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National Enhanced Elevation Assessment

3D elevation data are essential for flood mitigation, conservation management, infrastructure development, national security, and many other applications.

Benefits of a National 3D Elevation Program

The National Enhanced Elevation Assessment (NEEA) was conducted to document national level requirements for enhanced elevation data, estimate the benefits and costs of meeting those requirements, and evaluate multiple national enhanced elevation program scenarios across 34 Federal agencies, agencies from all 50 States, selected local government and Tribal offices, and private and not-for profit organizations.

Each need was characterized by the following:

  • Data accuracy

  • A refresh cycle for the data

  • Coverage for geographic areas of interest

Each business activity was described and the expected benefits derived from enhanced elevation data were identified wherever possible. When benefits were expressed as a range of values, the lower number represented the conservative benefit and the higher number represented the potential benefit. 

 

Ranking of Business Uses for Elevation Needs

  1. Flood risk management - annual benefit of \$295 million (conservative), \$502 million (potential)

  2. Infrastructure and construction management - annual benefit of \$206 million (conservative), \$942 million (potential)

  3. Natural resources conservation - annual benefit of \$159 million (conservative), \$225 million (potential)

  4. Agriculture and precision farming - annual benefit of \$122 million (conservative), \$2,011 million dollars (potential)

  5. Water supply and quality - annual benefit of \$85 million (conservative), \$156 million (potential)

  6. Wildfire management, planning and response - annual benefit of \$76 million (conservative), \$159 million (potential)

  7. Geologic resource assessment and hazard mitigation - annual benefit of \$52 million (conservative), \$1,067 million (potential)

  8. Forest resources management - annual benefit of \$44 million (conservative), \$62 million (potential)

  9. River and stream resource management - annual benefit of \$38 million (conservative), \$87 million (potential)

  10. Aviation navigation and safety - annual benefit of \$35 million (conservative), \$56 million (potential)

 

Analysis and Program Scenarios

Benefit - Cost Analysis Bar Chart

Benefit-cost analyses were developed and examined for more than 25 program scenarios. Each scenario included a different data- quality level and data refresh cycle- combination. Ten leading scenarios emerged from this analysis.

The estimated costs for each scenario include those for data collection and life-cycle management. The scenario outlined in red is a middle-range option that offers uniform medium to high-quality light detection and ranging (lidar) data for 49 States and U.S. territories and interferometric synthetic aperture radar (IfSAR) data for Alaska. These data would be acquired over an 8-year period and address 58 percent of the benefits associated with the requirements identified in the NEEA.

 

Elevation Data Inventory

An inventory of known high-resolution digital elevation data sources was conducted as part of the NEEA in the summer of 2011. The inventory was completed by the U.S. Geological Survey's Geospatial Liaisons in cooperation with the National Oceanic and Atmospheric Administration and the Federal Emergency Management Agency. The inventory included publicly available enhanced elevation data for any area where the coverage was complete for a county or was at least 300 square miles in size.

The following is an overview of the results of the inventory and resulting maps:

  • Lidar data have been collected over 28% of the conterminous United States and Hawaii.

  • IfSAR data have been collected over approximately 15% of Alaska.

  • Elevation data was collected at an average annual rate of 4% to 5% from 2009-2011.

  • The level of overlapping coverage is less than 10%.

  • The quality of the data varies from project to project.

 

Map of Publicly Available Enhanced Elevation Data Sept 2011
Publicly Available Enhanced Elevation Data produce the 1/9 arc-second National Elevation Dataset (NED).
Map of Publicly Available Lidar Point Cloud Data
Publicly Available Lidar Point Cloud Data.

 

Partners in NEEA Study

The NEEA was conducted under a contract between the U.S. Geological Survey and Dewberry (a consulting firm based in Fairfax, Va.). Additional support for the assessment came from other Federal agencies: the Federal Emergency Management Agency, the National Geospatial-Intelligence Agency, the National Oceanic and Atmospheric Administration, and the Natural Resources Conservation Service.

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