environmental gis tues hoyle-dodson wadoe

8/3/2019 Environmental Gis Tues Hoyle-Dodson WADOE

1/41

Integration of ArcGIS HydrologyIntegration of ArcGIS Hydrology

Modeling and Geoprocessing ToolsModeling and Geoprocessing Tools

With Dam Breach Flood AnalysisWith Dam Breach Flood Analysis

Guy Hoyle-Dodson

Washington State Department of EcologyDam Safety Office


2/41

The Washington State Department of Ecology Dam Safety Office

Is Tasked with Protecting Public Safety by Identifying the Downstream Risks to Life &Property

and Requiring the Appropriate Dam Designs Based on that Hazard


3/41

Downstream Breach Flood Profile AnalysisDownstream Breach Flood Profile Analysis

IsIs

Instrumental In Assessing The HazardInstrumental In Assessing The Hazard

Downstream Hazard to Life & PropertyDownstream Hazard to Life & Property

Hyperlink to portrait
http://c/Documents%20and%20Settings/cdaniel/Local%20Settings/Temp/Portrait%20Slide1%20-%20Breach%20Overview.pptx#Integration%20of%20ArcGIS%20Hydrology%20Modeling%20and%20Geoprocessing%20Tools%20With%20Dam%20Breach%20Flood%20Analysishttp://c/Documents%20and%20Settings/cdaniel/Local%20Settings/Temp/Portrait%20Slide1%20-%20Breach%20Overview.pptx#Integration%20of%20ArcGIS%20Hydrology%20Modeling%20and%20Geoprocessing%20Tools%20With%20Dam%20Breach%20Flood%20Analysishttp://c/Documents%20and%20Settings/cdaniel/Local%20Settings/Temp/Portrait%20Slide1%20-%20Breach%20Overview.pptx#Integration%20of%20ArcGIS%20Hydrology%20Modeling%20and%20Geoprocessing%20Tools%20With%20Dam%20Breach%20Flood%20Analysishttp://c/Documents%20and%20Settings/cdaniel/Local%20Settings/Temp/Portrait%20Slide1%20-%20Breach%20Overview.pptx#Integration%20of%20ArcGIS%20Hydrology%20Modeling%20and%20Geoprocessing%20Tools%20With%20Dam%20Breach%20Flood%20Analysishttp://c/Documents%20and%20Settings/cdaniel/Local%20Settings/Temp/Portrait%20Slide1%20-%20Breach%20Overview.pptx#Integration%20of%20ArcGIS%20Hydrology%20Modeling%20and%20Geoprocessing%20Tools%20With%20Dam%20Breach%20Flood%20Analysis


4/41

Dams Store Tremendous Potential EnergyDams Store Tremendous Potential Energy

For Example: The GravitationalPotential Energyof the Cle Elum

Reservoir at its nearestdownstream community, the townof Cle Elum, approaches

120 Kilotons of TNT120 Kilotons of TNT

During a Catastrophic Release

of the reservoirs contents, thisenergy would likely be releasedover a 1 2 hour period as theflood wave travels downstream,severely eroding the channel andImpacting Downstream ResidencesImpacting Downstream Residences

The quantification ofFloodWave Profile depths and velocitiesis the means by which the DamSafety Office predict risk and

thereby Protect the PublicProtect the Public


5/41

Engineering Analysis is Needed to Understand HowEngineering Analysis is Needed to Understand How

Best to Protect the Public from Catastrophic DamBest to Protect the Public from Catastrophic Dam

FailuresFailures

ArcGIS is an Engineering Tool


6/41

This Presentation Will Demonstrate How to:This Presentation Will Demonstrate How to:Add Orthophotos & DEM Rasters to a Project in the Correct Projection

Create Breach Paths & Watersheds Using the Texas A&M Watershed and Stream DelineationTool

Explain the Algorithms Involved in Calculating Reservoir Volume and Peak Breach Flow

Explain the Algorithms Involved in Calculating Breach Flood Attenuation for Flow & Velocity

Create Incremental Points with Elevations & Distances Along the Breach Path

Identify Hazards Adjacent to the Breach Path Using Underlying Orthophotos and ElevationContours

Create Points on the Breach Path Spatially Coincident to Hazard Points and Merge them withIncremental Points

Create Table of Distance and Elevation for Both Regular Intervals and Hazard Points Along

Breach Path and Enter Them into an Excel Breach Attenuation Calculator Worksheet

Find Distance from Selected Points on Breach Path to Successive Elevation Boundaries

Use the Attenuation Calculator to Determine the Breach Profile from (Top Width & Depth)for Selected Locations Along the Breach Path


