Section 1 Introduction..................................... 4 1.1 Propose...................................................................................................................... 4 1.2 Project Authority....................................................................................................... 4 1.3 Project Location ........................................................................................................ 5 1.3 Hydrologic and Hydraulic Methods.......................................................................... 5 1.4 Acknowledgment ...................................................................................................... 6 This study relied on assistance of RFCD GIS staff, who were integral to the development of the models and maps............................................................................. 6 1.5 Study Results ............................................................................................................ 6 Section 2 FEMA Forms ................................. 10 2.1 Study Documentation Abstract for FEMA submittals............................................ 10 2.1.1 Date Study Accepted........................................................................................ 10 2.1.2 Study Contractor .............................................................................................. 10 2.1.3 Local Technical Reviewer ............................................................................... 10 2.1.4 Reach Description............................................................................................ 10 2.1.5 USGS Quad Sheets .......................................................................................... 10 2.1.6 Unique Conditions and Problems .................................................................... 11 2.1.7 Coordination of Peak Discharges..................................................................... 11 2.2 FEMA Forms .......................................................................................................... 11 Section 3 Survey and Mapping Information 11 3.1 Field Survey Information........................................................................................ 11 3.2 Mapping .................................................................................................................. 11 Section 4 Hydrology...................................... 12 4.1 Method Description ................................................................................................ 12 4.2 Parameter Estimation .............................................................................................. 12 4.2.1 Drainage Area .................................................................................................. 12 4.2.2 Watershed Work Map ...................................................................................... 12 4.2.3 Gage Data......................................................................................................... 12 4.2.4 Spatial Parameters............................................................................................ 12 4.2.5 Precipitation ..................................................................................................... 13 4.2.6 Physical Parameters ......................................................................................... 13 4.3 Problems Encountered During the Study................................................................ 14 4.3.1 Special Problems and Solutions....................................................................... 14 4.3.2 Modeling Warning and Error Messages .......................................................... 15 4.4 Calibration............................................................................................................... 15 4.5 Final Results........................................................................................................ 15 4.5.1 Hydrologic Analysis Results........................................................................ 15 4.5.2 Verification results....................................................................................... 15 Section 5 Hydraulics ..................................... 16 5.1 Method Description ................................................................................................ 16 5.2 Work Study Maps ................................................................................................... 16 5.3 Parameter Estimation .............................................................................................. 16 5.3.1 Roughness Coefficients ................................................................................... 17 2 5.3.2 Expansion and Contraction Coefficients ......................................................... 17 5.4 Cross-Section Description ...................................................................................... 17 5.5 Modeling Consideration.......................................................................................... 17 5.5.1 Hydraulic Jump and Drop Analysis................................................................. 17 5.5.2. Bridges and Culverts....................................................................................... 17 5.5.3 Levees and Dikes ............................................................................................. 17 5.5.4 Island and Flow Splits...................................................................................... 17 5.5.5 Ineffective Flow Areas..................................................................................... 18 5.6 Floodway Modeling ................................................................................................ 18 5.7 Problems Encountered ............................................................................................ 18 5.7.1 Special Problems and Solutions....................................................................... 18 5.7.2 Model Warnings and Errors............................................................................. 18 5.8 Calibration............................................................................................................... 18 5.9 Final Results............................................................................................................ 19 5.9.1 Hydraulic Analysis Results.............................................................................. 19 5.9.2 Verification of Results ..................................................................................... 19 Section 6 Erosion and Sediment Transport 19 Section 7 Draft FIS Report Data ................... 19 7.1 Summary of Discharges.......................................................................................... 19 7.2 Floodway Data ........................................................................................................ 19 7.3 Annotated Flood Insurance Rate Map .................................................................... 19 7.4 Flood Profiles.......................................................................................................... 19 List of Tables Table 1 Methods used for a HEC-HMS analysis.............................................................. 13 Table 2 Physical Parameters for the Sub-Basins .............................................................. 14 Table 3 Summary of the Hydrologic Analysis Results for Sub-Basins............................ 15 Table 4 Summary of the Hydrologic Analysis Results at the Concentration Points ........ 15 Table 5 Comparison of a peak discharge.......................................................................... 16 List of Figures Figure 1.1 Sub-basins for the West Speedway Wash ......................................................... 7 Figure 1.2 Limits of the Sweetwater LOMR Study............................................................ 8 Figure 1.3 Hydrologic Soil Group ...................................................................................... 9 Appendix A: References Appendix B: FEMA MT-2 Form, General Documentation and Correspondence Appendix C: Survey Field Notes Appendix D: Hydrologic Analysis, Supporting Documents Appendix E: Hydraulic Analysis, Supporting Documents Appendix F: Erosion Analysis, Supporting Documents Exhibit Exhibit 1 100-yr floodplain limits for the West Speedway Wash Exhibit 2 Annotated Flood Insurance Rate Map for the West Speedway Wash 3 Section 1 Introduction 1.1 Propose This Technical Data notebook (TDN) has been prepared for a Letter of Map Revision (LOMR) application for a portion of the West Speedway Wash (WSP) located in Pima County, Arizona. The objective of the TDN and LOMR submission is provide regulatory discharge rates and floodplain limits along the West Speedway Wash using better topographic, hydrologic, and hydraulic data. This TDN was prepared in accordance with the “Instructions for Organizing and Submitting Technical Documentation for Flood Studies” prepared by the Arizona Department of Water Resources, Flood Mitigation Section (Arizona State Standard, SSA 1-97) and FEMA Guideline. FEMA LOMR forms are included in this TDN. 1.2 Project Authority The State of Arizona has delegated the responsibility to each county flood control district to adopt floodplain regulations designed to promote the public health, safety and general welfare of its citizenry as provided under the Arizona Revised Statutes, Title 48, Chapter 21, Article 1, Sections 48-3601 through 3627. More specifically, A.R.S. 3609 directs county flood control districts to adopt floodplain regulations that: A. Regulate all development of land, construction of residential, commercial or industrial structures or uses of any kind which may divert, retard or obstruct flood water and threaten public health or safety or the general welfare; and B. Establish minimum flood protection elevations and flood damage prevention requirements for uses, structures and facilities which are vulnerable to flood damage; and C. Comply with state and local land use plans and ordinances, if any. In conformance with A.R.S. 3609, this ordinance provides for protection of the public health safety and welfare by regulation of flood and erosion hazard areas to control flood hazards and prevent repetitive loss from flood damage. D. The flood hazard areas of Pima County are subject to periodic inundation which may result in loss of life and property, create health and safety hazards, disrupt commerce and governmental services, require extraordinary public expenditures for flood protection and relief, and impair the tax base, all of which adversely affect the public health, safety, and general welfare. E. These flood losses are caused by the cumulative effect of obstructions in areas of special flood hazards which increase flood heights, flow velocities, and cause flood and erosion damage. Uses that are inadequately flood-proofed, elevated, or otherwise protected from flood damage, also contribute to the flood loss. (Ord. 2005 FC-2 § 2 (part), 2005). 4 Section 16 of the Pima County Ordinance describes the provisions for floodplain regulation in Pima County. This study has been prepared by the Pima County Regional Flood Control District (RFCD): Pima County Regional Flood Control District 97 East Congress, Tucson, AZ 85701 The project was prepared by: Evan Canfield, PE, Chief Hydrologist Planning & Development Division Pima County Regional Flood Control District 97 East Congress, Tucson, AZ 85701 1.3 Project Location The study reach of the West Speedway Wash (WSP) is located within a Federal Emergency Management Agency (FEMA)-designated “Zone A” flood-hazard area, as depicted on FIRM Map Panel Numbers 04019C1618K, and 1619K (February 8, 1999). No documented hydraulic analyses were found to determine the “Zone A”, and the existing “Zone A” depiction is not consistent with current topography. The objective of the TDN and LOMR submission is provide regulatory discharge rates and floodplain limits along the West Speedway Wash using better topographic, hydrologic, and hydraulic data. The study reach of the West Speedway Wash is located primarily west of Silverbell Rd. and extends to Sections 32 & 33, Township 13 South, Range 13 East, Pima County, Arizona (Fig. 1.1). The upstream study limit for the West Speedway Wash begins approximately 2500 feet downstream Ironwood Hills Dr. The West Speedway Wash enters study limit from the west and flows east until it converges with Silvercroft Wash just upstream of the Santa Cruz River. 1.3 Hydrologic and Hydraulic Methods Hydrologic analysis was preformed to determine proposed regulatory discharge rate at Silberbell Rd using U.S. Army Corps of Engineers Computer Hydrologic Modeling System, HEC-HMS. Parameterization followed guidelines developed by Pima County Regional Flood Control District and described in technical Policy 018 (Tech 018, Appendix A). The proposed regulatory discharges are flow rates that have a 1-percent chance of being equaled or exceeded each year (“100-year” discharge rates). Hydraulic analysis was performed to delineate floodplain limit along the study reach of the West 5 Speedway Wash using U.S. Army Corps of Engineers Computer Backwater Model, HEC-RAS. . 1.4 Acknowledgment This study relied on assistance of RFCD GIS staff, who were integral to the development of the models and maps. 1.5 Study Results The regulatory peak discharge rate was calculated at Silverbell Rd (CP A; Fig. 1.3). The estimated regulatory discharge rate is 1,458 cubic feet per second (cfs) with a drainage area of 1.42 square mile at CP A. 6 EL MORAGA I10 I10 E FR LL BE AY EW R VE SIL GORET Figure 1.1 Watershed Map West Speedway Wash CP_A ( ! ( ! Speedway CP River Speedway_contour20ft Speedway Subbasins SPD_A SPD_B SPD_C GRANT GRANT IRONWOOD HILL SPD_D CP_C CP_B GREASEWOOD ( !! ( Pima County Index Map Index Map Scale 1:5,250,000 SPEEDWAY The information depicted on this display is the result of digital analyses performed on a variety of databases provided and maintained by several governmental agencies. The accuracy of the information presented is limited to the collective accuracy of these databases on the date of the analysis. The Pima County Regional Flood Control Department makes no claims regarding the accuracy of the information depicted herein. This product is subject to the Department of Transportation Technical Services Division's Use Restriction Agreement. Pima County Regional Flood Control District Scale 1:300' ANK LAM 03/2010 \\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\West_Speedway\Speedway_wash_Watershed_Fig1_1.mxd EL MORAGA I10 V SIL L BE ER GORET L CP_A Figure 1.2 Study Limit Map West Speedway Wash with FEMA Floodplains ! ( ! ( SpeedCP River Speedway Subbasins SPD_A Existing FEMA Floodplain ZONE A ZONE AE GRANT IRONWOOD HILL GRANT ZONE X - SHADED CP_C CP_B ! (! ( Study Limit Box CAMINO DE OESTE SPD_B Pima County Index Map SPEEDWAY S AN KL Index Map Scale 1:5,250,000 SPD_D AM The information depicted on this display is the result of digital analyses performed on a variety of databases provided and maintained by several governmental agencies. The accuracy of the information presented is limited to the collective accuracy of these databases on the date of the analysis. The Pima County Regional Flood Control Department makes no claims regarding the accuracy of the information depicted herein. This product is subject to the Department of Transportation Technical Services Division's Use Restriction Agreement. Pima County Regional Flood Control District Scale 1:300' GREASEWOOD TE GA AS SP SPD_C 03/2010 \\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\West_Speedway\Speedway_wash_Watershed_Fig1_2.mxd EL MORAGA V SIL Figure 1.3 Soil Classification Map West Speedway Wash GORET L BE ER L Subbasains Soil Classification Soil Group: B (100%), GLENDALE SILT LOAM, 0 TO 3 PERCENT SLOPES Soil Group: B (100%), GRABE GRAVELLY LOAM, 1 TO 3 PERCENT SLOPES Soil Group: B (100%), PINALENO VERY COBBLY SANDY LOAM, 1 TO 8 PERCENT SLOPES Soil Group: B (100%), PINALENO-STAGECOACH COMPLEX, 5 TO 16 PERCENT SLOPES Soil Group: B (82%) C (18%), PINALENO-STAGECOACH-PALOS VERDES COMPLEX, 10 TO 35 PERCENT SLOPES Soil Group: C (47%) D (53%), PANTANO-GRANOLITE COMPLEX, 5 TO 25 PERCENT SLOPES SPD_A Soil Group: D (100%), ANKLAM-CELLAR-ROCK OUTCROP COMPLEX, 15 TO 55 PERCENT SLOPES 2008PAGclr01ft.ecw GRANT IRONWOOD HILL CAMINO DE OESTE SPD_B SPD_C Pima County Index Map SPEEDWAY S PA S SPD_D Index Map Scale 1:5,250,000 The information depicted on this display is the result of digital analyses performed on a variety of databases provided and maintained by several governmental agencies. The accuracy of the information presented is limited to the collective accuracy of these databases on the date of the analysis. The Pima County Regional Flood Control Department makes no claims regarding the accuracy of the information depicted herein. This product is subject to the Department of Transportation Technical Services Division's Use Restriction Agreement. Pima County Regional Flood Control District Scale 1:300' GREASEWOOD S TE GA KL AN AM 05/2010 \\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\West_Speedway\Speedway_wash_Watershed_Fig1_3.mxd Section 2 FEMA Forms 2.1 Study Documentation Abstract for FEMA submittals 2.1.1 Date Study Accepted: ___________________ 2.1.2 Study Contractor: Planning and Development Division, Pima County Regional Flood Control District 97 East Congress, Tucson, AZ 85701 (520) 243-1800 Prepared by Evan Canfield, PE, Chief Hydrologist 2.1.3 Local Technical Reviewer: Terry Hendricks, C.F.M, Chief Hydrologist Planning and Development Division, Pima County Regional Flood Control District 97 East Congress, Tucson, AZ 85701 (520) 243-1800 2.1.4 Reach Description The study reach of the West Speedway Wash is located within a Federal Emergency Management Agency (FEMA)-designated “Zone A”, as depicted on FIRM Map Panel Numbers 04019C1618K, and 1619K (February 8, 1999). The study reach of the West Speedway Wash is located primarily west of Silverbell Rd., Pima County, Arizona (Fig. 1.1), though it originates at the confluence with Silvercroft Wash.. The study reach of the West Speedway Wash is primarily composed of sand channel and the bottom of the reach is relatively clean with vegetation cover. The overbank of the reach is covered with desert brush. 