LWI Region 5 Mermentau - Bayou Lacassine at River Station 11 HEC-RAS Simulation: Historic Event Scaled to 100-Year Design Storm
This simulation represents the 100-year design storm event for the Ungaged Bayou Lacassine at River Station 11 (ME_BALA_011_UG) KCDA area. The event is based on the August 2016 historical tropical storm scaled to the 100-year 24-hour design storm precipitation volume. The storm critical duration was determined by modeling the gridded precipitation over the KCDA area and identifying the peak flow leaving the KCDA area for a variety of storm lengths. To match the design storm volume, the August 2016 historical storm was configured with a 1.20 scale factor for KCDA ME_BALA_011_UG. The model simulation was created in HEC-RAS Version 6.5. This represents the 2017 to 2019 existing conditions Mermentau geometry with calibration regions configured for validation as an average of calibration events. The simulation includes: a constant boundary inflow hydrograph for the Mermentau River based the 50th percentile flow of 500 cfs; design storm precipitation based on scaling of the August 2016 storm event; a constant mean high high water variable downstream tidal boundary condition; a constant downstream stage hydrograph of constant 50th percentile of 2.49 ft (NAVD88) at the Gulf Intracoastal Water Way derived from USACE Gage #76800, and infiltration over the watershed. The initial simulation time step is 5 seconds with the control by courant condition option enabled, allowing HEC-RAS to adjust the timestep as condition warrant during the simulation. This model is most applicable from river station 11 (ungaged) of Bayou Lacassine to river station 24 of Bayou Lacassine.
Model Software Version
HEC-RAS version 6.5Model Application
LWI Region 5 Mermentau - Bayou Lacassine at River Station 11 HEC-RAS ModelSimulation Type
SCENARIOInput Files
| Title | Description | Location |
|---|---|---|
| Boundary Condition File | Stores boundary condition information for simulation | /ME_BALA_011_UG/Mermentau_DS.b05 |
| Initial Conditions File | Stores all configured hydraulic initial conditions for running simulation | /ME_BALA_011_UG/Mermentau_DS.ic.o05 |
| Unsteady Flow File | Stores user-defined flow options, initial conditions and hydrographs are stored | /ME_BALA_011_UG/Mermentau_DS.u05 |
| Plan File | Contains a list of associated input files and all simulation options | /ME_BALA_011_UG/Mermentau_DS.p05 |
Output files
| Title | Description | Location |
|---|---|---|
| Unsteady Flow Log Output File | Stores the computational log and hydraulic solution error computations | /ME_BALA_011_UG/Mermentau_DS.bco05 |
| Plan HDF File | Contains plan level execution results that focuses on runtime statistics, convergence metrics, and execution status | /ME_BALA_011_UG/Mermentau_DS.p05.hdf |
| DSS Output File | Stores time series hydraulics output for boundary conditions, 2D/SA connections, reference points and reference lines | /ME_BALA_011_UG/ME_BALA_011_UG_Aug2016_100yr_SF1p20/ME_BALA_011_UG_Aug2016_100yr_SF1p20.dss |
Temporal extent
| 3000-08-01 |
| 3000-08-07 |
Temporal resolution
5SECResource Files
Metadata record information
| Created By | hdr_lwi_region_5@hdrinc.com |
| Created At | 2025-06-10t05:15:45.648160+00:00 |
| Access Level | Public |
| Is Reviewed | True |
| Owner | hdr_lwi_region_5@hdrinc.com |