7/41

GIS Software and Geoprocessing Tools Allow a DetailedGIS Software and Geoprocessing Tools Allow a Detailed

Analysis of Downstream Flood Inundation ImpactsAnalysis of Downstream Flood Inundation Impacts


8/41

High Resolution (18 in) Orthophotos With SpatiallyHigh Resolution (18 in) Orthophotos With Spatially

Accurate Overlays Are Essential in Evaluating HazardsAccurate Overlays Are Essential in Evaluating Hazards


9/41

Orthophotos Are Rasters and the Proper Projection CanOrthophotos Are Rasters and the Proper Projection Can

Be Obtained By Using ArcToolboxs Project RasterBe Obtained By Using ArcToolboxs Project Raster

Open Data Management Tools : Projections and

Transformations : Raster : Project Raster

Import the Orthophoto and Check Input Coordinate System

If none, Define Projection

Check Coordinate System and use Cubic Resampling


10/41

Digital Elevation Models (DEMs) Provide the ThreeDigital Elevation Models (DEMs) Provide the Three

Dimensional Cartesian Coordinate System RequiredDimensional Cartesian Coordinate System Required

for Detailed Spatial Analysisfor Detailed Spatial Analysis


11/41

In Washington Many LiDAR DEMs Are AvailableIn Washington Many LiDAR DEMs Are Available

Through the Puget Sound LiDAR Consortium (PSLC)Through the Puget Sound LiDAR Consortium (PSLC)

LiDar DEMs are imported fromthe PSLC site as InterchangeFiles (e00), then converted inArcCatalog : ConversionTools : ArcView Import FromInterchange Files

Raster DEMs often need to beclipped using Spatial Analyst:1. Create mask using drawing tool

to set clip area, convert to shapefile and enter into SpatialAnalyst Options as AnalysisMask and Analysis Extent

2. Enter DEM into SpatialAnalysis : Raster Calculatorand Evaluate

3. Choose DATA: Make Permanent


12/41

Hydrologic Modeling Is Used to Create aHydrologic Modeling Is Used to Create a

Breach Path and a Watershed ExtentBreach Path and a Watershed Extent

Useful Tool : Texas A&M Watershed and Stream DelineationUseful Tool : Texas A&M Watershed and Stream Delineation

Texas A&M University

Department of Civil Engineering

Watershed and Streams Delineation

ToolOlivera, Francisco. (2001). Extracting hydrologic information from spatial data for

HMS modeling. Journal of Hydrologic Engineering, November/December

2001.

Detail of the main toolbar of Hydrology Modeling

Hydrology Modeling is a set of tools created byESRI for the application of the hydrologicalfunctions in ArcGIS .

These functions are automated by theWatershed and Streams Delineation Tool

Outline of steps to derive surface characteristics from a DEM


13/41

Step 1:Step 1:

Create an Initial FlowCreate an Initial Flow

Direction & Identify theDirection & Identify the

Number of SinksNumber of Sinks

A DEM free of sinks, a depressionless DEM,

is required for Hydrologic Modeling

Create 1stFlow Direction raster,

determining the flow direction of every cell

in the grid

From Flow Direction count sinks To many

sinks may render filling the sinks

impractical due to computation limitations

DEMs with Sinks in excess of 5,000 should

be clipped

This sets the stage for Filling the DEM


14/41

Step 2:Step 2:

Fill Sinks, CreatingFill Sinks, Creating

New Filled DEMNew Filled DEM

Input original LiDAR DEM and

set fill limit as necessary

Allow output Raster to be

Temporary

Once created, save by:Data : Make Permanent


15/41

Step 3: Create Filled Flow Direction andStep 3: Create Filled Flow Direction and

Flow Accumulation RastersFlow Accumulation Rasters

For Flow Direction Use Filled DEM as Input

Output as Temporary and save usingData : Make Permanent

For Flow Accumulation use Filled Flow Direction

Output as Temporary and save using

Data : Make Permanent


16/41

Step 4 : Create Flood PathStep 4 : Create Flood Path

& Watershed Extent Using& Watershed Extent Using

Raindrop andRaindrop and

Watershed DelineationWatershed Delineation

Enter Filled Flow Direction and Flow

Accumulation

Opens Watershed & Raindrop Buttons in

Toolbar

Choose Raindrop & Select Start Point

Choose Watershed & Select Start Point


17/41

Dam Safety Breach Hazard AnalysisDam Safety Breach Hazard Analysis

Requires an Evaluation of Flood Attenuation as theRequires an Evaluation of Flood Attenuation as the

Flood Progresses DownstreamFlood Progresses Downstream

Initial Analysis Requires:

