Loading...
HomeMy WebLinkAboutFDP202000005 Other 2020-10-09W8I2020 https:/Ihazards.fema.govlfemapartal/onlinelomcirevision/SummaryAoad.action LOMC Application Application ID. R3435034925093 Revision Revision Review Project Type Project Type: LOMR Payment Total Fee: $0.00 (LOMR Based Solely on Submission of More Detailed Data) Project Name/Identifier Project Namelldentifier: Red Hill Quarry Floodplaln Community Information State, District or Territory: VA County: Albemarle County Community Name: ALBEMARLE COUNTY Map Panel Number - Effective Date: 51003CO405D - 02/04/2005 CID: 510006 Flooding Flooding Source: Unnamed Tributary Types of Flooding: Riverine Flooding Source: North Fork Hardware River Types of Flooding: Riverine Basis for Request The basis for this revision request Is: Hydraulic Analysis . Hydrologic Analysis . Improved Methodology/Data https:/ihazards.fema.govtfemapartaIionlinelomc/revision/Summary/Ioad.action 1/3 5/28/2020 https://haz ards.fema.g ov/fem a portalloniinelom drevisiorVSumm aryl oad.action Zone Designation FEMA Zone designations affected: A Revision Structures The area of revision encompasses the following structures: No Project Primary Contact Information Title. Mr. First Name: Alexander Last Name: Flint Address 1: 999 Second St. SE, Ste 201 City: Charlottesville State, District or Territory: VA ZIP Code: 22902 E-mail Address: aflint@roudabush.com Company/Organization: Roudabush, Gale & Associates Phone: 434-260-7057 Community Official Information Title: First Name: Last Name: Professional Title: Community Name: Address 1: City: State, District of Territory: ZIP Code: E-mail Address: Mr. Frank Pohl P.E., CFM ALBEMARLECOUNTY' 401 McIntire Rd Charlottesville VA 22902 fpohl@albemarle.org As the CEO or designee responsible for the floodplain management, I hereby acknowledge that we have received and reviewed this Letter of Map Revision (LOMR) or conditional LOMR request. Based upon the community's review, we find the completed or proposed project meets or is designed to meet all of the community floodplain management requirements, including the requirement for when fill is placed in the regulatory floodway, and that all necessary Federal, State, and local permits have been, or in the case of a conditional LOMR, will be obtained. For conditional LOMR request, the applicant has documented Endangered Species Act (ESA) compliance to DHS/FEMA prior to DHS/FEMA's review of the Conditional LOMR application. For LOMR request. I acknowledge that compliance with sections 9 and 10 of the ESA has been achieved independently of DHSIFEMA's process. For actions authorized, funded or being carried out by Federal or State agencies; existing or proposed structures to be removed from the SFHA are or will be reasonably safe from Flooding as defined in 44 CFR 65.2(c), and that we have available upon request by DHS/FEMA, all analyses and documentation used to make this determination. https.Ilhazards.fema.gov/femaportal/onlinelomclrevision/SummaryAoad.action 2/3 5/28/2020 htlps:lrnazards.fema.govtfemaportal/onlimlomr mvision/Summarytload.action Community Official Signature: Date. Certification by Registered Professional Engineer and/or Land Surveyor This certification is to be signed and sealed by a licensed land surveyor, registered professional engineer, or architect authorized by law to certify elevation information data, hydrologic and hydraulic analysis, and any other supporting information as per NFIP regulations paragraph 65.2(b) and as described in the MT-2 Forms instruction. All documents submitted in support of this request are correct to the best of my knowledge. I understand that any false statement may be punishable by fine or imprisonment under Title 18 of the United States Code, Section 1001. First Name: Jim Taggart Last Name: License Number 022841 Expiration Date: 0112022 Company Name: Roudabush, Gale & Associates E-mail Address: itaggart@roudabush.com Telephone Number: (434) 260- 8 Fax Number: Certifier's Signature: Date 10/06/2020 AV Jv https:lfhazards.fema.govifemapartal/cnlinelomciremsion/Summary/load.action 3Q U.S. DEPARTMENT OF HOMELAND SECURITY FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B No. 1660-0016 RIVERINE HYDROLOGY & HYDRAULICS FORM Expires February 28, 2014 PAPERWORK BURDEN DISCLOSURE NOTICE Public reporting burden for this form is estimated to average 3.5 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, Department of Homeland Security, Federal