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HomeMy WebLinkAboutFDP201800020 Correspondence 2018-10-18 (2)COLLINS October 18, 2018 To: Albemarle County and Federal Emergency Management Agency Re: 511 Street, north of the intersection of 5th Street and Interstate 64 ............ ....................... 200 GARRETT ST, SUITE K CHARLOTTESVILLE VA 22902 434.293.3719 PH 434.293.2813 FX ................. www.collins-engincering.com Subject: Project Narrative for LORM-F on the 5th Street Commercial Property Development — Overview: The 5th Street Commercial Development project, located north of the intersection of 51h Street and Interstate 64, consists of (1) parcel with a total acreage of 4.070 acres. The parcel is located at the point where Moore's creek and Biscuit Run Creek merge together, The majority of the property is low lying area that is below the 100 year floodplain elevation for the Moore's Creek and Biscuit Run Creek. The property is sparely wooded in the portion of the property adjacent to 51h Street, and heavily wooded for the remaining portion of the property adjacent to the two creeks. The property is located within the development area for Albemarle County, Virginia. Owners of the property began a rezoning process and Special Use permit process back in 1999 to secure approvals to develop the property. The property to be developed is located adjacent to 5th Street, and is outside of the 100' stream buffer along Biscuit Run and 50' stream buffer along Moore's Creek. The proposed development is also located outside of the existing FEMA floodway, based on the FEMA mapping for this area. Special Use Permit / Rezoning /CLOMR-F Process: The original rezoning for the development on this property was approved by the Board of Supervisors in July, 2002. At the time, the Special Use permit was approved as well. The Special Use permit allowed Albemarle County approval of the proposed fill within the Floodplain. This approval of the Special Use permit was based on the Floodplain Study, analysis, and calculations provided by Dewberry and Davis, LLC between 1999 and 2002. The entire floodplain analysis, calculations, and modelling can be found within the Albemarle County records for SP1999-059. During the Special Use permit process, the applicant applied for and received approval for a LOMR (Letter of Map Revision) for the proposed fill within the floodplain. The LORM was signed off by the Albemarle County Engineer on March 31, 2000 and FEMA issued a LOMR on July 5, 2000 for the modification to the floodplain. However, when FEMA issued the new updated FIRMS on February 5, 2005, this approved LOMR was not included on the mapping. In 2007, the applicant at the request of Albemarle County, was asked to re-applyfor the Special Use permit for the filling in the floodplain. This was requested by Albemarle County to renew the previously approved SP1999-059 that was approved in 2002 because no construction activity or filling had been done on the property. This new Special Use permit (SP2007-063) was approved in 2008 for the original design of the fill within the floodplain. The floodplain analysis for the SP2007-063 was based on the Dewberry Davis LLC floodplain model and design from SP1999-059. In 2013, the applicant applied for another rezoning on the property, to adjust the approved development plan to a new layout for the buildings and parking on the property. This rezoning plan was just recently approved in 2016. The Special Use permit allowing the fill within the floodplain is still valid until June, 2017, based on State legislative changes to the approvals. With the new development plan approved, along with the current Special Use permit, the applicant applied for a CLOMR-F on the property and received approval on the CLORM-F in 2017. The fill was placed on the site in accordance with the conditions of the CLORM-F permit and the approved Albemarle County site plan. FEMA Hydraulic Analysis: During the Special Use Permit process, the Albemarle County Engineering department approved the floodplain study prepared by Dewberry and Davis for the proposed fill. The study was approved by Albemarle County in 2002, and it was determined by the engineering department and Board of Supervisors that the proposed fill for this project would not have an adverse impact on adjacent properties. In the April 3, 2001 Technical Memo issued by Dewberry & Davis, entitled Morris Creek Yacht Club Project Floodplain Analysis, the engineers site a maximum floodplain increase of 0.02 foot due to the proposed placement of the fill at 3:1 slopes within the floodplain (as approved with the SP1999-59 permit). However, this memo also discounted this rise due to modeling requirements on the floodplain analysis. These fluctuations are acceptable to FEMA in cases and situations such as this analysis, as pointed out in the technical memo. In addition, this memo indicated that the BFE was 383.83. The elevation datum for this elevation was NGVD29. The datum for the FEMA FIRM is NAVD88. The conversion of the BFE from the NGV029 datum to the NAVD88 datum resulted in a change of the Base Flood Elevation from 383.83 to 383.0, as listed on the FEMA FIRM. The 383.0 is shown on the attached plan and cross sections as the FEMA 100 year flood plain elevation. Since this Technical Memo was released, a new LORM for the 5th Street Station development (adjacent to this project site) has been reviewed and approved. The St" Street Station LORM has a corrected effective elevation of 382.8 ft. The existing BFE elevation for the 5th Street Commercial Development property is 0.2 ft above this at 383.0-ft. Based on the Post Development Elevations for the 5th Street Station project at STA22955, the new modeled and approved BFE elevation is 383.4 ft. Our development, which is 0.2 ft higher, will have a new BFE of 383.6-ft, based on this new LORM for the 51h Street Station project. Summary: The attached application to this narrative is for the LORM-F for the 511 Street Commercial Development property. The CLORM-F was previously approved and the fill has been placed on the site in accordance with the approved plans and the conditions of the CLOMR-F. Final surveying has been performed to ensure that all the area within the limits of the LORM-F area is at or above the BFE. In addition, the elevations of the BFE on this property have been coordinated with the recently approved LORM for the 5th Street Station project, which is a development adjacent to this property. Q`N SALTS v Please feel free to contact me if you have any additional questions. Sincerely, U SCO Scott Collins, PE tic IV PCs LLovs 7