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H&H Modeling
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
H&H Integration Overview
(HMS-RAS focus)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-2
Integration Approach
Mix of planning, GIS, and H&H modeling operations –
not a push button operation.
Types of integration
Modeling
support (preparing data for model input)
e.g. land use/soils/CN or rainfall processing – Arc Hydro or general
GIS data processing
Linked
GeoHMS
GeoRAS
Integrated
DSS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-3
Integration Approach (2)
Key steps:
Plan (roughly) hydrologic and hydraulic model layouts – flow exchange
locations
e.g. location of HMS modeling elements and RAS cross-sections
Identify sources of precipitation input into the hydrologic model and
techniques for their incorporation into the dataset
e.g. Nexrad rainfall
Develop GeoHMS model (and precipitation sub model)
Finalize and run HMS model and generate results (DSS)
Develop GeoRAS model
Finalize and run RAS taking HMS results as input
Feedback between HMS and RAS is manual
e.g. modification of time of concentration or routing parameters
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-4
Integration Planning
Identify where outputs from
one model (HMS) become
input to the second one
(RAS)
Place
hydrologic elements
(subbasins, reaches, junctions)
to capture flows at points of
interest (confluences, structures)
Place
hydraulic elements (crosssections) at points of interest
Identify/specify
element naming
conventions between the two
models (persistent or transient
names)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-5
Precipitation Sources
Identify sources of
precipitation input into the
hydrologic model and
techniques for their
incorporation into the
dataset
Point
(rain gage)
Polygon
Surface
(Nexrad cells)
(TIN/grid)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-6
Develop GeoHMS model
Follow all principles in development
of a hydrologic model
In addition, take into consideration
integration planning aspects
developed earlier
Placement
Naming
of flow exchange points
conventions
Incorporate precipitation submodel
Develop
Arc Hydro time series for the
final subbasin delineation and export to
DSS
Export to HMS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-7
Meteorological Component
Current GeoHMS
approach is to
develop a custom
“gage” for each
subbasin that
carries the
precipitation input
for that subbasin
Arc Hydro
Arc Hydro to DSS transfer
Export
the time
series for the
subbasin “gage”
from Arc Hydro time
series data structure
into DSS
DSS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-8
Finalize and Run HMS
Complete HMS
model with any
additional
parameters
including
meteorological
model and control
specifications
Follow all
principles in HMS
model
development
(calibration, etc.)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-9
Finalize and Run HMS (2)
Do the final run
and generate
results (DSS)
HMS View
DSS View
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-10
Develop GeoRAS model (pre-processing)
Follow all principles in
development of a hydraulic
model for element
placement (confluences,
structures, …)
In addition, take into
consideration integration
planning aspects developed
earlier
Naming
conventions (add
name of the HMS element to
the cross-section that will get
the element’s flows)
Export to RAS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-11
Finalize and Run RAS
Complete RAS
model with any
additional
parameters
including initial
and boundary
conditions
Follow all
principles in RAS
model
development
(calibration, etc.)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-12
Finalize and Run RAS (2)
Do the final run
and generate
results (export
to sdf file)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-13
Process RAS results in GeoRAS
Construct the
floodplain based on the
results in the sdf
Review the results with
respect to spatial
integrity (extents of
cross-sections,
ineffective flow areas,
disconnected flood
areas, …)
Clean results
Revisit RAS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-14
GIS – HMS – RAS Feedback
At present it is manual and at discretion of modeler
GIS
H
– H&H interaction
– H interaction
Visualization in both pre and post-processing – not just
a “pretty picture”
Fly-over
in preprocessing (GeoHMS and GeoRAS)
Identification of data problems
Modeling element placement
Post-processing
(GeoRAS)
Validity of element placement
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-15
HEC-HMS Background
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-16
About HEC-HMS
HEC-HMS, NexGen
successor to HEC-1
Precipitation-runoff
Lumped-link
model
model (basin-
reaches)
Some
pseudo-distributed
processes (ModClark)
Current release – version
2.2.2
Simplified HMS Watershed
Runoff Representation
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-17
HMS Components
Basin model
Watershed
physical
description
Meteorologic model
Precipitation
Evapotranspiration
Snowmelt
Control
specifications
Time
control during
simulation
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-18
Hydrologic Elements
Subbasin: watershed catchments
Reach: rivers and streams
Reservoir: dams and lakes
Junction: confluence
Diversion: bifurcations and withdrawals
Source: springs and other model sinks
Sink: outlets and terminal lakes
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-19
Basin Model
Subbasin
Reach
Reservoir
Junction
Diversion
Source
Sink
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-20
Basin Model (cont.)
