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Home My WebLink About20163520.tiffFederal Emergency Management Agency Washington, D.C. 20472 October 28, 2016 CERTIFIED MAIL RETURN RECEIPT REQUESTED The Honorable Michael Freeman Chairman, Weld County Board of Commissioners 1150 O Street Greeley, CO 80632 Dear Mr. Freeman: IN REPLY REFER TO: Case No.: 16-08-0342R Community Name: Weld County, CO Community No.: 080266 104 We are providing our comments with the enclosed Conditional Letter of Map Revision (CLOMR) on a proposed project within your community that, if constructed as proposed, could revise the effective Flood Insurance Study report and Flood Insurance Rate Map for your community. If you have any questions regarding the floodplain management regulations for your community, the National Flood Insurance Program (NFIP) in general, or technical questions regarding this CLOMR, please contact the Director, Mitigation Division of the Federal Emergency Management Agency (FEMA) Regional Office in Denver, Colorado, at (303) 235-4830, or the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP). Additional information about the NFIP is available on our website at http://www.fema.gov/national-flood-insurance-program. Sincerely, Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration List of Enclosures: Conditional Letter of Map Revision Comment Document cc: The Honorable Dennis Coombs Mayor, City of Longmont The Honorable Elise Jones Chair, Boulder County Board of Commissioners Mr. Thomas Parko. M.A. Director of Planning Services Weld County Cocc+i Or1s t\Ir1/ic4 RECEIVED NOV 0 9 2016 COUNTY .ThrJ M �S IONERS Mr. Nick Wolfrum, P.E. Director of Engineering Services City of Longmont Ms. Varda Blum Floodplain Program Manager Boulder County Ms. Jennifer Winters, P.E. Water Resources Engineer CH2M Hill Engineers, Inc. Oi-i - CRRJ,et. Cm m/'rP), Pwf7m),CA.(FH) tt/t/tG, 2016-3520 Page 1 of 8 tissue Date: October 28, 2016 (Case No.: 16-08-0342R I CLOMR-APP ,,Yale Federal Emergency ,� Washington, Management Agency D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT COMMUNITY INFORMATION PROPOSED PROJECT DESCRIPTION BASIS OF CONDITIONAL REQUEST COMMUNITY Weld County Colorado (Unincorporated Areas) CHANNELIZATION BRIDGE HYDRAULIC ANALYSIS HYDROLOGIC ANALYSIS UPDATED TOPOGRAPHIC DATA COMMUNITY NO.: 080266 IDENTIFIER Resilient St Vrain Project - City Reach 1 and Sandstone APPROXIMATE LATITUDE AND LONGITUDE: 40.152, -105.061 SOURCE: USGS QUADRANGLE DATUM: NAD 83 AFFECTED MAP PANELS TYPE: FIRM* NO.: 08123C1870E DATE: January 20, 2016 TYPE: FIRM* NO.: 08123C1890E DATE: January 20, 2016 * FIRM - Flood Insurance Rate Map FLOODING SOURCES AND REACH DESCRIPTION See Page 2 for Additional Flooding Sources St. Vrain Creek — from US Highway 119 to approximately 390 feet upstream of South Main Street PROPOSED PROJECT DESCRIPTION Flooding Source Proposed Project Location of Proposed Project St. Vrain Creek Channelization From approximately 6,700 feet downstream to approximately 320 feet downstream of County Line Road and from approximately 4,770 feet to approximately 5,050 feet upstream of US Highway 119 SUMMARY OF IMPACTS TO FLOOD HAZARD DATA Flooding Source Effective Flooding Proposed Flooding Increases Decreases St. Vrain Creek No BFEs* BFEs Yes None Zone A Zone AE Yes Yes Zone A Zone X (shaded) Yes Yes * BFEs - Base (1 -percent -annual -chance) Flood Elevations COMMENT This document provides the Federal Emergency Management Agency's (FEMA's) comment regarding a request for a CLOMR for the project described above. This document is not a final determination; it only provides our comment on the proposed project in relation to the flood hazard information shown on the effective National Flood Insurance Program (NFIP) map. We reviewed the submitted data and the data used to prepare the effective flood hazard information for your community and determined that the proposed project meets the minimum floodplain management criteria of the NFIP. Your community is responsible for approving all floodplain development and for ensuring that all permits required by Federal or State/Commonwealth law have been received. State/Commonwealth, county, and community officials, based on their knowledge of local conditions and in the interest of safety, may set higher standards for construction in the Special Flood Hazard Area (SFHA), the area subject to inundation by the base flood. If the State/Commonwealth, county, or community has adopted more restrictive or comprehensive floodplain management criteria, these criteria take precedence over the minimum NFIP criteria. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 2 of 8 Issue Date: October 28, 2016 Case No.: 16-08-0342R CLOMR-APP Federal Emergency Management Agency Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) ADDITIONAL FLOODING SOURCES AFFECTED BY THIS CONDITIONAL REQUEST FLOODING SOURCE(S) AND REACH DESCRIPTION Sandstone Split — from the confluence with St. Vrain Creek to the divergence from St. Vrain Creek PROPOSED PROJECT DESCRIPTION Flooding Source Sandstone Split Proposed Project Location of Proposed Project Channelization From the approximately 5,130 feet downstream to the divergence from St. Vrain Creek SUMMARY OF IMPACTS TO FLOOD HAZARD DATA Flooding Source Sandstone Split Effective Flooding Proposed Flooding Increases Decreases No BFEs* BFEs Yes None Zone A Zone AE Yes Yes Zone A Zone X (shaded) Yes Yes * BFEs - Base (1 -percent -annual -chance) Flood Elevations This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 3 of 8 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP Management Agency D.C. 20472 Federal Emergency o Washington, CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) OTHER COMMUNITIES AFFECTED BY THIS CONDITIONAL REQUEST CID Number: 080027 Name: City of Longmont, CO AFFECTED MAP PANELS TYPE: FIRM* NO.: 08013C0286J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0287J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0288J DATE: December 18, 2012 TYPE: FIRM* NO.. 08013C0289J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0293J DATE: December 18, 2012 TYPE: FIRM* NO.: 08123C1870E DATE: January 20, 2016 CID Number: 080023 Name: Boulder County, CO AFFECTED MAP