Flynn, R.H. Prepared for the Federal Emergency Management Agency, Region 1 —Scoping of Flood Hazard Mapping Needs for Belknap County, New Hampshire— Scoping of Flood Hazard Mapping Needs for Belknap County, New Hampshire Open-File Report 2006–1201 Open-File Open-File Report 2006–1201 U.S. Department of the Interior Printed on recycled paper U.S. Geological Survey Scoping of Flood Hazard Mapping Needs for Belknap County, New Hampshire By Robert H. Flynn Prepared for the Federal Emergency Management Agency, Region 1 Open-File Report 2006–1201 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey P. Patrick Leahy, Acting Director U.S. Geological Survey, Reston, Virginia: 2006 For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Contents Section 1. Introduction . 1 Background. 1 Scope of Work . 2 Section 2. Data Collected from Belknap County Communities. 6 Community Flood Insurance Studies and Flood Insurance Rate Maps . 6 Delineation of Detailed and Approximate Study Areas . 7 Letters of Map Change . 7 Letters of Map Change in Belknap County . 8 Mapping Needs Update Support System . 9 Mapping Needs in Belknap County, New Hampshire . 9 State and Community Meetings . 11 Meeting with New Hampshire Office of Emergency Management (NHOEM) and Scoping Team Members . 11 Belknap County Community Meetings . 12 Available Digital Mapping and Remotely Sensed Data . 17 Data-Collection Efforts . 17 NH GRANIT Data Sources . 17 Community Data Resources . 18 Stream Final Coverage Output . 18 Section 3. Options for Future Mapping and Digital Terrain Model Preparation. 20 Mapping Requirements . 20 Base Map . 20 Digital Terrain Models . 21 Flood Insurance Risk Zones . 22 Suitability of the Available Data . 22 USGS of GRANIT . 22 Community Data Resources . 22 County Data Resources . 22 Base Map . 22 Digital Terrain Model . 23 Flood Insurance Risk Zones . 23 Mapping Options . 24 Base Map . 24 Digital Terrain Model . 24 Flood Insurance Risk Zones . 24 Section 4. Hydrologic and Hydraulic Restudy Needs and Prioritization. 25 Mapping Needs . 25 Prioritization Process . 25 Prioritization Results . 26 Non-Participating Communities. 26 Section 5. Recommendations and Schedule . 27 Mapping Recommendations . 27 Mapping Options . 27 iii Project Alternatives . 27 Schedule . 27 Selected References . 28 Appendixes: Appendix A. Summary of Letters of Map Change (LOMC) Data in Belknap County . 29 Appendix B. Mapping Needs Update Support System (MNUSS) Needs Assessment Reports . 31 Appendix C. State and Community Meetings . ..