Estimate of Max Reservoir Volume from Normal Pool Surface Area

Dam Break Analysis: Calculating Breach Dimensions, Peak Flow, & Time to Peak

Well Defined Breach Flood Hydrograph and Constant Rate Peak FlowDevelopment

Stepwise Attenuation of Peak from Generalized Flood Attenuation Curves

Breach Path Slope from Incremental Breach Flow Lengths and Point Elevations

Incremental Breach Flood Wave Velocities from Slope & Channel Friction

Flood Profile Top Width & Average Flood Depth from Channel Profile Side Slopes


18/41

Reservoir VolumeReservoir Volume

CalculationCalculationAssume Volume varies with stage as a

power function, V = k y^m + C

The equations relating depth, surface

area and storage volume are:

1. A = Ao + m k y^(m-1)

2. V = Ao y + k y^m

Such That:

1. k = (A y - V) / [(m-1) y^m ]

2. Ao = (V / y) [ m / (m-1)] - A

{ [ m / (m-1)] - 1 }

(Walder and OConnor, October 1997)

is Surface Area of Reservoir at Normal

Pool and A0 is Bottom Surface Area

Relates Max Pool Volume to Normal Pool

Surface Area

Dimensionless exponent m is often

taken to be 2

Automated Incremental Calculations

(Increment: y) Gives Pertinent Estimated

Values for the Reservoir

Normal Pool

Stage

(ft)

Surface Area(acres)

CumulativeVolume

(Acre-ft)

1164.40 2.60 22.231

Max Pool

Stage

(ft)

Surface Area(acres)

CumulativeVolume

(Acre-ft)

1168.40 3.21 33.846


19/41

Initial Breach DevelopmentInitial Breach Development

&&

Peak Flow CalculationsPeak Flow Calculations

Outlined in Washington State Dam SafetyGuidelines; Tech Note #1: Dam BreakInundation Analysis

Dam Breach uses Breach FormationFactor (BFF), equating Volume of DamMaterial Eroded : VM with Volume of

Reservoir and Dam Hydraulic Height:

Erosion Resistant: VM = 3.75 (H) BFF

Cohesionless: VM = 2.5 (H) BFF

For a Trapezoidal Breach Configurationthe Bottom Width: Wb is related to theGeneral Height: H, Crest Width: C, SideSlopes: Z1, Z2, & Zb, and Volume Eroded:V

Mby

Wb = 27 VM - Hb2(CZb + HbZb(Z1+Z2)/3)

Hb(C +( Hb(Z1+Z2)/2))

*MacDonald & Langridge-Monopois and Froelich

An Empirical Equation Relates PeakDischarge: Qwitha. Average Breach Width: W = Wb + ZbH;

b. Elapsed Time: =0.42Vm0.36;

c. Initial Head: Hw; and

d. A = 23.4(Surface Area: SA)/W

Q = 3.1WH1.5[A/(A+ (H1/2)]3

*D.L. Fread

Cw

11

Z1Z2

Dam Cross Section

Figure #1 Breach Dimensions

Breach Cross Section

HW

Wb

1

Zb

Dam

Crest

Hb


20/41

Automated Calculations in Excel Produce a Step WiseAutomated Calculations in Excel Produce a Step Wise

Breach Hydrograph With a Peak FlowBreach Hydrograph With a Peak Flow


21/41

Breach Flow Can be Analyzed for Attenuation as the Flood WaveBreach Flow Can be Analyzed for Attenuation as the Flood Wave

Propagates Downstream From the Breach UsingPropagates Downstream From the Breach Using

Empirically Derived Generalized Attenuation CurvesEmpirically Derived Generalized Attenuation Curves

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 1 2 3 4 5 6 7 8 9 10 11 12

Distance Downstream (miles)

Ratio(Qx/Qp)

10 Acre-Feet

25 Acre-Feet

50 Acre-Feet

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 1 2 3 4 5 6 7 8 9 10 11 12

Distance Downstream (miles)

Ratio(Qx/Qp)

3000 Ac-Ft

100 Ac-Ft

200 Ac-Ft

500 Ac-Ft

1000 Ac-Ft

These curves were developed using the HEC-HMS model to develop Breach Outflow Hydrographs

and Channel Routings for multiple trials of Hypothetical Breach Floods at Varying Channel Distances

and Reservoir Volumes

The Routing was performed using the unsteady flow routine in the HEC-RAS model with hypothetical

channels developed using geometric characteristics (width and slope) of actual stream channels.

