DFHADprototype071409.. - Urban Drainage and Flood Control District

HOFFMAN MAJOR DRAINAGEWAY PLANNING
FLOOD HAZARD AREA DELINEATION
Section 1 Introduction.................................................................................. 1-1
1.1 Authorization .......................................................................................................1-1
1.2 Purpose and Scope ...............................................................................................1-1
1.3 Planning Process ..................................................................................................1-1
1.4 Mapping and Surveys...........................................................................................1-1
1.5 Data Collection ....................................................................................................1-2
1.6 Acknowledgements..............................................................................................1-2
Section 2 Study Area.................................................................................... 2-1
2.1 Project Area..........................................................................................................2-1
2.2 Land Use ..............................................................................................................2-1
2.3 Outfall Description...............................................................................................2-3
2.4 Previous Studies and Flood History.....................................................................2-5
2.5 Wetland and Riparian Zones................................................................................2-5
2.6 Flora, Fauna and Threatened or Endangered Species ..........................................2-5
Section 3 Hydrologic Analysis ..................................................................... 3-1
3.1 Overview..............................................................................................................3-1
3.2 Design Rainfall.....................................................................................................3-1
3.3 Subwatershed Characteristics ..............................................................................3-2
3.4 Hydrograph Routing ............................................................................................3-2
3.5 Results of Analysis...............................................................................................3-2
3.6 Previous Studies...................................................................................................3-3
Section 4 Hydraulic Analysis ....................................................................... 4-1
4.1 Evaluation of Existing Facilities ..........................................................................4-1
4.2 Flood Hazards ......................................................................................................4-1
Section 5 References ................................................................................... 5-1
List of Tables
List of Figures
APPENDICES
Appendix A
Appendix B
Appendix C
Table 2-1 Fully-Developed Land-Use........................................................................2-1
Table 3-1 Incremental Rainfall Depths ......................................................................3-1
Table 3-2 Comparison of 100-Year Peak Flow to Other Studies ..............................3-3
Table 4-1 Structure Capacity Table ...........................................................................4-3
Figure 2-1 Study Area Map.........................................................................................2-2
Figure 2-2 Conveyance Overview...............................................................................2-4
Figure 2-3 Flood Insurance Rate Map Limits .............................................................2-6
Figure 4-1 Conveyance Schematic..............................................................................4-2
Meeting Minutes
Hydrologic Analysis
EPA SWMM Input File
Table B-1 Subwatershed Characteristics
Table B-2 Peak Flow Summary
Figure B-1 Imperviousness Map
Figure B-2 Subwatershed Boundaries
Figure B-3 Soils Map
Figure B-4 EPA SWMM Routing
Figure B-5 EPA SWMM Routing Schematics
Chart B-1 Peak Flow Profile for Hoffman Drainageway Mainstem
Chart B-2 Peak Flow Profile for Hoffman Drainageway Rainbow Split
Chart B-3 100-Year Hydrograph, Baseline Hydrograph
Mannings “n” Photographs
Hydraulic Analysis
HEC-RAS Output
Structure Hydraulic Analysis Details Table
Drainge Structure Photos
Structure Sections
Appendix D
Floodplain and Floodway Data Table
Appendix E
Appendix F
Flood Map
Flood Profiles