NHDPlus Inundation Modeler V4.0 Beta

A Framework of ArcGIS-Based Flood Inundation Modeling and Mapping System

Dr. Zhe Li

National Water CenterNOAA NWS Office of Water Prediction

205 Hackberry LaneTuscaloosa, AL 35406

June 30, 2016

Project Lead:

Team Members (Alphabetically) :

Acknowledgements

NWC Supervisors & Managers

Hassan Mashriqui

Chandana GangodagamageJuzer Dhondia

Tomomi ItoMohammad Islam

Kazungu Maitaria

Kate Abshire

GID Director: Ed Clark

NWC IT and Project Management Team

Outline

Introduction of NHDPlus v2 dataset

NHDPlus Inundation Modeler v4.0 Beta

• Automated cross-section construction

• Open channel bathymetry generation

• Flood inundation modeling and mapping

Improved 1:100K National Hydrography Dataset (NHD) (About 3 million records) Improved 1 arc-second National Elevation Dataset (NED) Nationally complete Watershed Boundary Dataset (WBD) Catchment characteristics Headwater node areas Cumulative drainage area characteristics Flow direction, flow accumulation and elevation grids Flowline min/max elevations and slopes Flow volume & velocity estimates for each flowline in the stream network Catchment attributes and network accumulated attributes

NHDPlus Version 2 Data

Why ArcGIS?

Industry standard GIS software for spatial decision support; Provides the most comprehensive tools for spatial analysis and spatial

modeling; Excellent tool for working with hydrographic data, e.g., NHDPlus data; Uses data format standards to store geospatial data in a common format or

transfer data from system to system, e.g., NetCDF; Works well with both vector (points, lines and polygons) and raster data

(aerial photography, satellite imagery, DEM, LiDAR dataset, etc.) Python programming environment and Arcpy site package enable users to

create customized applications conveniently; A lot of hydraulic and hydrographic software packages are developed for

ArcGIS (extensions), such as Hec-GeoRAS, ArcHydro, TauDEM, etc.

ArcGIS Extension – NHDPlus Inundation Modeler V4.0 Beta Toolbox

Copyright © Li, 2016

Part I

Automated Cross-Section Construction

Cross sections

A set of transect lines to characterize the flow carrying capability of a stream and its adjacent flood plain

Extracts information from underling terrain model

Critical for hydraulic modeling

Cross sectional line

River reach

Figure source: Chris Goodell, P.E., D. WRE | WEST Consultantshttp://hecrasmodel.blogspot.com/2012/07/how-to-draw-cross-sections.html

Main channel / flow path centerlineImpression of the flow lineEdge of the flood plainCross section

Making cross sections mainly relies on manually drawn lines over streams and is quite labor intensive;

Cross sections must be perpendicular to the main channel at all locations; Cross sections must be perpendicular to the flowlines at all locations; Cross sections cannot intersect with each other; Cross sections must be wide enough to extend to potential flooding areas; Software (e.g., Hec-GeoRAS) generated cross sections need substantial post

processing work before they can be used for hydraulic models

How to draw cross sections

Cross sections at a 500 m interval generated from TransectMaker Interval v3.2 (Li, 2015)

Tar River

TransectMaker Interval v3.2

TransectMaker Interval v3.3

Cross sections at a 500 m interval generated from TransectMaker Interval v3.3 (Li, 2015)

James River

TransectMaker Midpoint v3.2

Cross sections at reach midpoints generated from TransectMaker Midpoint v3.2 (Li, 2015)

Tar River

Cross sections at reach end points generated from TransectMaker Endpoint v3.2 (Li, 2015)

TransectMaker Endpoint v3.2

Tar River

TransectMaker Interval v3.7

Developed to keep cross sections from intersecting each other at channel meanders, while perpendicular to flowlines

Tar River

50 m buffer lines

500 m buffer lines

1000 m buffer lines

3000 m buffer lines

Dog-legged cross sections

Buffer lines

Dog-legged cross sections at a 200 m interval generated from TransectMaker Interval v3.7 (Li, 2016)