Qx values at incremental distances downstream were divided by the Max Flow to produce a Qx/Qp

ratio as a measure of attenuation


22/41

The Solution of These Generalized Curves for aThe Solution of These Generalized Curves for a

Particular Breach Path and Max Peak Has BeenParticular Breach Path and Max Peak Has Been

Automated in an Excel WorksheetAutomated in an Excel Worksheet.Input for

Station

Distance

Calculated

Downstream

Distance

Calculated

River Mile

Calculated

Downstream

Distance

Input

Elevation

Calculate

Channel

Elevation

Calculated

Channel Gradient

Measured

Peak Flow

Calculated

Ratio

Calculated

Dam Break

Flow

(ft) (miles) (miles) (ft) (ft) (ft) (ft/ft) (ft/mile) (ft/sec) Qx/Qp Qx (cfs)

Reservoir Edge At

Dam:

(Inundated by Pond)

0.00 0.00 1.73 0.00 2179.05 2179 1008 Interpolated

from Table

1 Breach Path Point 25 223.78 0.04 1.73 223.78 2123.62 2123.62 0.25 1307.94 0.9961 1004.29


3 Near Hazard Point 67 604.67 0.11 1.62 604.67 2084.04 2084.04 0.02 117.86 0.9894 997.54





8 Breach Path Point 150 1358.23 0.26 1.47 1358.23 2025.65 2025.65 0.26 1365.88 0.9756 983.709 Breach Path Point 175 1586.58 0.30 1.43 1586.58 1992.73 1992.73 0.14 761.25 0.9688 976.76








17 Breach Path Point 725 6575.56 1.25 0.48 6575.56 1347.14 1347.14 #REF! #REF! 0.7991 805.73






23 Breach Path Point 8507710.01

1.46 0.27 7710.011197.81

1197.81 0.12 642.66 0.7501 756.28













Order

NumberStation Description

Flood Segment Point


23/41

Excel Worksheet Interpolates Attenuation Ratio from AttenuationExcel Worksheet Interpolates Attenuation Ratio from Attenuation

Lookup Table and Calculates Flows and Velocities at IncrementalLookup Table and Calculates Flows and Velocities at Incremental

DistancesDistancesPeak Breach Flow is AutomaticallyImported from the Dam BreakAnalysis Worksheet

Incremental Breach Path Distanceand Point Elevation are Cut andPasted from Pathway Data FilesGenerated in

In Excel, Bed Slope is calculatedand Channel Type is entered as anIndependent Variable and these areused to estimate Velocity fromempirically derived Tables

The Solution Gives Attenuated DamBreach Flows and AverageVelocities at Incremental Distances

Distance and Elevation Data Tablesare extracted using ArcGISGeoprocessing Tools

Dam Breach Peak Discharge

Description Parameter Input Equation Result

Peak Discharge (cfs) from

Dam Breach during

Normal Pool*

Qp(Normal) = QP = 3.1*Wavg*H1.5

*[A/(A+(t*H1/2

))]3

= 935.05

Peak Discharge (cfs) from

Dam Breach during

Max Pool*

Qp(Max) = QP = 3.1*Wavg*H1.5

*[A/(A+(t*H1/2

))]3

= 1136.51

Inpu for

Station

Distance

Input Water

Surface

Elevation

AttenuationFlow

Velocity

Dam (ft) (ft) Qx (cfs) (ft/sec)

Reservoir Edge At

Dam:

(Inundated by Pond)

0.00 2179.05 1008.25

1 Breach Path Point 25 223.78 2123.62 1004.29 12.00


3 Hazard 1 (67) 604.67 2084.04 997.54 6.57




7 Hazard 2 (149)1349.09 2028.01

983.98 12.00

Order

Number

Station

DescriptionFlood Segment Point

5 2.4 5 1.7 5 1.4

10 3.4 10 2.4 10 1.9

15 4.1 15 3.0 15 2.4

20 4.8 20 3.5 20 2.7

30 5.8 30 4.2 30 3.3

40 6.7 40 4.9 40 3.8

60 8.2 60 6.0 60 4.7

80 9.5 80 6.9 80 5.4

100 10.6 100 7.7 100 6.1

200 12.0 200 10.9 200 8.6

300 12.0 300 12.0 300 10.5

400 12.0 400 12.0 400 12.0

>400 12.0 >400 12.0 >400 12.0

Velocity

(ft/sec)

Bedslope

(ft/mi)

Velocity

(ft/sec)

Velocity

(ft/sec)

Type 3Main Channel - Gravel,

Coobles, & Bolders

Overbanks - Wooded

Type 1Main Channel - Gravel

Overbanks - Grass, Pasture

Bedslope

(ft/mi)

Bedslope

(ft/mi)

Type 2Main Channel - Gravel,

Cobbles

Overbanks - Irregular,


24/41

Create Incremental Elevations and Distances forCreate Incremental Elevations and Distances for