Emergency Management Agency, 1800 South Bell Street, Arlington VA 20958-3005, 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. PRIVACY ACT STATEMENT AUTHORITY: The National Flood Insurance Act of 1968, Public Law 90-448, as amended by the Flood Disaster Protection Act of 1973, Public Law 93-234, PRINCIPAL PURPOSE(S): This information is being collected for the purpose of determining an applicant's eligibility to request changes to National Flood Insurance Program (NFIP) Flood Insurance Rate Maps (FIRM). ROUTINE USE(S): The information on this form may be disclosed as generally permitted under 5 U.S.0 § 552a(b) of the Privacy Act of 1974, as amended. This includes using this information as necessary and authorized by the routine uses published in DHS/FEMA/NFIP/LOMA-1 National Flood Insurance Program (NFIP); Letter of Map Amendment (LOMA) February 15, 2006, 71 FR 7990. DISCLOSURE: The disclosure of information on this form is voluntary; however, failure to provide the information requested may delay or prevent FEMA from processing a determination regarding a requested change to a NFIP Flood Insurance Rate Maps (FIRM). Flooding Source: %t, 1Ybrk (Aa&6ut 9'%ver 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 9 Improved data ❑ Alternative methodology ❑ Proposed Conditions (CLOMR) ❑ Changed physical condition of watershed 2. Comparison of Representative 1%-Annual-Chance Discharges Location Drainage Area (Sq. Mi.) Effective/FIS (cfs) Revised (cfs) cm FIIutO c t BF un-namrd 24.1)6 ML7- vi g,52 , $ CA Y`lirk 4taf'&l rn,rt RZ \,ef- 3. Methodology for New Hydrologic Analysis (check all that apply) ❑ Statistical Analysis of Gage Records 9 Precipitation/Runoff Model -7> Specify Model: HCCC"Iin rj A 9-LI . 2 ❑ Regional Regression Equations ❑ 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 Is the hydrology for the revised flooding source(s) affected by sediment transport? ❑ Yes N No If yes, then fill out Section F (Sediment Transport) of Form 3. If No, then attach your explanation.. Set A(lxruk� tvl, . FEMA Form 086-0-27A, (212011) Previously FEMA Form 81-89 MT-2 Form 2 Page 1 of 3 B. HYDRAULICS 1. Reach to be Revised Description Cross Section Water -Surface Elevations (ft.) f Lr Effective Proposed/Revised Downstream Limit" �5� )$3� Yi uMntfn., Oh � u; R�vtr Upstream Limit' : q I6 ,... ffiMeF 34Mis N / A 591. �L 'Proposed/Revised elevations must tie -into the Effective elevations within 0.5 foot at the downstream and upstream limits of revision. 2. Hydraulic Method/Model Used: iicc" ,A'V 5,0,`9 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. We recommend that you review your HEC-2 and HEC-RAS models with CHECK-2 and CHECK-RAS. Models Submitted Natural Run Floodwav Run Datum Duplicate Effective Model' File Name: Plan Name: File Name: Plan Name: Corrected Effective Model' Existing or Pre -Project Conditions Model Revised or Post -Project Conditions Model File Name: PI n g�ame i1211F1nv1_rrwl.Pr) LIIF tilo,PO File Name: Plan Name: File Name: Plan Name: File Name: Plan Name: File Name: Plan Name: File Name: Plan Name: Other - (attach description) File Name: Plan Name: File Name: Plan Name: For details, refer to the corresponding section of the instructions. 71, Digital Models Submitted? (Required) C. MAPPING REQUIREMENTS A certified topographic work 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%-an nual-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.). igital Mapping (GISICy,DD) Data Sub tted ( eferred) Topographic Information:: M04 rLCByj'�K 1 ,Cri��551d 'ni0 �r'n n S - 2 Source: Vil`e11 (p LenQf L(.[7k fP1 irA1 NZ{LvVr� Date: 20-15 Accuracy: 2-' FE Col1�{'Ii km 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, at the same scale as the original, 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 0.20/-annual-chance floodplain and regulatory floodway at the upstream and downstream limits of the area on revision. EX Annotated FIRM and/or FBFM (Required) FEMA Form 086-0-27A, (2/2011) Previously FEMA Form 81-89 MT-2 Form 2 Page 2 of 3 D. COMMON REGULATORY REQUIREMENTS" 1. For LOMR/CLOMR requests, do Base Flood Elevations (BFEs) increase? ❑ Yes 6k 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 compared to pre -project conditions. The proposed project encroaches upon a SFHA with or without BFEs established and would result in increases above 100 foot compared to pre -project conditions b. Does this LOMR request cause increase in the BFE and/or SFHA compared with the effective BFEs and/or SFHA? ❑ Yes R No If Yes, please attach proof of property owner notification and acceptance (if available) Elements of and examples of property owner notifications can be found in the MT-2 Form 2 Instructions. 