50 m buffer line

50 m buffer line

Dog-legged cross sections at 200 m interval generated from TransectMaker Interval v3.7 (Li, 2016)

Tar River

Cross sections at 500 m interval generated from TransectMakerInterval v3.7 (Li, 2016)

FEMA cross sections

Automatic vs. manual cross sections

Part II

Open Channel Bathymetry Generation

Traditional DEM products, e.g., National Elevation Dataset (NED), are able to provide elevations of bare earth surface and above ground features, but not underwater

Availability of bathymetry data are limited in oceans and coastal areas Fine resolution bathymetry data are desired for inland flowline networks

Picture source: Copyright © 2013 Wildland Hydrology - Stream Habitat Measurement Techniques - Cross-Sectionhttp://training.fws.gov/courses/CSP/CSP3200/resources/documents/CrossSection_AFG2013.pdf

Estimating channel dimension

Bieger et al., 2015, Development and evaluation of bankfull hydrologic geometry relationships for the physiographic regions of the United States. Journal of the American Water Resources Association, (JAWRA) 1-17.

Estimating channel dimension

Extracting channel hydraulic geometry from NHDPlus v2 dataset

Channel dimensions are calculated at the river reach level (with unique COMID)

James River

Boundaries used for calculating channel dimensions from TransectMaker Endpoint v3.3(Li, 2016).

Bathymetry estimation

Makes a raster full DEM (including both above and under water) by interpolating these elevation points

Elev_lowest_pointBankfull 𝐷𝑒𝑝𝑡ℎ

James River

Given by field “TotDASqKM” from NHDPlus v2 dataset

𝐷𝑟𝑎𝑖𝑛𝑎𝑔𝑒 𝐴𝑟𝑒𝑎= 0.24 ∗ 0.323

𝑇𝑜𝑝𝑤𝑖𝑑𝑡ℎ

= – Bankfull 𝐷𝑒𝑝𝑡ℎ

Underwater elevations are calculated by assuming that the channel shapes are known, e.g., trapezoidal;

Elev_water_surface

Under water

Above water

NHDFlowline Bathymetry Generator v4.3

River boundary extraction from multiple sources

Landsat 8 OLI 30 m B534 composite

Object-based classification

IKONOS 1m panchromatic imagery

NHDArea data

Remote sensed imagery classification

OriginalDEM

Simulated channel shape

Bathymetry derived for river channels from 1m resolution LiDAR DEM (courtesy of Dr. Gangodagamage for LiDAR DEM)

Original 1 m DEM Simulated channel bottom shape

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Cross section profile from original DEM

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Cross section profile from simulated bathymetry

Eel River Eel River

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Original 10 m DEM Simulated channel bottom shape

Cross section profile from original DEM

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Cross section profile from simulated bathymetry

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James River James River

Simulated bathymetry for James River

Unit: Meter

Part III

Flood inundation modeling and mapping

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ater

su

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Discharge Q (cm/s)

𝑄 =1.0

𝑛𝐴𝑅2/3𝑆1/2

For uniform flow, Q is referred to as Normal discharge

𝑅 =𝐴

𝑃

R is the hydraulic radius for various channel shapesA is the cross-sectional flow areaP is the wetted perimeterS is the channel slopen is the Manning’s roughness coefficient

A

P

D

Manning’s Equation - Uniform steady flow

Natural channel

𝐴𝑅2/3 =𝑛𝑄

𝑆1/2

Channel geometry

Estimation of water surface elevation

B (x2, y2, z2)

C (x, y, z)

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Sampling points B’ (x2’, y2’, z2’)

z1

z2

z

C’ (x’, y’, z’)

z2’

z1’

z’

1 2 3 4 5 6 7 8 9 10 11 12 13Cross section sampling point ID

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n z

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Q1’ = A1’ *math.pow (R1’, 2/3) * math.pow (S, 0.5) / nQ2’ = A2’ * math.pow (R2’, 2/3) * math.pow (S, 0.5) / nWater surface elevation z = z2’ + (z1’ – z2’)*(Q – Q2’)/(Q1’ – Q2’)