Transform editor
Many input
forms
Baseflow method editor
Loss rate editor
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-21
Mathematical Model Choices
Many characteristics needed to compute model
parameters are spatially based
Area
Lengths/slopes
Average
properties over an area (e.g. CN)
Precipitation
…
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-22
HMS Meteorologic Model
Grid-based precipitation
Specify DSS pathname parts
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-23
HMS Control Specifications Model
Time window
Time related specifications
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-24
HMS Model
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-25
Calibration Results
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-26
HMS Results
Hydrographs at points of interest (DSS)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-27
HEC-GeoHMS Overview
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-28
About GeoHMS
HEC-GeoHMS – companion product to HMS
ArcGIS
I/O
support through HMS (ASCII, XML)
Beta
version (ESRI for HEC under CRADA)
expected in April
History
HEC-PrePro
Watershed
ArcView
(UT, 1997), CRWR-PrePro, PrePro 2003, …
Delineator (ESRI, 1997)
3.* versions (ESRI for HEC, 2001-04)
Development philosophy
Build
on top of Arc Hydro tools
Automate
GIS feasible functionality
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-29
GeoHMS Functionality
HEC-GeoHMS
DEM
preprocessing – “parent” definition (main view)
Watershed
delineation – on “baby” models (project view)
Topographic
Hydrologic
characteristics extraction
parameter computations
Model
schematization
Model
input preparation (ASCII)
Other GIS processing
Rainfall
distribution/interpolation
LU/soils
Copyright © 2005 ESRI. All rights reserved.
runoff coefficient mapping
H&H Using ArcGIS
3-30
GeoHMS Functionality (cont.)
HEC-GeoHMS and Arc Hydro tools are tightly linked
GeoHMS
computes as many Arc Hydro attributes as possible
(e.g. NextDownID, JunctionID, DrainID)
DEM
preprocessing (main view) is done using Arc Hydro tools
Topographic
characteristics extraction is based on Arc Hydro
tools
Arc
Hydro tools operate on both main and project views
Option to change stream definition threshold when
extracting the project view (one threshold for the main
view and different thresholds for different project views)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-31
DEM Preprocessing (parent definition)
Hydrologically correct DEM
Flow direction (D8 method)
Flow accumulation
Stream definition and segmentation
Watershed pre-delineation
Project (“baby”) data extraction
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-32
DEM Preprocessing (cont.)
Stream definition and
segmentation
Threshold
(performance)
Watershed predelineation
At
stream confluences
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-33
DEM Preprocessing (cont.)
Project (“baby”) data
extraction
Extract
specific area of
interest by defining the
outlet and inlets
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-34
Watershed Delineation
Flexible addition and removal of basin outlets
Merge
Split
existing basins
basin anywhere on the stream
Add
an outlet anywhere (trace the outlet stream to an existing
stream)
Profile
Interactive or batch processing
Understanding of basin character
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-35
Watershed Delineation (cont.)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-36
Topographic Characteristic Extraction
Well defined topographic descriptors
Longest
flowpath, basin centroid, stream slope, centroidal
length, CN, etc. (others planned)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-37
Hydrologic (Model) Parameter Extraction
Loss rate method (SCS CN)
Basin
Direct runoff method (SCS UH)
Basin
CN
lag (TR55, SCS CN)
Reach routing
Muskingum-Cunge
standard channel parameters
Precipitation
Weighted
gage (standard SCS type II, 24 hour, 100 year design
distribution)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-38
Model Schematization
Upstream/downstream connectivity
Development of lumped-link schema
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-39
Model Input Preparation
Native HMS ASCII input files (hms, basin, geometry, met,
dss, gage, control)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-40
HEC-GeoHMS Details
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-41
HMS Project Setup
Define outlet and sources
Extract applicable GIS data for ProjView
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-42
GeoHMS: Project View
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-43
Basin and Reach Manipulation
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-44
Basin Merge
Rules
The
subbasins must share a confluence OR
The
subbasins must be adjacent in an upstream and
downstream manner
More
than 2 subbasins are permitted.
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-45
Basin Merge
Select the two subbasins using the selection tool or any other selection
method
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-46
Basin Merge
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-47
Basin Subdivision
Method 1 - Subdivide an existing subbasin
Method 2 - Delineate a new subbasin
Method 3 - Delineate on a tributary branch where the
stream does not exist
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-48
Basin Subdivision - Method 1
Method 1 - An existing
basin can be subdivided
into two basins at an
existing stream.