PANELS TYPE: FIRM* NO.: 08013C0286J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0287J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0288J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0289J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0293J DATE: December 18, 2012 This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. ---,I Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 4 of 8 'Issue Date: October 28, 2016 (Case No.: 16-08-0342R I CLOMR-APP 1'6tR7-4,t Federal Emergency Management Agency Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED), COMMUNITY INFORMATION To determine the changes in flood hazards that will be caused by the proposed project, we compared the hydraulic modeling reflecting the proposed project (referred to as the proposed conditions model) to the hydraulic modeling reflecting the existing conditions. The table below shows the changes in the base flood water -surface elevations (WSEL5). Base Flood WSEL Comparison Table Flooding Source: St. Vrain Creek Base Flood WSEL Change (feet) Location of maximum change Proposed vs. Existing Maximum increase 2.1 Approximately 7,000 feet downstream from County Line Road Maximum decrease 3.0 Approximately 10,550 feet downstream from County Line Road Flooding Source: Sandstone Split Base Flood WSEL Change (feet) Location of maximum change Proposed vs. Existing Maximum increase 0.7 Approximately 5,110 feet downstream from the split with St. Vrain Creek Maximum decrease 0.6 Approximately 4,230 feet downstream from the split with St. Vrain Creek Increases due to the proposed project that exceed those permitted under Paragraphs (c)(10) or (d)(3) of Section 60.3 of the NFIP regulations must adhere to Section 65.12 of the NFIP regulations. With this request, your community has complied with all requirements of Paragraph 65.12(a) of the NFIP regulations. Compliance with Paragraph 65.12(b) also is necessary before FEMA can issue a Letter of Map Revision when a community proposes to permit encroachments into the effective floodplain that will cause BFE increases in excess of those permitted under Paragraph 60.3(c)(10). NFIP regulations Subparagraph 60.3(b)(7) requires communities to ensure that the flood -carrying capacity within the altered or relocated portion of any watercourse is maintained. This provision is incorporated into your community's existing floodplain management ordinances; therefore, responsibility for maintenance of the altered or relocated watercourse, including any related appurtenances such as bridges, culverts, and other drainage structures, rests with your community. We may request that your community submit a description and schedule of maintenance activities necessary to ensure this requirement. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. (—--',3141 Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 5 of 8 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP ART,, Federal Emergency Management Agency -�° Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) Increases due to the proposed project that exceed those permitted under Paragraphs (c)(10) or (d)(3) of Section 60.3 of the NFIP regulations must adhere to Section 65.12 of the NFIP regulations. With this request, your community has complied with all requirements of Paragraph 65.12(a) of the NFIP regulations. Compliance with Paragraph 65.12(b) also is necessary before FEMA can issue a Letter of Map Revision when a community proposes to permit encroachments into the effective floodplain that will cause BFE increases in excess of those permitted under Paragraph 60.3(c)(10). NFIP regulations Subparagraph 60.3(b)(7) requires communities to ensure that the flood -carrying capacity within the altered or relocated portion of any watercourse is maintained. This provision is incorporated into your community's existing floodplain management ordinances; therefore, responsibility for maintenance of the altered or relocated watercourse, including any related appurtenances such as bridges, culverts, and other drainage structures, rests with your community. We may request that your community submit a description and schedule of maintenance activities necessary to ensure this requirement. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. •at 1—PAII Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 6 of 8 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP AR Federal Emergency Management Agency Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) DATA REQUIRED FOR FOLLOW-UP LOMR Upon completion of the project, your community must submit the data listed below and request that we make a final determination on revising the effective FIRM and FIS report. If the project is built as proposed and the data below are received, a revision to the FIRM and FIS report would be warranted. • Detailed application and certification forms must be used for requesting final revisions to the maps. Therefore, when the map revision request for the area covered by this letter is submitted, Form 1, entitled "Overview and Concurrence Form," must be included. A copy of this form may be accessed at https://www.fema.gov/media-library/assets/documents/1343. • The detailed application and certification forms listed below may be required if as -built conditions differ from the proposed plans. If required, please submit new forms, which may be accessed at https://www.fema.gov/media-library/assets/documents/1343, or annotated copies of the previously submitted forms showing the revised information. Form 2, entitled "Riverine Hydrology and Hydraulics Form." Hydraulic analyses for as -built conditions of the base flood, the 10 -percent, 2 -percent, and 0.2 -percent -annual -chance floods must be submitted with Form 2. Form 3, entitled "Riverine Structures Form." • A certified topographic work map showing the revised and effective base and 0.2 -percent -annual -chance floodplain boundaries. Please ensure that the revised information ties -in with the current effective information at the downstream and upstream ends of the revised reach. • An annotated copy of the FIRM, at the scale of the effective FIRM, that shows the revised base and 0.2 -percent -annual -chance floodplain boundary delineations shown on the submitted work map and how they tie-in to the base and 0.2 -percent -annual -chance floodplain boundary delineations shown on the current effective FIRM at the downstream and upstream ends of the revised reach. • As -built plans, certified by a registered Professional Engineer, of all proposed project elements. • Documentation of the individual legal notices sent to property owners who will be affected by any widening or shifting of the base floodplain and/or any BFE increases or establishment along St. Vrain Creek and Sandstone Split. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. _�_�_f/f —'''(1411 Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 7 of 8 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP Agency 'pp�w�pz Federal Emergency Management Yln k>• Washington, D.C. 20472 {,wb CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) DATA REQUIRED FOR FOLLOW-UP LOMR (continued) • FEMA's fee schedule for reviewing and processing requests for conditional and final modifications to published flood information and maps may be accessed at https://www.fema.gov/flood-map-related-fees. The fee at the time of the map revision submittal must be received before we can begin processing the request. Payment of this fee can be made through a check or money order, made payable in U.S. funds to the National Flood Insurance Program, or by credit card (Visa or MasterCard only). Please either forward the payment, along with the revision application, to the following address: LOMC Clearinghouse Attention: LOMR Manager 847 South Pickett Street Alexandria, Virginia 22304-4605 or submit the LOMR using the Online LOMC portal at https://hazards.fema.gov/femaportal/onlinelomc/signin. After receiving appropriate documentation to show that the project has been completed, FEMA will initiate a revision to the FIRM and FIS report. Because the flood hazard information (i.e., base flood elevations, base flood depths, SFHAs, zone designations, and/or regulatory floodways) will change as a result of the project, a 90 -day appeal period will be initiated for the revision, during which community officials and interested persons may appeal the revised flood hazard information based on scientific or technical data. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. 6?1 A Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 8 of 8 Ilssue Date: October 28, 2016 ICase No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency Washington, D.C. 20472 p"t+ 1) S`.. CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) COMMUNITY REMINDERS We have designated a Consultation Coordination Officer (CCO) to assist your community. The CCO will be the primary liaison between your community and FEMA. For information regarding your CCO, please contact: Ms. Jeanine P. Petterson Director, Mitigation Division Federal Emergency Management Agency, Region VIII Denver Federal Center, Building 710 P.O. Box 25267 Denver, CO 80225-0267 (303) 235-4830 This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Federal Emergency Management Agency CERTIFIED MAIL RETURN RECEIPT REQUESTED The Honorable Dennis Coombs Mayor, City of Longmont 350 Kimbark Street Longmont, CO 80501 Washington, D.C. 20472 October 28, 2016 IN REPLY REFER TO: Case No.: 16-08-03428 Community Name: City of Longmont, CO Community No.: 080027 104 Dear Mayor Coombs: We are providing our comments with the enclosed Conditional Letter of Map Revision (CLOMR) on a proposed project within your community that, if constructed as proposed, could revise the effective Flood Insurance Study report and Flood Insurance Rate Map for your community. If you have any questions regarding the floodplain management regulations for your community, the National Flood Insurance Program (NFIP) in general, or technical questions regarding this CLOMR, please contact the Director, Mitigation Division of the Federal Emergency Management Agency (FEMA) Regional Office in Denver, Colorado, at (303) 235-4830, or the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP). Additional information about the NFIP is available on our website at http://www.fema.gov/national-flood-insurance-program. Sincerely, /94 Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration List of Enclosures: Conditional Letter of Map Revision Comment Document cc: The Honorable Elise Jones Chair, Boulder County Board of Commissioners The Honorable Michael Freeman Chairman, Weld County Board of Commissioners Mr. Nick Wolfrum, P.E. Director of Engineering Services City of Longmont Ms. Varda Blum Floodplain Program Manager Boulder County Mr. Thomas Parko, M.A. Director of Planning Services Weld County Ms. Jennifer Winters, P.E. Water Resources Engineer CH2M Hill Engineers, Inc. Page 1 of 10 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency ,..,� ' Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT COMMUNITY INFORMATION PROPOSED PROJECT DESCRIPTION BASIS OF CONDITIONAL REQUEST COMMUNITY City of Longmont Boulder County Colorado CHANNELIZATION BRIDGE HYDRAULIC ANALYSIS HYDROLOGIC ANALYSIS UPDATED TOPOGRAPHIC DATA COMMUNITY NO.: 080027 IDENTIFIER Resilient St Vrain Project - City Reach 1 and Sandstone APPROXIMATE LATITUDE AND LONGITUDE: 40.152, -105.061 SOURCE: USGS QUADRANGLE DATUM: NAD 83 AFFECTED MAP PANELS TYPE: FIRM' NO.: 08013C0286J DATE: December 18, 2012 TYPE: FIRM' NO.: 08013C0287J DATE: December 18, 2012 TYPE: FIRM" NO.: 08013C0288J DATE: December 18, 2012 TYPE: FIRM' NO.: 08013C0289J DATE: December 18, 2012 TYPE: FIRM' NO.: 08013C0293J DATE: December 18, 2012 TYPE: FIRM* NO.: 08123C1870E DATE: January 20, 2016 ' FIRM - Flood Insurance Rate Map FLOODING SOURCES AND REACH DESCRIPTION See Page 2 for Additional Flooding Sources St. Vrain Creek — from US Highway 119 to approximately 390 feet upstream of South Main Street PROPOSED PROJECT DESCRIPTION Flooding Source Proposed Project Location of Proposed Project St. Vrain Creek New Bridge Three pedestrian bridges, approximately 790 feet downstream of South Main Street, approximately 840 feet upstream of Martin Street, and approximately 7,780 feet downstream of County Line Road Channelization From approximately 2,640 feet downstream of Martin Street to approximately 50 feet upstream of Main Street and from