2.1.5 USGS Quad Sheets Not available for this study 10 2.1.6 Unique Conditions and Problems None. 2.1.7 Coordination of Peak Discharges The 100-year regulatory discharge rate at the Silverbell Rd. was computed using HECHMS, assuming no base flow in the watersheds and no transmission loss within the reaches. The hydraulic data used to derive parameters for HEC-HMS was obtained using HEC-RAS. The discharge rate was acceptable per Suzanne Shields, Director of the Pima County Regional Flood Control District and Andy Dinauer of the City of Tucson 2.2 FEMA Forms The FEMA MT-2 forms are included in Appendix B of this TDN. Section 3 Survey and Mapping Information 3.1 Field Survey Information None. 3.2 Mapping The topographic data was obtained using HEC-GeoRas and ArcGIS. Digital Terrain Model (DTM) derived from 2008 Light Detection and Ranging (LiDAR) data was used to create 2-foot interval contour map. The following data was used in this TDN; The aerial photo: 2008 PAG aerial photo Projection: UTM, Zone 12 Units: International feet The contour interval of the topographic map is 2 feet. The documentation showing that this Lidar data set is FEMA-compliant is included in Appendix C. 11 Section 4 Hydrology 4.1 Method Description The 100-year peak discharges for the four subbasins of the West Speedway Wash (WSP A, B, C, and D; Fig. 1.3) were calculated using U.S. Army Corps of Engineers Computer Hydrologic Modeling System, (HEC-HMS) version 3.4. The HEC-HMS model requires the parameters regarding rainfall, topography, soil, vegetation, and channel characteristics to determine runoff volume and peak discharge. Those parameters were determined according to the Pima County Regional Flood Control District Technical Policy 018 (Tech-018). Tech-018 is included in Appendix A. The HEC-HMS model is included in Appendix D. 4.2 Parameter Estimation 4.2.1 Drainage Area Subbasin boundaries were delineated using the hydrology function of ArcGIS with 2008 Lidar Data. A 2-ft contour map was used to make sure if the subbasin delineation was reasonable. 4.2.2 Watershed Work Map A watershed work map is shown on Figure 1.3. Four subbasins were delineated for HECHMS hydrologic analysis. Three concentration points were included in the study watershed (CP A, B, C, and D). A 100-year peak discharge at Silverbell Rd. (CP A) was used for HEC-RAS hydraulic analysis. 4.2.3 Gage Data No gage data were used in this TDN. 4.2.4 Spatial Parameters No spatial parameters were used in this TDN. 12 4.2.5 Precipitation According to the Tech-018, the 3-hour storm shall be used as rainfall data in the HECHMS model in the case that a time of concentration (Tc) is equal or less than three hours. A 3-hour storm was selected for a peak discharge calculation for the West Speedway Wash, since Tc was less than 3 hours in all the sub-basins. A point 3-hour rainfall depth at the coordinates of the centroid of the watershed was obtained from NOAA Atlas 14, upper 90% confidence interval precipitation frequency estimate (NOAA 14 rainfall). Areal reduction factor was applied to watersheds larger than 1 square mile, as described in Tech-018. The 3-hour rainfall depth for the West Speedway Wash watershed is 3.14 inches. The areal reduction factor of 0.96 was applied to CP A. 4.2.6 Physical Parameters The physical parameters for the subbasins and reaches of the HEC-HMS model were summarized in Tables 1 and 2. As mentioned in 4.1, all the methods and parameters were determined following Tech-018. Table 1 summarizes the method used for a HEC-HMS analysis. Table 1 Methods used for a HEC-HMS analysis Rainfall Depth Rainfall Distribution Rainfall Loss Time of Concentration Transform Routing Selected Method NOAA 14, upper 90% Confidence Interval 3-hr SCS Type II Storm SCS Curve number SCS Segmental Method SCS Unit Hydrograph Modified-Puls The SCS Curve Number (CN) method was utilized as a rainfall loss method in the HECHMS model. The CN was determined using the Curve Number table associated with the PC Hydro User Guide (Arroyo Engineering, 2007) and a Hydrologic Soils Group map. The CN was not adjusted for rainfall intensity or antecedent moisture conditions. The SCS Unit Hydrograph method was used as a transform method. Impervious cover was determined using the 2008 PAG aerial photograph and Table 3 in the PC Hydro User Guide (Arroyo Engineering, 2007). The combination of the kinematic wave method and the U.S. Natural Resources Conservation Service (NRCS) segmented Time of Concentration (Tc) calculation method (USDA-NRCS, 1986) was used to determine Tc, following the recommendation on Tech-018. The Tc was calculated by summing the travel time for sheet flow, shallow concentrated flow and channel flow. The Tc for sheet flow was estimated using the kinematic wave equation. Manning’s roughness coefficient for sheet flow was obtained using Table 3-1 in Technical Release 55, Urban Hydrology for Small Watersheds (USDA-NRCS, 1986). HEC-GeoRAS and HEC RAS were used to 13 estimate average velocity of channels. The detail of the Tc calculation is included in Appendix D. Table 2 Physical Parameters for the Sub-Basins SubBasin SPD_A SPD_B SPD_C SPD_D Area (sq mi) 0.44 0.3 0.154 0.53 CN 84.8 87.3 85.6 89.1 Impervious Area (%) 15.0 10.0 20.0 5.0 Vegetation Cover (%) 30 30 30 30 Lag Time (min) 26.1 15.4 11.8 13.5 Runoff from subbasins was routed using the Modified-Puls method.Storage discharge tables for the channel routing were developed using HEC-GeoRAS and HEC-RAS. Six different discharges were used for storage-discharge relations. The number of subreaches was calculated using the following method: Vw = 1.5 * Vave .........eq.1 K= L ...................eq.2 Vw Therefore, K N = ..................eq.3 Δt where Vave is average flow velocity, L is reach length, Vw is velocity of flood wave (a conversion factor of 1.5 is used for natural channels), K is hydrograph travel time, Δt is the time interval for computations in the model, and N is the number of steps in the reach routing. Eq.4 was obtained from eq.1, 2, and 3. The detail of the calculation of the number of subreach is included in Appendix D. 4.3 Problems Encountered During the Study 4.3.1 Special Problems and Solutions There were no problems with the hydrologic modeling. 14 4.3.2 Modeling Warning and Error Messages The time interval of the rainfall data used in this study is 5 minutes, while the simulation time interval is 1 minute. The HEC-HMS model interpolated the 5-minute time interval of the rainfall data to 1-minute time interval. 4.4 Calibration No calibration was conducted in this study. 4.5 Final Results 4.5.1 Hydrologic Analysis Results The 100-year peak discharges for the West Speedway Wash subbasins and at CP A were determined using the HEC-HMS. The results are summarized Tables 3 and 4. Table 3 Summary of the Hydrologic Analysis Results for Sub-Basins SubBasin SPD_A SPD_B SPD_C SPD_D Area (sq mi) 0.44 0.3 0.154 0.53 Runoff Volume (in) 1.58 1.77 1.64 1.92 Rainfall Depth (in) 3.14 3.14 3.14 3.14 Peak Discharge (cfs) 496 541 298 1107 Table 4 Summary of the Hydrologic Analysis Results at the Concentration Points Concentration Point Location Area (sq mile) Rainfall Depth (in) Runoff Volume (in) Q100 HMS (cfs) Time to Peak CP A CP B CP C at Sliverbell Rd at Ironwood Hills at Speedway Blvd 1.42 0.98 0.53 3.14 3.14 3.14 1.69 1.89 1.75 1,458 1,637 1,107 2:24 1:45 1:37 4.5.2 Verification results An existing 100-year regulatory discharge near the CP A was shown in Table 5. The comparison shows that the 100-year peak discharges estimated in this study is very close to the existing value. The peak discharge was also compared with the peak discharge obtained from USGS Regression Equation 13 (Thomas et al., 1997) (Table 5). The 15 comparison showed that the HMS-derived peak discharge was approximately the same as the ones derived from the Regression Equation. Table 5 Comparison of a peak discharge Concentration Point Location Area (sq mile) Q100 HMS (cfs) Q100 RRE (cfs) CP A CP B CP C at Sliverbell Rd at Ironwood Hills at Speedway Blvd 1.42 0.98 0.53 1,458 1,637 1,107 1,584 1,242 810 Section 5 Hydraulics 5.1 Method Description The hydraulic modeling for the Sweetwater was performed using Hec-Ras, Version 4.0 (HEC-RAS), HEC-GeoRAS, Version 4.1.1 (HEC-GeoRAS), and ArcGIS, Version 9.3. As previously mentioned, DTM derived from 2008 LiDAR data was used to create a 2foot contour map. The locations of the stream centerline, cross-sections, and bank of the West Speedway Wash were determined using the contour map and 2008 PAG aerial photos. The physical attributes of the wash were digitized in ArcGIS using the HECGeoRAS extension and then exported to HEC-RAS to create geospatially referenced geometric data (cross section, reach profile). Other parameters for the steady-state analysis, such as Manning’s n-values, expansion and contraction coefficients, boundary condition, and ineffective flow areas were manually input into HEC-RAS. The hydraulic data obtained from HEC-RAS were then imported into HEC-GeoRAS to delineate a floodplain boundary in the study area. Hydraulic analysis was performed in the area currently mapped as FEMA Zone A. Steady flow analysis was performed to determine 100-year water surface elevations in the study area by using HEC-RAS. As described above, geometric data for HEC-RAS including stream centerline, flow paths and cross-sections were obtained using HEC-GeoRAS. Normal-depth with a slope of 0.01 was assumed for the upstream boundary condition for the western reach. 5.2 Work Study Maps The work study map for the West Speedway Wash is included in Exhibit 1. 5.3 Parameter Estimation 16 5.3.1 Roughness Coefficients Manning’s n values were determined by a combination of a site visit and 2008 PAG aerial photo. Manning’s n value of 0.06 was assigned for the overbank with desert brush along the West Speedway Wash. The value of 0.06 was assigned to a channel upstream of Silverbell Rd, and 0.035 in the constructed reach downstream of Silverbell Rd. 5.3.2 Expansion and Contraction Coefficients The channel of the West Speedway Wash is assumed to have generally gradual transitions with minimum curvature. The expansion coefficient of 0.30 and contraction coefficient of 0.10 were used for the entire study reach. 5.4 Cross-Section Description A 5-foot interval contour map was used to select the location of cross sections. Crosssection locations were determined primarily based on the channel topography. The crosssection lines were drawn to be perpendicular to flow paths in Hec-GeoRAS. 5.5 Modeling Consideration 5.5.1 Hydraulic Jump and Drop Analysis No hydraulic, drop analyses or adjustment of the floodplain was conducted in this study. 5.5.2. Bridges and Culverts A box culvert was on Speedway Wash at Silverbell Rd in 1986. It consists of six 10’ x 6’ boxes that are about 0.5’ filled with sediment. It is aligned with the wash, which means the boxes are oriented about 45 degrees to the road (i.e. about 45 degrees off perpendicular). The plans for this culvert are presented in Appendix E. 5.5.3 Levees and Dikes There are no levees or dikes located within the study limit. 5.5.4 Island and Flow Splits There were no islands or flow splits modeled. 17 5.5.5 Ineffective Flow Areas Ineffective flow option was modeled in the following situations. In general these ineffective flow areas were disconnected overbank areas that would not convey flow to the next downstream cross-section. 5.6 Floodway Modeling No floodway modeling was performed in this study. 5.7 Problems Encountered 5.7.1 Special Problems and Solutions There are no special problems in the study limit. 5.7.2 Model Warnings and Errors No errors occurred. The following warning messages occurred: Divided flow Energy loss greater than 1.0 Energy equation could not be balanced and defaulted to critical. Cross-section extended vertically. Multiple critical depths calculated. Conveyance ratio is less than 0.7 or greater than 1.4. Inspection indicated that the modeling is accurate given the channel conditions. In most cases, a subcritical solution was found. However, in some cases the errors require a critical solution which is reasonable for in steeper portions of this watercourse. A summary of errors is available in the error summary in the HEC-RAS model in Appendix E. 5.8 Calibration The model was not calibrated in this study. 18 5.9 Final Results 5.9.1 Hydraulic Analysis Results The HEC-RAS modeling results are summarized in Appendix E. 5.9.2 Verification of Results The floodplain limit produced in this West Speedway Wash LOMR study was compared to the existing FEMA floodplain limit. The proposed floodplain limit tends to follow the existing floodplain limit. The results suggest that the proposed floodplain limit is reasonable based on the topography. Section 6 Erosion and Sediment Transport No erosion or sediment transport analysis was conducted in this study. Section 7 Draft FIS Report Data 7.1 Summary of Discharges Peak discharges at CP A was used for the hydraulic analysis in this study. The estimated regulatory discharge rates are 1458 cubic feet per second (cfs) with a drainage area of 1.42 square mile. 7.2 Floodway Data Not applicable. 7.3 Annotated Flood Insurance Rate Map An annotated Flood Insurance Rate Map (FIRM) is included in Exhibit 2. 7.4 Flood Profiles Flood profiles are included in the HEC-RAS model in Appendix E. 19 A.1 Data Collection Summary Aldridge, B. and J. Garrett. 1973. Roughness Coefficients for Stream Channels in Arizona. US Department of the Interior Geological Survey. Tucson, AZ. Arizona Department of Water Resources, Flood Mitigation Section “Instruction for Organization and Submitting Technical Document for Flood Studies” SSA1-97, November 1997 Arizona Department of Water Resources, Flood Mitigation Section “Requirements for Flood Study Technical Documentation” SS1-97, November 1997 Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control District City of Tucson (COT), Department of Transportation, 1989. Standards Manual for Drainage Design and Floodplain Management in Tucson, Arizona. Revised in 1998. National Weather Service. 1984. Depth-Area Ratios in the Semi-Arid Southwest United States, NOAA Technical Memorandum NWS Hydro-40 Phillips, J., and S. Tadayon. 2006. Selection of Manning’s roughness coefficient for natural and constructed vegetated and non-vegetated channels, and vegetation maintenance plan guidelines for vegetated channels in central Arizona: U.S. Geological Survey Scientific Investigations Report 2006–5108, 41 p. Phillips, J., and T. Ingersoll. 1998. Verification of Roughness Coefficients for Selected Natural and Constructed Stream Channels in Arizona. U.S. Geological Survey Professional Paper 1584. Pima County Regional Flood Control District “Pima County Mapguide Map”, 2008 U.S. Army Corps of Engineers (COE). 1998. HEC-1 Flood Hydrograph Package, Users Manual, CPD-1A, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2001. HEC-RAS, River Analysis System, Hydraulic Reference Manual, CPD-69, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2003. Geospatial Hydrologic Modeling Extension HEC-GeoHMS, (v 1.1) CPD-77, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2006. HEC-HMS, Hydrologic Modeling System User’s Manual, (v. 3.1.0) CPD-74A, Hydraulic Engineering Center, Davis, CA. U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986. Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC. A 2. Referenced Documents Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control District Eychaner, J.H., 1984. Estimation of magnitude and frequency of floods in Pima County, Arizona, with comparisons of alternative methods: U.S. Geological Survey WaterResources Investigations Report 84-4142, 69 p. Haan, C.T., Barfield, B.J., Hayes, J.C. 1994. Design Hydrology and Sedimentology for Small Catchments, Academic Press. Thomas, B.E., H.W. Hjalmarson, and S.D. Waltemeyer. 1997. Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States. USGS Water Supply Paper 2433. 195 p. U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986. Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC. PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT TECHNICAL POLICY (DRAFT) POLICY NAME: Acceptable Model Parameterization for Determining Peak Discharge POLICY NUMBER: Technical Policy, TECH-018 EFFECTIVE DATE: To be Determined (comment period from October 1, 2008 to March 1, 2009) PURPOSE To standardize the parameterization of hydrologic models. BACKGROUND When peak discharges need to be established or revised, a computer-based hydrologic model or previously-accepted discharge value may be used. Technical Policy 015 describes which models are acceptable for determining peak discharges. Once a model is selected, this policy describes which parameterization shall be used for submittals to the Pima County Regional Flood Control District (District). POLICY A. Watershed Delineation: The accuracy of watershed delineation and flow path identification is critical in hydrologic modeling. The District requires the use of 2-foot contour interval (or finer where available) contour maps, such as the Pima Association of Governments (PAG) contour maps for delineation of basin boundaries and flow paths in all areas other than steep terrain. In areas of steep terrain, or where 2-foot or finer contour interval maps are not available, U.S. Geologic Survey (USGS) contour maps (7.5 minute series) may be used. At the discretion of the District, it may be necessary to acquire topographic data that has been sealed by a Professional Civil Engineer (PE), or Registered Land Surveyor (RLS) registered in the State of Arizona. In regulatory sheetflood areas, both 2foot or finer contour interval maps and aerial photos with a resolution sufficient to determine flow paths and watershed boundaries shall be used. If Geo-HMS (COE, 2003) is used, Digital Elevation Models (DEMs) or Digital Terrain Models (DTMs), or DEMs derived from lidar data from PAG or other reputable vendors, may be used. With the approval of the District, alternative topographic data, such as stereo photography may be used. B. Pima County Hydrology Procedures: Peak discharges calculations performed using the Pima County Hydrology Procedures shall follow the guidance for parameterization provided in the PC- Hydro User Guide (Arroyo Engineering, 2007). C. HEC-1 and HEC-HMS: Peak discharges calculated using HEC-HMS (COE, 2006) or HEC-1 (COE, 1998) shall employ the following parameterization: a. Rainfall Loss Method: Models shall employ the U.S Soil Conservation Service (SCS) Curve Number method using the Curve Number tables and Hydrologic Soils Group maps associated with the PC Hydro User Guide (Arroyo Engineering, 2007). The Curve Number shall not be adjusted for rainfall intensity or antecedent moisture conditions. b. Time of Concentration Calculation: The U.S. Natural Resources Conservation Service (NRCS) segmented Time of Concentration (Tc) calculation shall be employed (USDA-NRCS, 1986). The Tc shall be calculated by summing the travel time for overland flow, shallow concentrated flow and channel flow, along the primary flow path. Manning’s roughness coefficient for sheet flow shall be obtained using Table 3-1 in Technical Release 55, Urban Hydrology for Small Watersheds (USDA-NRCS, 1986). Maximum slope length for sheet flow shall be 100 feet. Manning’s roughness coefficient for concentrated flow shall be determined using the method described in the District’s Technical Policy 019. c. Transform: The SCS Unit Hydrograph method shall be used. d. Channel Routing: i. Routing in Natural Channels: Runoff can be routed using the Modified-Puls method for natural channels with the slope less than 1%. If HEC-1 is used, an 8-point cross-section may be used. A storage discharge table must be developed if HEC-HMS is used. Such a table can be developed using cross-sections and slopes derived from a Manning normal depth analysis or HEC-RAS (COE, 2001). The number of subreaches shall be calculated using the methods described in the HEC-HMS User’s Manuals. Selection of Manning’s n values shall conform to the guidance in Technical Policy 019. ii. Routing in Constructed Channels and Steep Channel: Shall use the kinematic wave for constructed channels and channels with the slope greater than 1%. Reach length, slope, bottom of width and side slope may be obtained using the data utilized for watershed delineation (e.g. 2-foot contour interval contour maps, Digital Elevation Models (DEMs) or Digital Terrain Models (DTMs), or DEMs). Selection of Manning’s n values shall conform to the guidance in Technical Policy 019. The number of subreaches shall be calculated using the methods described in the HEC-HMS User’s Manuals. e. Rainfall: The NOAA 14 Upper 90% rainfall shall be used as described in the District’s Technical Policy 010. Point rainfall depth shall be evaluated for each basin or subbasin, based on the latitude and longitude of the centroid of the basin or subbasin. f. Rainfall Distribution: Pima County is evaluating rainfall data to determine if the following rainfall distributions are reasonable. In the interim, the higher peak discharge calculated using the following two distributions shall be used: i. SCS Type II 3-hr Storm: The 3-hr distribution shall be used as the local storm. In general, this includes watersheds with a time of concentration (Tc) equal to or less than three hours (see Haan et al 1994). ii. SCS Type I (24 hr): The SCS Type I rainfall (NRCS, 1986) may apply for general storms on watersheds with times of concentration (Tc) greater than three hours. g. Rainfall Aerial Reduction: Aerial reduction shall be estimated using Hydro-40 (National Weather Service, 1984) for the watershed and event of interest (i.e. same tables as Arizona State Standard). Aerial reduction shall be applied to watersheds larger than 1 square mile. D. Comparison of peak discharge: Recommend to compare the peak discharge calculated using the Pima County Hydrology Procedures and the peak discharge obtained from USGS Regression Equation 13 (Thomas et al., 1997) and/or the equation developed by Eychaner (1984) (See Appendix). REFERENCES Aldridge, B. and J. Garrett. 