12 Mar 2021

FEMA Flood Hazard Zones

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The Flood Hazard Zones are extracted from the National Flood Hazard Layer, which is a database that contains FEMA’s flood hazard map data. The database contains flood hazard information and supporting data used to develop the information. The primary flood hazard classification is indicated in the Flood Hazard Zones layer.

Flood zones are geographic areas that FEMA has defined according to varying levels of flood risk and type of flooding. For complete information about different flood zone designations, please visit the Definitions of FEMA Flood Zones web page.

Flood Hazard Zone Descriptions:
  Floodway: The stream channel and that portion of the adjacent floodplain which must remain open to permit passage of the base flood.
  1% Annual Chance Flood Zone: The 100-year or base floodplain.
  0.2% Annual Chance Flood Zone: Area of moderate flood hazard, usually the area between the limits of the 100-year and 500-year floodplains, but also shallow flooding areas (< 1 foot) or flood zones for small drainage areas (< 1 square mile).
  Area with Reduced Risk Due to Levee: Areas protected by levees from the 100-year flood.
  1% Annual Chance Future Considerations: The 100-year floodplain based on anticipated future land-use conditions.
  Area of Undetermined Hazard: Area of undetermined but possible flood hazard, typically occurring in counties with partial flood studies.

This information was acquired by state-level release February, 2020. Data release dates by state range from December 07, 2016 (Vermont) to February 12, 2020 (Utah).

12 Mar 2021

Location Affordability Index for Family at AMI

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This layer displays the estimated percentage of household income for housing and transportation for a family earning the Area Median Income (AMI). The expected values for housing and transportation are modeled by HUD using data from the US Census Bureau and the US Department of Transportation, including:

  • The average household size for a family earning AMI in the neighborhood
  • The average number of workers, vehicles, and vehicle miles travelled for a family in the neighborhood
  • The average utility and rental costs or average utility and mortgage costs for a housing unit to accommodate the family size above
  • The proportion of housing units that are either rentals or owner-occupied in the neighborhood

Note: The LAI does not predict what families are actually paying to live in a particular area, but rather what a family would pay (either in USD or as a percentage of income) if average or reasonable housing and commuting conditions for a particular neighborhood were achieved.

12 Mar 2021

Location Affordability Index for Family Below AMI

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This layer displays the estimated monthly cost for housing and transportation for a low-income, single-parent family (earning 50% of the Area Median Income). The values for housing and transportation are modeled by HUD using data from the US Census Bureau and the US Department of Transportation, including:

  • The average household size for a single-parent family earning 50% AMI in the neighborhood
  • The average number of workers, vehicles, and vehicle miles traveled for a family in the neighborhood
  • The average utility and rental costs or average utility and mortgage costs for a housing unit to accommodate the family size above
  • The proportion of housing units that are either rentals or owner-occupied in the neighborhood

Note: The LAI does not predict what families earning 50% AMI are actually paying to live in a particular area, but rather what a family would pay (either in USD or as a percentage of income) if average or reasonable housing and commuting conditions for a particular neighborhood were achieved.

12 Mar 2021

Cropland Data Layer

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This layer displays the Cropland Data Layer (CDL) developed by the USDA National Agricultural Statistics Service (NASS). The CDL is a raster, geo-referenced, crop-specific land cover data layer created annually for the continental United States using moderate resolution satellite imagery and extensive agricultural ground truth. The CDL has a ground resolution of 30 meters, and is validated using data from the USDA Farm Services Agency and United States Geological Survey. Historical CDL products are available for use and free for download through CropScape (https://nassgeodata.gmu.edu/CropScape/).

12 Mar 2021

Wildfire Perimeters

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The layer displays historic wildland fire perimeters. The Geospatial Multi-Agency Coordination group, or GeoMAC, is an internet-based mapping tool originally designed for fire managers to access online maps of current fire locations and perimeters in the U.S. Perimeters are submitted to GeoMAC by field offices and made available to the public. Perimeter data is not the final or official perimeter for any incident and is provided for informational purposes only. The final official perimeter should be obtained from the host unit which can be determined by looking at the Unit ID for any specific fire.

12 Mar 2021

Watershed Boundary Dataset, 2-Digit Hydrologic Units

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The 2-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the major water resource regions of the United States. A water resource region is the first level of classification used by the United States Geological Survey to divide and sub-divide the United States into successively smaller hydrologic units. This first level of classification divides the United States into 22 major geographic areas, or regions. These geographic areas contain either the drainage area of a major river or the combined drainage areas of a series of rivers.

12 Mar 2021

Watershed Boundary Dataset, 4-Digit Hydrologic Units

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The 4-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the second level hydrologic subdivision of the United States. A 4-digit hydrologic unit includes the area drained by a river system, a reach of a river and its tributaries in that reach, a closed basin(s), or a group of streams forming a coastal drainage area. There are 240 4-digit hydrologic units with an average size of 17,521 square miles (45,378 sq. km.).

12 Mar 2021

Watershed Boundary Dataset, 6-Digit Hydrologic Units

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The 6-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the third level hydrologic subdivision of the United States. A 6-digit hydrologic unit may subdivide a 4-digit hydrologic unit or may be equivalent. There are 401 6-digit hydrologic units with an average size of 10,486 square miles (27,159 sq. km.).

12 Mar 2021

Watershed Boundary Dataset, 8-Digit Hydrologic Units

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The 8-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the fourth level hydrologic subdivision of the United States. A hydrologic unit can accept surface water from upstream drainage areas and may define a drainage area with single or multiple outlet points. An 8-digit hydrologic unit, or sub-basin, is a common management unit for water resource planning and analysis. There are 2,362 8-digit hydrologic units with an average size of 1,783 square miles (4,619 sq. km.).

12 Mar 2021

Watershed Boundary Dataset, 10-Digit Hydrologic Units

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The 10-Digit Hydrologic Units, a component of the Watershed Boundary Dataset (WBD), depict the fifth level hydrologic subdivision of the United States. A hydrologic unit can accept surface water from upstream drainage areas and may define a drainage area with single or multiple outlet points. A 10-digit hydrologic unit, or watershed, divides sub-basins into smaller management areas. There are 18,679 10-digit hydrologic units with an average size of 226 square miles (585 sq. km.).