Christian Hebert,
Daniel Kahl, Yeseul Lee, Megan Mirkhanian, Rachel Seidner, Yunfei Shang, and Nathan Siu
Scope of Modeling
•Final project of Flood Risk and Modeling - a graduate level course at UC Irvine.
•Global trends in flooding
•Factors affecting these trends (urbanization, land use change, climate change, and behavioral factors)
•Review of US flood policy
•Students learn 2D hydrodynamic modeling of flooding (San Diego Creek @ SJ Marsh)
•Experience with stakeholder engagement - two-way communication.
•Focus is on understanding flood hazards along San Diego Creek!
Model Extent
Data Sources
•Terrain: 2012 OCPW terrain elevation model from aerial laser scanning – 1 meter resolution, 0.25 cm vertical error on hard surfaces and 0.35 cm error combined landcover types.
•Landcover: 2016 landcover data from National Land Cover Database (NLCD) – 30 m resolution, 16 different classes.
•Flood frequency: 42 year record of annual maximum discharge at Campus Drive - 7 year record from USGS gauge 11048555 [9], and 35 year record obtained from OCPW.
•Flood hydrograph shape: 27 year record of hourly water level data at Campus Drive from OCPW. Period 07/01/91 to 07/09/18.
Numerical Model
•USACE HEC-RAS 2D.
•Well established tool for open channel flow analysis.
•Simulations of flow, sediment transport and water quality analysis.
Current Channel Conditions
•Tetra Tech, Inc. (2019). Lower San Diego Creek Vegetated Buffer Analysis.
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Current Channel Conditions
•Tetra Tech, Inc. (2019). Lower San Diego Creek Vegetated Buffer Analysis.
100 ft vegetation
buffers
40 ft
vegetation
buffers
Flood Hazard Modeling Scenarios
Baseline Flood Hazard
Diversion Design – Campus
IRWD Parcel
To Newport Bay
11.5 ft NAVD88
* drawing not to scale
Diversion Design – Campus
To Newport Bay
11.5 ft NAVD88
To IRWD Parcel
* drawing not to scale
Diversion Flood Management – Campus
Flood depths (meters)
Diversion Flood Management – Campus
Flood depths (meters)
Diversion Design – MacArthur
Lower Marsh
To Newport Bay
10 ft NAVD88
* drawing not to scale
Diversion Design – MacArthur
To Newport Bay
10 ft NAVD88
To Lower
Marsh
* drawing not to scale
Diversion Flood Management – MacArthur
Flood depths (meters)
Diversion Flood Management – MacArthur
Flood depths (meters)
Implications of Diversions
•Campus Diversion only diverts flood water during the largest flood
events. Does not reduce flood hazard.
•MacArthur Diversion diverts flood water over a wide range of flow
events. Has flood stage reduction benefits as well as ecological
benefits (i.e., a source of freshwater).
•MacArthur Diversion allows for natural drainage of flood plain after
flood event.
Implications of Diversions
•Diverting flood flows would result in closures of Campus Dr.
•Will cause sediment transport into SJ Marsh.
•A series of settling ponds exist to capture sediment for small flows.
•Increased pollutant loads into SJ Marsh.
•Potential disruption of established UCI research projects.
Thank You!
Dr. Jochen Schubert – j.schubert@uci.edu
Prof. Brett Sanders – bdsanders@uci.edu
UCI Flood Lab
https://floodlab.eng.uci.edu/