utilizing lidar for engineering applications conservation our purpose, our passion
TRANSCRIPT
Utilizing LiDAR for Engineering Applications
Conservation
Our Purpose, Our Passion
Objectives
Identify some engineering applications Present an Overview for Breach Routing Review a Breach Routing Case Study
Utilizing LiDAR
Applications include design and planning of physical land modifications or mitigations
LiDAR is suitable for planning and in some cases even final design or aspects of final design.
Applicability depends on degree of accuracy required. Hydraulic and Hydrology Modeling, Farm Field Terracing
Systems, Irrigation Systems, Floodwater Retarding Structures, Grade Stabilization Structures, Water Supply Structures, etc.
Surface Modeling
Stage – Storage Earthfill & Excavation
Quantities
Hydrology Modeling
Delineation of Watersheds and Water Flow Paths
More Modeling
Identify and map Flood Frequencies
Identify and map hazard areas downstream of structures
Inundation Boundary Mapping
Structures, Ponds, Lakes
Small Structure Case Study
Breach Routing a Small Structure to Identify hazards downstream
Three data sets: – Traditional Survey – ESRI TIN from LiDAR – ESRI TIN from USGS DEM
Accuracy required, Budget, Time Constraints
Traditional Process
Using Total Station or Survey Grade GPS a survey crew would gather data at each cross section in the field
Downloaded with CAD Copied & Entered into
Hec-RAS
LiDAR Process
Using a ESRI TIN developed from LiDAR
Extract Valley Cross Sections with Hec-GeoRAS & ArcGIS
Immediate file import into Hec-Ras
Hec-GeoRas “Pre-Ras”
USGS DEM Process
Same as LiDAR, except extracting data from the USGS DEM dataset
Survey Data Analysis
Kept all factors the same, except the differences in the two data sets
Cut cross sections exactly at the same spot Utilized the same manning’s N values Hec-Ras Steady State analysis run with TR-
20 flood routing
H-39a Centerline Dam R.S. 200
705
710
715
720
725
730
735
740
745
0 100 200 300 400 500 600 700 800 900 1000
Station (ft)
Ele
v. (
Ft)
Trimble GPS Survey LiDAR Data USGS Data
711.0711.3
H-39a Centerline Dam R.S. 190
700
705
710
715
720
725
730
735
0 100 200 300 400 500 600 700 800 900 1000
Station (ft)
Ele
v. (
Ft)
Trimble GPS Survey LiDAR Data USGS Data
704.9 ft
706.8 ft
H-39a Centerline Dam R.S. 160
700
705
710
715
720
725
730
0 100 200 300 400 500 600 700 800 900 1000
Station (ft)
Ele
v. (
Ft)
Trimble GPS Survey LiDAR Data USGS Data
701.6 ft702.7 ft.
0
1000
2000
3000
4000
5000
6000
7000
704 705 706 707 708 709 710 711 712 713
WSP (ft)
Q (
cfs)
0
500
1000
1500
2000
2500
3000
3500
Are
a (s
qu
are
ft)
Lidar_Flow Trimble_Flow LiDAR_Area Trimble_Area
River Station 160
Profile Rating
LiDAR data compared to Survey
Grade GPS Trimble Data
Site H-39a Results
Trimble GPS Survey; overtopped Hwy YY by 1.6’ LiDAR Survey; overtopped Hwy YY by 1.0’
0 500 1000 1500 2000 2500 3000 3500690
695
700
705
710
715
720
BCHC H-39a breachroute.prj Plan: TR-20_final Run_w interpolated xsecs 10/3/2007
Main Channel Distance (ft)
Ele
vation (
ft)
Legend
WS TR-20 Breach
Ground
cross s
ection s
urvey 2
-552 d
ow
nst...
Box c
ulv
ert on h
wy Y
Y r
oad c
ente
rline u
...
surveyed c
ross s
ection 5
-2510
surveyed c
ross-section 6
-3300 c
l dam
H-39a 1
Hec-GeoRas“Post-RAS”
Reference Links
Hec-Ras:http://www.hec.usace.army.mil/software/hec-ras/
Hec-GeoRas: http://www.hec.usace.army.mil/software/hec-ras/hec-georas.html
TR-60:http://www.info.usda.gov/CED/ftp/CED/TR_210_60_Second_Edition.pdf
TR-20:http://www.wcc.nrcs.usda.gov/hydro/hydro-tools-models-tr20.html
Ag. Research Servicehttp://www.ars.usda.gov/main/site_main.htm?modecode=62-17-10-00
Helping People Help the LandHelping People Help the Land
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