Q1’

Q2’Q

Q1

Q2

Q1’, Q2’: flow discharge calculated for water surface level z1’, z2’, resp. A1’, A2’: wetted area for water surface level z1’ z2’, resp.R1’, R2’: hydraulic radius for surface level z1’ z2’, resp.S: channel slopen: Manning’s roughness coefficient(Courtesy of Juzer Dhondia for consultancy of algorithm design)

Elev

atio

n z

(m)

B (x2, y2, z2)

C (x, y, z)

A (x1, y1, z1) A’ (x1’, y1’, z1’)

Cross sectional line

Sampling points B’ (x2’, y2’, z2’)

z1

z2

z

C’ (x’, y’, z’)

Distance_AB = math.sqrt (math.pow((x2 - x1), 2) + math.pow((y2 - y1), 2))Distance_AC = Distance_AB * (z - z2)/(z1 - z2)proportion = Distance_AC / Distance_ABInundation edge point coordinate x = (1 - proportion) * x2 + proportion * x1

Inundation edge point coordinate y = (1 - proportion) * y2 + proportion * y1

z2’

z1’

z’

1 2 3 4 5 6 7 8 9 10 11 12 13Cross section sampling point ID

Calculation of inundation boundary point coordinates

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NHDPlus v2 Mean Annual Flow between 1971 and 2000

All Flow estimates represent the flow at the bottom (downstream end) of the NHDFlowline feature.

Q0001E: Gage adjusted flow (cfs)

Real-time stream flow information from NWS and USGS

http://wimcloud.usgs.gov/apps/FIM/FloodInundationMapper.html

NHDPlus v2 Slope of Flowline

Estimation of Manning’s Roughness n

Channel Description n

Smooth earth 0.018

Clean excavated earth 0.022

Natural channel with stones and weeds 0.030

Natural channel with light brush 0.050

Natural channel with tall grasses and reeds 0.060

Natural channel with heavy brush 0.100

NHDPlus v2 River Reach Strahler Stream Order

n

1 0.14

2 0.12

3 0.09

4 0.09

5 0.07

6 0.06

7 0.03

8 0.03

9 0.03

10 0.03

Courtesy of Dr. Hassan Mashriqui

Manning’s Roughness n Estimated from NHDPlus v2

TransectMaker Interval v3.7

TransectMaker Interval v3.7a

Developed for using existing cross section cut lines. It outputs cross section points with hydraulic parameters.

Inundation Mapper v3.1

Tar River flood inundation simulation at the reginal level --- (Animation)

Tar River inundation caused by Hurricane Floyd 1999

Photo date: September 24, 1999Photographer: FEMA / Dave GatleyPhoto location: Greenville NCRead more: http://www.city-data.com/disaster-photos/377.html#ixzz46I3JBzvD

Photo date: September 24, 1999Photographer: FEMA / Dave GatleyPhoto location: Greenville NCRead more: http://www.city-data.com/disaster-photos/458.html#ixzz46I5toVQ0

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Cross section

Tar River maximum flow discharge during Hurricane Floyd (1999) and normal discharge (1971 - 2000)

Maximum discharge

Normal discharge

Discharge during flooding was 22 - 29 times of normal!Tar River

Average 25 times

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Flood boundary during Hurricane Floyd (Sep 20, 1999)

Under 16 times of normal flow discharge

Under 30 times of normal flow discharge

Tar River flood inundation boundaries under different scenarios

Under 20 times of normal flow discharge

Under normal flow discharge

25 times of normal discharge!

Tar River flood depth during Hurricane Floyd (September 20, 1999)

Meter

Inundation boundaries during Hurricane Floyd generated from Inundation Mapper v3.1a (Li, 2016), using water surface elevation information on September 20, 1999

(Courtesy of Tomomi Ito for deriving water surface elevations from Hec-RAS)

Tar River inundation caused by Hurricane Floyd 1999

Hurricane Floyd caused the flood-swollen Tar River to overflow its banks.