1973. Roughness Coefficients for Stream Channels in Arizona. US Department of the Interior Geological Survey. Tucson, AZ. Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control District City of Tucson (COT), Department of Transportation, 1989. Standards Manual for Drainage Design and Floodplain Management in Tucson, Arizona. Revised in 1998. Eychaner, J.H., 1984. Estimation of magnitude and frequency of floods in Pima County, Arizona, with comparisons of alternative methods: U.S. Geological Survey WaterResources Investigations Report 84-4142, 69 p. Haan, C.T., Barfield, B.J., Hayes, J.C. 1994. Design Hydrology and Sedimentology for Small Catchments, Academic Press. National Weather Service. 1984. Depth-Area Ratios in the Semi-Arid Southwest United States, NOAA Technical Memorandum NWS Hydro-40 Phillips, J., and S. Tadayon. 2006. Selection of Manning’s roughness coefficient for natural and constructed vegetated and non-vegetated channels, and vegetation maintenance plan guidelines for vegetated channels in central Arizona: U.S. Geological Survey Scientific Investigations Report 2006–5108, 41 p. Phillips, J., and T. Ingersoll. 1998. Verification of Roughness Coefficients for Selected Natural and Constructed Stream Channels in Arizona. U.S. Geological Survey Professional Paper 1584. Thomas, B.E., H.W. Hjalmarson, and S.D. Waltemeyer. 1997. Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States. USGS Water Supply Paper 2433. 195 p. U.S. Army Corps of Engineers (COE). 1998. HEC-1 Flood Hydrograph Package, Users Manual, CPD-1A, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2001. HEC-RAS, River Analysis System, Hydraulic Reference Manual, CPD-69, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2003. Geospatial Hydrologic Modeling Extension HEC-GeoHMS, (v 1.1) CPD-77, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2006. HEC-HMS, Hydrologic Modeling System User’s Manual, (v. 3.1.0) CPD-74A, Hydraulic Engineering Center, Davis, CA. U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986. Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC. APPROVED BY: _________________________________________ ______________________________ Suzanne Shields, P.E. Director and Chief Engineer Date Appendix for Tech-018 1.) USGS Regression Equation 13: The current regional regression relationship for southern Arizona is regression equation 13 from Thomas et al (1994). This method predicts peak discharge in cfs (Qp) as a function of watershed Area (square miles) only. It has the form: −0.12 Qp100 = 10 (5.52− 2.42* A ) 2.) Eychaner 1984 (rural): This is a USGS publication that was prepared in cooperation with the City and County. It presents a series of regression equations that rely on watershed area (sq. miles), main channel slope (%), channel length (miles) and a shape factor to account for the differences in runoff noted between long watersheds and more traditionally-shaped watersheds. The equation for the 100 year peak discharge is: 2 2 Qp100 = 10 ( 3.044+ 0.646 (log A) −0.49 (log A) + 0.706 (log S ) −0.367 (log S ) −0.614 (log S )( LogSh )) The shape factor (Sh) is calculated as (channel length)2/(Area) 3.) Eychaner 1984 (urban): This equation adjusts Eychaner’s rural equation to account for the amount of impervious area, channel lining and channel modification. It is: Qp100 = 7.7 A 0.15 (13 − BDF ) −0.32 Qp100 0.82 The Basin Development Factor (BDF) is a scoring factor to account for the degree of urbanization. The specific scoring is based on four factors described in pages 10-13 of the manual.The lower, middle and upper portions of a watershed are scored separately and the results are summed. The maximum BDF score is 12, and a score of 0 indicates that the rural equation should be used. (The Qp100 in the equation is the Qp100 calculated using Eychaner’s rural method described in section 2 above.) PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT TECHNICAL POLICY POLICY NAME: Acceptable Model Parameterization for Determining Peak Discharges POLICY NUMBER: Technical Policy, TECH-018 EFFECTIVE DATE: May 1, 2010 PURPOSE To standardize the parameterization of hydrologic models. BACKGROUND When determining peak discharges, a computer-based hydrologic model or previously-accepted discharge value may be used. Technical Policy TECH-015, Hydrologic Model Selection for Peak Discharge Determination, describes which models are acceptable for determining peak discharges. The Pima County Hydrology Procedures shall be used for riverine watersheds with an area less than 1 square mile. Peak discharges calculations performed using the Pima County Hydrology Procedures shall follow the guidance for parameterization provided in the PC- Hydro User Guide (Arroyo Engineering, 2007). Technical Policy TECH-018 shall be applied to riverine watersheds with an area larger than 1 square mile but smaller than 20 square mile. This policy describes which parameterization shall be used for submittals to the Pima County Regional Flood Control District (District). POLICY A. Watershed Delineation: The accuracy of watershed delineation and flow path identification is critical in hydrologic modeling. The District requires the use of 2-foot contour interval (or finer where available) maps, such as the Pima Association of Governments (PAG) contour maps for delineation of basin boundaries and flow paths in all areas other than steep terrain. In areas of steep terrain, or where 2-foot or finer contour interval maps are not available, U.S. Geologic Survey (USGS) contour maps (7.5 minute series) may be accepted. At the discretion of the District, topographic data that has been sealed by an Arizona registered civil engineer (PE), or land surveyor (RLS) may be required. In regulatory sheetflood areas, both 2-foot or finer contour interval maps and aerial photos with a resolution sufficient to determine flow paths and watershed boundaries shall be used. If Geo-HMS (COE, 2003) is used, Digital Elevation Models (DEMs) or Digital Terrain Models (DTMs), or DEMs derived from lidar data from PAG or other reputable vendors, may be used. With the approval of the District, alternative topographic data, such as stereo photography may be used. B. Pima County Hydrology Procedures: Peak discharges calculations performed using the Pima County Hydrology Procedures shall follow the guidance for parameterization provided in the PC- Hydro User Guide (Arroyo Engineering, 2007). C. HEC-1 and HEC-HMS: Peak discharges calculated using HEC-HMS (COE, 2006) or HEC-1 (COE, 1998) shall employ the following parameterization: a. Rainfall Loss Method: Models shall employ the U.S Soil Conservation Service (SCS) Curve Number method using the Curve Number tables, Vegetation map and Hydrologic Soils Group map associated with the PC Hydro User Guide (Arroyo Engineering, 2007) shall be used. The default vegetation cover percent provided in the PC- Hydro User Guide (Arroyo Engineering, 2007) shall be used. unless additional justification is provided. The Curve Number shall not be adjusted for rainfall intensity or antecedent moisture conditions. b. Time of Concentration Calculation: The modified U.S. Natural Resources Conservation Service (NRCS) segmented Time of Concentration (Tc) calculation shall be employed (USDA-NRCS, 1986). The Tc shall be calculated by summing the travel time for sheet flow, shallow concentrated flow and channel flow, along the primary flow path. i. For sheet flow segment: 1. Manning’s roughness coefficient for sheet flow shall be obtained using Table 3-1 in Technical Release 55, Urban Hydrology for Small Watersheds (USDA-NRCS, 1986). 2. Maximum slope length for sheet flow shall be 100 feet. 3. The Kinematic wave method shall be used to estimate the travel time for sheet flow. ii. For shallow concentrated flow segment: 1. The travel time for shallow concentrated flow using the velocity determined from Figure 3-1 of Technical Release 55, Urban Hydrology for Small Watersheds (USDA-NRCS, 1986). iii. For channel flow 1. Manning’s roughness coefficient for channel flow shall be determined using the method described in the District’s Technical Policy TECH-019, Standards for Floodplain Hydraulic Modeling. 2. HEC-RAS velocity or the Manning’s equation may be used to estimate the travel time for channel flow. 3. The discharge used to calculate velocity shall be estimated by integrating the Regional Regression Equation 13 (Thomas et al., 1997) with respect to area (which is 0.667 x the discharge value calculated with Regional Regression Equation 13). c. Transform: The SCS Unit Hydrograph method shall be used. d. Channel Routing: 1.) Routing in Natural Channels: Runoff shall be routed using the ModifiedPuls method for natural channels with the slope less than 1.5%. A storage discharge table is required if HEC-HMS is used. Such a table can be developed using cross-sections and slopes derived from a Manning normal depth analysis or HEC-RAS (COE, 2001). The number of subreaches shall be calculated using the methods described in the HEC-HMS User’s Manual. Initial discharge to estimate HEC-RAS velocity for channel flow should be determined using discharge calculated with USGS Regression Equation 13 (Thomas et al., 1997). 2.) Routing in Constructed Channels and Steep Channel: Kinematic wave may be used for constructed channels and natural channels with slopes greater than 1%. Reach length, slope, bottom width and side slope may be obtained using the data utilized for watershed delineation (e.g. 2-foot contour interval contour maps, Digital Elevation Models (DEMs) or Digital Terrain Models (DTMs), or DEMs). Selection of Manning’s n values shall conform to the guidance in Technical Policy TECH-019, Standards for Floodplain Hydraulic Modeling.. The number of subreaches shall be calculated using the methods described in the HEC-HMS User’s Manuals. e. Rainfall: The NOAA 14 Upper 90% rainfall shall be used as described in the District’s Technical Policy TECH-010, Rainfall Input for Hydrologic Modeling. Point rainfall depth shall be evaluated for a watershed, based on the latitude and longitude of the centroid of the watershed. If appreciable elevation change occurs on a watershed, users should use different values for higher and lower elevations. f. Rainfall Aerial Reduction: Aerial reduction shall be applied to watersheds larger than 1 square mile. Aerial reduction shall be estimated using Hydro-40 (National Weather Service, 1984) for the watershed and event of interest (i.e. same tables as Arizona State Standard). g. Rainfall Distribution: The following rainfall distributions shall be used, with the highest peak discharge selected in order to determine the critical (i.e. storm that produces the highest discharge) : 1. SCS Type II 3-hr Storm: The 3-hr distribution shall be used as the local storm. In general, this includes watersheds with a time of concentration (Tc) equal to or less than three hours (Haan et al 1994). 3. SCS Type I (24 hr): The SCS Type I rainfall (NRCS, 1986) may apply for general storms on watersheds with times of concentration (Tc) greater than three hours. D. Comparison of peak discharge: The peak discharge shall be compared with the peak discharge obtained from USGS Regression Equation 13 (Thomas et al., 1997) and/or the equation developed by Eychaner (1984) (See Appendix), and existing regulatory discharge estimate. REFERENCES Aldridge, B. and J. Garrett. 1973. Roughness Coefficients for Stream Channels in Arizona. US Department of the Interior Geological Survey. Tucson, AZ. Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control District City of Tucson (COT), Department of Transportation, 1989. Standards Manual for Drainage Design and Floodplain Management in Tucson, Arizona. Revised in 1998. Eychaner, J.H., 1984. Estimation of magnitude and frequency of floods in Pima County, Arizona, with comparisons of alternative methods: U.S. Geological Survey Water-Resources Investigations Report 84-4142, 69 p. Haan, C.T., Barfield, B.J., Hayes, J.C. 1994. Design Hydrology and Sedimentology for Small Catchments, Academic Press. National Weather Service. 1984. Depth-Area Ratios in the Semi-Arid Southwest United States, NOAA Technical Memorandum NWS Hydro-40 Phillips, J., and S. Tadayon. 2006. Selection of Manning’s roughness coefficient for natural and constructed vegetated and non-vegetated channels, and vegetation maintenance plan guidelines for vegetated channels in central Arizona: U.S. Geological Survey Scientific Investigations Report 2006–5108, 41 p. Phillips, J., and T. Ingersoll. 1998. Verification of Roughness Coefficients for Selected Natural and Constructed Stream Channels in Arizona. U.S. Geological Survey Professional Paper 1584. Thomas, B.E., H.W. Hjalmarson, and S.D. Waltemeyer. 1997. Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States. USGS Water Supply Paper 2433. 195 p. U.S. Army Corps of Engineers (COE). 1998. HEC-1 Flood Hydrograph Package, Users Manual, CPD-1A, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2001. HEC-RAS, River Analysis System, Hydraulic Reference Manual, CPD-69, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2003. Geospatial Hydrologic Modeling Extension HECGeoHMS, (v 1.1) CPD-77, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2006. HEC-HMS, Hydrologic Modeling System User’s Manual, (v. 3.1.0) CPD-74A, Hydraulic Engineering Center, Davis, CA. U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986. Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC. APPROVED BY: _________________________________________ Suzanne Shields, P.E. Director and Chief Engineer ______________________________ Date Appendix 1.) USGS Regression Equation 13: The current regional regression relationship for southern Arizona is regression equation 13 from Thomas et al (1994). This method predicts peak discharge in cfs (Qp) as a function of watershed Area (square miles) only. It has the form: −0.12 Qp100 = 10 (5.52− 2.42* A ) 2.) Eychaner 1984 (rural): This is a USGS publication that was prepared in cooperation with the City and County. It presents a series of regression equations that rely on watershed area (sq. miles), main channel slope (%), channel length (miles) and a shape factor to account for the differences in runoff noted between long watersheds and more traditionally-shaped watersheds. The equation for the 100 year peak discharge is: 2 2 Qp100 = 10 ( 3.044+ 0.646 (log A) −0.49 (log A) + 0.706 (log S ) −0.367 (log S ) −0.614 (log S )( LogSh )) The shape factor (Sh) is calculated as (channel length)2/(Area) 3.) Eychaner 1984 (urban): This equation adjusts Eychaner’s rural equation to account for the amount of impervious area, channel lining and channel modification. It is: Qp100 = 7.7 A 0.15 (13 − BDF ) −0.32 Qp100 0.82 The Basin Development Factor (BDF) is a scoring factor to account for the degree of urbanization. The specific scoring is based on four factors described in pages 10-13 of the manual.The lower, middle and upper portions of a watershed are scored separately and the results are summed. The maximum BDF score is 12, and a score of 0 indicates that the rural equation should be used. (The Qp100 in the equation is the Qp100 calculated using Eychaner’s rural method described in section 2 above.) Appendix B FEMA MT-2 Form, General Documentation and Correspondence U.S. DEPARTMENT OF HOMELAND SECURITY - FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B No. 1660-0016 Expires: 12/31/2010 OVERVIEW & CONCURRENCE FORM PAPERWORK BURDEN DISCLOSURE NOTICE Public reporting burden for this form is estimated to average 1 hour per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You are not required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction Project (1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed survey to the above address. A. REQUESTED RESPONSE FROM DHS-FEMA This request is for a (check one): CLOMR: A letter from DHS-FEMA commenting on whether a proposed project, if built as proposed, would justify a map revision, or proposed hydrology changes (See 44 CFR Ch. 1, Parts 60, 65 & 72). LOMR: A letter from DHS-FEMA officially revising the current NFIP map to show the changes to floodplains, regulatory floodway or flood elevations. (See 44 CFR Ch. 1, Parts 60, 65 & 72) B. OVERVIEW 1. The NFIP map panel(s) affected for all impacted communities is (are): Community No. Ex: 480301 480287 040073 Community Name City of Katy Harris County Pima County State TX TX AZ Map No. 480301 48201C 04019C Panel No. 0005D 0220G 1618K 1619K Effective Date 02/08/83 09/28/90 02/08/99 040078 City oif Tucson AZ 04019C 1619K 02/08/99 2. a. Flooding Source: West Speedway Wash b. Types of Flooding: Riverine Coastal Alluvial fan Shallow Flooding (e.g., Zones AO and AH) Lakes Other (Attach Description) 3. Project Name/Identifier: WSpeedway 4. FEMA zone designations affected: A (choices: A, AH, AO, A1-A30, A99, AE, AR, V, V1-V30, VE, B, C, D, X) 5. Basis for Request and Type of Revision: a. The basis for this revision request is (check all that apply) Physical Change Improved Methodology/Data Regulatory Floodway Revision Coastal Analysis Hydraulic Analysis Hydrologic Analysis Weir-Dam Changes Levee Certification Alluvial Fan Analysis New Topographic Data Other (Attach Description) Base Map Changes Corrections Natural Changes Note: A photograph and narrative description of the area of concern is not required, but is very helpful during review. b. The area of revision encompasses the following structures (check all that apply) Structures: DHS- FEMA Form 81-89,DEC 07 Channelization Levee/Floodwall Bridge/Culvert Dam Fill Other (Attach Description) Overview & Concurrence Form MT-2 Form 1 Page 1 of 2 U.S. DEPARTMENT OF HOMELAND SECURITY - FEDERAL EMERGENCY MANAGEMENT AGENCY RIVERINE HYDROLOGY & HYDRAULICS FORM O.M.B No. 1660-0016 Expires: 12/31/2010 PAPERWORK REDUCTION ACT Public reporting burden for this form is estimated to average 3.25 hours per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You are not required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction Project (1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed survey to the above address. Flooding Source: West Speedway Wash Note: Fill out one form for each flooding source studied A. HYDROLOGY 1. Reason for New Hydrologic Analysis (check all that apply) Not revised (skip to section B) No existing analysis Improved data Alternative methodology Proposed Conditions (CLOMR) Changed physical condition of watershed 2. Comparison of Representative 1%-Annual-Chance Discharges Location at Silverbell Rdi Drainage Area (Sq. Mi.) 1.42 Effective/FIS (cfs) N/A Revised (cfs) 1458 3. Methodology for New Hydrologic Analysis (check all that apply) Statistical Analysis of Gage Records Regional Regression Equations Precipitation/Runoff Model HEC-HMS Other (please attach description) Please enclose all relevant models in digital format, maps, computations (including computation of parameters) and documentation to support the new analysis. 