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HomeMy WebLinkAboutFDP201900013 Correspondence 2020-02-18Case No.: 20-03-0027R Requester: Ms. Sheila S. Reeves, P.E., CFM Communities: Independent City of Charlottesville and Community Nos.: 510033 and 510006 Unincorporated Areas of Albemarle County, Virginia Response to Comments Comments are provided below in bold font. Responses are provided immediately below each comment. The issues listed below must be addressed before we can continue the review of your request. 1. Our review of your request revealed that the City of Charlottesville and Albemarle County are affected by this revision. Please submit a completed copy of Application/Certification Form 1, entitled "Overview and Concurrence Form," signed by an official from each community. Allforms and instructions are available for your information on the FEMA website at https://www.fema.2ov/library/viewRecord.do?id=1493. The City of Charlottesville is no longer an affected community with the truncated model. The Albemarle County floodplain administrator has indicated that they will not sign the document until FEMA has approved the submittal. 2. Our review of the submitted proposed plan entitled, "Pedestrian Bridge General Notes, Plan, and Elevation," prepared by Timmons Group, Inc., dated February 18, 2019, revealed that it is not certified (sealed, signed and dated) by a registered Land Surveyor or Professional Engineer(P.E.). Please submit a certified copy of the proposed plan. Included. 3. Our review of the submitted proposed conditions Hydrologic Engineering Center's River Analysis System HEC-RAS 5.0.7 hydraulic analysis revealed the model includes more cross sections than are necessary for this review. Please submit a further truncated model where the downstream most cross section is Cross Section 1491.63 and the most upstream cross section is Cross Section 2640.37. Please update the downstream boundary condition to be the Known Water -Surface Elevation (KWSEL) from the effective profile at the location of Cross Section 1491.63. The model has been truncated as directed. The boundary condition has been revised as directed. 4. Our review revealed that the encroached (floodway) profile is included with the multiple profile plan. Please create two separate plans; the multiple profile plan and the floodway plan. The floodway plan should only include the encroached (floodway) and unencroached (natural) base flood profiles. The unencroached and encroached profiles for the proposed conditions floodway plan should use the geometry file from the proposed conditions multiple profile plan along with the base flood discharge from the proposed conditions multiple profile plan. Revised as directed. 5. The submitted map entitled, "Floodplain Workmap Exhibit," prepared by Timmons Group, dated September 6, 2019, does not provide some of the essential information required to complete our detailed review of this request. Please provide the following information. a. Our review revealed that the entire revised reach is under backwater effects from the Rivanna River at elevation 324.0 feet as per LOMR 16-03-1207P, effective February 6, 2017. The proposed conditions 1-percent-annual-chance (base) and 0.2-percent-annual- chance floodplains should be mapped to the contour of the backwater elevation of 324.0 and 334.2 feet, respectively. Our review determined that the proposed base and 0.2- percent-annual-chance floodplain delineations on the left bank were not mapped to the correct contour at Cross Sections 1570.82, 1491.63,1337.95, and 1175. Please revise the submitted work map so that all proposed floodplain delineations are mapped to the correct backwater elevation. Revised. Topographic data (proposed conditions) has been provided with the digital submittal. b. Please revise the effective delineations shown on the above -referenced work map to be a different color than the included topographic contours to easily distinguish between them. Revised. Effective delineation is now shown as blue. c. Please ensure that all proposed cross sections are extended beyond the revised proposed 0.2- percent -annual -chance floodplain extents. Revised. d. Based on the changes requested in Item 3, please remove all cross sections that are not included in the revised proposed conditions model. Revised. 6. To assist our review and to expedite processing of this request, please provide digital Computer- Aided Design (CAD) data that reflect the revised topographic work map. Please ensure the digital data are spatially referenced and cite what projection (coordinate system, example: UTM/State Plane) was used, so that the data may be used for accurate mapping. The important data to show on the digital work map are the contour information, the stream centerline, the cross section lines, the road crossings and hydraulic structures, the preliminary and proposed flood hazard delineations andthe tie-in locations. Everything should be clearly labeled and all information should be contained within the drawing and not externally referenced. Provided. 7. Based on any changes to the work map due to the resolution of the items above, please submit an updated annotated Flood Insurance Rate Map (FIRM) on the FIRM from LOMR 16-03- 1207P, effective February 6, 2017, that shows the revised boundary delineations of the base floodplain, 0.2- percent -annual -chance floodplain, and regulatory floodway as shown on the updated work map and how they tie-in to the boundary delineations shown at the downstream and upstream ends of the revised reach. Please use different colors to differentiate the proposed and effective boundary delineations. Also, please show the title block of the effective FIRM on the annotated FIRM. Provided. 8. Our review indicates that the Letter of Map Revision (LOMR) that follows this CLOMR will revise the flood hazard information along Moores Creek. Please submit a copy of the newspaper notice distributed by the Independent City of Charlottesville and Albemarle County stating their intent to revise the flood hazard information (i.e., revise or establish base flood elevations, the base flood floodplain and regulatory floodway) along Moores Creek. Alternatively, please submit documentation that affected property owners have been notified of the proposed flood hazard revisions. Documentation of legal notice may take the form of a signed copy of the letter sent along with either a mailing list or certified mailing receipts. The 316-AD Case No.: 20-03-0027R individual legal notices must include the extent of the proposed revision and contact information for any interested parties and must also mention the community's intent to revise the regulatory floodway. The individual legal notices must be sent on community letterhead or the community must provide a statement confirming that all affected property owners have been notified of the proposed floodway revision. Please submit a draft copy of the notification for verification of content, prior to distribution. One of the attached templates may be used to prepare the draft notification. Draft letter provided. Please upload the required data using your account on the online LOMC website at htips://hazards.fema. gov/femgportal/onlinelomc/si . ngnin.