Flooded residential area in Greenville, North Carolina, during Hurricane Floyd (September 18, 1999)

http://nc.water.usgs.gov/flood/floods99/photos/IMG023.htmlPhoto credit: Jerry Ryan

Inundation boundaries under a scenario of 30 times of normal discharge (NHDPlus v2) and 10 m DEM generated from Inundation Mapper v3.1 (Li, 2016)

Flood inundation simulation – Tar River (Greenville, NC)

Inundation boundaries during Hurricane Floyd generated from Inundation Mapper v3.1a (Li, 2016), using water surface elevation information on September 20, 1999

Flood inundation simulation – Tar River (Greenville, NC)

Inundation boundaries during Hurricane Floyd generated from Inundation Mapper v3.1a (Li, 2016), using water surface elevation information on September 20, 1999

Inundation boundaries under a scenario of 30 times of normal discharge (NHDPlus v2) and 10 m DEM generated from Inundation Mapper v3.1 (Li, 2016)

Flood inundation simulation – Tar River (Greenville, NC)

Inundation boundaries during Hurricane Floyd generated from Inundation Mapper v3.1a (Li, 2016), using water surface elevation information on September 20, 1999

Inundation boundaries under a scenario of 30 times of normal discharge (NHDPlus v2) and 10 m DEM generated from Inundation Mapper v3.1 (Li, 2016)

import arcpyarcpy.ImportToolbox("C:/MyProject/Software/Inundation Mapper v3.1.tbx")

env.workspace = "C:/data" Workspace = env.workspaceenv.overwriteOutput = True

Output_Space = env.workspaceNHDPlus_v2_Stream_File = “tar_rivers.shp“Field_Name_of_Flow_Discharge = “Q0001E”Field_Name_of_Channel_Slope = “SLOPE”Field_Name_of_Manning_s_n = “WRF_MannN”Cross_Sectional_Location_File = “xs_locations”Cross_Sectional_Elevation_File = “xs_elevation”Times_of_Normal_Discharge = 20.0Output_Inundation_Boundary = “inundation_boundary_tar_river.shp”

arcpy.InundationMapper31 (Output_Space, NHDPlus_v2_Stream_File, Field_Name_of_Flow_Discharge, Field_Name_of_Channel_Slope, Field_Name_of_Manning_s_n, Cross_Sectional_Location_File, Cross_Sectional_Elevation_File, Times_of_Normal_Discharge, Output_Inundation_Boundary)

Macro processing by running stand-alone Python script

InundationMapper31 (Output_Space, NHDPlus_v2_Stream_File, Field_Name_of_Flow_Discharge, Field_Name_of_Channel_Slope, Field_Name_of_Manning_s_n, Cross_Sectional_Location_File, Cross_Sectional_Elevation_File, Times_of_Normal_Discharge, Output_Inundation_Boundary, {Output_Water_Depth_Raster}, {Output_Raster_Cell_Size})

Syntax

Stand-alone script

Future Work

Validate generated data products against ground truth and observation data

Generate national wide bathymetry products for NHDPlus v2 and NHD high resolution data based on physiographic divisions (Biegeret al., 2015)

Apply the developed models and use high resolution DEM (e.g., LiDAR DEM) to predict inundation at the street level;

Apply the developed models at national level by taking National Water Model output data and real time flow observations.

Phone: 205-347-1352Email: zhe.li@noaa.gov

zheli@ucar.edu

Correct citations:

Li, Z., 2016, NHDPlus Inundation Modeler V4.0 Beta – ArcGIS Extension, National Water Center, NOAA NWS Office of Water Prediction, Tuscaloosa, Alabama.

Li, Z. et al., 2016, NHDPlus Inundation Modeler v4.0 Beta – ArcGIS Extension for Flood Inundation Modeling and Mapping System , Esri International User Conference, San Diego, California, June 27 – July 1, 2016.