Breach Points Along Breach PathBreach Points Along Breach PathTo calculate the Attenuation of thePeak, Data Tables for Distances and

Elevations at Specific Points alongthe Breach Path Are Needed forExport as dbf files

Several Methods Are AvailableUsing ArcGIS Geoprocessing Tools,But ET GeoWizard 9.2 (freeware)Offers Simple Automated Tool:Station Points

Tool Allows the Selection of a SetDistance Between Points to AddStation Points to 3D PolylineBreach Path 3D (Created using 3D-Analyst : Convert : Features to 3D)

1. Save duplicate of Breach Path 3D usingData : Export Data

2. Open ET GeoWizards 9.2 : Point : CreateStation Points Save output file asBreachpath3DPoints

3. Enter value for Set distance betweenstations

4. Field Calculator enter the flowing script:PerctDist = Et_Station/ Length ToCalculate the Percent Distance


25/41

Identify Structures At Risk Along Breach Path by ComparingIdentify Structures At Risk Along Breach Path by Comparing

Underlying Orthophotos to Contour Elevations,Underlying Orthophotos to Contour Elevations,

Creating Centroidal Hazard PointsCreating Centroidal Hazard Points

Create Contour Elevations using both SpatialAnalysts Surface Analyst : Contour Tool

and the Clipped DEM

Use Drawing Tool to circle those Structures

that could be inundated by the Breach Flood

(Identified by Contours to be within a 4 to 6

foot elevation, orthogonal to Breach Path

polyline)

Use XTools : Feature Conversions :

Convert Graphics to Shapes tool to convert

first circle graphic to a shape file

Use Editor : Copy & Move tools to copy

and move this initial circle to other

structures this will create a list of hazard

features in a shape file

Create a Properties At Risk Points shape

file from this circle feature using Tool Boxs

Data Management Tools : Features :

Feature to Points


26/41

The Attenuation Analysis Requires that We Identify Points on BreachThe Attenuation Analysis Requires that We Identify Points on Breach

Path that Are Spatially Coincident to the Structures At Risk PointsPath that Are Spatially Coincident to the Structures At Risk Points

Use Tool Boxs Analysis Tools : Proximity :

Near Tool to find points on the Breach Paththat are nearest to the Properties At Risk

Points

Make copy of the Properties At Risk Points

shape file using Export data and use

Properties At Risk Points Dummy as the

Input Features for the Near Tool

Add the Breach Path Points3D shape file, as

the Near feature - This will Choose Points on

the Breach Path Adjacent to the Properties At

Risk Points

Check the Location and Angleboxes and

set the Environments : General Setting :

Output Coordinate System to the ProperProjection

Open the Attribute Table and save the table

as a data dbf file using the Export tool in the

Options Menu. Save as Adjacent Points.dbf


27/41

Create X, Y, Z Coordinated for Each PointCreate X, Y, Z Coordinated for Each Point

Create a new shape file from the dbf table using theAdd XY Data tool in the Tools dropdown menu thiscreates a new Events feature.

Use the NEAR_X field for the X coordinates and theNEAR_Y field for the Y coordinates

Set the Input Coordinate System to the ProperProjection

Convert Events Feature to a 3D feature (Point ZM)using the DEM and 3D Analysts "Convert : Featuresto3D", saving as a new 3D Feature Save as AdjacentPoints 3D

Remove Original Events Feature

Add the Z coordinate using XTools : TableOperations : Add X,Y,Z Coordinates. Be sure that theOnly for 3D shapes box is checked and specify theProper output projection. Save as Adjacent Points XYZ


28/41

Delineate Distances for Points on the Breach PathDelineate Distances for Points on the Breach Path

To add a Distance Along the Breach Path to each

points, Join Adjacent Points XYZ to Breach

Path Points 3D retaining only those record that

match

Select Join attribute from a table in Adjacent

Points XYZ Choose the field Near_FID for the

field that the join will be based on

Choose Breach Path Points 3D as the shape file

table that is to be joined

Choose the FIDfield from the Breach Path

Points3D shape file as the field that the join is to

be based on

Check the Advances : Keep only matching

records box

Select all Features in the Attribute Table and then

open Data : Export Data Make sure that the

Export is set to select features and save as a

New feature: Adjacent Points XYZ & Distance

Open Attribute Tables and Remove Unnecessary

Fields.

S l t E 25th (i t l f i t t d) P i t Al thS l t E 25th (i t l f i t t d) P i t Al th


29/41

Select Every 25th (interval of interested) Point Along theSelect Every 25th (interval of interested) Point Along the

Breach Path and Create a Selected Interval Breach Points ShapeBreach Path and Create a Selected Interval Breach Points Shape

FileFileExport a copy of the Breach Path 3D Points file byselecting Data : ExportData. Save as a dummy file thatcan eventually be eliminated Breach Path 3D PointsDummy .