4. Review/Approval of Analysis If your community requires a regional, state, or federal agency to review the hydrologic analysis, please attach evidence of approval/review. 5. Impacts of Sediment Transport on Hydrology Yes No If yes, then fill out Section F (Sediment Transport) of Form 3. If No, then attach your Was sediment transport considered? explanation for why sediment transport was not considered. B. HYDRAULICS 1. Reach to be Revised Description Cross Section Water-Surface Elevations (ft.) Effective Downstream Limit Atthe confluence with Silvercroft Wash St# 33 Upstream Limit 5060 ft above Silverbell St# 7701 Proposed/Revised 2. Hydraulic Method/Model Used HEC-RAS DHS - FEMA Form 81-89A, DEC 07 Riverine Hydrology & Hydraulics Form MT-2 Form 2 Page 1 of 2 B. HYDRAULICS (CONTINUED) 3. Pre-Submittal Review of Hydraulic Models DHS-FEMA has developed two review programs, CHECK-2 and CHECK-RAS, to aid in the review of HEC-2 and HEC-RAS hydraulic models, respectively. These review programs may help verify that the hydraulic estimates and assumptions in the model data are in accordance with NFIP requirements, and that the data are comparable with the assumptions and limitations of HEC-2/HEC-RAS. CHECK-2 and CHECK-RAS identify areas of potential error or concern. These tools do not replace engineering judgment. CHECK-2 and CHECK-RAS can be downloaded from http://www.fema.gov/plan/prevent/fhm/frm_soft.shtm. We recommend that you review your HEC-2 and HEC-RAS models with CHECK-2 and CHECK-RAS. Review of your submittal and resolution of valid modeling discrepancies may result in reduced review time. 4. Natural Run Models Submitted Duplicate Effective Model* Corrected Effective Model* Existing or Pre-Project Conditions Model Revised or Post-Project Conditions Model Other - (attach description) File Name: File Name: File Name: File Name: File Name: Floodway Run Datum N/A Plan Name: N/A File Name: N/A Plan Name: NA WSpeedway Plan Name: Plan01 File Name: Plan Name: N/A Plan Name: File Name: Plan Name: N/A Plan Name: File Name: Plan Name: N/A Plan Name: File Name: Plan Name: NA NAVD88 * For details, refer to the corresponding section of the instructions. Digital Models Submitted? (Required) C. MAPPING REQUIREMENTS A certified topographic map must be submitted showing the following information (where applicable): the boundaries of the effective, existing, and proposed conditions 1%-annual-chance floodplain (for approximate Zone A revisions) or the boundaries of the 1%- and 0.2%-annual-chance floodplains and regulatory floodway (for detailed Zone AE, AO, and AH revisions); location and alignment of all cross sections with stationing control indicated; stream, road, and other alignments (e.g., dams, levees, etc.); current community easements and boundaries; boundaries of the requester's property; certification of a registered professional engineer registered in the subject State; location and description of reference marks; and the referenced vertical datum (NGVD, NAVD, etc.). Digital Mapping (GIS/CADD) Data Submitted Note that the boundaries of the existing or proposed conditions floodplains and regulatory floodway to be shown on the revised FIRM and/or FBFM must tie-in with the effective floodplain and regulatory floodway boundaries. Please attach a copy of the effective FIRM and/or FBFM, annotated to show the boundaries of the revised 1%- and 0.2%-annual-chance floodplains and regulatory floodway that tie-in with the boundaries of the effective 1%- and 0.2%-annual-chance floodplain and regulatory floodway at the upstream and downstream limits of the area of revision. Annotated FIRM and/or FBFM (Required) D. COMMON REGULATORY REQUIREMENTS* 1. For LOMR/CLOMR requests, do Base Flood Elevations (BFEs) increase? Yes No a. For CLOMR requests, if either of the following is true, please submit evidence of compliance with Section 65.12 of the NFIP regulations: • The proposed project encroaches upon a regulatory floodway and would result in increases above 0.00 foot. • The proposed project encroaches upon a SFHA with or without BFEs established and would result in increases above 1.00 foot. b. 2. Yes No For LOMR requests, does this request require property owner notification and acceptance of BFE increases? If Yes, please attach proof of property owner notification and acceptance (if available). Elements of and examples of property owner notification can be found in the MT-2 Form 2 Instructions. Does the request involve the placement or proposed placement of fill? Yes No If Yes, the community must be able to certify that the area to be removed from the special flood hazard area, to include any structures or proposed structures, meets all of the standards of the local floodplain ordinances, and is reasonably safe from flooding in accordance with the NFIP regulations set forth at 44 CFR 60.3(a)(3), 65.5(a)(4), and 65.6(a)(14). Please see the MT-2 instructions for more information. 3. For LOMR requests, is the regulatory floodway being revised? Yes No If Yes, attach evidence of regulatory floodway revision notification. As per Paragraph 65.7(b)(1) of the NFIP Regulations, notification is required for requests involving revisions to the regulatory floodway. (Not required for revisions to approximate 1%-annual-chance floodplains [studied Zone A designation] unless a regulatory floodway is being added. Elements and examples of regulatory floodway revision notification can be found in the MT-2 Form 2 Instructions.) 4. For LOMR/CLOMR requests, does this request have the potential to impact an endangered species? Yes No If Yes, please submit documentation to the community to show that you have complied with Sections 9 and 10 of the Endangered Species Act (ESA). Section 9 of the ESA prohibits anyone from “taking” or harming an endangered species. If an action might harm an endangered species, a permit is required from U.S. Fish and Wildlife Service or National Marine Fisheries Service under Section 10 of the ESA. For actions authorized, funded, or being carried out by Federal or State agencies, please submit documentation from the agency showing its compliance with Section 7(a)(2) of the ESA. * Not inclusive of all applicable regulatory requirements. For details, see 44 CFR parts 60 and 65. DHS - FEMA Form 81-89A, DEC 07 Riverine Hydrology & Hydraulics Form MT-2 Form 2 Page 2 of 2 U.S. DEPARTMENT OF HOMELAND SECURITY - FEDERAL EMERGENCY MANAGEMENT AGENCY RIVERINE STRUCTURES FORM O.M.B No. 1660-0016 Expires: 12/31/2010 PAPERWORK REDUCTION ACT Public reporting burden for this form is estimated to average 7 hours per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You are not required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction Project (1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed survey to the above address. Flooding Source: West Speedway Wash Note: Fill out one form for each flooding source studied A. GENERAL Complete the appropriate section(s) for each Structure listed below: Channelization ............... complete Section B Bridge/Culvert ................ complete Section C Dam/Basin ..................... complete Section D Levee/Floodwall ............. complete Section E Sediment Transport........ complete Section F (if required) Description Of Structure 1. Name of Structure: Culvert #1 Type (check one): Channelization Bridge/Culvert Levee/Floodwall Dam/Basin Bridge/Culvert Levee/Floodwall Dam/Basin Bridge/Culvert Levee/Floodwall Dam/Basin Location of Structure: Silverbell Rd Downstream Limit/Cross Section: West of Silverbell Rdl Upstream Limit/Cross Section: East ofSilverbell Rd 2. Name of Structure: Type (check one): Channelization Location of Structure: Downstream Limit/Cross Section: Upstream Limit/Cross Section: 3. Name of Structure: Type (check one) Channelization Location of Structure: . Downstream Limit/Cross Section: . Upstream Limit/Cross Section: . NOTE: For more structures, attach additional pages as needed. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 1 of 10 B. CHANNELIZATION Flooding Source: Name of Structure: 1. Accessory Structures The channelization includes (check one): Levees [Attach Section E (Levee/Floodwall)] Superelevated sections Debris basin/detention basin [Attach Section D (Dam/Basin)] Other (Describe): 2. Drop structures Transitions in cross sectional geometry Energy dissipator Drawing Checklist Attach the plans of the channelization certified by a registered professional engineer, as described in the instructions. 3. Hydraulic Considerations The channel was designed to carry (cfs) and/or the -year flood. The design elevation in the channel is based on (check one): Subcritical flow Critical flow Supercritical flow Energy grade line If there is the potential for a hydraulic jump at the following locations, check all that apply and attach an explanation of how the hydraulic jump is controlled without affecting the stability of the channel. Inlet to channel Outlet of channel Other locations (specify): 4. At Drop Structures At Transitions Sediment Transport Considerations Yes No If Yes, then fill out Section F (Sediment Transport). Was sediment transport considered? If No, then attach your explanation for why sediment transport was not considered. C. BRIDGE/CULVERT Flooding Source: West Speedway Wash Name of Structure: Culverts #1 (Existing) 1. This revision reflects (check one): Bridge/culvert not modeled in the FIS Modified bridge/culvert previously modeled in the FIS Revised analysis of bridge/culvert previously modeled in the FIS 2. Hydraulic model used to analyze the structure (e.g., HEC-2 with special bridge routine, WSPRO, HY8): HEC-RAS If different than hydraulic analysis for the flooding source, justify why the hydraulic analysis used for the flooding source could not analyze the structures. Attach justification. 3. Attach plans of the structures certified by a registered professional engineer. The plan detail and information should include the following (check the information that has been provided): Dimensions (height, width, span, radius, length) Shape (culverts only) Material Beveling or Rounding Wing Wall Angle Skew Angle Distances Between Cross Sections 4. Erosion Protection Low Chord Elevations – Upstream and Downstream Top of Road Elevations – Upstream and Downstream Structure Invert Elevations – Upstream and Downstream Stream Invert Elevations – Upstream and Downstream Cross-Section Locations Sediment Transport Considerations Was sediment transport considered? Yes No If yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why sediment transport was not considered. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 2 of 10 D. DAM/BASIN Flooding Source: Name of Structure: 1. This request is for (check one): Existing dam New dam Modification of existing dam 2. The dam was designed by (check one): Federal agency State agency Local government agency Private organization Name of the agency or organization: 3. The Dam was permitted as (check one): a. Federal Dam State Dam Provide the permit or identification number (ID) for the dam and the appropriate permitting agency or organization Permit or ID number b. Permitting Agency or Organization Local Government Dam Private Dam Provided related drawings, specification and supporting design information. 4. Does the project involve revised hydrology? Yes No If Yes, complete the Riverine Hydrology & Hydraulics Form (Form 2). Was the dam/basin designed using critical duration storm? Yes, provide supporting documentation with your completed Form 2. No, provide a written explanation and justification for not using the critical duration storm. 5. Does the submittal include debris/sediment yield analysis? Yes No If yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why debris/sediment analysis was not considered. 6. Does the Base Flood Elevation behind the dam or downstream of the dam change? Yes No If Yes, complete the Riverine Hydrology & Hydraulics Form (Form 2) and complete the table below. Stillwater Elevation Behind the Dam FREQUENCY (% annual chance) FIS REVISED 10-year (10%) 50-year (2%) 100-year (1%) 500-year (0.2%) Normal Pool Elevation 7. Please attach a copy of the formal Operation and Maintenance Plan DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 3 of 10 E. LEVEE/FLOODWALL 1. System Elements a. This Levee/Floodwall analysis is based on (check one): upgrading of an existing levee/floodwall system a newly constructed levee/floodwall system reanalysis of an existing levee/floodwall system b. Levee elements and locations are (check one): Station Station Station earthen embankment, dike, berm, etc. structural floodwall Other (describe): c. to to to Structural Type (check one): monolithic cast-in place reinforced concrete reinforced concrete masonry block sheet piling Other (describe): d. Has this levee/floodwall system been certified by a Federal agency to provide protection from the base flood? Yes No If Yes, by which agency? e. 2. Attach certified drawings containing the following information (indicate drawing sheet numbers): 1. Plan of the levee embankment and floodwall structures. Sheet Numbers: 2. A profile of the levee/floodwall system showing the Base Flood Elevation (BFE), levee and/or wall crest and foundation, and closure locations for the total levee system. Sheet Numbers: 3. A profile of the BFE, closure opening outlet and inlet invert elevations, type and size of opening, and kind of closure. Sheet Numbers: 4. A layout detail for the embankment protection measures. Sheet Numbers: 5. Location, layout, and size and shape of the levee embankment features, foundation treatment, floodwall structure, closure structures, and pump stations. Sheet Numbers: Freeboard a. The minimum freeboard provided above the BFE is: Riverine 3.0 feet or more at the downstream end and throughout 3.5 feet or more at the upstream end 4.0 feet within 100 feet upstream of all structures and/or constrictions Yes Yes Yes No No No Yes No Yes No Coastal 1.0 foot above the height of the one percent wave associated with the 1%-annual-chance stillwater surge elevation or maximum wave runup (whichever is greater). 2.0 feet above the 1%-annual-chance stillwater surge elevation E. LEVEE/FLOODWALL (CONTINUED) DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 4 of 10 2. Freeboard (continued) Please note, occasionally exceptions are made to the minimum freeboard requirement. If an exception is requested, attach documentation addressing Paragraph 65.10(b)(1)(ii) of the NFIP Regulations. If No is answered to any of the above, please attach an explanation. b. Is there an indication from historical records that ice-jamming can affect the BFE? Yes No If Yes, provide ice-jam analysis profile and evidence that the minimum freeboard discussed above still exists. 3. Closures a. Openings through the levee system (check one): exists does not exist If opening exists, list all closures: Channel Station Left or Right Bank Opening Type Highest Elevation for Opening Invert Type of Closure Device (Extend table on an added sheet as needed and reference) Note: Geotechnical and geologic data In addition to the required detailed analysis reports, data obtained during field and laboratory investigations and used in the design analysis for the following system features should be submitted in a tabulated summary form. (Reference U.S. Army Corps of Engineers [USACE] EM-1110-2-1906 Form 2086.) 4. Embankment Protection a. The maximum levee slope landside is: b. The maximum levee slope floodside is: c. The range of velocities along the levee during the base flood is: (min.) to (max.) d. Embankment material is protected by (describe what kind): Velocity e. Riprap Design Parameters (check one): Attach references Reach Sta to Sta to Sta to Sta to Sta to Sta to Sideslope Flow Depth Velocity Curve or Straight Tractive stress Stone Riprap D100 D50 Thickness Depth of Toedown (Extend table on an added sheet as needed and reference each entry) DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 5 of 10 E. LEVEE/FLOODWALL (CONTINUED) 4. Embankment Protection (continued) f. Is a bedding/filter analysis and design attached? g. Describe the analysis used for other kinds of protection used (include copies of the design analysis): Yes No Attach engineering analysis to support construction plans. 5. Embankment And Foundation Stability a. Identify locations and describe the basis for selection of critical location for analysis: Overall height: Sta. ; height ft. Limiting foundation soil strength: Sta. strength , depth φ= slope: SS = to degrees, c = (h) to psf (v) (Repeat as needed on an added sheet for additional locations) b. Specify the embankment stability analysis methodology used (e.g., circular arc, sliding block, infinite slope, etc.): c. Summary of stability analysis results: Case Loading Conditions Critical Safety Factor Criteria (Min.) I End of construction 1.3 II Sudden drawdown 1.0 III Critical flood stage 1.4 IV Steady seepage at flood stage 1.4 VI Earthquake (Case I) 1.0 (Reference: USACE EM-1110-2-1913 Table 6-1) d. Was a seepage analysis for the embankment performed? Yes No If Yes, describe methodology used: e. Was a seepage analysis for the foundation performed? Yes No f. Were uplift pressures at the embankment landside toe checked? Yes No g. Were seepage exit gradients checked for piping potential? Yes No h. The duration of the base flood hydrograph against the embankment is hours. Attach engineering analysis to support construction plans. