TITLE:

Quantifying Impact of Climate Change on Reservoir Sedimentation

DATE:

Friday, October 11th, 2013

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Dr. Svetlana Kostic. Computational Science Research Center at San Diego State University.

ABSTRACT:

Researchers predict that climate-fueled extreme weather events will continue to put many

communities worldwide at increased risk for devastation from floods. FEMA estimates that areas at

risk of flooding in the US would increase 45 percent by 2100, mainly due to climate change. A

comprehensive numerical model of reservoir sedimentation is developed and used to assess the

impact of flooding on reservoir performance. The model captures: a) the formation and evolution of

the river-delta and associated deposits, and b) the morphodynamic effects of a dam at the

downstream end of the reservoir. The outflow boundary condition is selected to emulate the release

of flow over an uncontrolled or open-gate controlled spillway. The turbidity current is thus not

allowed to vent until the underflow-clear water interface rises above the elevation of the overflow

point. The model allows for a smooth and continuous progression from a stagnation to an overflow

condition, which is a serious computational challenge. Two types of flood events are analyzed.

First, a short, single-event turbidity current entering a reservoir is considered to demonstrate that the

model reproduces, for the first time, all stages of the turbidity current propagation and interaction

with the dam, including: a) the expansion of the current toward the dam; b) the runup against the face

of the dam; c) the formation of an upstream-migrating bore as the current reflects off the dam; and d)

the establishment of an internal hydraulic jump. Next, a series of sustained turbidity current events

entering a reservoir are simulated to capture the loss of reservoir storage capacity in time due to

continuous growth of the bottomset deposit and its interaction with the fluvial delta. In the future,

the model will be expanded into a valuable tool for evaluating sediment routing, flushing and other

operational procedures in reservoirs that can be used as effective climate change mitigation

strategies.

HOST:

Dr. Jose Castillo

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