Open Attributes table, open Options tab, right clickAdd Field and add a new field. - Name it ( i.e.Select25th) and select Type as Long Integer

Open the Field Calculator for Select25th Enter thefollowing Pre-Logic Script Code:

Dim a as Double

IF ( [FID] Mod 25 ) = 0 Then

a = [FID]

End If

Set Select25th = to a

Select desired records interval Open Options tab andright click Select by Attribute In Calculation windowEnter

Select25th >0 x

Save using the Data : Export Data tool. Rename SelectedBreach Path Points

Remove Dummy File


30/41

Merge Adjacent Points 3D & Distance and Selected Breach PathMerge Adjacent Points 3D & Distance and Selected Breach Path

Points to Create Distance and Elevation Table of Selected IntervalsPoints to Create Distance and Elevation Table of Selected Intervals

Along Breach PathAlong Breach Path

In ArcToolboxuse Data Management Tools :

General : Merge Add both to Input Datasets

Stipulate the output dataset:

Every25th&AdjacentBreachPoints as the saved

shape file

This will merge important field such as ET_Order,

ET_Z, and Distance. ET_Order can be used to sort

all records from lowest to Highest Distance and

Highest to lowest Elevation

Open Attribute Table and Export as a dbf file.

This can be open in Excel

Used Distance & Elevation Fields for

Input into Flood Attenuation Excel

Spreadsheets Cut & Paste Distance

and Elevation data into appropriate

cells


31/41

Output From Distance and Elevation AnalysisOutput From Distance and Elevation Analysis


32/41

Distance and Elevation is Exported to the Excel Attenuation WorksheetDistance and Elevation is Exported to the Excel Attenuation Worksheet

Input for

Station

Distance

Calculated

Downstream

Distance

Calculated

River Mile

Calculated

Downstream

Distance

Input

Elevation

(ft) (miles) (miles) (ft) (ft)

Reservoir Edge At

Dam:

(Inundated by Pond)

0.00 0.00 1.73 0.00 2179.05

1 Breach Path Point 25 223.78 0.04 1.73 223.78 2123.62


3 Near Hazard Point 67 604.67 0.11 1.62 604.67 2084.04












15 Breach Path Point 300 2717.36 0.51 1.22 2717.36 1836.0016 Breach Path Point 325 2943.89 0.56 1.17 2943.89 1778.61
















32 Breach Path Point 725 6575.56 1.25 0.48 6575.56 1347.1433 Near Hazard Point 739 6702.53 1.27 0.46 6702.53 1331.04


















Order

Number

Station

DescriptionFlood Segment Point


33/41

Estimation of Breach Path Profile Top Widths & DepthsEstimation of Breach Path Profile Top Widths & Depths

Has Also Been Automated in an Excel WorksheetHas Also Been Automated in an Excel Worksheet

Calculated

Downstream

Distance

Calculate

Channel

Elevation

Average

Inverse Slope

of Channel

Walls

Average

Inverse Slope

of Reach Wall

Cross

Sectional

Area in

Flood

Depth of

Flood

Water

Surface

Elevation

0Reservoir

At

Left Interval

(ft)

Right Interval

(ft)

Left (ft) Right (ft) (miles) (ft)Z(Left)(ft/ft)

Z (Right)(ft/ft)

Z(Inverse)(ft/ft)

Z(Average)(ft/ft)

(ft2) (ft) (ft) Left (ft) Right (ft)

1 Breach Path Point 25 0.10 7.31 400.00 400.53 0.04 2123.62 0.0003 0.0183 108.0905 108.0905 83.69 0.20 2123.82 812.70 11.13

2 Breach Path Point 50 8.11 3.07 100.14 121.51 0.09 2087.47 0 .0809 0.0252 18.8385 63.4645 83.35 1.79 2089.26 22.12 70.97

3 Hazard 1 (67) 0.10 31.37 404.34 517.86 0.11 2084.04 0.0002 0.0606 32.8814 25.8599 151.86 0.27 2084.32 1105.91 4.52




7 Hazard 2 (149) 2.82 18.11 100.00 100.00 0.26 2028.01 0.0282 0.1811 9.5553 10.5520 82.00 2.00 2030.01 70.97 11.04




11 Hazard 3 (216) 1.32 2.59 200.00 201.51 0.37 1962.23 0 .0066 0.0128 102.9300 91.5400 80.46 0.84 1963.06 127.13 65.1412 Breach Path Point 225 4.88 16.18 412.15 411.41 0.39 1948.64 0.0118 0.0393 39.1045 71.0172 80.25 1.21 1949.85 102.13 30.73