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 6 of 10 E. LEVEE/FLOODWALL (CONTINUED) 6. Floodwall And Foundation Stability a. Describe analysis submittal based on Code (check one): UBC (1988) b. or Other (specify): Stability analysis submitted provides for: Overturning c. Sliding If not, explain: Loading included in the analyses were: Lateral earth @ PA = psf; Surcharge-Slope @ Wind @ Pw = , Pp = surface psf psf Seepage (Uplift); d. psf Earthquake @ Peq = 1%-annual-chance significant wave height: ft. 1%-annual-chance significant wave period: sec. %g Summary of Stability Analysis Results: Factors of Safety. Itemize for each range in site layout dimension and loading condition limitation for each respective reach. Criteria (Min) Sta To Sta To Overturn Sliding Overturn Sliding Loading Condition Overturn Sliding Dead & Wind 1.5 1.5 Dead & Soil 1.5 1.5 Dead, Soil, Flood, & Impact 1.5 1.5 Dead, Soil, & Seismic 1.3 1.3 (Ref: FEMA 114 Sept 1986; USACE EM 1110-2-2502) (Note: Extend table on an added sheet as needed and reference) e. Foundation bearing strength for each soil type: Bearing Pressure Sustained Load (psf) Short Term Load (psf) Computed design maximum Maximum allowable f. Foundation scour protection is, is not provided. If provided, attach explanation and supporting documentation: Attach engineering analysis to support construction plans. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 7 of 10 E. LEVEE/FLOODWALL (CONTINUED) 7. Settlement a. Has anticipated potential settlement been determined and incorporated into the specified construction elevations to maintain the established freeboard margin? Yes No b. The computed range of settlement is c. Settlement of the levee crest is determined to be primarily from : ft. to ft. Foundation consolidation Embankment compression Other (Describe): d. Differential settlement of floodwalls has has not been accommodated in the structural design and construction. Attach engineering analysis to support construction plans. 8. Interior Drainage a. Specify size of each interior watershed: Draining to pressure conduit: Draining to ponding area: b. acres acres Relationships Established Ponding elevation vs. storage Ponding elevation vs. gravity flow Differential head vs. gravity flow Yes Yes Yes No No No c. The river flow duration curve is enclosed: Yes No d. Specify the discharge capacity of the head pressure conduit: e. Which flooding conditions were analyzed? • • • • Gravity flow (Interior Watershed) Common storm (River Watershed) Historical ponding probability Coastal wave overtopping cfs Yes Yes Yes Yes No No No No If No for any of the above, attach explanation. f. Interior drainage has been analyzed based on joint probability of interior and exterior flooding and the capacities of pumping and outlet facilities to provide the established level of flood protection. Yes No If No, attach explanation. g. The rate of seepage through the levee system for the base flood is h. The length of levee system used to drive this seepage rate in item g: DHS - FEMA Form 81-89B, DEC 07 cfs ft. Riverine Structures Form MT-2 Form 3 Page 8 of 10 E. LEVEE/FLOODWALL (CONTINUED) 8. Interior Drainage (continued) i. Will pumping plants be used for interior drainage? Yes No If Yes, include the number of pumping plants: For each pumping plant, list: Plant #1 Plant #2 The number of pumps The ponding storage capacity The maximum pumping rate The maximum pumping head The pumping starting elevation The pumping stopping elevation Is the discharge facility protected? Is there a flood warning plan? How much time is available between warning and flooding? Will the operation be automatic? Yes No If the pumps are electric, are there backup power sources? Yes No (Reference: USACE EM-1110-2-3101, 3102, 3103, 3104, and 3105) Include a copy of supporting documentation of data and analysis. Provide a map showing the flooded area and maximum ponding elevations for all interior watersheds that result in flooding. 9. Other Design Criteria a. The following items have been addressed as stated: Liquefaction is is not a problem is is not a problem Hydrocompaction Heave differential movement due to soils of high shrink/swell b. is is not a problem For each of these problems, state the basic facts and corrective action taken: Attach supporting documentation c. If the levee/floodwall is new or enlarged, will the structure adversely impact flood levels and/or flow velocities floodside of the structure? Yes No Attach supporting documentation d. Sediment Transport Considerations: Was sediment transport considered? Yes No If Yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why sediment transport was not considered. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 9 of 10 E. LEVEE/FLOODWALL (CONTINUED) 10. Operational Plan And Criteria a. Are the planned/installed works in full compliance with Part 65.10 of the NFIP Regulations? b. Does the operation plan incorporate all the provisions for closure devices as required in Paragraph 65.10(c)(1) of the NFIP regulations? Yes No c. Does the operation plan incorporate all the provisions for interior drainage as required in Paragraph 65.10(c)(2) of the NFIP regulations? Yes No Yes No If the answer is No to any of the above, please attach supporting documentation. 11. Maintenance Plan a. 12. Are the planned/installed works in full compliance with Part 65.10 of the NFIP Regulations? If No, please attach supporting documentation. Yes No Operations and Maintenance Plan Please attach a copy of the formal Operations and Maintenance Plan for the levee/floodwall. F. SEDIMENT TRANSPORT Flooding Source: Name of Structure: If there is any indication from historical records that sediment transport (including scour and deposition) can affect the Base Flood Elevation (BFE); and/or based on the stream morphology, vegetative cover, development of the watershed and bank conditions, there is a potential for debris and sediment transport (including scour and deposition) to affect the BFEs, then provide the following information along with the supporting documentation: Sediment load associated with the base flood discharge: Volume acre-feet Debris load associated with the base flood discharge: Volume acre-feet Sediment transport rate (percent concentration by volume) Method used to estimate sediment transport: Most sediment transport formulas are intended for a range of hydraulic conditions and sediment sizes; attach a detailed explanation for using the selected method. Method used to estimate scour and/or deposition: Method used to revise hydraulic or hydrologic analysis (model) to account for sediment transport: Please note that bulked flows are used to evaluate the performance of a structure during the base flood; however, FEMA does not map BFEs based on bulked flows. If a sediment analysis has not been performed, an explanation as to why sediment transport (including scour and deposition) will not affect the BFEs or structures must be provided. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 10 of 10 Explanation of Fee Payment This LOMR is based on better data. The previous A-Zone did not follow the topography in the area. The new mapping uses FEMA-compliant Lidar data which greatly improves the topographic data used for the mapping. The hydrology was also updated using this better data. An existing box culvert is included in the model. Since the culvert has been in place since 1986, it was included in the previous mapping. Because this LOMR is based on better data, it is eligible to be reviewed without fee as described in the December 14, 2009 review fee schedule. Appendix C: Survey Field Notes Exhibit 1: 2008 LiDAR Coverage and FEMA Special Flood Hazard Areas 2008 LiDAR Coverage FEMA Floodplains Major Streets Jurisdiction Lines Not Shown: Western Pima County, including Ajo and LiDAR coverage on Tohono O'dham Nation. Pima County Index Map Index Map Scale 1:5,250,000 The information depicted on this display is the result of digital analyses performed on a variety of databases provided and maintained by several governmental agencies. The accuracy of the information presented is limited to the collective accuracy of these databases on the date of the analysis. The Pima County Regional Flood Control Department makes no claims regarding the accuracy of the information depicted herein. This product is subject to the Department of Transportation Technical Services Division's Use Restriction Agreement. Pima County Regional Flood Control District Scale 1:415,000 \\gislib\rfcd\projects\imd\ken\lidar08\fema_08cov.mxd km Page 1 of 2 Evan Canfield From: Kenneth Maits Sent: Monday, May 03, 2010 12:20 PM To: Evan Canfield Subject: FW: PAG 2008 Orthos/Lidar From: Curtis, Edward [mailto:Edward.Curtis@dhs.gov] Sent: Tuesday, November 10, 2009 2:44 PM To: Manny M. Rosas Cc: Terry Hendricks; Lucero, Andrew; Caldwell, Jason; Akl, Pascal Subject: RE: PAG 2008 Orthos/Lidar Mr. Rosas – I apologize for the delay in responding to you regarding the Sanborn LiDAR report. Pascal Akl of Michael Baker, Jr. reviewed the updated July 2009 report on behalf of FEMA and advised me that all of the concerns raised in his May 18, 2009 memorandum titled “Pima County, CA [sic] Sanborn LiDAR Report Items” were addressed in the updated report except the comment that the original report lacked a sufficient number of checkpoints in urban areas and dense vegetation areas. No additional checkpoints were surveyed in such arease to permit analysis of data accuracy in these land cover categories. However, in the data voids analysis section of the updated report (p. 16), Sanborn states the following: "Specific areas, dense vegetation or undergrowth near small streams, for example, prevents the LiDAR pulses to fully penetrate to the true ground surface. Thus, for mapping products such as floodplain or contour mapping, LiDAR data must often be manually supplemented with breaklines and mass-points to accurately model the terrain surface." As long as the data is used with caution and supplemented with additional ground survey data where necessary in accordance with this statement, I am satisfied that the terrain data meets FEMA standards for use in detailed flood studies. Please contact me if you have any questions regarding our review and comments. Ed Curtis, P.E., CFM Risk Analysis Branch FEMA Region IX (510) 627-7207 - office (510) 295-5249 - mobile From: Manny M. Rosas [mailto:MRosas@pagnet.org] Sent: Tuesday, November 10, 2009 7:29 AM To: 'Lucero, Andrew'; 'Caldwell, Jason' Cc: 'Terry Hendricks'; Curtis, Edward Subject: PAG 2008 Orthos/Lidar Hi Andy, I resent Sanborn’s Version 3 document produced in July 2009 and yet to receive any comments from FEMA, Pima County and Michael Baker Inc. therefore please proceed with direct communications with Michael Baker Inc (Pascal Akl) to resolve all issues regarding the FEMA guidelines Thank You Manny 5/6/2010 Page 2 of 2 Manny M. Rosas Jr. GIS Administrator 177 N Church Ave. Suite 405 Tucson, Arizona 85701 520-792-1093 (tel) 520-620-6981 (fax) 5/6/2010 Appendix D: Hydrologic Analysis Supporting Documentation (models, spreadsheets and supporting information is provided digitally in the TDN disk) Appendix E: Hydraulic Analysis and As-Built Drawings for Hydraulic Structures (models, spreadsheets and supporting information is provided digitally in the TDN disk) Appendix F: Erosion and Sediment Transport Analysis Supporting Documentation None 2290 2280 22 2280 2270 70 2280 229 2280 22 80 226 80 2280 80 0 22 22 80 229 0 22 229 2280 0 228 2300 2280 0 22 2280 2290 2320 2280 80 80 22 0 80 2280 22 2280 0 228 2280 0 23 10 90 2310 70 22 22 2280 2280 228 Exhibit 1 100-year Floodplain Workmap with cross sections West Speedway Wash 2280 22 80 2320 80 2280 2280 2310 22 228 2280 0 90 22 60 ! ( 23 20 22 22 Discharge point 80 2280 2280 2280 0 80 2280 2280 2280 XSection & Elevations 2280 2280 22 0 233 233 22 90 2320 22 2280 23 80 20 2280 22 River 80 2300 2290 2290 2280 22 2330 22 90 80 Speedway_contour10ft (2008) 90 229 22 0 234 Speedway_contour2ft (2008) 0 2340 2330 Existing Zone AE 2300 0 230 2270 V U 428 269 V U 2283.14 2283.59 562 2284.06 2284.6 2285.52 2285.76 689 983 838 U V V U V U V U V U 1110 2286.42 2286.86 2287.3 2287.68 2288.1 2288.44 2288.84 1247 1349 1458 1557 1659 1753 1842 2289.51 2290. 1 2290 . 21 35 2291. 1936 2028 2 2292.3 5 0 0 2325 2280 . 24 90 90 23 5 530 90 30 . 08 23 33 3 233 .11 2290 .3 2337 6. 6 2310 5. 6 80 2338.5 22 90 Pima County Index Map 2300 2350 9. 51 23 0 229 23 0 2310 4 1 . 61 2310 2339. 8 40 52 235 23 V U 22 2280 2290 0 2 2290 2300 .8 22 V U . 79 234 . 17 234 7 660 1 651 2348 8 641 V U V U U V 3 67 6853 V U U V 5 696 7077 V U U V 2341.88 90 233 1 5644 .2 V U 22 28 5779 2290 . 63 23 0 26 5428 2344 6219 V U 4. 02 0 6 3 51 V U 23 V U 8 611 V U U V 5 632 V U 2360 2322 229 6 3 49 232 22 Silverbell Wash 229 2300 232 90 3 22 0 0 90 6 1. 5 2300 . 83 22 20 3 45 V U 232 19 2290 0 23 3 2290 229 229 2290 .4 2290 229 00 2290 23 2290 2290 1 7 47 V U V U U V 70 5995 V U 0 5888 . 78 2300 . 05 18 23 7 46 23 2360 V U 2283 82 85 13 23 9 44 3 2343.5 9 22 . 54 . 11 8 V U 2360 236 0 2340 8 .8 9 72 2 2360 59 2290 2290 7 23 1 10 V U 5 75 . 69 .7 61 7 67 23 23 V U 1 76 23 70 .8 5 23 57 1 74 1 23 V U U V 236 0 . 02 2290 54 2360 23 5 2300 2350 55 2 554 V U 23 2360 72 0 V U 2293 .1 2113 2183 2304 U V V U V U V U V U V U V U V U V U V U V U V U 2425 2483 U V V U .0 2295 00 5 268 V U . 09 09 Study Limit 23 43 0 60 81 . 61 2 08 23 2290 90 23 42 1 23 V U 94 . 93 22 94 . 89 .6 23 4. 3 2300 04 . 14 95 03 22 23 23 231 22 Aerial Photo:2008 by Pima Association of Governments Topo created: 04/2010 Datum: NAVD 1988 23 ! ( 1. 42 CP_A 22 230 .8 5 . 77 . 19 15 17 23 23 7 3 U V V U 236 Proposed Zone A 4 5 06 9 2360 V U 0. 0 5. 7 23 8 3 35 4 363 3 2 V U 6 39 8 40 0 2300 1 25 230 230 3 34 V U V U U V 6 37 V U V U 7 38 ET GOR V U 236 00 1 265 5 272 9 279 4 9 7 318 3 329 V U V U U V 299 8 30 2290 23 2 288 V U 0 V U V U V U U V 235 . 32 Index Map Scale 1:1,500,000 .5 5. 0 2350 . 54 236 8 63 68 23 23 2310 80 70 The information depicted on this display is the result of digital analyses performed on a variety of databases provided and maintained by several governmental agencies. The accuracy of the information presented is limited to the collective accuracy of these databases on the date of the analysis. The Pima County Department of Transportation Technical Services Division makes no claims regarding the accuracy of the information depicted herein. 4 23 23 23 00 23 2310 . 65 69 2310 0 231 200 400 Feet 30 232 23 23 20 2350 360 0 00 23 0 90 2340 20 23 23 23 0 233 230 20 70 2330 23 2340 00 10 23 0 20 4 23 2300 2310 23 235 0 00 10 2410 0 0 2390 239 2 23 24 This product is subject to the Department of Transportation Technical Services Division's Disclaimer and Use Restrictions. Pima County Regional Flood Control District LL Study Limit 24 2300 BE 2310 2350 10 1 V U 0 77 2390 23 0 0 6 23 R VE SIL 9 231 .2 2390 2300 23 00 Pima County Regional Flood Control 97 East Congress Street - 3rd Floor Tucson. Arizona 85701-1207 (520)243-1800 - FAX (520)243-1821 http://www.rfcd.pima.gov 05/2010 gislib\rfcd\projects\imd\xavi\mdx\AKITSU\west_speedway\Speedway_watershed_100yrFINALexh1.mxd ZONE X - SHADED PIMA COUNTY 21 ZONE X - SHADED ç ççç ççç ç ç çç ç çççççç çç ç ç ç2ç ç262 ç ç ç çç ç ç ç çç ç çççççç çç ççççççç ççç çççççç çççç çççç 2 ç ç ç ç268 çççç çççç ç çççç çç ç ç çççç çç ZONE X - SHADED ZONE X - SHADED çç ç ç çç çç ççççç 73 ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç 2ç 2 çç çççç ççç ççç ççç ç ç ç ç ç çç PRINCE çççç ççç ççç ççç ççç PRINCE 27 " ) EW EV EU " ) ç ç ç ç çç ç ç ç ç ç çç ç ç çççççç çç ç ç ç ç çççççç çççççç çççççç çççççç ç ç ç ç2ç ç265 ççççççç ççççç çç ç ç ç " ) ç ç çç ç ET " ) ç çç ç çç ç çç E ç çç 6ç9ç ç ç ç ç 2 2ç ç ç ç çç çç ç çç çç ç G TA ON FR 28 ZONE X I10 ç ç ç ç ç2ç 263 ççççççç çççççç ç ç ç çç ç ççç çç çç ç çç çç ç çç ç ç ç çç çç ç ç ç2ç 260 ççç ç çç çç çç ç ççç ç çç çç ç ççç ççç ZONE AO 1 I10 L Streets FIRM X-Sections ç çç çç çç çç çç çç çç Base Flood Elevations Proposed Floodplain LOMRs FIRM - Flood Insurance Rate Map Floodways Sections Jurisdictions Existing Floodplain Zone A AE AO X X - (SHADED) E ççç ES ç ç ç22 ç ç ç 58 ççç ççç çç " ) G TA ON FR ççç çç ç ç çç I10 L BE ER LV SI 29 ZONE AO 1 I10 ZONE X çççç ççç ççç EX 25 çç ç ç ZONE X AY EW FRE çç ç 78ç ç ç ç ç ç çççç 2ç 2ç ç ç ç ç ç ççç ççç ç çç ç " ) ç çç ç çç FA çççç çç ç çç ç N 2 ç ç ç2ç 80 2 ç ç çç çç ç ç281 çççç 80 ç ç 2ç ç2ç ç ç ç ç ç ç ç çç ç ç çç ççç O 5 25 IT EX 0 P I1 AM FR OF Proposed 100 year Floodplain 255 ç ç ç 22 ç ç ç 80 ç çç çç ç çç IT EX ççç ç ç çç ç ççç I10 ççç ççç GE NTA ç ç ç228 ç çç 0 ççç ç çç çç FRO ççç çç I10 ZONE X çç DE RAN AG CAS EY EZ ç ç ç çç M RA " ) " ) ççç ON ZONE AE ZONE A TUCSON çç çç çç çç MP RA FF P 4 ççç 6 22ç ç8ç çç 4O 25 ç çç ç çç çççç ç çç ç ç T ZONE X - SHADED çç ç ç ç çç ç ç ç çç ç ç 78ç ç ç ç ç ç ç ç 2ç 2 ç çç ç ç ç çç ç ç ç ç çç I EX ççç ç ç ççç I10 " ) IT EX ç ç ç ç ç ç ç çç 227ç 4 ççç ççç çç ççç ç ç ççç ççç ççç ç ççç çç ççç ççç ç 3 çç ç ç ççç ç çç ç ç ç ç çç ç çç çç ç ççç çç çç ç ç çç ç çç çç ç ç çç ç LOMR Case 99-09-200P Effective Date5/11/1999 çç ç 7 çç ç çç ç 2ç2ç ç ç5ç ç ç ç ç ç ç P M RA N O 4 25 IT ER EX NT 0 I1 CE SS I10 NE SI BU ZONE A PIMA COUNTY 22 22 ç 9 " ) çç ççç çççç çç 20 ER Exhibit 2 Annotated Flood Insurance Rate Map 04019C1619 K West Speedway Wash ZONE X - SHADED ççç 2287 çç ç ç ç ç ç çç 2ç2ç ç5ç ç3ç ç ç ç ç ç ç ç ç ç ç ç ç ç " ) M RA ç LOMR Case 99-09-434P Effective Date 4/26/2000 P FB 2282 ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç çç ç ç ç ç ç IL E EM L C A MIR ET GOR 2282 ççç çç ç " ) FC 22ç ç83 çç çç çç çç ç çç çç çç çç Pima County Index Map I10 ZONE A 83 22 ç çç çç ç 84 2ç 2 ç çç çç çç çç ççç çç çç çç ç ç çç çç ççç çç çç FR ON TA G E 2285 çç ç çç çç çç 91ç ç ç ç 2ç2ç ç ç ç ç çç ç ç çç ç ççç ççç çç ç çç ççç çç ççç ççç ç ç ZONE X çç 95ç ç ç ç 2 ç ç ç ç3ç 20 ç ç ç çç ççç ç ç ç2ç ç322 ç çç çç çç ç ç ç 3 ç ç ç ç2 ç ç ç ç ç24 ç ç ç çç ç ççç ç ç çç ç çç çç ççç çç ç çç ç çç çç çç çç çç çç çç 04 çç ççç FF ç ç ç ç ç " ) 4 ççç ççç ç ç ç 22 çç 9 ççç The information depicted on this display is the result of digital analyses performed on a variety of databases provided and maintained by several governmental agencies. The accuracy of the information presented is limited to the collective accuracy of these databases on the date of the analysis. The Pima County Department of Transportation Technical Services Division makes no claims regarding the accuracy of the information depicted herein. This product is subject to the Department of Transportation Technical Services Division's Disclaimer and Use Restrictions. 