2 Does the request involve the placement or proposed placement of fill? ❑ Yes 5Q 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 IX 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 established. Elements and examples of regulatory floodway revision notification can be found in the MT-2 Form 2 Instructions.) 4. For CLOMR requests, please submit documentation to FEMA and the community to show that you have complied with Sections 9 and 10 of the Endangered Species Act (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. Please see the MT-2 instructions for more detail. ' Not inclusive of all applicable FEMA Form 086-0-27A, (2/2011) Previously FEMA Form 81-89 MT-2 Form 2 Page 3 of 3 U.S. DEPARTMENT OF HOMELAND SECURITY FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B No. 1660-0016 RIVERINE HYDROLOGY & HYDRAULICS FORM Expires February 28, 2014 PAPERWORK BURDEN DISCLOSURE NOTICE Public reporting burden for this form is estimated to average 3.5 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, Department of Homeland Security, Federal Emergency Management Agency, 1800 South Bell Street, Arlington VA 20958-3005, 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. PRIVACY ACT STATEMENT AUTHORITY: The National Flood Insurance Act of 1968, Public Law 90-448, as amended by the Flood Disaster Protection Act of 1973, Public Law 93-234. PRINCIPAL PURPOSES): This information is being collected for the purpose of determining an applicant's eligibility to request changes to National Flood Insurance Program (NFIP) Flood Insurance Rate Maps (FIRM). ROUTINE USE(S): The information on this form may be disclosed as generally permitted under 5 U.S.0 § 552a(b) of the Privacy Act of 1974, as amended. This includes using this information as necessary and authorized by the routine uses published in DHS/FEMA/NFIP/LOMA-1 National Flood Insurance Program (NFIP); Letter of Map Amendment (LOMA) February 15, 2006, 71 FR 7990. DISCLOSURE: The disclosure of information on this form is voluntary; however, failure to provide the information requested may delay or prevent FEMA from processing a determination regarding a requested chanqe to a NFIP Flood Insurance Rate Maos (FIRM). Flooding Source: ��(1- (wOtfl •;i 'u 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 9 Improved data ❑ Alternative methodology ❑ Proposed Conditions (CLOMR) ❑ Changed physical condition of watershed 2. Comparison of Representative 1%-Annual-Chance Discharges Locall Drainage Area (Sq. Mi.) Effective/FIS (cfs) Revised (cfs) G�nFlatacecl Un nrau� p iriLui6,�) ti1� �k.`fdi� (✓,0$n'l�Z C �c;lr- Nrx-dwdr�- TCrver 3. Methodology for New Hydrologic Analysis (check all that apply) yy ,1 (� t El Statistical Analysis of Gage Records Precipitation/Runoff Model 4 Specify Model: to E(- n MS -1 L) 1 ❑ Regional Regression Equations ❑ 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 Is the hydrology for the revised flooding source(s) affected by sediment transport? ❑ Yes E4 No 1, If yes, then fill out Section F (Sediment Transport) of Form 3. If No, then attach your explanation.. 4;,-It ilWf fAA'`�L FEMA Form 086-0-27A, (2/2011) Previously FEMA Form 81-89 MT-2 Form 2 Page 1 of 3 I HYDRAULICS 1 Reach to be Revised Description Cross Section Water -Surface Elevations (ft.) Effective Proposed/Rvised Downstream Umit• ��a: 4Pslrta m o,jk04 Fork � N/!} _5-1 Ll hj Upstream Limit 3 Kr2 kai jgQO�WPk "Proposed/Revised elevations must tie -into the Effective elevations within 0.5 loot at the downstream and upstream limits of revision. 2 Hydraulic Method/Model Used: H E- 9 1 sy 5 0 � 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. We recommend that you review your HEC-2 and HEC-RAS models with CHECK-2 and CHECK-RAS. 4. Models Submitted Natural Run Floodwav Run Datum Duplicate Effective Model" File Name: Plan Name: File Name: Plan Name: Corrected Effective Model' Existing or Pre -Project Conditions Model Revised or Post -Project Conditions Model Other - (attach description) de NaPI n Name: File Name: Ktme: 41,Pr) r 'I I an.poy File Name: Plan Name: File Name: File Name: File Name: Plan Name: Plan Name: `For details, refer to the corresponding section of the instructions. File Name: File Name: 1K