peak flow estimation tools for culvert and catch basin … · 2018-11-01 · speaker background...
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Peak Flow Estimation Tools for Culvert and Catch Basin Assessments
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Speaker Background
➢ Corps of Engineers
➢ 26 years experience
➢ NYS Floodplain Mapping
➢ LiDARBen Houston, P.E.Principal at GroundPoint Engineering
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What the heck?
• Who is WRI and what are they doing?
• Standards Based Data Structures
• Adaptation for using LiDAR
⁻ Runoff Characteristics
⁻ Peak Flow Estimates
• Case Studies in Urban Pittsburgh and Ulster County NY
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Ulster County, NY NYS Water Resources Institute
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A Brief Aside on Scale
30m resolution = 900 m2 USGS DEM, LANDSAT
10m resolution = 100 m2 resampled from 30m
1m resolution = 1 m2 LIDAR DEM
1ft resolution = 0.1 m2 Standard Ortho Imagery
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And now…back to our Story…
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Almost there…
What we have
• NOAA Atlas 14
• NAACC Culverts
• LiDAR
• Imagery
• CN
What we need
• Drainage Area
• Average Slope
• Average CN
• ToC
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WRI Data Processes• NED (10m DEM)• Burn NHD Streams• Fill
• (Depressionless DEM)
GroundPoint Data Processes• LiDAR
• Remove Artifacts• Fill/ Mask
• Remove Artifacts• Some Sinks are OK!
• Flow Accumulation• Breaklines
• Stream centerlines• Berms/Gutters/Culverts
Result is a drainage surface16
Workflow- Surface Prep
Original DEM Fill Sinks Flow DirectionFlow
Accumulation
Are breaklines
(still) needed?
Highways Gutters Sink MaskBermsVoidsCenterlines
Modified DEM
Begin Modeling
NO
YES
Original and Modified DEM are Exported from LP360.LP360 tasks include re-classifying points and adding Breaklines.
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Workflow- Surface Prep
Original DEM Fill Sinks Flow DirectionFlow
Accumulation
Are breaklines
(still) needed?
Highways Gutters Sink MaskBermsVoidsCenterlines
Modified DEM
Begin Modeling
NO
YES
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Surface Prep Workflow- Modeling
Stream Network QC
GO BACK toSurface Prep
Catchment Polygons
Pour Point Analysis
QC
Merge Catchments
Pour Point Adjustments
Finish!
AccumulationThreshold
Points or Streams?
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Saw Kill Creek Watershed
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Catch Basin (Drain) Issues
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Conclusions• Surface prep works for catch basins as well as
culverts. Can be applied in urban settings
• Workflow is iterative
• Prepare the surface!• Prepare the surface
• Prepare the surface• Prepare the surface
• Prepare the surface
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www.drainagemapping.com
We. Know. Drainage.
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