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-49
River Merge
Reduce the number of routing reaches
Often simplify routing as single reach with less model
parameters requirements.
Select at least two rivers within the same subbasin and
run River Merge tool.
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-50
River Profile
Method 1 - Access through menu
Method 2 - Access through profile tool
Subdivide at grade break
click on the desired point on the profile, and that point is transferred
onto the map and the basin is subdivided at that point
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-51
Split Basin at Confluences
Rules
Only
one basin can be selected for each
operation.
This
menu item can be used with basin
having multiple confluences.
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-52
Batch Subbasin Delineation
Rule - The point should be located within the grid cell
that has an existing stream.
Import Batch Points
Places
all selected points in the map into the batch point file. Id
source feature classes have “Name” and “Description”
attributes, they area assigned to the batch points
Delineate Batch Points
Takes
points from batch point feature class and uses them to do
basin subdivision.
BatchDone and SnapOn attributes to control snapping
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-53
Extraction of Physical
Characteristics
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-54
River Length and Slope
Z unit is obtained from the spatial reference of the data.
If that is not found, the spatial reference of the map is
used for unit conversion.
Added characteristics
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-55
Basin Centroid
Method 1 - Bounding Box
Method 2 - Flow Path
Method 3 - User specified location (out of box
ArcGIS)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-56
Longest Flow Path
From ArcHydro Tools
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-57
Centroidal Flow Path
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-58
Attributes of subbasin
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-59
Additional Subbasin Attributes
Utilize Arc Hydro characteristic extraction
CN
Impervious
Basin
User
area
slope
defineable
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-60
Assembling Data for HMS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-61
Outline
Develop HMS inputs from GeoHMS
HMS
Schematic
Basin
Model
Background
Grid
Map File
Cell Parameter File
Assemble an HMS model
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-62
Subbasin Naming
Basin AutoName menu
Editable to suit project needs
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-63
Reach Naming
Reach AutoName menu
Editable to suit project needs
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-64
Unit Conversion
Convert Map units to HMS units
(unit conversion defined in
configuration file)
Additional attributes can be
managed by editing the
configuration file
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-65
Development of HMS Schematic
Run HMS Schematic from HMS menu
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-66
Add Coordinates
Run Add Coordinates from HMS menu
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-67
Develop Background Map
Run Background Map
File from HMS menu
ASCII
(.map) format as
well as XML format
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-68
Develop Lumped Basin Model
Run Lumped Basin File
from HMS menu
ASCII
(.basin) format as
well as XML format
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-69
Developing HMS Model
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-70
Hydrologic Analysis (HEC-HMS)
Basin import
Geometry (background) import
Hydrologic (model) parameters – complete the model for the
parameters not defined through GeoHMS
Basin (precipitation-runoff transformation)
Reach (routing)
Precipitation
Calibration
Final run (hydrographs as results)
None of the results are sent back to GIS at this time
Use of DSS for time series storage and exchange with RAS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-71
Model Results (DSS)
Basin
Copyright © 2005 ESRI. All rights reserved.
Summary
H&H Using ArcGIS
3-72
HEC-RAS Background
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-73
About HEC-RAS
HEC-RAS, NexGen successor to HEC-2
1-Dimensional hydraulic program
Steady and Unsteady Flow
Compute water surface from channel geometry and flow
Current release – version 3.1.2
Flow
Water depth?