Digital Models Submitted? (Required) C. MAPPING REQUIREMENTS Plan Name: Plan Name: Plan Name: Plan Name: A certified topographic work 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 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.). Topographic Information: Pt&,>t rlIt(CiX L 05AK At�Ld[i� '��J6mr-i5re Source: ilttq �T4CG fQDFNC - 4rtiguAf) 'V2(i.Ct L Date: i Accuracy: 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, at the same scale as the original, 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 on revision. ffi Annotated FIRM and/or FBFM (Required) FEMA Form 086-0-27A, (2/2011) Previously FEMA Form 81-89 MT-2 Form 2 Page 2 of 3 D. COMMON REGULATORY REQUIREMENTS` 1. For LOMR/CLOMR requests, do Base Flood Elevations (BFEs) increase? ❑ Yes IX No a. For CLOMR requests, if either of the following is true, please submit evidence of compliance with Section 66.12 of the NFIP regulations: The proposed project encroaches upon a regulatory floodway and would result in increases above 0.00 foot compared to pre -project conditions. The proposed project encroaches upon a SFHA with or without BFEs established and would result in increases above 1.00 foot compared to pre -project conditions. Does this LOMR request cause increase in the BFE and/or SFHA compared with the effective BFEs and/or SFHA? ❑ Yes 54 No If Yes, please attach proof of property owner notification and acceptance (if available). Elements of and examples cf property owner notifications can be found in the MT-2 Form 2Instructions 2. Does the request involve the placement or proposed placement of fill? El Yes 54No 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 accordancewith the NFIP regulations set forth at 44 CFR 60.3(A)(3), 65.5(a)(4), and 65.6(a)(14). Please seethe MT-2 instructions for more information. 3. For LOMR requests, is the regulatory floodway being revised? ❑ Yes PA 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-chancefloodplains [studied Zone A designation] unless a regulatory floodway is being established. Elements and examples of regulatory floodway revision notification can be found in the MT-2 Form 2 Instructions.) 4. For CLOMR requests, please submit documentation to FEMA and the community to show that you have complied with Sections 9 and 10 of the Endangered Species Act (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. Please see the MT-2 instructions for more detail. requirements. For details, see 44 CFR parts 60 and 65. FEMA Form 086-0-27A, (2/2011) Previously FEMA Form 81-89 MT-2 Form 2 Page 3 of 3 DEPARTMENT OF HOMELAND SECURITY FEDERAL EMERGENCY MANAGEMENT AGENCY RIVERINE STRUCTURES FORM O.M.B. NO. 1660.0016 Expires February 28, 2014 PAPERWORK BURDEN DISCLOSURE NOTICE 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, Department of Homeland Security, Federal Emergency Management Agency, 1800 South Bell Street, Arlington, VA 20598-3005, 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. PRIVACY ACT STATEMENT AUTHORITY: The National Flood Insurance Act of 1968, Public Law 90-448, as amended by the Flood Disaster Protection Act of 1973, Public Law 93-234, PRINCIPAL PURPOSE(S): This information is being collected for the purpose of determining an applicant's eligibility to request changes to National Flood Insurance Program (NFIP) Flood Insurance Rate Maps (FIRM). ROUTINE USE(S): The information on this form may be disclosed as generally permitted under 5 U.S.0 § 552a(b) of the Privacy Act of 1974, as amended. This includes using this information as necessary and authorized by the routine uses published in DHS/FEMA/NFIP/LOMA-1 National Flood Insurance Program; Letter of Map Amendment (LOMA) February 15, 2006, 71 FR 7990. DISCLOSURE: The disclosure of information on this form is voluntary; however, failure to provide the information requested may delay or prevent FEMA from processing a determination regarding a requested change to a NFIP Flood Insurance Rate Maps (FIRM). Flooding Source: V_, 1pu pa tf `mil i t 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... ........................ ... complete Section D Levee/Floodwall.............complete Section E Sediment Transport ....... .complete Section F (if required) Description Of Modeled Structure 1 1. Name of Structure: t1 A 6C I9 Cl.A4r Type (check one): ❑ Channle�lization71 Bridge/Culvert ❑ Levee/Floodwall ❑ Dam Location of Structure: e-10, w, �l� Ttr �� • Downstream Limit/Cross Section: 1 Upstream Limit/Cross Section: �V) 2. Name of Structure: Type (check one): ❑ Channelization ❑ Bridge/Culvert ❑ Levee/Floodwall ❑ Dam Location of Structure: Downstream LimittCross Section: Upstream Limit/Cross Section: 3. Name of Structure: Type (check one) ❑ Channelization ❑ Bridge/Culvert ❑ Levee/Floodwall ❑ Dam Location of Structure: Downstream Limit/Cross Section: Upstream Limit/Cross Section: NOTE: FOR MORE STRUCTURES, ATTACH ADDITIONAL PAGES AS NEEDED. FEMA Form 086-0-27B, (212011) Previously FEMA Form 81.89B MT-2 Form 3 Page 1 of 11 B. CHANNELIZATION Flooding Source: _ Name of Structure: 1. Hydraulic Considerations The channel was designed to carry _ (ds) 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 ❑ At Drop Structures ❑ At Transitions ❑ Other locations (specify): 2. Channel Design Plans Attach the plans of the channelization certified by a registered professional engineer, as described in the instructions. 3. Accessory Structures The channelization includes (check one): ❑ Levees [Attach Section E (Levee/Floodwall)] ❑ Drop structures ❑ Superelevated sections ❑ Transitions in cross sectional geometry ❑ Debris basin/detention basin [Attach Section D (Dam/Basin)] ❑ Energy dissipator ❑ Weir ❑ Other (Describe): 4. Sediment Transport Considerations Are the hydraulics of the channel affected by sediment transport? ❑ Yes ❑ No If yes, then fill out Section F (Sediment Transport) of Form 3. If No, then attach your explanation for why sediment transport was not considered. —t' 1- C. BRIDGE/CULVERT Flooding Source: Un OGvplf�l 1`�I`I']UkL�r�i Name of Structure: iio4tWy Cuw�+C��1 J 1. This revision reflects (check one): tK Bridge/culvert not modeled in the FIS ❑ Modified bridge/culvert previously modeled in the FIS ❑ Revised analysis of bridgelculvert previously modeled in the FIS 2. Hydraulic model used to analyze the structure (e.g., HEC-2 with special bridge routine, WSPRO, HY8): _ 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): X Dimensions (height, width, span, radius, length) Distances Between Cross Sections ® Shape (culverts only) ❑ Erosion Protection [A Material ❑ Low Chord Elevations— Upstream and Downstream ❑ Beveling or Rounding Top of Road Elevations — Upstream and Downstream CK Wing Wall Angle Structure Invert Elevations— Upstream and Downstream ❑ Skew Angle ❑ Stream Invert Elevations — Upstream and Downstream M Cross -Section Locations 14. Sediment Transport Considerations Are the hydraulics of the structure affected by sediment transport? ❑ Yes R No FEMA Form 086.0.27B, (2/2011) Previously FEMA Form 81.89B Ill Form 3 Page 2 of 11 ® ROUDABUSH, GALE & ASSOCIATES, INC. EN(3INEEN9BUNVEYOR9 ANU lANU PIANNEF3 PROJECT NARRATIVE/MT-2 FORMS 1-3 SUPPLEMENTALS Project Narrative: S.L. Williamson is a third -generation asphalt paving and road construction company. It leases property at the Martin Marietta quarry along Red Hill Road. The Red Hill lease is located on tax map parcel 88-18, on a 4.4-acre portion of the larger 579-acre parcel (the 'Property'), pursuant to a lease with Martin Marietta Materials, Inc., the owner of the Property that comprises the Red Hill Quarry. The Property is zoned Rural Areas and Natural Resource Overlay District, and within Rural Area 4 of the Comprehensive Plan. The property also has areas that are zoned Flood Hazard Overlay District. Portions of the property are located within the 100-year floodplain per the FEMA 100-year from FIRM panel 51003C0405D. Roudabush, Gale & Associates, the project engineers, have performed a floodplain study using HEC-HMS (Version 4.3) and HEC-RAS (Version 5.0.7) to determine the extent of the 100-year Floodplain in two areas: the creek located along the lease, and the Hardware River to the southwest and west of the plant. Updated hydrologic analysis was performed only on the creek, while updated hydraulic analyses were performed on both the creek and the Hardware River. In the course of normal business operation, it has become desirable to gain a more accurate representation of flood hazards. Therefore, more accurate flood mapping is sought. Methodology: The topography used in this study comes from two sources. LiDAR point cloud data from 2016, provided by the Virginia Geographical Information Network, was used to develop 2-ft contours for the drainage area to the tributary, as well as downstream of its confluence with the North Fork Hardware River (Hardware River). Topography for drainage to the Hardware River was generated in Autodesk