17 Breach Path Point 350 62.87 34.93 102.65 100.00 0.60 1730.39 0.6125 0.3493 2.0796 2.4488 77.51 5.87 1736.26 9.59 16.8118 Breach Path Point 375 78.53 33.76 100.14 105.12 0.64 1680.47 0.7842 0.3211 1.8094 1.9445 76.99 5.92 1686.40 7.55 18.44














33 Hazard 4 (739) 47.31 49.09 108.24 99.14 1.27 1331.04 0.4371 0.4951 2.1453 2.1658 66.68 5.56 1336.61 12.73 11.24




37 Breach Path Point 825 0.34 20.87 100.00 100.00 1.42 1225.38 0.0034 0.2087 9.4259 6.6846 63.85 0.66 1226.03 191.16 3.1538 Breach Path Point 850 7.43 10.91 100.00 100.00 1.46 1197.81 0 .0743 0.1091 10.9051 10.1655 63.02 2.36 1200.17 31.77 21.64


40 Hazard 5 (879) 10.79 7.70 99.14 108.24 1.51 1163.69 0 .1088 0.0711 11.1140 12.5967 62.11 2.31 1166.00 21.24 32.49

41 Hazard 6 (881) 9.36 8.39 100.00 102.65 1.51 1163.00 0 .0936 0.0817 11.4042 11.2591 87.30 2.76 1165.76 29.48 33.77


44 Hazard 7 (932) 1.40 5.48 200.90 200.00 1.60 1124.78 0 .0070 0.0274 58.2226 43.1682 139.47 1.25 1126.03 178.57 45.48

45 Hazard 8 (935) 2.32 4.55 200.00 200.00 1.61 1123.11 0 .0116 0.0227 58.2785 58.2505 66.03 1.01 1124.11 86.86 44.30


47 Hazard 9 & 10 (955) 5.99 2.21 400.00 402.77 1.64 1111.20 0 .0150 0.0055 97.8045 117.1851 64.47 0.72 1111.92 48.06 131.21

48 Hazard 11 (958) 4.52 3.90 400.00 406.87 1.65 1109.51 0 .0113 0.0096 95.8118 96.8082 66.20 0.83 1110.33 73.38 86.44



Input

Distance to Contour Lines

from

Center of Channel

Order

NumberChannel Input

Contour Line Elevation Interval

Station DescriptionCross Section

Slope of Channel

WallsInundation Flood Plain


34/41

Automated Spreadsheet Requires the Input of SequentialAutomated Spreadsheet Requires the Input of Sequential

Channel Contour Elevation Intervals and Distance IntervalsChannel Contour Elevation Intervals and Distance Intervals

Channel profile Elevation and Distance Intervals can

be extracted using ArcGIS Geoprocessing tools and

cut and pasted into spreadsheet cells for Automatic

Calculation

This requires the creation ofBuffer Zones around the

Breach Path and the delineation ofLeft and Right

Bank Lines

The Goal is to create dbf tables ofChannel Profiles

from which Slopes can be calculated at specific

stations along the Breach path


35/41

Delineate a Left and Right Bank Polygons fromDelineate a Left and Right Bank Polygons from

Buffer Zones of Varying WidthsBuffer Zones of Varying Widths

In ArcToolBox, use the Analyst Tools : Proximity :Buffer tool to create a buffer around the Breach

path

Enter Input Feature : Breach Path & Output

Feature Class : BreachPathXXX???Buffer

Its best to use a well-defined nomenclature to

keep track of files, where

xxx= Distance

??? = Left of Right

Enter Linear unit as distance from Breach Path

to Outer Boundary of the Buffer

Create Buffer Boundary Line usingXTools : Feature Conversions : Convert Polygons

to Polylines or ArcToolbox : Data Management

Tool : Features : Polygon To Line - Name

feature: i.e. BreachPathXXXBuffer???Polyline


36/41

Find Distance from the Breach Path to theFind Distance from the Breach Path to the

Left and Right Outer Boundary LinesLeft and Right Outer Boundary Lines

Use Editor : Spit Tool to split the Inner Boundary

of the Polyline from the Outer Boundary, Creatingan single Outer Polyline

1. Left Click Editor and choose Start Editing Polyline

2. Use Edit Tool to select the Polyline feature - reveal

vertices

3. Use split tool to clip a vertex on the Bottom and Top of

Polygon outline

4. Delete the Inner Boundary, leaving only the OuterBoundary Polyline

5. Save and close Editor

Convert Polyline to 3D using 3D Analyst : Convert

: Features to 3D

Use this Polyline as the Outer Boundary of buffer

around the Breach Path


37/41

Find Distance from Selected Points on Breach Path to theFind Distance from Selected Points on Breach Path to the

Nearest Point of the Right and Left Outer Boundary LinesNearest Point of the Right and Left Outer Boundary Lines

Use ToolBoxs Analysis Tools : Proximity : Near Tool tofind points and distances for selected Points on the BreachPath to the nearest segment of the Left or Right Polylinesforming the outer boundaries of the buffer.