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-74
HEC-RAS Components
Graphical User Interface
Data storage/management
Graphics, Tabular Output & Reporting
GeoRAS – GIS pre and postprocessor
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-75
Geometric Data
Cross Sections
Detailed Bridge Analysis
Detailed Culvert Analysis (9 shapes)
Multiple openings (bridge, culverts, conveyance)
Inline Weirs/Spillways, Gated Structures
Lateral Weirs/Spillways, Gated Structures
Storage Areas and Hydraulic Connections
Rating Curves
Data importers: HEC-2, UNET, Mike11, GIS, Survey Data
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-76
RAS Schematic
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-77
Cross Sections
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-78
Flow Data and Boundary Conditions
Steady flow data - peak flows or time lines
Unsteady flow data - hydrographs
Boundary Conditions
Stage
and/or flow hydrographs
Rating
Curves
Normal
or critical depth
Lateral
and uniform lateral inflow hydrographs
Groundwater
Time
interflow
series of gate openings
Elevation
controlled gates
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-79
Analyses Types
FEMA Floodway Analysis
Channel Modifications
Split Flow Optimization – steady flow
Bridge Scour Analysis
Detailed Flow Distribution
Mixed Flow Regime in Unsteady Flow
Subcritical and Supercritical flow, draw downs, and hydraulic jumps
Dam Break Analysis
Levee Breaching and Overtopping
Pump Stations – multiple pumps, on and off elevations
Navigation Dams – Dam and hinge point control
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-80
Viewing Results
Graphics
Cross sections
Water surface profiles
Stage and flow hydrographs
XYZ Plot
Rating Curves
Generic plots – Any variable in profile, rating
Animation – (cross section, profile, 3D plots)
Tabular Output
Pre-defined detailed and summary tables
User-define output tables
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-81
Cross Section Plot
.065
.04
.09
620
Legend
EG 22FEB1999 0500
Elevation (ft)
600
WS 22FEB1999 0500
Crit 22FEB1999 0500
580
Ground
Levee
560
Ineff
Bank Sta
540
520
0
200
400
600
800
1000
1200
1400
Station (ft)
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-82
Profile Plot
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-83
XYZ Plot
Legend
WS 22FEB1999 0500
Ground
Bank Sta
Ground
Levee
Ineff
Copyright © 2005 ESRI. All rights reserved.
Source: HEC
H&H Using ArcGIS
3-84
Stage and Flow Hydrographs
R iv er: Truc k ee
R each: Lower
RS: 11496. 09
4396
22000
Legend
20000
Stage
Flow
4394
18000
16000
14000
4390
12000
4388
Flow (cfs)
Stage (ft)
4392
10000
8000
4386
6000
4384
31
01
Dec96
Copyright © 2005 ESRI. All rights reserved.
02
03
Jan97
T ime
04
Source: HEC
05
4000
H&H Using ArcGIS
3-85
HEC-GeoRAS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-86
About HEC-GeoRAS
HEC-GeoRAS – companion product to RAS
ArcGIS
I/O
support through RAS (ASCII, XML)
Beta
version (ESRI for HEC under CRADA)
released (in pre-beta for almost 2 years)
History
ARC/HEC2
(UT, 1992)
Philadelphia
ArcView
version (ESRI) – AVRas 2.2
ARC/INFO
COE (ARC/INFO solution)
and ArcView 3.* versions (HEC/ESRI)
Development philosophy
Automate
Provide
boring tasks
tools for “involved” tasks, otherwise standard ArcGIS
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-87
GeoRAS Functionality
HEC-GeoRAS
Preprocessing
Layer construction
Data entry utilities
Characteristics extraction (stream and cross-section properties)
Model input preparation (ASCII)
Postprocessing
Import of RAS results into a geodatabase
Generation of water depth and floodplain extent
Other GIS processing
Mapping
Visualization
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-88
HEC-GeoRAS
Preprocessing
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-89
GeoRAS Data Layers - Required
Terrain Model – representation
of both the main channel and
adjacent floodplain area
TIN
or GRID
tiled
or monolith
Stream Centerline
Cross Section Cut Lines
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-90
GeoRAS Data Layers – Optional
Flow paths
Stream banks
Land use
Ineffective areas
Levee alignments
Storage areas
Blocked obstructions
Bridge/culverts
…
Contours, images,
orthophotos, (visualization)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-91
GeoRAS Database Generation
Through code
“Create
RAS Layers”
function in GeoRAS UI
Each
function will generate
layers/attributes as needed
ArcCatalog
From
geodatabase schema
Careful with spatial reference
Careful with SDE
implementation (write
access)
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-92
GIS Data Layer – Terrain
Terrain
TIN
or GRID
Used
to:
Provide elevation values
Georeference GIS layers !