approximately 940 feet upstream of US Highway 119 to approximately 320 feet downstream of County Line Road SUMMARY OF IMPACTS TO FLOOD HAZARD DATA Flooding Source Effective Flooding Proposed Flooding Increases Decreases St. Vrain Creek BFEs' BFEs Yes Yes No BFEs BFEs Yes None Zone AE Zone AE Yes Yes Zone A Zone AE Yes Yes Zone A Zone X (shaded) Yes Yes Zone X (shaded) Zone X (shaded) Yes Yes * BFEs - Base (1 -percent -annual -chance) Flood Elevations COMMENT This document provides the Federal Emergency Management Agency's (FEMA's) comment regarding a request for a CLOMR for the project described above. This document is not a final determination; it only provides our comment on the proposed project in relation to the flood hazard information shown on the effective National Flood Insurance Program (NFIP) map. We reviewed the submitted data and the data used to prepare the effective flood hazard information for your community and determined that the proposed project meets the minimum floodplain management criteria of the NFIP. Your community is responsible for approving all floodplain , development and for ensuring that all permits required by Federal or State/Commonwealth law have been received. State/Commonwealth, county, and community officials, based on their knowledge of local conditions and in the interest of safety, may set higher standards for construction in the Special Flood Hazard Area (SFHA), the area subject to inundation by the base flood. If the State/Commonwealth, county, or community has adopted more restrictive or comprehensive floodplain management criteria, these criteria take precedence over the minimum NFIP criteria. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. 61:---',21 Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 2 of 10 Issue Date: October 28, 2016 Case No.: 16-08-0342R CLOMR-APP Federal Emergency Management A , a g Agency Washington, D.C. 20472 avr� s CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) ADDITIONAL FLOODING SOURCES AFFECTED BY THIS CONDITIONAL REQUEST FLOODING SOURCE(S) AND REACH DESCRIPTION Sandstone Split — from the confluence with St. Vrain Creek to the divergence from St. Vrain Creek Issac Walton Split - from the confluence with St. Vrain Creek to the divergence from St. Vrain Creek Dry Creek No. 1 (Old Channel) - from the confluence to approximately 540 feet upstream from the confluence with St. Vrain Creek Lefthand Creek - from the confluence to approximately 920 feet upstream from the confluence with St. Vrain Creek Spring Gulch - from the confluence to approximately 700 feet upstream from the confluence with St. Vrain Creek PROPOSED PROJECT DESCRIPTION Flooding Source Proposed Project Location of Proposed Project Sandstone Split Bridge Modification Approximately 6,280 feet downstream of the divergence from St. Vrain Creek Channelization From the confluence with St. Vrain Creek to the divergence from St. Vrain Creek Issac Walton Split No Project Dry Creek No. 1 (Old Channel) No Project Lefthand Creek No Project Spring Gulch No Project SUMMARY OF IMPACTS TO FLOOD HAZARD DATA Flooding Source Effective Flooding Proposed Flooding Increases Decreases Sandstone Split No BFEs* BFEs Yes None Zone A Zone AE Yes Yes Zone A Zone X (shaded) Yes Yes Dry Creek No. 1 (Old Channel) BFEs BFEs None Yes Zone AE Zone AE None Yes Lefthand Creek Zone AE Zone AE Yes Yes Spring Gulch BFEs BFEs Yes None Zone AE Zone AE Yes Yes Zone X (unshaded) Zone X (shaded) Yes None * BFEs - Base (1 -percent -annual -chance) Flood Elevations This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. l(::;/—",-/41/ Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 3 of 10 Issue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) OTHER COMMUNITIES AFFECTED BY THIS CONDITIONAL REQUEST CID Number: 080023 Name: Boulder County, CO AFFECTED MAP PANELS TYPE: FIRM* NO.: 08013C0286J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0287J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0288J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0289J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0293J DATE: December 18, 2012 CID Number: 080266 Name: Weld County, CO AFFECTED MAP PANELS TYPE: FIRM* NO.: 08123C1870E DATE: January 20, 2016 TYPE: FIRM* NO.: 08123C1890E DATE: January 20, 2016 This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information exchange (FM IX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 4 of 10 Ilssue Date: October 28, 2016 ICase No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency Washington, D.C. 20472 42 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION To determine the changes in flood hazards that will be caused by the proposed project, we compared the hydraulic modeling reflecting the proposed project (referred to as the proposed conditions model) to the hydraulic modeling used to prepare the Flood Insurance Study (FIS) (referred to as the effective model). If the effective model does not provide enough detail to evaluate the effects of the proposed project, an existing conditions model must be developed to provide this detail. This existing conditions model is then compared to the effective model and the proposed conditions model to differentiate the increases or decreases in flood hazards caused by more detailed modeling from the increases or decreases in flood hazards that will be caused by the proposed project. The table below shows the changes in the BFEs: BFE Comparison Table Flooding Source: St. Vrain Creek BFE Change (feet) Location of maximum change Existing vs. Effective Maximum increase 4.9 Approximately 200 feet upstream of Ken Pratt Boulevard Maximum decrease 2.0 Approximately 2,790 feet upstream of Ken Pratt Boulevard Proposed vs. Existing Maximum increase 2.3 Approximately 80 feet downstream of Martin Street Maximum decrease 3.7 Approximately 190 feet downstream of Main Street Proposed vs. Effective Maximum increase 3.6 Approximately 2,760 feet downstream of Main Street Maximum decrease 2.4 Approximately 2,670 feet upstream of Ken Pratt Boulevard Flooding Source: Issac Walton Split BFE Change (feet) Location of maximum change Existing vs. Effective Maximum increase 3.9 Approximately 900 feet upstream of the confluence with St. Vrain