HEC-RAS flood modeling Little River basin with animation slides
-
Upload
william-mullen -
Category
Engineering
-
view
104 -
download
5
Transcript of HEC-RAS flood modeling Little River basin with animation slides
![Page 1: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/1.jpg)
EVALUATING SEA LEVEL RISE AND CLIMATE CHANGE ON FLOODINGCase study: Little River basin, Newburyport, MAPrepared by: River Hydraulics, January 2017
![Page 2: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/2.jpg)
Determine potential flood impacts associated with:
1. sea level rise;2. climate change;3. altering watershed infrastructure.
Problem statement
![Page 3: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/3.jpg)
Opportunity New: HEC-RAS 2-dimensional unsteady flow
“bare earth” LiDAR terrain, free, accuracy in inches
Seamlessly combine LiDAR terrain with surveyed channel bathymetry
HEC-RAS modeling of river and tidal flows throughout a flood event
HEC-RAS automated floodplain delineation on aerial or topo maps
HEC-RAS evaluation of changes associated with culvert and bridge modifications
![Page 4: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/4.jpg)
HEC-Hydrologic Modeling System (HEC-HMS)
Rainfall-runoff modeling for model calibration and determination of flood flow frequencies
Historic precipitation modified to reflect impacts of climate change
Drainage areas, runoff curve numbers, and times of concentration determined using Quantum GIS
![Page 5: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/5.jpg)
The next four slides were produced by River Hydraulics using Quantum Geographical Information System (QGIS)
![Page 6: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/6.jpg)
![Page 7: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/7.jpg)
![Page 8: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/8.jpg)
![Page 9: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/9.jpg)
![Page 10: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/10.jpg)
HEC-RAS model
![Page 11: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/11.jpg)
cell size of 250’ x 250’ selected (large size OK with slope of water surface changes slowly)
Finer mesh with smaller cells along road and railroad embankments
Culverts modeled
One single 2D flow area
Overbank terrain from LiDAR seamlessly merged with previously-surveyed channel bathymetry
Calibration using Mothers Day flood of May 2006 (15” rain over 4 days)
HEC-RAS model parameters
![Page 12: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/12.jpg)
![Page 13: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/13.jpg)
![Page 14: HEC-RAS flood modeling Little River basin with animation slides](https://reader031.fdocuments.net/reader031/viewer/2022020113/587e8d581a28ab672b8b4f2f/html5/thumbnails/14.jpg)
Next Steps
Calibration of HEC-RAS Model
Determine flood boundaries, depths, velocities for various flood frequencies or events using HEC-RAS
• Determine impacts of proposed changes at culverts and bridges to upstream and downstream areas using HEC-RAS