Contours
can be created and
used for visualization only
Assists
in stream centerline
and cross section layout
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-93
GIS Data Layer – Stream Centerline
Terrain
Stream Centerline
Establishes
cross-sectional
river stationing
Created
in the direction of flow from upstream to downstream
Each
reach must have a unique
river-reach name
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-94
GIS Data Layer – Stream Banks
Terrain
Stream Centerline
Stream Banks (Optional)
Delineates
the main river
channel from the overbank
areas
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-95
GIS Data Layer – Flow Paths
Contours
Stream Centerline
Stream Banks
Flow Paths (Optional)
Created
in the direction of flow
Located
at the center-of-mass
of flow
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-96
GIS Data Layer – Cross Sections
Contours
Stream Centerline
Stream Banks
Flow Paths
Cross Sections
XS
locations (cut lines) are
oriented from the left to right
bank
Perpendicular
Copyright © 2005 ESRI. All rights reserved.
to flow
H&H Using ArcGIS
3-97
River Stationing
Cross-sectional station
calculated from intersection
of Stream Centerline and XS
Cut Lines
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-98
Bank Stations
Calculated at the intersection
of Cross-sectional Cut Lines
and Banks themes
Banks Stations are
calculated as a fraction of
the cut line
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-99
Downstream Reach Lengths
Calculated at the
intersection of Crosssectional Cut Lines and
Flow Path Centerlines
themes
Reach lengths are
calculated as the length
between cut lines
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-100
Station-elevation Data
Elevation data extracted
from intersection of Crosssectional Cut Line theme
with the terrain
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-101
Station-elevation Data
Cross-sectional Cut Line
TIN
Resultant Cross Section
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-102
GIS Data Layer – Manning’s n
Contours
Stream Centerline
Stream Banks
Flow Paths
Cross Sections
Land Use
Estimate
n values
Copyright © 2005 ESRI. All rights reserved.
H&H Using ArcGIS
3-103
Manning’s n Values
Intersection of Cross
Section Cut Lines and Land
Use themes
N value break points are
reported as a fraction of the
cut line
Copyright © 2005 ESRI. All rights reserved.
n2
n3
n4
n5
H&H Using ArcGIS
3-104
GIS Data Layer – Other
Contours
Stream Centerline
Levees
Stream Banks
Ineffective flow areas
Flow Paths
Blocked obstructions
Cross Sections
Bridge/Culverts
Land Use
Inline structures
Lateral structures
Storage areas
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Other
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GIS Data Layer – 3D Elements
Contours
Stream Centerline
Stream Banks
Flow Paths
Cross sections
Cross Sections
Stream centerline
Land Use
Bridge/Culverts
Other
Inline structures
Lateral structures
Storage areas
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3D elements are
extracted from their
2D counterparts and
the terrain
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Geometric Import File (GIS
RAS)
Content
Header
River
Information
Network Definition
Rivers, reaches, and
junctions
Channel
and Floodplain
Geometry
Station-elevation data
Bank stations
Downstream reach lengths
Manning’s n values
Other
Storage areas
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Geometric Import File (cont.)
Format
sdf
(RAS I/O ASCII
format)
XML
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Completing HEC-RAS
and HEC-GeoRAS Postprocessing
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Analysis Process Overview
(GIS data Development completed)
Import GIS data into HEC-RAS
Complete data entry
Geometry
Required information not covered by GIS
Modeling run
Initial and boundary conditions
Perform the computations
QC of results
Calibration
Export results to GIS (GeoRAS postprocessing)
Floodplain delineation
Water depth determination
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Completing HEC-RAS
Input
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Imported Data
River system schematic
River,
reach and junction labels
Cross-section data
River,
reach, and river station labels
Cross
section cut lines (x,y)
Cross
section surface line (x,y,z)
Main
channel banks stations (optional)
Downstream
reach lengths (optional)
Manning’s
n values (optional)
Ineffective
flow areas (optional)
Levees
(optional)
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Imported Data (cont.)
Storage areas
Structures (only 2 and 3D geometry and placement are
generated – detailed structure characteristics are
currently not – work in progress)
Bridge/culverts
Inline
structures
Lateral
structures
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Data NOT Imported
Contraction and expansion coefficients
Optional cross-section properties
Ice,
vertical n values, etc…
Hydraulic structure survey data
Bridge
and culvert openings, weir characteristics, etc...
Flow characteristics
Initial
conditions
Boundary
conditions
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Importing GIS Data into RAS
Extract the geometric
data from GIS
From the geometric
data editor, select
import geometry data
GIS format
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Importing GIS Data into RAS (cont.)
Imported river
system schematic
Save Geometric Data
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Completing the Data
GIS does not generate all required data. Some are
optional (e.g. Manning’s n or bank stations) and some
are not supported (e.g. structure characteristics or
flows).