1. Use dummy Every25th&NearHazardBreachPoints as the InputFeature

2. Use The Right or Left Polyline as the Near Feature

3. Check Location and Angle boxes

4. Open point file Attribute table and save as dbf file in Options :Export as OuterXXXBuffer???AdjacentPoints

5. This will give you Distances and the x & Y coordinates for pointsadjacent to selected points on the Breach Path

Use Tools : Add XY Data as outlined before to Create aPoints Event file of the Boundary Polyline

1. Open Tools : Add XY Data and choose the OuterXXXBuffer???AdjacentPoints dbf table

2. Use the NEAR_X field for the X coordinates and the NEAR_Y fieldfor the Y coordinates

3. Convert Event file to 3D Feature Using 3D-Analyst and save asOuterXXXBuffer???AdjacentPoints3D

Find Z-Value elevation for all points on the BufferPolyline using XTools : Table Operations : Add X,Y,ZCoordinates

Repeat for other boundary widths adjacent


38/41

Cut and Paste Data into Breach Attenuation Calculation Excel SpreadsheetsCut and Paste Data into Breach Attenuation Calculation Excel Spreadsheets

This will require sorting to put the data from thepoints on the Breach Path into ascending Distanceand descending Elevation

Multiple Boundaries may be necessary to accountfor Channel Profile variations

For each Hazard Point along the Breach Path aChange in Elevation for a Known Distances to theContour Boundary can be exported to and ExcelFile then Cut & Pasted into the AttenuationWorksheet

From this Data, in conjunction with previouslycalculated Peak Breach Flow Volume the followingcan be calculated at selected points, :

1. The Cross Sectional Flood Area for every selected pointalong the Breach Path

2. The Average Depth Of Flood for every selected point alongthe Breach Path

3. The Water Surface Elevation of the flood at every selected

point along the Breach Path

4. The Flood Top Width at every selected point along theBreach Path

From previous Calculation We also have

5. Attenuation Of Peak Flow for every selected point alongthe Breach Path

6. Velocity Of The Peak Flow at every selected point alongthe Breach Path


39/41

Depth and Velocity Data At Each Hazard Point is Used inDepth and Velocity Data At Each Hazard Point is Used in

A Hazard Assessment AnalysisA Hazard Assessment Analysis

Attenuation determines The Breach FloodProfile downstream of the breach

Top Widths and Water Surface Elevationallow us to determine if the structures arelikely to be Inundated

Average Depth and Velocity allow us toPrioritize the Hazard to persons andproperty

Hazard Assessment Curve For Flood Danger To Adults

from Flood Velocity And Flood Depth Developed by

The United State Bureau of Reclamation (USBR)

Left (ft) Right (ft) Left (ft) Right (ft)

Reservoir Edge At Dam:

(Inundated by Pond)

Breach Path Point 25


Near Hazard Point 67 109.00 Sheds


Breach Path Point 125Near Hazard Point 149 72.00 Clubhouse



Near Hazard Point 216 77.00 Utility Building



Near Hazard Point 739 18.00 Unknown



Near Hazard Point 879 102.00 Residence 5


Breach Path Point 900Breach Path Point 925

Near Hazard Point 932 11.00 Shed/Residence 7





Station Description

Flood Segment Point

Hazard Location of Structures(Distance from Breach Path)

Type of Structure

AtRisk

Judgment ZoneLow Hazard

Zone

High HazardZone


40/41

With These Techniques We CanWith These Techniques We Can

Efficiently and EffectivelyEfficiently and Effectively

Determine Dam Breach Flood Impacts on The PublicDetermine Dam Breach Flood Impacts on The Public

This Analysis Allows Us to:

Select Design & Performance Goals for Critical Project Elements

Assign a Preliminary Design Step

Select Proper Design Storm Criteria for that Design Step

Evaluate the Adequacy of Current Embankment Designs

Prepare Emergency Action Plans


41/41

. . . The importance of the universal machine is clear. We do

not need to have an infinity of different machines doing

different jobs. A single one will suffice. The engineering

problem of producing various machines for various jobs is

replaced by the office work of "programming" the universal

machine to do these jobs. (Alan Turing 1948)

ArcGIS: A Universal Turing Machine?ArcGIS: A Universal Turing Machine?