2ç2ç ç ç ç ç ç çç çç 9ç ç7ç ç ç ç ç 2 2ç ç ç ç ç çç ç 0 250 500 1,000 Feet ç ç 3 6 ç ç ç2 ç ç ç ç2 çççççç LOMR Case 99-09-1305P Effective Date7/24/2000 2330 çç ç ç ç ç ç ç ççç çç ç ç ZONE X - SHADED ç 9ç3ç ç ç ç ç 2 2ç ç ç ç ç çç çç 2289 ç çççççç ç F ç ççç çç ççç çç ççç ç çç ç ç ç ç ç2 ç ç ç3ç ç1ç 8 çççççç ç çç ç çç ççç ççç ç ç ç23 ç ç ç 12 ççç ççç çç ç çç ççç ç FE ç çç ç " ) çç 06ç ç ç ç ç 23ç ç ç ç ç çç çç IRONWOOD HILL ç LOMR Case 00-09-793P Effective Date 9/25/2000 " )F ççç çç 10ç ç ç ç ç 23ç ç ç ç ç E ççç ççç " ) 3 6 çç ç ç ç2 ç ç ç ç1 çççççç çç ç çç ZONE AE ççç D çç ç ççç çç " ) ZONE X ç çç Cç ç ç ç çç ç ççç " ) çç ç 05 çç 8ç7ç ç ç ç ç ç 2 2 çç ç çç çç ç çç ç 9ç ç ç ç ç ç ç ç 8 2ç2ç ç ç ç ç ççç ç PIMA COUNTY çç çDç ç ç ç ç LOMR Case 00-09-407P Effective Date8/8/2000 2293 ççç 2292ç ç ç ç ç ç ç ç ç çç ç çç çç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç çç çç çç ç çç 8ç5ç ç çç ç 2 ç 2ç ç çç ççççç ç 86 2ç 2 ç çç ç ç ç 34 çç " 2287 ) ZONE X - SHADED ççç çç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç ç 32 çç ççç ççç çç ç çç ççç çç çç çç ç 33 ç çç IRONWOOD HILL GRANT 03 çç ç çç çç 9ç9ç ç ç ç ç ç 0 ç ç ç ç ç 2 2 ç ç ç 30 ç ç ç ççç 2 çççç çç ç ç çç ç GRANT Pima County Regional Flood Control 97 East Congress Street - 3rd Floor Tucson. Arizona 85701-1207 (520)243-1800 - FAX (520)243-1821 http://www.rfcd.pima.gov gislib\rfcd\projects\imd\xavi\mdx\AKITSU\West_Speedway\Speedway_watershed_Anno_FIRM28x40.mxd A.1 Data Collection Summary Aldridge, B. and J. Garrett. 1973. Roughness Coefficients for Stream Channels in Arizona. US Department of the Interior Geological Survey. Tucson, AZ. Arizona Department of Water Resources, Flood Mitigation Section “Instruction for Organization and Submitting Technical Document for Flood Studies” SSA1-97, November 1997 Arizona Department of Water Resources, Flood Mitigation Section “Requirements for Flood Study Technical Documentation” SS1-97, November 1997 Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control District City of Tucson (COT), Department of Transportation, 1989. Standards Manual for Drainage Design and Floodplain Management in Tucson, Arizona. Revised in 1998. National Weather Service. 1984. Depth-Area Ratios in the Semi-Arid Southwest United States, NOAA Technical Memorandum NWS Hydro-40 Phillips, J., and S. Tadayon. 2006. Selection of Manning’s roughness coefficient for natural and constructed vegetated and non-vegetated channels, and vegetation maintenance plan guidelines for vegetated channels in central Arizona: U.S. Geological Survey Scientific Investigations Report 2006–5108, 41 p. Phillips, J., and T. Ingersoll. 1998. Verification of Roughness Coefficients for Selected Natural and Constructed Stream Channels in Arizona. U.S. Geological Survey Professional Paper 1584. Pima County Regional Flood Control District “Pima County Mapguide Map”, 2008 U.S. Army Corps of Engineers (COE). 1998. HEC-1 Flood Hydrograph Package, Users Manual, CPD-1A, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2001. HEC-RAS, River Analysis System, Hydraulic Reference Manual, CPD-69, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2003. Geospatial Hydrologic Modeling Extension HEC-GeoHMS, (v 1.1) CPD-77, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2006. HEC-HMS, Hydrologic Modeling System User’s Manual, (v. 3.1.0) CPD-74A, Hydraulic Engineering Center, Davis, CA. U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986. Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC. A 2. Referenced Documents Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control District Eychaner, J.H., 1984. Estimation of magnitude and frequency of floods in Pima County, Arizona, with comparisons of alternative methods: U.S. Geological Survey WaterResources Investigations Report 84-4142, 69 p. Haan, C.T., Barfield, B.J., Hayes, J.C. 1994. Design Hydrology and Sedimentology for Small Catchments, Academic Press. Thomas, B.E., H.W. Hjalmarson, and S.D. Waltemeyer. 1997. Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States. USGS Water Supply Paper 2433. 195 p. U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986. Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC. PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT TECHNICAL POLICY (DRAFT) POLICY NAME: Acceptable Model Parameterization for Determining Peak Discharge POLICY NUMBER: Technical Policy, TECH-018 EFFECTIVE DATE: To be Determined (comment period from October 1, 2008 to March 1, 2009) PURPOSE To standardize the parameterization of hydrologic models. BACKGROUND When peak discharges need to be established or revised, a computer-based hydrologic model or previously-accepted discharge value may be used. Technical Policy 015 describes which models are acceptable for determining peak discharges. Once a model is selected, this policy describes which parameterization shall be used for submittals to the Pima County Regional Flood Control District (District). POLICY A. Watershed Delineation: The accuracy of watershed delineation and flow path identification is critical in hydrologic modeling. The District requires the use of 2-foot contour interval (or finer where available) contour maps, such as the Pima Association of Governments (PAG) contour maps for delineation of basin boundaries and flow paths in all areas other than steep terrain. In areas of steep terrain, or where 2-foot or finer contour interval maps are not available, U.S. Geologic Survey (USGS) contour maps (7.5 minute series) may be used. At the discretion of the District, it may be necessary to acquire topographic data that has been sealed by a Professional Civil Engineer (PE), or Registered Land Surveyor (RLS) registered in the State of Arizona. In regulatory sheetflood areas, both 2foot or finer contour interval maps and aerial photos with a resolution sufficient to determine flow paths and watershed boundaries shall be used. If Geo-HMS (COE, 2003) is used, Digital Elevation Models (DEMs) or Digital Terrain Models (DTMs), or DEMs derived from lidar data from PAG or other reputable vendors, may be used. With the approval of the District, alternative topographic data, such as stereo photography may be used. B. Pima County Hydrology Procedures: Peak discharges calculations performed using the Pima County Hydrology Procedures shall follow the guidance for parameterization provided in the PC- Hydro User Guide (Arroyo Engineering, 2007). C. HEC-1 and HEC-HMS: Peak discharges calculated using HEC-HMS (COE, 2006) or HEC-1 (COE, 1998) shall employ the following parameterization: a. Rainfall Loss Method: Models shall employ the U.S Soil Conservation Service (SCS) Curve Number method using the Curve Number tables and Hydrologic Soils Group maps associated with the PC Hydro User Guide (Arroyo Engineering, 2007). The Curve Number shall not be adjusted for rainfall intensity or antecedent moisture conditions. b. Time of Concentration Calculation: The U.S. Natural Resources Conservation Service (NRCS) segmented Time of Concentration (Tc) calculation shall be employed (USDA-NRCS, 1986). The Tc shall be calculated by summing the travel time for overland flow, shallow concentrated flow and channel flow, along the primary flow path. Manning’s roughness coefficient for sheet flow shall be obtained using Table 3-1 in Technical Release 55, Urban Hydrology for Small Watersheds (USDA-NRCS, 1986). Maximum slope length for sheet flow shall be 100 feet. Manning’s roughness coefficient for concentrated flow shall be determined using the method described in the District’s Technical Policy 019. c. Transform: The SCS Unit Hydrograph method shall be used. d. Channel Routing: i. Routing in Natural Channels: Runoff can be routed using the Modified-Puls method for natural channels with the slope less than 1%. If HEC-1 is used, an 8-point cross-section may be used. A storage discharge table must be developed if HEC-HMS is used. Such a table can be developed using cross-sections and slopes derived from a Manning normal depth analysis or HEC-RAS (COE, 2001). The number of subreaches shall be calculated using the methods described in the HEC-HMS User’s Manuals. Selection of Manning’s n values shall conform to the guidance in Technical Policy 019. ii. Routing in Constructed Channels and Steep Channel: Shall use the kinematic wave for constructed channels and channels with the slope greater than 1%. Reach length, slope, bottom of width and side slope may be obtained using the data utilized for watershed delineation (e.g. 2-foot contour interval contour maps, Digital Elevation Models (DEMs) or Digital Terrain Models (DTMs), or DEMs). Selection of Manning’s n values shall conform to the guidance in Technical Policy 019. The number of subreaches shall be calculated using the methods described in the HEC-HMS User’s Manuals. e. Rainfall: The NOAA 14 Upper 90% rainfall shall be used as described in the District’s Technical Policy 010. Point rainfall depth shall be evaluated for each basin or subbasin, based on the latitude and longitude of the centroid of the basin or subbasin. f. Rainfall Distribution: Pima County is evaluating rainfall data to determine if the following rainfall distributions are reasonable. In the interim, the higher peak discharge calculated using the following two distributions shall be used: i. SCS Type II 3-hr Storm: The 3-hr distribution shall be used as the local storm. In general, this includes watersheds with a time of concentration (Tc) equal to or less than three hours (see Haan et al 1994). ii. SCS Type I (24 hr): The SCS Type I rainfall (NRCS, 1986) may apply for general storms on watersheds with times of concentration (Tc) greater than three hours. g. Rainfall Aerial Reduction: Aerial reduction shall be estimated using Hydro-40 (National Weather Service, 1984) for the watershed and event of interest (i.e. same tables as Arizona State Standard). Aerial reduction shall be applied to watersheds larger than 1 square mile. D. Comparison of peak discharge: Recommend to compare the peak discharge calculated using the Pima County Hydrology Procedures and the peak discharge obtained from USGS Regression Equation 13 (Thomas et al., 1997) and/or the equation developed by Eychaner (1984) (See Appendix). REFERENCES Aldridge, B. and J. Garrett. 1973. Roughness Coefficients for Stream Channels in Arizona. US Department of the Interior Geological Survey. Tucson, AZ. Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control District City of Tucson (COT), Department of Transportation, 1989. Standards Manual for Drainage Design and Floodplain Management in Tucson, Arizona. Revised in 1998. Eychaner, J.H., 1984. Estimation of magnitude and frequency of floods in Pima County, Arizona, with comparisons of alternative methods: U.S. Geological Survey WaterResources Investigations Report 84-4142, 69 p. Haan, C.T., Barfield, B.J., Hayes, J.C. 1994. Design Hydrology and Sedimentology for Small Catchments, Academic Press. National Weather Service. 1984. Depth-Area Ratios in the Semi-Arid Southwest United States, NOAA Technical Memorandum NWS Hydro-40 Phillips, J., and S. Tadayon. 2006. Selection of Manning’s roughness coefficient for natural and constructed vegetated and non-vegetated channels, and vegetation maintenance plan guidelines for vegetated channels in central Arizona: U.S. Geological Survey Scientific Investigations Report 2006–5108, 41 p. Phillips, J., and T. Ingersoll. 1998. Verification of Roughness Coefficients for Selected Natural and Constructed Stream Channels in Arizona. U.S. Geological Survey Professional Paper 1584. Thomas, B.E., H.W. Hjalmarson, and S.D. Waltemeyer. 1997. Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States. USGS Water Supply Paper 2433. 195 p. U.S. Army Corps of Engineers (COE). 1998. HEC-1 Flood Hydrograph Package, Users Manual, CPD-1A, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2001. HEC-RAS, River Analysis System, Hydraulic Reference Manual, CPD-69, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2003. Geospatial Hydrologic Modeling Extension HEC-GeoHMS, (v 1.1) CPD-77, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2006. HEC-HMS, Hydrologic Modeling System User’s Manual, (v. 3.1.0) CPD-74A, Hydraulic Engineering Center, Davis, CA. U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986. Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC. APPROVED BY: _________________________________________ ______________________________ Suzanne Shields, P.E. Director and Chief Engineer Date Appendix for Tech-018 1.) USGS Regression Equation 13: The current regional regression relationship for southern Arizona is regression equation 13 from Thomas et al (1994). This method predicts peak discharge in cfs (Qp) as a function of watershed Area (square miles) only. It has the form: −0.12 Qp100 = 10 (5.52− 2.42* A ) 2.) Eychaner 1984 (rural): This is a USGS publication that was prepared in cooperation with the City and County. It presents a series of regression equations that rely on watershed area (sq. miles), main channel slope (%), channel length (miles) and a shape factor to account for the differences in runoff noted between long watersheds and more traditionally-shaped watersheds. The equation for the 100 year peak discharge is: 2 2 Qp100 = 10 ( 3.044+ 0.646 (log A) −0.49 (log A) + 0.706 (log S ) −0.367 (log S ) −0.614 (log S )( LogSh )) The shape factor (Sh) is calculated as (channel length)2/(Area) 3.) Eychaner 1984 (urban): This equation adjusts Eychaner’s rural equation to account for the amount of impervious area, channel lining and channel modification. It is: Qp100 = 7.7 A 0.15 (13 − BDF ) −0.32 Qp100 0.82 The Basin Development Factor (BDF) is a scoring factor to account for the degree of urbanization. The specific scoring is based on four factors described in pages 10-13 of the manual.The lower, middle and upper portions of a watershed are scored separately and the results are summed. The maximum BDF score is 12, and a score of 0 indicates that the rural equation should be used. (The Qp100 in the equation is the Qp100 calculated using Eychaner’s rural method described in section 2 above.) PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT TECHNICAL POLICY POLICY NAME: Acceptable Model Parameterization for Determining Peak Discharges POLICY NUMBER: Technical Policy, TECH-018 EFFECTIVE DATE: May 1, 2010 PURPOSE To standardize the parameterization of hydrologic models. BACKGROUND When determining peak discharges, a computer-based hydrologic model or previously-accepted discharge value may be used. Technical Policy TECH-015, Hydrologic Model Selection for Peak Discharge Determination, describes which models are acceptable for determining peak discharges. The Pima County Hydrology Procedures shall be used for riverine watersheds with an area less than 1 square mile. Peak discharges calculations performed using the Pima County Hydrology Procedures shall follow the guidance for parameterization provided in the PC- Hydro User Guide (Arroyo Engineering, 2007). Technical Policy TECH-018 shall be applied to riverine watersheds with an area larger than 1 square mile but smaller than 20 square mile. This policy describes which parameterization shall be used for submittals to the Pima County Regional Flood Control District (District). POLICY A. Watershed Delineation: The accuracy of watershed delineation and flow path identification is critical in hydrologic modeling. The District requires the use of 2-foot contour interval (or finer where available) maps, such as the Pima Association of Governments (PAG) contour maps for delineation of basin boundaries and flow paths in all areas other than steep terrain. In areas of steep terrain, or where 2-foot or finer contour interval maps are not available, U.S. Geologic Survey (USGS) contour maps (7.5 minute series) may be accepted. At the discretion of the District, topographic data that has been sealed by an Arizona registered civil engineer (PE), or land surveyor (RLS) may be required. In regulatory sheetflood areas, both 2-foot or finer contour interval maps and aerial photos with a resolution sufficient to determine flow paths and watershed boundaries shall be used. If Geo-HMS (COE, 2003) is used, Digital Elevation Models (DEMs) or Digital Terrain Models (DTMs), or DEMs derived from lidar data from PAG or other reputable vendors, may be used. With the approval of the District, alternative topographic data, such as stereo photography may be used. B. Pima County Hydrology Procedures: Peak discharges calculations performed using the Pima County Hydrology Procedures shall follow the guidance for parameterization provided in the PC- Hydro User Guide (Arroyo Engineering, 2007). C. HEC-1 and HEC-HMS: Peak discharges calculated using HEC-HMS (COE, 2006) or HEC-1 (COE, 1998) shall employ the following parameterization: a. Rainfall Loss Method: Models shall employ the U.S Soil Conservation Service (SCS) Curve Number method using the Curve Number tables, Vegetation map and Hydrologic Soils Group map associated with the PC Hydro User Guide (Arroyo Engineering, 2007) shall be used. The default vegetation cover percent provided in the PC- Hydro User Guide (Arroyo Engineering, 2007) shall be used. unless additional justification is provided. The Curve Number shall not be adjusted for rainfall intensity or antecedent moisture conditions. b. Time of Concentration Calculation: The modified U.S. Natural Resources Conservation Service (NRCS) segmented Time of Concentration (Tc) calculation shall be employed (USDA-NRCS, 1986). The Tc shall be calculated by summing the travel time for sheet flow, shallow concentrated flow and channel flow, along the primary flow path. i. For sheet flow segment: 1. Manning’s roughness coefficient for sheet flow shall be obtained using Table 3-1 in Technical Release 55, Urban Hydrology for Small Watersheds (USDA-NRCS, 1986). 2. Maximum slope length for sheet flow shall be 100 feet. 3. The Kinematic wave method shall be used to estimate the travel time for sheet flow. ii. For shallow concentrated flow segment: 1. The travel time for shallow concentrated flow using the velocity determined from Figure 3-1 of Technical Release 55, Urban Hydrology for Small Watersheds (USDA-NRCS, 1986). iii. For channel flow 1. Manning’s roughness coefficient for channel flow shall be determined using the method described in the District’s Technical Policy TECH-019, Standards for Floodplain Hydraulic Modeling. 2. HEC-RAS velocity or the Manning’s equation may be used to estimate the travel time for channel flow. 3. The discharge used to calculate velocity shall be estimated by integrating the Regional Regression Equation 13 (Thomas et al., 1997) with respect to area (which is 0.667 x the discharge value calculated with Regional Regression Equation 13). c. Transform: The SCS Unit Hydrograph method shall be used. d. Channel Routing: 1.) Routing in Natural Channels: Runoff shall be routed using the ModifiedPuls method for natural channels with the slope less than 1.5%. A storage discharge table is required if HEC-HMS is used. Such a table can be developed using cross-sections and slopes derived from a Manning normal depth analysis or HEC-RAS (COE, 2001). The number of subreaches shall be calculated using the methods described in the HEC-HMS User’s Manual. Initial discharge to estimate HEC-RAS velocity for channel flow should be determined using discharge calculated with USGS Regression Equation 13 (Thomas et al., 1997). 