Creek Maximum decrease None N/A Proposed vs. Existing Maximum increase None N/A Maximum decrease 7.1 - Approximately 900 feet upstream of the confluence with St. Vrain Creek Proposed vs. Effective Maximum increase None N/A Maximum decrease _ None N/A Flooding Source: Dry Creek No. 1 (Old Channel) BFE Change (feet) Location of maximum change Existing vs. Effective Maximum increase None N/A Maximum decrease 0.4 At the confluence with St. Vrain Creek Proposed vs. Existing Maximum increase None N/A Maximum decrease 0.3 At the confluence with St. Vrain Creek Proposed vs. Effective Maximum increase None N/A Maximum decrease 0.7 At the confluence with St. Vrain Creek This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.aov/national-flood-insurance-program. ----,2 Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 5 of 10 tissue Date: October 28, 2016 (Case No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency ° Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION To determine the changes in flood hazards that will be caused by the proposed project, we compared the hydraulic modeling reflecting the proposed project (referred to as the proposed conditions model) to the hydraulic modeling used to prepare the Flood Insurance Study (FIS) (referred to as the effective model). If the effective model does not provide enough detail to evaluate the effects of the proposed project, an existing conditions model must be developed to provide this detail. This existing conditions model is then compared to the effective model and the proposed conditions model to differentiate the increases or decreases in flood hazards caused by more detailed modeling from the increases or decreases in flood hazards that will be caused by the proposed project. The table below shows the changes in the BFEs: BFE Comparison Table Flooding Source: Lefthand Creek BFE Change (feet) Location of maximum change Existing vs. Effective Maximum increase 1.4 At the confluence with St. Vrain Creek Maximum decrease None N/A Proposed vs. Existing Maximum increase None N/A Maximum decrease - 2.2 At the confluence with St. Vrain Creek Proposed vs. Effective Maximum increase None N/A Maximum decrease None N/A Flooding Source: Spring Gulch BFE Change (feet) Location of maximum change Existing vs. Effective Maximum increase 0.8 Approximately 100 feet upstream of the confluence with St. Vrain Creek Maximum decrease None N/A Proposed vs. Existing Maximum increase 1.2 Approximately 130 feet downstream of Martin Street Maximum decrease 1.0 Approximately 140 feet upstream of the confluence with St. Vrain Creek Proposed vs. Effective Maximum increase 1.3 Approximately 130 feet downstream of Martin Street Maximum decrease 0.3 Approximately 140 feet upstream of the confluence with St. Vrain Creek Increases due to the proposed project that exceed those permitted under Paragraphs (c)(10) or (d)(3) of Section 60.3 of the NFIP regulations must adhere to Section 65.12 of the NFIP regulations. With this request, your community has complied with all requirements of Paragraph 65.12(a) of the NFIP regulations. Compliance with Paragraph 65.12(b) also is necessary before FEMA can issue a Letter of Map Revision when a community proposes to permit encroachments into the effective floodplain that will cause BFE increases in excess of those permitted under Paragraph 60.3(c)(10). NFIP regulations Subparagraph 60.3(b)(7) requires communities to ensure that the flood -carrying capacity within the altered or relocated portion of any watercourse is maintained. This provision is incorporated into your community's existing floodplain management ordinances; therefore, responsibility for maintenance of the altered or relocated watercourse, including any related appurtenances such as bridges, culverts, and other drainage structures, rests with your community. We may request that your community submit a description and schedule of maintenance activities necessary to ensure this requirement. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.aaoovv/f//national-flood-insurance-program. l��rr�7 Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 6 of 10 Ilssue Date: October 28, 2016 (Case No.: 16-08-0342R 1 CLOMR-APP "`. ti Federal Emergency Management Agency Washington, D.C. 20472 OS :... CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION To determine the changes in flood hazards that will be caused by the proposed project, we compared the hydraulic modeling reflecting the proposed project (referred to as the proposed conditions model) to the hydraulic modeling reflecting the existing conditions. The table below shows the changes in the base flood water -surface elevations (WSELs). Base Flood WSEL Comparison Table Flooding Source: St. Vrain Creek Base Flood WSEL Change (feet) Location of maximum change Proposed vs. Existing Maximum increase 2.2 Approximately 7,340 feet downstream from County Line Road Maximum decrease 3.0 Approximately 10,550 feet downstream from County Line Road Flooding Source: Sandstone Split Base Flood WSEL Change (feet) Location of maximum change Proposed vs. Existing Maximum increase 0.9 Approximately 6,020 feet downstream from the split with St. Vrain Creek Maximum decrease - 0.2 Approximately 1,830 feet downstream from the split with St. Vrain Creek This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 7 of 10 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP w <: Federal Emergency Management Agency Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) Increases due to the proposed project that exceed those permitted under Paragraphs (c)(10) or (d)(3) of Section 60.3 of the NFIP regulations must adhere to Section 65.12 of the NFIP regulations. With this request, your community has complied with all requirements of Paragraph 65.12(a) of the NFIP regulations. Compliance with Paragraph 65.12(b) also is necessary before FEMA can issue a Letter of Map Revision when a community proposes to permit encroachments into the effective floodplain that will cause BFE increases in excess of those permitted under Paragraph 60.3(c)(10). NFIP regulations Subparagraph 60.3(b)(7) requires communities to ensure that the flood -carrying capacity within the altered or relocated portion of any watercourse is maintained. This provision is incorporated into your community's existing floodplain management ordinances; therefore, responsibility for maintenance of the altered or relocated watercourse, including any related appurtenances such as bridges, culverts, and other drainage structures, rests with your community. We may request that your community submit a description and schedule of maintenance activities necessary to ensure this requirement. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 8 of 10 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP O\ Federal Emergency Management Agency n n svc ., Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) DATA REQUIRED FOR FOLLOW-UP LOMR Upon completion of the project, your community must submit the data listed below and request that we make a final determination on revising the effective FIRM and FIS report. If the project is built as proposed and the data below are received, a revision to the FIRM and FIS report would be warranted. • Detailed application and certification forms must be used for requesting final revisions to the maps. Therefore, when the map revision request for the area covered by this letter is submitted, Form 1, entitled "Overview and Concurrence Form," must be included. A copy of this form may be accessed at https://www.fema.gov/media-library/assets/documents/1343. • The detailed application and certification forms listed below may be required if as -built conditions differ from the proposed plans. If required, please submit new forms, which may be accessed at https://www.fema.gov/media-library/assets/documents/1343, or annotated copies of the previously submitted forms showing the revised information. Form 2, entitled "Riverine Hydrology and Hydraulics Form." Hydraulic analyses for as -built conditions of the base flood, the 10 -percent, 2 -percent, and 0.2 -percent -annual -chance floods must be submitted with Form 2. Form 3, entitled "Riverine Structures Form." • A certified topographic work map showing the revised and effective base and 0.2 -percent -annual -chance floodplain boundaries. Please ensure that the revised information ties -in with the current effective information at the downstream and upstream ends of the revised reach. • An annotated copy of the FIRM, at the scale of the effective FIRM, that shows the revised base and 0.2 -percent -annual -chance floodplain boundary delineations shown on the submitted work map and how they tie-in to the base and 0.2 -percent -annual -chance floodplain boundary delineations shown on the current effective FIRM at the downstream and upstream ends of the revised reach. • As -built plans, certified by a registered Professional Engineer, of all proposed project elements. • Documentation of the individual legal notices sent to property owners who will be affected by any widening or shifting of the base floodplain and/or any BFE increases or establishment along St. Vrain Creek, Sandstone Split, Spring Gulch, Lefthand Creek, and Dry Creek No. 1 (Old Channel). This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 9 of 10 Ilssue Date: October 28, 2016 (Case No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency Washington, D.C. 20472 D S ,, CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) DATA REQUIRED FOR FOLLOW-UP LOMR (continued) • FEMA's fee schedule for reviewing and processing requests for conditional and final modifications to published flood information and maps may be accessed at https://www.fema.gov/flood-map-related-fees. The fee at the time of the map revision submittal must be received before we can begin processing the request. Payment of this fee can be made through a check or money order, made payable in U.S. funds to the National Flood Insurance Program, or by credit card (Visa or MasterCard only). Please either forward the payment, along with the revision application, to the following address: LOMC Clearinghouse Attention: LOMR Manager 847 South Pickett Street Alexandria, Virginia 22304-4605 or submit the LOMR using the Online LOMC portal at https://hazards.fema.gov/femaportal/onlinelomc/signin. After receiving appropriate documentation to show that the project has been completed, FEMA will initiate a revision to the FIRM and FIS report. Because the flood hazard information (i.e., base flood elevations, base flood depths, SFHAs, zone designations, and/or regulatory floodways) will change as a result of the project, a 90 -day appeal period will be initiated for the revision, during which community officials and interested persons may appeal the revised flood hazard information based on scientific or technical data. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 10 of 10 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency ,.�`� Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) COMMUNITY REMINDERS We have designated a Consultation Coordination Officer (CCO) to assist your community. The CCO will be the primary liaison between your community and FEMA. For information regarding your CCO, please contact: Ms. Jeanine P. Petterson Director, Mitigation Division Federal Emergency Management Agency, Region VIII Denver Federal Center, Building 710 P.O. Box 25267 Denver, CO 80225-0267 (303) 235-4830 This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Federal Emergency Management Agency Washington, D.C. 20472 October 28, 2016 CERTIFIED MAIL RETURN RECEIPT REQUESTED The Honorable Elise Jones Chair, Boulder County Board of Commissioners 1325 Pearl Street Boulder, CO 80302 Dear Ms. Jones: IN REPLY REFER TO: Case No.: 16-08-0342R Community Name: Boulder County, CO Community No.: 080023 104 We are providing our comments with the enclosed Conditional Letter of Map Revision (CLOMR) on a proposed project within your community that, if constructed as proposed, could revise the effective Flood Insurance Study report and Flood Insurance Rate Map for your community. If you have any questions regarding the floodplain management regulations for your community, the National Flood Insurance Program (NFIP) in general, or technical questions regarding this CLOMR, please contact the Director, Mitigation Division of the Federal Emergency Management Agency (FEMA) Regional Office in