Natural Resources Conservation Service Hydraulic Modeling Karl Visser
- Slides: 11
Natural Resources Conservation Service Hydraulic Modeling Karl Visser, PE Ft Worth National Design, Construction & Soil Mechanics Center
Current Modeling Projects What type of RAS modeling projects have you completed? What type of RAS modeling projects do you hope to complete? Nov 2016 Hydraulic Modeling 2
Modeling Purpose • Why are you hydraulic modeling this stream or floodplain? • What is your ultimate design purpose? § § § Nov 2016 Inundated area Hazard class Design wse Velocity Shear stress Hydraulic Modeling 3
GIS • Data § Do you have statewide LIDAR? § LIDAR to cover your projects? • DEM § Hydrologically enforced? § Water flow through or over bridges? Culverts? • User expertise § How much GIS capability/support do you have? § Are you willing to learn? Nov 2016 Hydraulic Modeling 4
Know your GIS data Z • Is xyz units consistent? § Meters/meters § Ft/ft/ft (state plane) x § Meter/meter/ft (some UTM) y • RAS Mapper will convert units § English SI § SI English Nov 2016 Hydraulic Modeling 5
Precision & Accuracy • How close do you need to be? +/- 0. 1 ft? • Planning level vs final design Nov 2016 Hydraulic Modeling 6
Steady vs Hydrograph Steady flow 1 -D • No hydrograph needed Unsteady flow 2 -D • Eg. Dam breach hydrograph Nov 2016 Hydraulic Modeling 7
LIDAR vs Survey • What models does LIDAR work better? • What project does 1 D field cross-sections more appropriate? Nov 2016 Hydraulic Modeling 8
Channel vs Floodplain • In-channel flow analysis § § Need full-depth channel data LIDAR doesn’t penetrate water surface E. g. Stream restoration projects Any LIDAR data have full channel surface? • Floodplain analysis § Full depth channel data probably not needed § LIDAR surface – appropriate § E. g. Dam breach analysis Nov 2016 Hydraulic Modeling 9
Will I ever model 1 D again? 2 D is wonderful! • Bridges – currently are 1 D only features Nov 2016 Hydraulic Modeling 10
Natural Resources Conservation Service END Richland Creek 113 2015 Nov 2016 Hydraulic Modeling 11