2.) Routing in Constructed Channels and Steep Channel: Kinematic wave may be used for constructed channels and natural channels with slopes greater than 1%. Reach length, slope, bottom width and side slope may be obtained using the data utilized for watershed delineation (e.g. 2-foot contour interval contour maps, Digital Elevation Models (DEMs) or Digital Terrain Models (DTMs), or DEMs). Selection of Manning’s n values shall conform to the guidance in Technical Policy TECH-019, Standards for Floodplain Hydraulic Modeling.. The number of subreaches shall be calculated using the methods described in the HEC-HMS User’s Manuals. e. Rainfall: The NOAA 14 Upper 90% rainfall shall be used as described in the District’s Technical Policy TECH-010, Rainfall Input for Hydrologic Modeling. Point rainfall depth shall be evaluated for a watershed, based on the latitude and longitude of the centroid of the watershed. If appreciable elevation change occurs on a watershed, users should use different values for higher and lower elevations. f. Rainfall Aerial Reduction: Aerial reduction shall be applied to watersheds larger than 1 square mile. Aerial reduction shall be estimated using Hydro-40 (National Weather Service, 1984) for the watershed and event of interest (i.e. same tables as Arizona State Standard). g. Rainfall Distribution: The following rainfall distributions shall be used, with the highest peak discharge selected in order to determine the critical (i.e. storm that produces the highest discharge) : 1. SCS Type II 3-hr Storm: The 3-hr distribution shall be used as the local storm. In general, this includes watersheds with a time of concentration (Tc) equal to or less than three hours (Haan et al 1994). 3. SCS Type I (24 hr): The SCS Type I rainfall (NRCS, 1986) may apply for general storms on watersheds with times of concentration (Tc) greater than three hours. D. Comparison of peak discharge: The peak discharge shall be compared with the peak discharge obtained from USGS Regression Equation 13 (Thomas et al., 1997) and/or the equation developed by Eychaner (1984) (See Appendix), and existing regulatory discharge estimate. REFERENCES Aldridge, B. and J. Garrett. 1973. Roughness Coefficients for Stream Channels in Arizona. US Department of the Interior Geological Survey. Tucson, AZ. Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control District City of Tucson (COT), Department of Transportation, 1989. Standards Manual for Drainage Design and Floodplain Management in Tucson, Arizona. Revised in 1998. Eychaner, J.H., 1984. Estimation of magnitude and frequency of floods in Pima County, Arizona, with comparisons of alternative methods: U.S. Geological Survey Water-Resources Investigations Report 84-4142, 69 p. Haan, C.T., Barfield, B.J., Hayes, J.C. 1994. Design Hydrology and Sedimentology for Small Catchments, Academic Press. National Weather Service. 1984. Depth-Area Ratios in the Semi-Arid Southwest United States, NOAA Technical Memorandum NWS Hydro-40 Phillips, J., and S. Tadayon. 2006. Selection of Manning’s roughness coefficient for natural and constructed vegetated and non-vegetated channels, and vegetation maintenance plan guidelines for vegetated channels in central Arizona: U.S. Geological Survey Scientific Investigations Report 2006–5108, 41 p. Phillips, J., and T. Ingersoll. 1998. Verification of Roughness Coefficients for Selected Natural and Constructed Stream Channels in Arizona. U.S. Geological Survey Professional Paper 1584. Thomas, B.E., H.W. Hjalmarson, and S.D. Waltemeyer. 1997. Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States. USGS Water Supply Paper 2433. 195 p. U.S. Army Corps of Engineers (COE). 1998. HEC-1 Flood Hydrograph Package, Users Manual, CPD-1A, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2001. HEC-RAS, River Analysis System, Hydraulic Reference Manual, CPD-69, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2003. Geospatial Hydrologic Modeling Extension HECGeoHMS, (v 1.1) CPD-77, Hydraulic Engineering Center, Davis, CA. U.S. Army Corps of Engineers (COE). 2006. HEC-HMS, Hydrologic Modeling System User’s Manual, (v. 3.1.0) CPD-74A, Hydraulic Engineering Center, Davis, CA. U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986. Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC. APPROVED BY: _________________________________________ Suzanne Shields, P.E. Director and Chief Engineer ______________________________ Date Appendix 1.) USGS Regression Equation 13: The current regional regression relationship for southern Arizona is regression equation 13 from Thomas et al (1994). This method predicts peak discharge in cfs (Qp) as a function of watershed Area (square miles) only. It has the form: −0.12 Qp100 = 10 (5.52− 2.42* A ) 2.) Eychaner 1984 (rural): This is a USGS publication that was prepared in cooperation with the City and County. It presents a series of regression equations that rely on watershed area (sq. miles), main channel slope (%), channel length (miles) and a shape factor to account for the differences in runoff noted between long watersheds and more traditionally-shaped watersheds. The equation for the 100 year peak discharge is: 2 2 Qp100 = 10 ( 3.044+ 0.646 (log A) −0.49 (log A) + 0.706 (log S ) −0.367 (log S ) −0.614 (log S )( LogSh )) The shape factor (Sh) is calculated as (channel length)2/(Area) 3.) Eychaner 1984 (urban): This equation adjusts Eychaner’s rural equation to account for the amount of impervious area, channel lining and channel modification. It is: Qp100 = 7.7 A 0.15 (13 − BDF ) −0.32 Qp100 0.82 The Basin Development Factor (BDF) is a scoring factor to account for the degree of urbanization. The specific scoring is based on four factors described in pages 10-13 of the manual.The lower, middle and upper portions of a watershed are scored separately and the results are summed. The maximum BDF score is 12, and a score of 0 indicates that the rural equation should be used. (The Qp100 in the equation is the Qp100 calculated using Eychaner’s rural method described in section 2 above.) Appendix B FEMA MT-2 Form, General Documentation and Correspondence U.S. DEPARTMENT OF HOMELAND SECURITY - FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B No. 1660-0016 Expires: 12/31/2010 OVERVIEW & CONCURRENCE FORM PAPERWORK BURDEN DISCLOSURE NOTICE Public reporting burden for this form is estimated to average 1 hour per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You are not required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction Project (1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed survey to the above address. A. REQUESTED RESPONSE FROM DHS-FEMA This request is for a (check one): CLOMR: A letter from DHS-FEMA commenting on whether a proposed project, if built as proposed, would justify a map revision, or proposed hydrology changes (See 44 CFR Ch. 1, Parts 60, 65 & 72). LOMR: A letter from DHS-FEMA officially revising the current NFIP map to show the changes to floodplains, regulatory floodway or flood elevations. (See 44 CFR Ch. 1, Parts 60, 65 & 72) B. OVERVIEW 1. The NFIP map panel(s) affected for all impacted communities is (are): Community No. Ex: 480301 480287 040073 Community Name City of Katy Harris County Pima County State TX TX AZ Map No. 480301 48201C 04019C Panel No. 0005D 0220G 1618K 1619K Effective Date 02/08/83 09/28/90 02/08/99 040078 City oif Tucson AZ 04019C 1619K 02/08/99 2. a. Flooding Source: West Speedway Wash b. Types of Flooding: Riverine Coastal Alluvial fan Shallow Flooding (e.g., Zones AO and AH) Lakes Other (Attach Description) 3. Project Name/Identifier: WSpeedway 4. FEMA zone designations affected: A (choices: A, AH, AO, A1-A30, A99, AE, AR, V, V1-V30, VE, B, C, D, X) 5. Basis for Request and Type of Revision: a. The basis for this revision request is (check all that apply) Physical Change Improved Methodology/Data Regulatory Floodway Revision Coastal Analysis Hydraulic Analysis Hydrologic Analysis Weir-Dam Changes Levee Certification Alluvial Fan Analysis New Topographic Data Other (Attach Description) Base Map Changes Corrections Natural Changes Note: A photograph and narrative description of the area of concern is not required, but is very helpful during review. b. The area of revision encompasses the following structures (check all that apply) Structures: DHS- FEMA Form 81-89,DEC 07 Channelization Levee/Floodwall Bridge/Culvert Dam Fill Other (Attach Description) Overview & Concurrence Form MT-2 Form 1 Page 1 of 2 U.S. DEPARTMENT OF HOMELAND SECURITY - FEDERAL EMERGENCY MANAGEMENT AGENCY RIVERINE HYDROLOGY & HYDRAULICS FORM O.M.B No. 1660-0016 Expires: 12/31/2010 PAPERWORK REDUCTION ACT Public reporting burden for this form is estimated to average 3.25 hours per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You are not required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction Project (1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed survey to the above address. Flooding Source: West Speedway Wash Note: Fill out one form for each flooding source studied A. HYDROLOGY 1. Reason for New Hydrologic Analysis (check all that apply) Not revised (skip to section B) No existing analysis Improved data Alternative methodology Proposed Conditions (CLOMR) Changed physical condition of watershed 2. Comparison of Representative 1%-Annual-Chance Discharges Location at Silverbell Rdi Drainage Area (Sq. Mi.) 1.42 Effective/FIS (cfs) N/A Revised (cfs) 1458 3. Methodology for New Hydrologic Analysis (check all that apply) Statistical Analysis of Gage Records Regional Regression Equations Precipitation/Runoff Model HEC-HMS Other (please attach description) Please enclose all relevant models in digital format, maps, computations (including computation of parameters) and documentation to support the new analysis. 4. Review/Approval of Analysis If your community requires a regional, state, or federal agency to review the hydrologic analysis, please attach evidence of approval/review. 5. Impacts of Sediment Transport on Hydrology Yes No If yes, then fill out Section F (Sediment Transport) of Form 3. If No, then attach your Was sediment transport considered? explanation for why sediment transport was not considered. B. HYDRAULICS 1. Reach to be Revised Description Cross Section Water-Surface Elevations (ft.) Effective Downstream Limit Atthe confluence with Silvercroft Wash St# 33 Upstream Limit 5060 ft above Silverbell St# 7701 Proposed/Revised 2. Hydraulic Method/Model Used HEC-RAS DHS - FEMA Form 81-89A, DEC 07 Riverine Hydrology & Hydraulics Form MT-2 Form 2 Page 1 of 2 B. HYDRAULICS (CONTINUED) 3. Pre-Submittal Review of Hydraulic Models DHS-FEMA has developed two review programs, CHECK-2 and CHECK-RAS, to aid in the review of HEC-2 and HEC-RAS hydraulic models, respectively. These review programs may help verify that the hydraulic estimates and assumptions in the model data are in accordance with NFIP requirements, and that the data are comparable with the assumptions and limitations of HEC-2/HEC-RAS. CHECK-2 and CHECK-RAS identify areas of potential error or concern. These tools do not replace engineering judgment. CHECK-2 and CHECK-RAS can be downloaded from http://www.fema.gov/plan/prevent/fhm/frm_soft.shtm. We recommend that you review your HEC-2 and HEC-RAS models with CHECK-2 and CHECK-RAS. Review of your submittal and resolution of valid modeling discrepancies may result in reduced review time. 4. Natural Run Models Submitted Duplicate Effective Model* Corrected Effective Model* Existing or Pre-Project Conditions Model Revised or Post-Project Conditions Model Other - (attach description) File Name: File Name: File Name: File Name: File Name: Floodway Run Datum N/A Plan Name: N/A File Name: N/A Plan Name: NA WSpeedway Plan Name: Plan01 File Name: Plan Name: N/A Plan Name: File Name: Plan Name: N/A Plan Name: File Name: Plan Name: N/A Plan Name: File Name: Plan Name: NA NAVD88 * For details, refer to the corresponding section of the instructions. Digital Models Submitted? (Required) C. MAPPING REQUIREMENTS A certified topographic map must be submitted showing the following information (where applicable): the boundaries of the effective, existing, and proposed conditions 1%-annual-chance floodplain (for approximate Zone A revisions) or the boundaries of the 1%- and 0.2%-annual-chance floodplains and regulatory floodway (for detailed Zone AE, AO, and AH revisions); location and alignment of all cross sections with stationing control indicated; stream, road, and other alignments (e.g., dams, levees, etc.); current community easements and boundaries; boundaries of the requester's property; certification of a registered professional engineer registered in the subject State; location and description of reference marks; and the referenced vertical datum (NGVD, NAVD, etc.). Digital Mapping (GIS/CADD) Data Submitted Note that the boundaries of the existing or proposed conditions floodplains and regulatory floodway to be shown on the revised FIRM and/or FBFM must tie-in with the effective floodplain and regulatory floodway boundaries. Please attach a copy of the effective FIRM and/or FBFM, annotated to show the boundaries of the revised 1%- and 0.2%-annual-chance floodplains and regulatory floodway that tie-in with the boundaries of the effective 1%- and 0.2%-annual-chance floodplain and regulatory floodway at the upstream and downstream limits of the area of revision. Annotated FIRM and/or FBFM (Required) D. COMMON REGULATORY REQUIREMENTS* 1. For LOMR/CLOMR requests, do Base Flood Elevations (BFEs) increase? Yes No a. For CLOMR requests, if either of the following is true, please submit evidence of compliance with Section 65.12 of the NFIP regulations: • The proposed project encroaches upon a regulatory floodway and would result in increases above 0.00 foot. • The proposed project encroaches upon a SFHA with or without BFEs established and would result in increases above 1.00 foot. b. 2. Yes No For LOMR requests, does this request require property owner notification and acceptance of BFE increases? If Yes, please attach proof of property owner notification and acceptance (if available). Elements of and examples of property owner notification can be found in the MT-2 Form 2 Instructions. Does the request involve the placement or proposed placement of fill? Yes No If Yes, the community must be able to certify that the area to be removed from the special flood hazard area, to include any structures or proposed structures, meets all of the standards of the local floodplain ordinances, and is reasonably safe from flooding in accordance with the NFIP regulations set forth at 44 CFR 60.3(a)(3), 65.5(a)(4), and 65.6(a)(14). Please see the MT-2 instructions for more information. 3. For LOMR requests, is the regulatory floodway being revised? Yes No If Yes, attach evidence of regulatory floodway revision notification. As per Paragraph 65.7(b)(1) of the NFIP Regulations, notification is required for requests involving revisions to the regulatory floodway. (Not required for revisions to approximate 1%-annual-chance floodplains [studied Zone A designation] unless a regulatory floodway is being added. Elements and examples of regulatory floodway revision notification can be found in the MT-2 Form 2 Instructions.) 4. For LOMR/CLOMR requests, does this request have the potential to impact an endangered species? Yes No If Yes, please submit documentation to the community to show that you have complied with Sections 9 and 10 of the Endangered Species Act (ESA). Section 9 of the ESA prohibits anyone from “taking” or harming an endangered species. If an action might harm an endangered species, a permit is required from U.S. Fish and Wildlife Service or National Marine Fisheries Service under Section 10 of the ESA. For actions authorized, funded, or being carried out by Federal or State agencies, please submit documentation from the agency showing its compliance with Section 7(a)(2) of the ESA. * Not inclusive of all applicable regulatory requirements. For details, see 44 CFR parts 60 and 65. DHS - FEMA Form 81-89A, DEC 07 Riverine Hydrology & Hydraulics Form MT-2 Form 2 Page 2 of 2 U.S. DEPARTMENT OF HOMELAND SECURITY - FEDERAL EMERGENCY MANAGEMENT AGENCY RIVERINE STRUCTURES FORM O.M.B No. 1660-0016 Expires: 12/31/2010 PAPERWORK REDUCTION ACT Public reporting burden for this form is estimated to average 7 hours per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You are not required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction Project (1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed survey to the above address. Flooding Source: West Speedway Wash Note: Fill out one form for each flooding source studied A. GENERAL Complete the appropriate section(s) for each Structure listed below: Channelization ............... complete Section B Bridge/Culvert ................ complete Section C Dam/Basin ..................... complete Section D Levee/Floodwall ............. complete Section E Sediment Transport........ complete Section F (if required) Description Of Structure 1. Name of Structure: Culvert #1 Type (check one): Channelization Bridge/Culvert Levee/Floodwall Dam/Basin Bridge/Culvert Levee/Floodwall Dam/Basin Bridge/Culvert Levee/Floodwall Dam/Basin Location of Structure: Silverbell Rd Downstream Limit/Cross Section: West of Silverbell Rdl Upstream Limit/Cross Section: East ofSilverbell Rd 2. Name of Structure: Type (check one): Channelization Location of Structure: Downstream Limit/Cross Section: Upstream Limit/Cross Section: 3. Name of Structure: Type (check one) Channelization Location of Structure: . Downstream Limit/Cross Section: . Upstream Limit/Cross Section: . NOTE: For more structures, attach additional pages as needed. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 1 of 10 B. CHANNELIZATION Flooding Source: Name of Structure: 1. Accessory Structures The channelization includes (check one): Levees [Attach Section E (Levee/Floodwall)] Superelevated sections Debris basin/detention basin [Attach Section D (Dam/Basin)] Other (Describe): 2. Drop structures Transitions in cross sectional geometry Energy dissipator Drawing Checklist Attach the plans of the channelization certified by a registered professional engineer, as described in the instructions. 3. Hydraulic Considerations The channel was designed to carry (cfs) and/or the -year flood. The design elevation in the channel is based on (check one): Subcritical flow Critical flow Supercritical flow Energy grade line If there is the potential for a hydraulic jump at the following locations, check all that apply and attach an explanation of how the hydraulic jump is controlled without affecting the stability of the channel. Inlet to channel Outlet of channel Other locations (specify): 4. At Drop Structures At Transitions Sediment Transport Considerations Yes No If Yes, then fill out Section F (Sediment Transport). Was sediment transport considered? If No, then attach your explanation for why sediment transport was not considered. C. BRIDGE/CULVERT Flooding Source: West Speedway Wash Name of Structure: Culverts #1 (Existing) 1. This revision reflects (check one): Bridge/culvert not modeled in the FIS Modified bridge/culvert previously modeled in the FIS Revised analysis of bridge/culvert previously modeled in the FIS 2. Hydraulic model used to analyze the structure (e.g., HEC-2 with special bridge routine, WSPRO, HY8): HEC-RAS If different than hydraulic analysis for the flooding source, justify why the hydraulic analysis used for the flooding source could not analyze the structures. Attach justification. 