Converting a NEXRAD Rainfall Map into a Flood Inundation Map by ...

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(standard or user-defined) creating workflow sequences that perform morecomplex tasks.As mentioned before, a GIS-based Flood Information Systems is deemedsuitable as the central controller provided that it has adopted the pieces oftechnology to enable it, in particular Object Orientation and Relational DatabaseManagement System. With current technology, the GIS Integration Developmentcan be executed into alternative ways, through toolbars and command buttons orthrough the newly developed “Model Builder” functionalities of ArcGIS 9.0.With each option having its own pros and cons, the coupling withengineering models via these approaches facilitates a modular development thatpromotes reuse and straight forward maintenance and updates on each module ofthe interface system. The main model linkage components to be included in thisGIS system are listed below.3.5.2 Mapping Time Series to WatershedsThe Time Series records associated with NEXRAD cells are map to thewatersheds to generate a hyetograph to each hydro response unit in the rainfallrunofftransformations in HEC-HMS. The time series transfer operation is doneby means of a previously created intersection layer generated from the NEXRADand the watershed polygons. By computing the NEXRAD cell area inside a givenwatershed polygon the tool estimates the average rainfall over the watershed(aerially weighted hyetographs).44
3.5.3 Model-Specific ElementsA geographic description of the features represented in the hydrologic andhydraulic models is needed. In the case of HEC-HMS, this means a geographicrepresentation of the seven feature types that can be represented in a basin file(sub basin, reach, source, sink, diversion, reservoir, and junction).Each of the model-defined features has a name that identifies the elementinside the model’s structure. In order to achieve the proposed geographicintegration the feature and its name as defined in the existing model needs to beknown to the spatial representation of the model’s topology (the Arc Hydro datamodel). Thus, besides having the spatial features in GIS a new attribute fieldcontaining the features name (ModelCode) needs to be created and populatedbased on the model’s notation. For HEC-HMS the ModelCode is called theHMSCode and for HEC-RAS it is called the RASCode.Arc Hydro provides functionality to construct a Schematic Network thatresembles the HEC-HMS conceptual topology of hydrologic elements. Thisschematic network creates a geographic match between the GIS geodatabase andthe HEC-HMS model features. Additionally, the schematic node, a component ofthe schematic network, is used to denote the outlet nodes in HEC-HMS bypopulating them with the specific HMSCode, to enable the connectivity of themodels. Figure 3.10 illustrates the schematic network for the Salado and RosilloCreeks which closely follows the HEC-HMS conceptual configuration is shown.45
Page 3 and 4: Table of ContentsList of Figures ..
Page 5 and 6: 4.1.12 The XML2GDB Script Tool ....
Page 7 and 8: Figure 3.24 Components of a Steady
Page 9 and 10: Figure 4.50 Create Flood Inundation
Page 11 and 12: Chapter 1 Introduction1.1 BACKGROUN
Page 13 and 14: for undeveloped or natural conditio
Page 15 and 16: All the previous statements favor t
Page 17 and 18: science, and engineering models as
Page 19 and 20: Different approaches have been used
Page 21 and 22: generic and self-described formats,
Page 23 and 24: externally executed from a central
Page 25 and 26: though GIS-based, the system does n
Page 27 and 28: Geographic Information Systems, Arc
Page 29 and 30: By defining the three basic functio
Page 31 and 32: containing an inventory of damage s
Page 33 and 34: Data Models in charge of storing an
Page 35 and 36: Figure 3.1 Floodplain Modeling Sche
Page 37 and 38: either with Schematic Nodes (for Su
Page 39 and 40: channel cross sections, available H
Page 41 and 42: sequential data, called pathnames,
Page 43 and 44: Figure 3.5 NEXRAD square cells (873
Page 45 and 46: geodatabase formatted with the Arc
Page 47 and 48: The CrossSection feature class in A
Page 49 and 50: geodatabase (under Arc Hydro format
Page 51 and 52: 3.4.4 External Execution of HEC-RAS
Page 53: analysis. In particular, GIS has be
Page 57 and 58: Figure 3.11 Geographic and Hydrolog
Page 59 and 60: For HEC-RAS, the connectivity is ac
Page 61 and 62: cross sections in the hydraulic mod
Page 63 and 64: Section line for a RAS cross-sectio
Page 65 and 66: from the geodatabase back into the
Page 67 and 68: Figure 3.19 Relationship Classes fo
Page 69 and 70: Figure 3.20 DSS Time Series content
Page 71 and 72: Figure 3.22 Extended Time Series Co
Page 73 and 74: Figure 3.23 Creating a Flow File fr
