Flood Risk Assessment on the Congraree River – USA
Flood defense prediction harnessing the power of simulation modeling
- Location: Columbia, South Carolina, USA
- Date: 2001 – 2004
- Client: Exponent
- Project Type: Flood risk reduction
Understanding levee safety for flood-prone development
A developer in Columbia, South Carolina wanted to understand how resilient levees on their land are to withstanding severe flood events along the Congaree River. But predicting the levee’s performance is challenging because of the complex river dynamics in the area and the extra risk posed by changing climate. Consulting firm Exponent commissioned Hydro Nova to conduct an assessment of levee performance under future flood events and predict what could happen to land nearby when a big flood occurs.
Our hydraulic engineering team conducted modeling to assess the river conditions, simulate future floods and analyze the function of the levees when subjected to extreme floods. Our study helped the developer understand the risk of levee breech and determine best options for flood defense going forward.
Services Provided
Assessment of river conditions
We constructed a 2D hydraulic finite elements model, with about 90 km2 computation grid extension, enabling us to characterize the complex nature of the Congaree River in the residential and environmental areas.
Extreme flood simulation
Using our Surface Water Modeling System (SMS) modelling tool, we simulated and mapped river extent and velocity of a 100-year flood of 292,000 cfs. and during future climate change scenarios.
Levee performance prediction
We tested the levees under different flood scenarios and determined the breaching point and resulting river flows, predicting that the levees can hold up during more frequent, intermediate floods and will likely fail during a 100-year extreme flood while still reducing flood levels downstream.