In most cases, additional work will have to be done on
cross-sections
“Banks”
Manning’s
n
Simplification
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of cross-section points (weeding)
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Completing the Data – Flow Characteristics
Flow data
Boundary
conditions
Profile names
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Flow Data and Boundary Conditions
Steady flow data - peak flows or time lines
Unsteady flow data - hydrographs
Boundary Conditions
Stage
and/or flow hydrographs
Rating
Curves
Normal
or critical depth
Lateral
and uniform lateral inflow hydrographs
Groundwater
Time
interflow
series of gate openings
Elevation
controlled gates
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Performing Computations and Viewing Results
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Viewing Results (RAS)
Graphics
Cross sections
Water surface profiles
Stage and flow hydrographs
XYZ Plot
Rating Curves
Generic plots – Any variable in profile, rating
Animation – (cross section, profile, 3D plots)
Tabular Output
Pre-defined detailed and summary tables
User-define output tables
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Water Surface Bounding Polygons
Cross section extents
Limited at Levees
Bridges, Culverts and
Weirs
FEMA Floodways
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Exporting Results to GIS
From HEC-RAS “File”
menu select “Export
GIS Data”
Many options
Make sure that the
result requested in
RAS is matching GIS
export requirements
(e.g. velocities)
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Exporting Results to GIS (cont.)
Cross section cut lines
Water surface elevations
Bounding polygon data
Stream centerline (optional)
Bank points (optional)
Storage areas (optional)
Velocity distribution information (optional)
Cross section properties (optional)
Cross section points (optional)
interpolated or not
channel or channel + floodplain area
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Post-processing in
HEC-GeoRAS
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Floodplain Delineation Methods
Import of model results into GIS
Construction
of GIS coverage through water surface as defined
by the hydraulic model (e.g. HEC-RAS).
fast, simple implementation
limited to solution at the cross-section - non-terrain based
interpolation between the cross-sections
Construction
of GIS coverage by construction of a water TIN and
then intersection of the water and terrain TINs to produce the
final floodplain outline.
slow, complex implementation
needs conversion of TIN into lattice (A/I)
more precise interpolation
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Post-processing
Specify data and
output locations
Read the RAS output
and generate results
geodatabase
Process GIS data to
generate floodplain
polygons and depth
grids
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RAS GIS Export File
Cross-sectional Cut Lines
Water surface elevations
Bounding polygon data
Stream Centerline (optional)
Velocity points (optional)
Other elements planned (banks, …)
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RAS GIS Export File (cont.)
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Inundation Processing
Multiple steps
Generate
water surface TIN
Use cross-sections as breaklines with known water surface elevation
coming from RAS.
Use bounding polygon as TIN extent (clip water surface extent)
Convert
water surface TIN into a water surface GRID
Rasterization cell is user defined (if terrain is in GRID format, it
should be terrain’s resolution)
Positive
difference between the water surface and terrain GRID is
the water depth grid (negative values are discarded)
The
perimeter of the water depth grid is the floodplain boundary
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Inundation Processing (cont.)
Line layer of cross-sectional
cut lines with water surface
elevations in attribute table
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Inundation Processing (cont.)
Water surface TIN is created
using cut lines as breaklines
WS TIN is created
irrespective of land surface
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Inundation Processing (cont.)
Water surface TIN is
clipped with a “bounding
polygon”
For a levee, bridges,
culvert, or floodway
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Inundation Processing (cont.)
TIN represents a continuous
water surface
Water
surface interpolation
between cross sections is based
purely on geometry
GeoRAS
performs no hydraulic
calculations
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Inundation Processing (cont.)
Terrain model and water
surface TIN are converted
to registered grids
Depth grid determined from
the difference of the water
surface and land surface
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Inundation Processing (cont.)
Floodplain boundaries at
the intersection of the
water surface and land
surface grids
Floodplain polygon is
created in GeoRAS by
vectorizing the depth grid
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Visualization
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Modeling Feedback
Visual inspection/interpretation of results (or sooner)
Terrain
problems
Ineffective
areas
Problematic
cross-section location
Floodplain discontinuity
Short cross-sections
Problematic
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RAS auto cross-section interpolation
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Floodplain Discontinuity
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Floodplain Discontinuity (cont.)
“Dry”
Water surface profile
Terrain
Cross-sections
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Cross-section Interpolation
TIN interpolated crosssections
RAS interpolated crosssections
RAS assumed terrain
Terrain
Original cross-sections
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Automating the
execution
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Map2Map (rainfall to floodplain)
Flood map
as output
FLO
ODP
LAIN
MAP
Model for
flood flow
HMS
Nexrad rainfall map as input
Copyright © 2005 ESRI. All rights reserved.
Model
for flood
depth
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