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

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script DesignStorm2HMS thereafter, it reuses and proceeds with the same tasks asin the historic event use case.Figure 4.52 Map2Map Workflow in ModelBuilder for Design Storm Use CaseThe determination of a suitable rainfall event to be used in water resourcesplanning and design projects is one of the most relevant factors to be considered.The standard approach (agency-approved) is the use of design storms whosecharacteristics are commensurate with the importance of the study project at hand.To obtain a given design storm, statistical frequency analysis is performed overthe entire history of available point precipitation records. For each year ofhistorical record, annual maxima are extracted from standard storm durations andhistograms constructed using probability models to obtain maximum values for agiven duration and precipitation depths associated with standard frequencies(return periods). After rain depths are found for specific frequencies and durationsat point gage locations, areal precipitation might be inferred by drawing iso-rain178
contours (isohyetals) or by interpolating point values to generate iso-surfacesrepresenting precipitation values for a given frequency and storm duration.The execution of the aforementioned procedure over a region produces acollection of synthetic precipitation events that can be used for regulatorypurposes and to promote standard and comparable engineering practices. Thesetypes of studies have been developed over the U.S. by the National WeatherService and used as a national reference. These studies have been presented in theform of reports that serve as the standard in the U.S. The U.S. Weather Bureautechnical paper no. 40, also known as NWS TP-40, for durations from 30 minutesto 24 hours and developed by Hershfield in 1961. The need for inclusion of biggerstorm durations prompted supplemental studies in 1964 that included stormdurations for 2 days to 10 days, reported as NWS TP-49. The need for smallerstorm durations of 30 minutes or less (in urban drainage design or storm sewerdesign) prompted another study by the National Weather Service in 1977commonly known as Hydro-35 for storm events having durations from 5 minutesto 60 minutes.A digital rainfall atlas for Texas (containing raster isohyetal maps ofdesign rainfall depth for various event durations and for standard return periods)was made available for this study by Halff Associates, Inc. based on the threereports mentioned above (TP-40, TP-49, Hydro-35). This digital atlas containsraster isohyetal maps for storm durations of 5 minutes, 15 minutes, 30 minutes, 60minutes, 2 hours, 3 hours, 6 hours, 12 hours, 24 hours, 2 days, and 4 days. Foreach of the listed durations the series of frequency values corresponds to 1-year,179
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Table of ContentsList of Figures ..
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4.1.12 The XML2GDB Script Tool ....
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Figure 3.24 Components of a Steady
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Figure 4.50 Create Flood Inundation
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Chapter 1 Introduction1.1 BACKGROUN
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for undeveloped or natural conditio
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All the previous statements favor t
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science, and engineering models as
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Different approaches have been used
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generic and self-described formats,
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externally executed from a central
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though GIS-based, the system does n
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Geographic Information Systems, Arc
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By defining the three basic functio
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containing an inventory of damage s
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Data Models in charge of storing an
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Figure 3.1 Floodplain Modeling Sche
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either with Schematic Nodes (for Su
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channel cross sections, available H
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sequential data, called pathnames,
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Figure 3.5 NEXRAD square cells (873
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geodatabase formatted with the Arc
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The CrossSection feature class in A
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geodatabase (under Arc Hydro format
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3.4.4 External Execution of HEC-RAS
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analysis. In particular, GIS has be
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3.5.3 Model-Specific ElementsA geog
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Figure 3.11 Geographic and Hydrolog
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For HEC-RAS, the connectivity is ac
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cross sections in the hydraulic mod
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Section line for a RAS cross-sectio
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from the geodatabase back into the
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Figure 3.19 Relationship Classes fo
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Figure 3.20 DSS Time Series content
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Figure 3.22 Extended Time Series Co
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Figure 3.23 Creating a Flow File fr
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etween the HEC-DSS file system and
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The more specific steps for the pos
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Chapter 4 Map2Map Components4.1 MOD
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A subset of NEXRAD time series data
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A folder location is also provided
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Figure 4.4 Radar2GDB Model Componen
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ecords. Figure 4.6 illustrates the
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Figure 4.8 Time Series Tables and R
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having different formats and that a
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Part E: Time Interval of stored dat
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execution time and for their corres
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on the steps needed to transfer the
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Len_sBTime (I): The length of the s
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52: Invalid precision exponent spec
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methods: user hyetograph, user gage
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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
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These simple command line statement
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To programmatically accomplish this
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to provide the hydraulic input for
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information into the extended Arc H
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The HydroJunction, used for connect
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Once the identification of flow cha
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As with the GDB2HMSDSS, the first t
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4.1.7 Time Series ExtractionOnce th
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accomplish this have been developed
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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
Page 141 and 142: ZCAT DSS subroutines) and stored in
Page 143 and 144: Table 4.5: Time Interval Equivalenc
Page 145 and 146: 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
Page 159 and 160: 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
Page 179 and 180: standard ArcGIS tool), is used in M
Page 181 and 182: By doing this, the water surface el
Page 183 and 184: Figure 4.49 Create Flood Polygon Mo
Page 185 and 186: Int OperationThe Integer operation
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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
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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
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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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Converting a NEXRAD Rainfall Map into a Flood Inundation Map by ...

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