Infraworks, which uses USGS 10 and 30 meter contours. The primary study point for this analysis is located at the confluence of the tributary and the Hardware River. Other study points considered include directly downstream of a pond, located in the drainage area to the tributary. Loss in this analysis for all drainage areas was determined using SCS Curve Numbers, which take hydrologic soil group and condition into account. The USDA Web Soil Survey was utilized to provide soil group classifications in each drainage area. The design curve numbers used in this analysis were based on the Runoff Curve Number Tables provided in the NRCS National Engineering Handbook (NEH) (Part 630, Ch. 9) and the land use classifications verified with aerial imagery. The curve numbers shown in these tables are composite, accounting for both pervious and impervious areas. Subsequently, impervious values in HEC-HMS were left blank to avoid double -counting impervious areas. As a conservative assumption, when the hydrologic soil group ranged between soil groups, the soil group resulting in higher runoff was assumed, and the corresponding curve number was used in estimation. The weighted curve number generated from this analysis was used to generate maximum potential retention "S", and Initial Abstraction " la". Per SCS Methodology, maximum potential retention was considered in determining the time of concentration. Other characteristics considered in this method include flow length, friction coefficient, land slope, and time of concentration. Equations used to determine time of concentration can be found in the TR-55 manual, and flow length was determined using topography as shown in CAD software. ® ROUDABUSH, GALE & ASSOCIATES, INC. EN(3INEEN9BUNVEYOR9 ANU lANU PIANNEF3 There is a pond located in the drainage area to the tributary. To simulate a worst -case scenario, the elevation of water in the pond was set at maximum, and the embankment coefficient was inflated outside standard values to minimize attenuation caused by the pond. Also, because this pond is a major characteristic in the drainage area, it was selected as a location to split the drainage area into two sub -basins. For modeling, two programs were used. HEC-HMS (Version 4.4.1) was analyzed the defined watersheds (shown in the drainage maps) in a precipitation/runoff process using the parameters discussed above. From this information, a peak flow was generated at the study point. HEC- RAS (Version 5.0.7) was used to evaluate stream network and flood surface elevations, and calculate water surface profiles for flow in natural channels. The topography used in parameter analysis was imported into the RAS Mapper to create a terrain. This was then used to generate reach centerlines and cross -sections. Centerlines and cross -sections are shown on the certified topographic work map. HEC-RAS also accounts for energy losses due to friction. These losses are associated with a specific Manning's friction coefficient, "n". These values were taken from Table 3.1 of the HEC- RAS User's Manual. A channel n-value of .04 was used in this analysis. Overbank n-values ranged from 0.03 to 0.1, depending upon the overall cover of the overbank area. HEC-RAS convention requires that at the most upstream cross-section of any reach, a hydrograph must be input as a boundary condition. The reach representing the tributary begins at the base of the pond embankment in the HEC-RAS model. This is also the location where the tributary's drainage area is split, as discussed previously. HEC-RAS analyzes water flow velocities, travel times, flow areas, top widths, and surface elevations. Since the RAS Mapper includes associated terrain data, these parameters help to generate an inundation boundary. This inundation boundary has also been applied at scale to the FIRM map, generated from FEMA's FIRM-ette creation tool online. ® ROUDABUSH, GALE & ASSOCIATES, INC. ENp/NEENH81/NVEYOR9 AN0lANO PIMNNEfiB SUPPLEMENTALS Form 2: Riverine Hydrology & Hydraulics Form Form 2, Section A.S and Form 3, Section CA: Sediment transport typically is considered in site developments. There is minimal development in the drainage area upstream of the structure. While a quarry does partially lie within the drainage area, it does not contribute to sediment transport. Form 2, Section D.1.b: LOMR request seeks to establish BFE's. BFE's are neither increased nor decreased, as they are not currently established.