Scoping of Flood Hazard Mapping Needs for Coos County, New Hampshire

Abstract

This report was prepared by the U.S. Geological Survey (USGS) New Hampshire/Vermont Water Science Center for scoping of flood-hazard mapping needs for Coos County, New Hampshire, under Federal Emergency Management Agency (FEMA) Inter-Agency agreement Number HSFE01-05X-0018. This section of the report explains the objective of the task and the purpose of the reports. FEMA is embarking on a map modernization program nationwide to: 1. Gather and develop updated data for all flood prone areas in support of flood plain management. 2. Provide maps and data in a digital format for the improvement in the efficiency and precision of the mapping program. 3. Integrate FEMA's community and state partners into the mapping process. One of the priorities for FEMA, Region 1, is to develop updated Digital Flood Insurance Rate Maps (DFIRMs) and Flood Insurance Studies (FIS) for Coos County, New Hampshire. The information provided in this report will be used to develop the scope for the first phase of a multiyear project that will ultimately result in the production of new DFIRMs and FIS for the communities and flooding sources in Coos County. The average age of the FEMA flood plain maps in Coos County, New Hampshire is 20 years. Most of these studies were computed in the mid 1970s to the mid 1980s. However, in the ensuing 20-30 years, development has occurred in many of the watersheds, and the rivers and streams and their flood plains have changed with time. In addition, as development has occurred, the peak flooding has increased downstream of the development due to increased flows from impervious surfaces. Therefore, many of the older studies may not depict current conditions nor accurately estimate risk in terms of flood heights. Coos County gained 544 residents between 2000 and 2005. This represents a growth of 1.6 percent compared to 6.0 percent for the state as a whole.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2006
Accession Number
ADA454274

Entities

People

  • Robert H. Flynn

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Data Sets
  • Databases
  • Department Of Homeland Security
  • Digital Data
  • Drainage Basins
  • Flood Control
  • Flood Hazards
  • Floods
  • Geographic Information Systems
  • Geography
  • Information Systems
  • New Hampshire
  • Photographs
  • Photography
  • Remote Sensing
  • Rivers
  • Topography

Fields of Study

  • Geology

Readers

  • Computational Modeling and Simulation
  • Emergency Management and Homeland Security.
  • Hydrologic Risk Analysis and Mitigation.