The large-scale impact of climate change to Mississippi flood hazard in New Orleans
Other literature type, Article
Driessen, T. L. A.
- Publisher: Copernicus Publications on behalf of the TU Delft
(issn: 1996-9465, eissn: 1996-9465)
T | Environmental technology. Sanitary engineering | Technology | TD1-1066
The objective of this paper was to describe the impact of climate change on
the Mississippi River flood hazard in the New Orleans area. This city has a
unique flood risk management challenge, heavily influenced by climate
change, since it faces flood hazards from multiple geographical locations
(e.g. Lake Pontchartrain and Mississippi River) and multiple sources
(hurricane, river, rainfall). Also the low elevation and significant
subsidence rate of the Greater New Orleans area poses a high risk and
challenges the water management of this urban area. Its vulnerability to
flooding became dramatically apparent during Hurricane Katrina in 2005 with
huge economic losses and a large number of casualties.
A SOBEK Rural 1DFLOW model was set up to simulate the general hydrodynamics.
This model included the two important spillways that are operated during
high flow conditions. A weighted multi-criteria calibration procedure was
performed to calibrate the model for high flows. Validation for floods in
2011 indicated a reasonable performance for high flows and clearly
demonstrated the influence of the spillways.
32 different scenarios were defined which included the relatively large sea
level rise and the changing discharge regime that is expected due to climate
change. The impact of these scenarios on the water levels near New Orleans
were analysed by the hydrodynamic model. Results showed that during high
flows New Orleans will not be affected by varying discharge regimes, since
the presence of the spillways ensures a constant discharge through the city.
In contrary, sea level rise is expected to push water levels upwards. The
effect of sea level rise will be noticeable even more than 470 km upstream.
Climate change impacts necessitate a more frequent use of the spillways and
opening strategies that are based on stages.