Denver, Colorado, at (303) 235-4830, or the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP). Additional information about the NFIP is available on our website at http://www.fema.gov/national-flood-insurance-program. Sincerely, Patrick "Rick' F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration List of Enclosures: Conditional Letter of Map Revision Comment Document cc: The Honorable Dennis Coombs Mayor, City of Longmont The Honorable Michael Freeman Chairman, Weld County Board of Commissioners Ms. Varda Blum Floodplain Program Manager Boulder County Mr. Nick Wolfrum, P.E. Director of Engineering Services City of Longmont Mr. Thomas Parko, M.A. Director of Planning Services Weld County Ms. Jennifer Winters, P.E. Water Resources Engineer CH2M Hill Engineers, Inc. Page 1 of 6 Ilssue Date: October 28, 2016 (Case No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency s./ Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT COMMUNITY INFORMATION PROPOSED PROJECT DESCRIPTION BASIS OF CONDITIONAL REQUEST COMMUNITY Boulder County Colorado (Unincorporated Areas) CHANNELIZATION BRIDGE HYDRAULIC ANALYSIS HYDROLOGIC ANALYSIS UPDATED TOPOGRAPHIC DATA COMMUNITY NO.: 080023 IDENTIFIER Resilient St Vrain Project - City Reach 1 and Sandstone APPROXIMATE LATITUDE AND LONGITUDE: 40.152, -105.061 SOURCE: USGS QUADRANGLE DATUM: NAD 83 AFFECTED MAP PANELS TYPE: FIRM* NO.: 08013C0286J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0287J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0288J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0289J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0293J DATE: December 18, 2012 ' FIRM - Flood Insurance Rate Map , FLOODING SOURCES AND REACH DESCRIPTION See Page 2 for Additional Flooding Sources St. Vrain Creek — from US Highway 119 to approximately 390 feet upstream of South Main Street PROPOSED PROJECT DESCRIPTION Flooding Source Proposed Project Location of Proposed Project St. Vrain Creek No Project SUMMARY OF IMPACTS TO FLOOD HAZARD DATA Flooding Source Effective Flooding Proposed Flooding Increases Decreases St. Vrain Creek BFEs* BFEs Yes Yes No BFEs BFEs Yes None Zone AE Zone AE Yes Yes Zone A Zone AE Yes Yes Zone A Zone X (shaded) Yes Yes Zone X (shaded) Zone X (shaded) Yes Yes ' BFEs - Base (1 -percent -annual -chance) Flood Elevations COMMENT This document provides the Federal Emergency Management Agency's (FEMA's) comment regarding a request for a CLOMR for the project described above. This document is not a final determination; it only provides our comment on the proposed project in relation to the flood hazard information shown on the effective National Flood Insurance Program (NFIP) map. We reviewed the submitted data and the data used to prepare the effective flood hazard information for your community and determined that the proposed project meets the minimum floodplain management criteria of the NFIP. Your community is responsible for approving all floodplain development and for ensuring that all permits required by Federal or State/Commonwealth law have been received. State/Commonwealth, county, and community officials, based on their knowledge of local conditions and in the interest of safety, may set higher standards for construction in the Special Flood Hazard Area (SFHA), the area subject to inundation by the base flood. If the State/Commonwealth, county, or community has adopted more restrictive or comprehensive floodplain management criteria, these criteria take precedence over the minimum NFIP criteria. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 2 of 6 I Issue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) OTHER COMMUNITIES AFFECTED BY THIS CONDITIONAL REQUEST CID Number: 080027 Name: City of Longmont, CO AFFECTED MAP PANELS TYPE: FIRM* NO.: 08013C0286J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0287J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0288J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0289J DATE: December 18, 2012 TYPE: FIRM* NO.: 08013C0293J DATE: December 18, 2012 TYPE: FIRM* NO.: 08123C1870E DATE: January 20, 2016 CID Number: 080266 Name: Weld County, CO AFFECTED MAP PANELS TYPE: FIRM* NO.: 08123C1870E DATE: January 20, 2016 TYPE: FIRM* NO.: 08123C1890E DATE: January 20, 2016 This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 3 of 6 Ilssue Date: October 28, 2016 (Case No.: 16-08-0342R I CLOMR-APP Emergency Management Agency Washington, D.C. 20472 ausFederal 1...O D CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION To determine the changes in flood hazards that will be caused by the proposed project, we compared the hydraulic modeling reflecting the proposed project (referred to as the proposed conditions model) to the hydraulic modeling used to prepare the Flood Insurance Study (FIS) (referred to as the effective model). If the effective model does not provide enough detail to evaluate the effects of the proposed project, an existing conditions model must be developed to provide this detail. This existing conditions model is then compared to the effective model and the proposed conditions model to differentiate the increases or decreases in flood hazards caused by more detailed modeling from the increases or decreases in flood hazards that will be caused by the proposed project. The table below shows the changes in the BFEs: BFE Comparison Table Flooding Source: St. Vrain Creek BFE Change (feet) Location of maximum change Existing vs. Effective Maximum increase 4.9 Approximately 200 feet upstream of Ken Pratt Boulevard Maximum decrease 2.0 Approximately 2,790 feet upstream of Ken Pratt Boulevard Proposed vs. Existing Maximum increase None N/A Maximum decrease 0.4 Approximately 2,310 feet upstream of Ken Pratt Boulevard Proposed vs. Effective Maximum increase 1.0 Approximately 1,880 feet upstream of Ken Pratt Boulevard Maximum decrease 1.0 Approximately 2,450 feet upstream of Ken Pratt Boulevard Increases due to the proposed project that exceed those permitted under Paragraphs (c)(10) or (d)(3) of Section 60.3 of the NFIP regulations must adhere to Section 65.12 of the NFIP regulations. With this request, your community has complied with all requirements of Paragraph 65.12(a) of the NFIP regulations. Compliance with Paragraph 65.12(b) also is necessary before FEMA can issue a Letter of Map Revision when a community proposes to permit encroachments into the effective floodplain that will cause BFE increases in excess of those permitted under Paragraph 60.3(c)(10). NFIP regulations Subparagraph 60.3(b)(7) requires communities to ensure that the flood -carrying capacity within the altered or relocated portion of any watercourse is maintained. This provision is incorporated into your community's existing floodplain management ordinances; therefore, responsibility for maintenance of the altered or relocated watercourse, including any related appurtenances such as bridges, culverts, and other drainage structures, rests with your community. We may request that your community submit a description and schedule of maintenance activities necessary to ensure this requirement. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 4 of 6 Issue Date: October 28, 2016 ICase No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) DATA REQUIRED FOR FOLLOW-UP LOMR Upon completion of the project, your community must submit the data listed below and request that we make a final determination on revising the effective FIRM and FIS report. If the project is built as proposed and the data below are received, a revision to the FIRM and FIS report would be warranted. • Detailed application and certification forms must be used for requesting final revisions to the maps. Therefore, when the map revision request for the area covered by this letter is submitted, Form 1, entitled "Overview and Concurrence Form," must be included. A copy of this form may be accessed at https://www.fema.gov/media-library/assets/documents/1343. • The detailed application and certification forms listed below may be required if as -built conditions differ from the proposed plans. If required, please submit new forms, which may be accessed at https://www.fema.gov/media-library/assets/documents/1343, or annotated copies of the previously submitted forms showing the revised information. Form 2, entitled "Riverine Hydrology and Hydraulics Form." Hydraulic analyses for as -built conditions of the base flood, the 10 -percent, 2 -percent, and 0.2 -percent -annual chance floods must be submitted with Form 2. Form 3, entitled "Riverine Structures Form." • A certified topographic work map showing the revised and effective base and 0.2 -percent -annual -chance floodplain boundaries. Please ensure that the revised information ties -in with the current effective information at the downstream and upstream ends of the revised reach. • An annotated copy of the FIRM, at the scale of the effective FIRM, that shows the revised base and 0.2 -percent -annual -chance floodplain boundary delineations shown on the submitted work map and how they tie-in to the base and 0.2 -percent -annual -chance floodplain boundary delineations shown on the current effective FIRM at the downstream and upstream ends of the revised reach. • As -built plans, certified by a registered Professional Engineer, of all proposed project elements. • Documentation of the individual legal notices sent to property owners who will be affected by any widening or shifting of the base floodplain and/or any BFE increases or establishment along St. Vrain Creek. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. ic,:, A Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 5 of 6 Ilssue Date: October 28, 2016 'Case No.: 16-08-0342R I CLOMR-APP Federal Emergency Management Agency Washington, D.C. 20472 Styr CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) DATA REQUIRED FOR FOLLOW-UP LOMR (continued) • FEMA's fee schedule for reviewing and processing requests for conditional and final modifications to published flood information and maps may be accessed at https://www.fema.gov/flood-map-related-fees. The fee at the time of the map revision submittal must be received before we can begin processing the request. Payment of this fee can be made through a check or money order, made payable in U.S. funds to the National Flood Insurance Program, or by credit card (Visa or MasterCard only). Please either forward the payment, along with the revision application, to the following address: LOMC Clearinghouse Attention: LOMR Manager 847 South Pickett Street Alexandria, Virginia 22304-4605 or submit the LOMR using the Online LOMC portal at https://hazards.fema.gov/femaportal/onlinelomc/signin. After receiving appropriate documentation to show that the project has been completed, FEMA will initiate a revision to the FIRM and FIS report. Because the flood hazard information (i.e., base flood elevations, base flood depths, SFHAs, zone designations, and/or regulatory floodways) will change as a result of the project, a 90 -day appeal period will be initiated for the revision, during which community officials and interested persons may appeal the revised flood hazard information based on scientific or technical data. This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. 6—./ A Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Page 6 of 6 Ilssue Date: October 28, 2016 (Case No.: 16-08-0342R I CLOMR-APP v R7gq Federal Emergency Management Agency Washington, D.C. 20472 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) COMMUNITY REMINDERS We have designated a Consultation Coordination Officer (CCO) to assist your community. The CCO will be the primary liaison between your community and FEMA. For information regarding your CCO, please contact: Ms. Jeanine P. Petterson Director, Mitigation Division Federal Emergency Management Agency, Region VIII Denver Federal Center, Building 710 P.O. Box 25267 Denver, CO 80225-0267 (303) 235-4830 This comment is based on the flood data presently available. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at 1-877-336-2627 (1-877-FEMA MAP) or by letter addressed to the LOMC Clearinghouse, 847 South Pickett Street, Alexandria, VA 22304-4605. Additional information about the NFIP is available on the FEMA website at http://www.fema.gov/national-flood-insurance-program. Patrick "Rick" F. Sacbibit, P.E., Branch Chief Engineering Services Branch Federal Insurance and Mitigation Administration 16-08-0342R 104 Hello