Page 75 and 76: etween the HEC-DSS file system and
Page 77 and 78: The more specific steps for the pos
Page 79 and 80: Chapter 4 Map2Map Components4.1 MOD
Page 81 and 82: A subset of NEXRAD time series data
Page 83 and 84: A folder location is also provided
Page 85 and 86: Figure 4.4 Radar2GDB Model Componen
Page 87 and 88: ecords. Figure 4.6 illustrates the
Page 89 and 90: Figure 4.8 Time Series Tables and R
Page 91 and 92: having different formats and that a
Page 93 and 94: Part E: Time Interval of stored dat
Page 95 and 96: execution time and for their corres
Page 97 and 98: on the steps needed to transfer the
Page 99 and 100: Len_sBTime (I): The length of the s
Page 101 and 102: 52: Invalid precision exponent spec
Page 103 and 104: methods: user hyetograph, user gage
Page 105 and 106:
Once the hyetograph is defined (for
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The resulting runoff hydrograph is
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Thus, the time period for the entir
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After the ZSRTS subroutine is execu
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Figure 4.12 HMSCaller Model Compone
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ased on a process handle (a program
Page 117 and 118:
These simple command line statement
Page 119 and 120:
To programmatically accomplish this
Page 121 and 122:
to provide the hydraulic input for
Page 123 and 124:
information into the extended Arc H
Page 125 and 126:
The HydroJunction, used for connect
Page 127 and 128:
Once the identification of flow cha
Page 129 and 130:
As with the GDB2HMSDSS, the first t
Page 131 and 132:
4.1.7 Time Series ExtractionOnce th
Page 133 and 134:
accomplish this have been developed
Page 135 and 136:
straight forward for all time stamp
Page 137 and 138:
As opposed to HEC-DSS, the Arc Hydr
Page 139 and 140:
Table 4.4: Variable Type Equivalenc
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ZCAT DSS subroutines) and stored in
Page 143 and 144:
Table 4.5: Time Interval Equivalenc
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There are not specific valid values
Page 147 and 148:
catalog list. For the DSS2GDB appli
Page 149 and 150:
4.1.9.1 Opening the HEC-DSS fileThe
Page 151 and 152:
channel (the hydraulic representati
Page 153 and 154:
the model if the new configuration
Page 155 and 156:
the main program as a public module
Page 157 and 158:
Then, the RASCaller application acc
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Figure 4.31 ProjectName Property in
Page 161 and 162:
Figure 4.33 RunSteady Method in RAS
Page 163 and 164:
Figure 4.34 ExportGIS Method in RAS
Page 165 and 166:
data structures delivered by every
Page 167 and 168:
The two most well-known models for
Page 169 and 170:
The water surface elevations obtain
Page 171 and 172:
Once the water surface elevations f
Page 173 and 174:
Generate a suitable water surface m
Page 175 and 176:
Figure 4.42 2 Foot-Contour Lines fo
Page 177 and 178:
Figure 4.43 Rosillo Creek’s terra
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standard ArcGIS tool), is used in M
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By doing this, the water surface el
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Figure 4.49 Create Flood Polygon Mo
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Int OperationThe Integer operation
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case that was developed for Map2Map
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contours (isohyetals) or by interpo
Page 191 and 192:
design storm input given its possib
Page 193 and 194:
Figure 4.55 Workflow for Extracting
Page 195 and 196:
for it. Finally, the DigitalStorm2H
Page 197 and 198:
model for water resources (Maidment
Page 199 and 200:
Hydro, the HydroJunctionHasCrossSec
Page 201 and 202:
involved in the transformation of r
Page 203 and 204:
process model in sequence. For the
Page 205 and 206:
5.6 A TRUE SPATIAL APPROACHAutomate
Page 207 and 208:
time series between NEXRAD, the HEC
Page 209 and 210:
value of the entire runoff hydrogra
Page 211 and 212:
case study. Bigger watersheds (abov
Page 213 and 214:
The first step consists in installi
Page 215 and 216:
3.7 Map2Map UsageAll of the model b
Page 217 and 218:
Congratulations! You have successfu
Page 219 and 220:
Once the simplified version of Arc
Page 221 and 222:
cells that cover your study area an
Page 223 and 224:
Second, the user needs to modify th
Page 225 and 226:
Appendix BMap2Map CD Content1 CD Da
Page 227 and 228:
o hmsproj - contains folders with H
Page 229 and 230:
Goodchild, M.F., Steyaert, L.T., an
Page 231 and 232:
Olsen R. J., Beling, P. A., Lambert
Page 233 and 234:
Werner, M. G. F. 2001. Impact of gr
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