3. Attach plans of the structures certified by a registered professional engineer. The plan detail and information should include the following (check the information that has been provided): Dimensions (height, width, span, radius, length) Shape (culverts only) Material Beveling or Rounding Wing Wall Angle Skew Angle Distances Between Cross Sections 4. Erosion Protection Low Chord Elevations – Upstream and Downstream Top of Road Elevations – Upstream and Downstream Structure Invert Elevations – Upstream and Downstream Stream Invert Elevations – Upstream and Downstream Cross-Section Locations Sediment Transport Considerations Was sediment transport considered? Yes No If yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why sediment transport was not considered. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 2 of 10 D. DAM/BASIN Flooding Source: Name of Structure: 1. This request is for (check one): Existing dam New dam Modification of existing dam 2. The dam was designed by (check one): Federal agency State agency Local government agency Private organization Name of the agency or organization: 3. The Dam was permitted as (check one): a. Federal Dam State Dam Provide the permit or identification number (ID) for the dam and the appropriate permitting agency or organization Permit or ID number b. Permitting Agency or Organization Local Government Dam Private Dam Provided related drawings, specification and supporting design information. 4. Does the project involve revised hydrology? Yes No If Yes, complete the Riverine Hydrology & Hydraulics Form (Form 2). Was the dam/basin designed using critical duration storm? Yes, provide supporting documentation with your completed Form 2. No, provide a written explanation and justification for not using the critical duration storm. 5. Does the submittal include debris/sediment yield analysis? Yes No If yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why debris/sediment analysis was not considered. 6. Does the Base Flood Elevation behind the dam or downstream of the dam change? Yes No If Yes, complete the Riverine Hydrology & Hydraulics Form (Form 2) and complete the table below. Stillwater Elevation Behind the Dam FREQUENCY (% annual chance) FIS REVISED 10-year (10%) 50-year (2%) 100-year (1%) 500-year (0.2%) Normal Pool Elevation 7. Please attach a copy of the formal Operation and Maintenance Plan DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 3 of 10 E. LEVEE/FLOODWALL 1. System Elements a. This Levee/Floodwall analysis is based on (check one): upgrading of an existing levee/floodwall system a newly constructed levee/floodwall system reanalysis of an existing levee/floodwall system b. Levee elements and locations are (check one): Station Station Station earthen embankment, dike, berm, etc. structural floodwall Other (describe): c. to to to Structural Type (check one): monolithic cast-in place reinforced concrete reinforced concrete masonry block sheet piling Other (describe): d. Has this levee/floodwall system been certified by a Federal agency to provide protection from the base flood? Yes No If Yes, by which agency? e. 2. Attach certified drawings containing the following information (indicate drawing sheet numbers): 1. Plan of the levee embankment and floodwall structures. Sheet Numbers: 2. A profile of the levee/floodwall system showing the Base Flood Elevation (BFE), levee and/or wall crest and foundation, and closure locations for the total levee system. Sheet Numbers: 3. A profile of the BFE, closure opening outlet and inlet invert elevations, type and size of opening, and kind of closure. Sheet Numbers: 4. A layout detail for the embankment protection measures. Sheet Numbers: 5. Location, layout, and size and shape of the levee embankment features, foundation treatment, floodwall structure, closure structures, and pump stations. Sheet Numbers: Freeboard a. The minimum freeboard provided above the BFE is: Riverine 3.0 feet or more at the downstream end and throughout 3.5 feet or more at the upstream end 4.0 feet within 100 feet upstream of all structures and/or constrictions Yes Yes Yes No No No Yes No Yes No Coastal 1.0 foot above the height of the one percent wave associated with the 1%-annual-chance stillwater surge elevation or maximum wave runup (whichever is greater). 2.0 feet above the 1%-annual-chance stillwater surge elevation E. LEVEE/FLOODWALL (CONTINUED) DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 4 of 10 2. Freeboard (continued) Please note, occasionally exceptions are made to the minimum freeboard requirement. If an exception is requested, attach documentation addressing Paragraph 65.10(b)(1)(ii) of the NFIP Regulations. If No is answered to any of the above, please attach an explanation. b. Is there an indication from historical records that ice-jamming can affect the BFE? Yes No If Yes, provide ice-jam analysis profile and evidence that the minimum freeboard discussed above still exists. 3. Closures a. Openings through the levee system (check one): exists does not exist If opening exists, list all closures: Channel Station Left or Right Bank Opening Type Highest Elevation for Opening Invert Type of Closure Device (Extend table on an added sheet as needed and reference) Note: Geotechnical and geologic data In addition to the required detailed analysis reports, data obtained during field and laboratory investigations and used in the design analysis for the following system features should be submitted in a tabulated summary form. (Reference U.S. Army Corps of Engineers [USACE] EM-1110-2-1906 Form 2086.) 4. Embankment Protection a. The maximum levee slope landside is: b. The maximum levee slope floodside is: c. The range of velocities along the levee during the base flood is: (min.) to (max.) d. Embankment material is protected by (describe what kind): Velocity e. Riprap Design Parameters (check one): Attach references Reach Sta to Sta to Sta to Sta to Sta to Sta to Sideslope Flow Depth Velocity Curve or Straight Tractive stress Stone Riprap D100 D50 Thickness Depth of Toedown (Extend table on an added sheet as needed and reference each entry) DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 5 of 10 E. LEVEE/FLOODWALL (CONTINUED) 4. Embankment Protection (continued) f. Is a bedding/filter analysis and design attached? g. Describe the analysis used for other kinds of protection used (include copies of the design analysis): Yes No Attach engineering analysis to support construction plans. 5. Embankment And Foundation Stability a. Identify locations and describe the basis for selection of critical location for analysis: Overall height: Sta. ; height ft. Limiting foundation soil strength: Sta. strength , depth φ= slope: SS = to degrees, c = (h) to psf (v) (Repeat as needed on an added sheet for additional locations) b. Specify the embankment stability analysis methodology used (e.g., circular arc, sliding block, infinite slope, etc.): c. Summary of stability analysis results: Case Loading Conditions Critical Safety Factor Criteria (Min.) I End of construction 1.3 II Sudden drawdown 1.0 III Critical flood stage 1.4 IV Steady seepage at flood stage 1.4 VI Earthquake (Case I) 1.0 (Reference: USACE EM-1110-2-1913 Table 6-1) d. Was a seepage analysis for the embankment performed? Yes No If Yes, describe methodology used: e. Was a seepage analysis for the foundation performed? Yes No f. Were uplift pressures at the embankment landside toe checked? Yes No g. Were seepage exit gradients checked for piping potential? Yes No h. The duration of the base flood hydrograph against the embankment is hours. Attach engineering analysis to support construction plans. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 6 of 10 E. LEVEE/FLOODWALL (CONTINUED) 6. Floodwall And Foundation Stability a. Describe analysis submittal based on Code (check one): UBC (1988) b. or Other (specify): Stability analysis submitted provides for: Overturning c. Sliding If not, explain: Loading included in the analyses were: Lateral earth @ PA = psf; Surcharge-Slope @ Wind @ Pw = , Pp = surface psf psf Seepage (Uplift); d. psf Earthquake @ Peq = 1%-annual-chance significant wave height: ft. 1%-annual-chance significant wave period: sec. %g Summary of Stability Analysis Results: Factors of Safety. Itemize for each range in site layout dimension and loading condition limitation for each respective reach. Criteria (Min) Sta To Sta To Overturn Sliding Overturn Sliding Loading Condition Overturn Sliding Dead & Wind 1.5 1.5 Dead & Soil 1.5 1.5 Dead, Soil, Flood, & Impact 1.5 1.5 Dead, Soil, & Seismic 1.3 1.3 (Ref: FEMA 114 Sept 1986; USACE EM 1110-2-2502) (Note: Extend table on an added sheet as needed and reference) e. Foundation bearing strength for each soil type: Bearing Pressure Sustained Load (psf) Short Term Load (psf) Computed design maximum Maximum allowable f. Foundation scour protection is, is not provided. If provided, attach explanation and supporting documentation: Attach engineering analysis to support construction plans. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 7 of 10 E. LEVEE/FLOODWALL (CONTINUED) 7. Settlement a. Has anticipated potential settlement been determined and incorporated into the specified construction elevations to maintain the established freeboard margin? Yes No b. The computed range of settlement is c. Settlement of the levee crest is determined to be primarily from : ft. to ft. Foundation consolidation Embankment compression Other (Describe): d. Differential settlement of floodwalls has has not been accommodated in the structural design and construction. Attach engineering analysis to support construction plans. 8. Interior Drainage a. Specify size of each interior watershed: Draining to pressure conduit: Draining to ponding area: b. acres acres Relationships Established Ponding elevation vs. storage Ponding elevation vs. gravity flow Differential head vs. gravity flow Yes Yes Yes No No No c. The river flow duration curve is enclosed: Yes No d. Specify the discharge capacity of the head pressure conduit: e. Which flooding conditions were analyzed? • • • • Gravity flow (Interior Watershed) Common storm (River Watershed) Historical ponding probability Coastal wave overtopping cfs Yes Yes Yes Yes No No No No If No for any of the above, attach explanation. f. Interior drainage has been analyzed based on joint probability of interior and exterior flooding and the capacities of pumping and outlet facilities to provide the established level of flood protection. Yes No If No, attach explanation. g. The rate of seepage through the levee system for the base flood is h. The length of levee system used to drive this seepage rate in item g: DHS - FEMA Form 81-89B, DEC 07 cfs ft. Riverine Structures Form MT-2 Form 3 Page 8 of 10 E. LEVEE/FLOODWALL (CONTINUED) 8. Interior Drainage (continued) i. Will pumping plants be used for interior drainage? Yes No If Yes, include the number of pumping plants: For each pumping plant, list: Plant #1 Plant #2 The number of pumps The ponding storage capacity The maximum pumping rate The maximum pumping head The pumping starting elevation The pumping stopping elevation Is the discharge facility protected? Is there a flood warning plan? How much time is available between warning and flooding? Will the operation be automatic? Yes No If the pumps are electric, are there backup power sources? Yes No (Reference: USACE EM-1110-2-3101, 3102, 3103, 3104, and 3105) Include a copy of supporting documentation of data and analysis. Provide a map showing the flooded area and maximum ponding elevations for all interior watersheds that result in flooding. 9. Other Design Criteria a. The following items have been addressed as stated: Liquefaction is is not a problem is is not a problem Hydrocompaction Heave differential movement due to soils of high shrink/swell b. is is not a problem For each of these problems, state the basic facts and corrective action taken: Attach supporting documentation c. If the levee/floodwall is new or enlarged, will the structure adversely impact flood levels and/or flow velocities floodside of the structure? Yes No Attach supporting documentation d. Sediment Transport Considerations: Was sediment transport considered? Yes No If Yes, then fill out Section F (Sediment Transport). If No, then attach your explanation for why sediment transport was not considered. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 9 of 10 E. LEVEE/FLOODWALL (CONTINUED) 10. Operational Plan And Criteria a. Are the planned/installed works in full compliance with Part 65.10 of the NFIP Regulations? b. Does the operation plan incorporate all the provisions for closure devices as required in Paragraph 65.10(c)(1) of the NFIP regulations? Yes No c. Does the operation plan incorporate all the provisions for interior drainage as required in Paragraph 65.10(c)(2) of the NFIP regulations? Yes No Yes No If the answer is No to any of the above, please attach supporting documentation. 11. Maintenance Plan a. 12. Are the planned/installed works in full compliance with Part 65.10 of the NFIP Regulations? If No, please attach supporting documentation. Yes No Operations and Maintenance Plan Please attach a copy of the formal Operations and Maintenance Plan for the levee/floodwall. F. SEDIMENT TRANSPORT Flooding Source: Name of Structure: If there is any indication from historical records that sediment transport (including scour and deposition) can affect the Base Flood Elevation (BFE); and/or based on the stream morphology, vegetative cover, development of the watershed and bank conditions, there is a potential for debris and sediment transport (including scour and deposition) to affect the BFEs, then provide the following information along with the supporting documentation: Sediment load associated with the base flood discharge: Volume acre-feet Debris load associated with the base flood discharge: Volume acre-feet Sediment transport rate (percent concentration by volume) Method used to estimate sediment transport: Most sediment transport formulas are intended for a range of hydraulic conditions and sediment sizes; attach a detailed explanation for using the selected method. Method used to estimate scour and/or deposition: Method used to revise hydraulic or hydrologic analysis (model) to account for sediment transport: Please note that bulked flows are used to evaluate the performance of a structure during the base flood; however, FEMA does not map BFEs based on bulked flows. If a sediment analysis has not been performed, an explanation as to why sediment transport (including scour and deposition) will not affect the BFEs or structures must be provided. DHS - FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 10 of 10 Explanation of Fee Payment This LOMR is based on better data. The previous A-Zone did not follow the topography in the area. The new mapping uses FEMA-compliant Lidar data which greatly improves the topographic data used for the mapping. The hydrology was also updated using this better data. An existing box culvert is included in the model. Since the culvert has been in place since 1986, it was included in the previous mapping. Because this LOMR is based on better data, it is eligible to be reviewed without fee as described in the December 14, 2009 review fee schedule. Appendix C: Survey Field Notes Exhibit 1: 2008 LiDAR Coverage and FEMA Special Flood Hazard Areas 2008 LiDAR Coverage FEMA Floodplains Major Streets Jurisdiction Lines Not Shown: Western Pima County, including Ajo and LiDAR coverage on Tohono O'dham Nation. Pima County Index Map Index Map Scale 1:5,250,000 The information depicted on this display is the result of digital analyses performed on a variety of databases provided and maintained by several governmental agencies. The accuracy of the information presented is limited to the collective accuracy of these databases on the date of the analysis. The Pima County Regional Flood Control Department makes no claims regarding the accuracy of the information depicted herein. This product is subject to the Department of Transportation Technical Services Division's Use Restriction Agreement. Pima County Regional Flood Control District Scale 1:415,000 \\gislib\rfcd\projects\imd\ken\lidar08\fema_08cov.mxd km Page 1 of 2 Evan Canfield From: Kenneth Maits Sent: Monday, May 03, 2010 12:20 PM To: Evan Canfield Subject: FW: PAG 2008 Orthos/Lidar From: Curtis, Edward [mailto:Edward.Curtis@dhs.gov] Sent: Tuesday, November 10, 2009 2:44 PM To: Manny M. Rosas Cc: Terry Hendricks; Lucero, Andrew; Caldwell, Jason; Akl, Pascal Subject: RE: PAG 2008 Orthos/Lidar Mr. Rosas – I apologize for the delay in responding to you regarding the Sanborn LiDAR report. Pascal Akl of Michael Baker, Jr. reviewed the updated July 2009 report on behalf of FEMA and advised me that all of the concerns raised in his May 18, 2009 memorandum titled “Pima County, CA [sic] Sanborn LiDAR Report Items” were addressed in the updated report except the comment that the original report lacked a sufficient number of checkpoints in urban areas and dense vegetation areas. No additional checkpoints were surveyed in such arease to permit analysis of data accuracy in these land cover categories. However, in the data voids analysis section of the updated report (p. 16), Sanborn states the following: "Specific areas, dense vegetation or undergrowth near small streams, for example, prevents the LiDAR pulses to fully penetrate to the true ground surface. Thus, for mapping products such as floodplain or contour mapping, LiDAR data must often be manually supplemented with breaklines and mass-points to accurately model the terrain surface." As long as the data is used with caution and supplemented with additional ground survey data where necessary in accordance with this statement, I am satisfied that the terrain data meets FEMA standards for use in detailed flood studies. Please contact me if you have any questions regarding our review and comments. Ed Curtis, P.E., CFM Risk Analysis Branch FEMA Region IX (510) 627-7207 - office (510) 295-5249 - mobile From: Manny M. Rosas [mailto:MRosas@pagnet.org] Sent: Tuesday, November 10, 2009 7:29 AM To: 'Lucero, Andrew'; 'Caldwell, Jason' Cc: 'Terry Hendricks'; Curtis, Edward Subject: PAG 2008 Orthos/Lidar Hi Andy, I resent Sanborn’s Version 3 document produced in July 2009 and yet to receive any comments from FEMA, Pima County and Michael Baker Inc. therefore please proceed with direct communications with Michael Baker Inc (Pascal Akl) to resolve all issues regarding the FEMA guidelines Thank You Manny 5/6/2010 Page 2 of 2 Manny M. Rosas Jr. GIS Administrator 177 N Church Ave. Suite 405 Tucson, Arizona 85701 520-792-1093 (tel) 520-620-6981 (fax) 5/6/2010 Appendix D: Hydrologic Analysis Supporting Documentation (models, spreadsheets and supporting information is provided digitally in the TDN disk) Appendix E: Hydraulic Analysis and As-Built Drawings for Hydraulic Structures (models, spreadsheets and supporting information is provided digitally in the TDN disk) Appendix F: Erosion and Sediment Transport Analysis Supporting Documentation None