Category Archives: SWAN
The Lower Mississippi River protrudes into the Gulf of Mexico, and manmade levees line only the west bank for 55 km of the Lower Plaquemines section. Historically, sustained easterly winds from hurricanes have directed surge across Breton Sound, into the Mississippi River and against its west bank levee, allowing for surge to build and then propagate efficiently upriver and thus increase water levels past New Orleans. This case study applies a new and extensively validated basin- to channel-scale, high-resolution, unstructured-mesh ADvanced CIRCulation model to simulate a suite of historical and hypothetical storms under low to high river discharges. The results show that during hurricanes, (1) total water levels in the lower river south of Pointe à La Hache are only weakly dependent on river flow, and easterly wind-driven storm surge is generated on top of existing ambient strongly flow-dependent river stages, so the surge that propagates upriver reduces with increasing river flow; (2) natural levees and adjacent wetlands on the east and west banks in the Lower Plaquemines capture storm surge in the river, although not as effectively as the manmade levees on the west bank; and (3) the lowering of manmade levees along this Lower Plaquemines river section to their natural state, to allow storm surge to partially pass across the Mississippi River, will decrease storm surge upriver by 1 to 2 m between Pointe à La Hache and New Orleans, independent of river flow.
Presentation: CARTHE 2013
Conference: ADCIRC 2013
Simulating Hurricane Storm Surge in the Lower Mississippi River under Varying Flow Conditions
Hurricanes in southeastern Louisiana develop significant surges within the lower Mississippi River. Storms with strong sustained easterly winds push water into shallow Breton Sound, overtop the river’s east bank south of Pointe à la Hache, Louisiana, penetrate into the river, and are confined by levees on the west bank. The main channel’s width and depth allow surge to propagate rapidly and efficiently up river. This work refines the high-resolution, unstructured mesh, wave current Simulating Waves Nearshore + Advanced Circulation (SWAN+ADCIRC) SL16 model to simulate river flow and hurricane-driven surge within the Mississippi River. A river velocity regime–based variation in bottom friction and a temporally variable riverine flow-driven radiation boundary condition are essential to accurately model these processes for high and/or time-varying flows. The coupled modeling system is validated for riverine flow stage relationships, flow distributions within the distributary systems, tides, and Hurricane Gustav (2008) riverine surges.
News: Large-Scale Simulations of Coastal Flooding
2013/04/04 – The Daily Texan
UT research group uses math, simulations to analyze hurricanes
by Mark Carrion
UT research group uses math, simulations to analyze hurricanes
by Mark Carrion
Casey Dietrich is one of 14 researchers besides Dawson who works in the research group. He said having access to Stampede, UT’s new and powerful supercomputer, is important for the simulations the group runs.
“We’re very lucky we get access to one of the largest supercomputers in the world,” Dietrich said. “That opens the door for us to run larger, more interesting problems.”
Dietrich said the models they run use calculations from Stampede that allow them to analyze changes in an area as small as 20 meters.
“We can really see how the flooding is affecting the environment,” Dietrich said.
Conference: FEF 2013
JC Dietrich, CN Dawson, H Arabshahi, A Muhammad. “Coastal Models of Oil Transport in the Gulf of Mexico during Normal and Extreme Conditions.” Advances in Computational Mechanics, with special track: Finite Elements in Flow Problems, San Diego, California, 24-27 February 2013.
Please click here for more information about the FEF 2013 conference.