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1 [1] (August 6, 2025)

handle is hein.crs/iuaegi0001 and id is 1 raw text is: * ICongressional Research Service Inforrning the legislative debate since 1914 August 6, 2025 The 3D Elevation Program (3DEP) and Its Role in Mapping Hazards and Resources In 2021, Congress passed two laws establishing and directing the 3-dimensional Elevation Program (3D Elevation Program, or 3DEP) to support identification of hazards and resources, among other purposes: (1) the National Landslide Preparedness Act (NLPA; P.L. 116- 323) and (2) the Infrastructure Investment and Jobs Act (IIJA; §40201 of P.L. 117-58; 43 U.S.C. §311). The NLPA directed the Secretary of the Interior, acting through the Director of the U.S. Geological Survey (USGS), to establish 3DEP (43 U.S.C. §3104) to provide 3D elevation data for the United States; produce standard, publicly accessible 3D data; and coordinate, facilitate, and promote the collection, dissemination, and use of 3D elevation data and data products among federal and nonfederal entities. Lidar (light detection and ranging) is a technology used to acquire high-resolution models of ground elevation with a vertical accuracy of 10 centimeters (4 inches). 3DEP acquires nationwide 3D elevation data using lidar and other methods. NLPA authorized $40 million annually from FY2021 to FY2024 for the USGS to carry out 3DEP. The act also established a National Landslide Hazards Reduction Program to identify, map, assess, and research landslide hazards. P.L. 117-58 established the Earth Mapping Resources Initiative (Earth MRI) and required Earth MRI to integrate 3DEP data with other USGS mapping programs. The IIJA provided $320 million for Earth MRI to accelerate the USGS's resources and mapping mission while prioritizing finding critical mineral resources. P.L. 117-169 (commonly known as the Inflation Reduction Act of 2022, or IRA) provided an additional $23.5 million in funding for 3DEP to remain available until September 30, 2031. 3D Elevation Program According to the USGS, the goal of 3DEP is to provide the first-ever national baseline of consistent high-resolution topographic elevation data, including both the bare Earth surface and 3D point clouds that map the Nation's natural and constructed features. Lidar The lidar data assist in identifying natural hazards; engineered structures; energy, mineral, and water resources; and vegetative cover. Lidar data increase the spatial precision of geologic mapping to more accurately define the surface extent of a deposit and may help identify other structures, such as faults or folds, that may impact the model of the subsurface extent of a mineral deposit or a natural hazard feature. According to the USGS, 3DEP may have annual benefits of $7.9 billion for resources, hazards, and infrastructure plus flood and coastal risk management; agricultural and land management; and security, safety, and disaster response; among other benefits. Lidar data are collected as a point cloud of individual points reflected from everything on the surface at different elevations (Figure 1). Airborne lidar consists of a laser scanner mounted on an aircraft that transmits light pulses to the surface. The light pulses are reflected back from various points on the surface, and the pulses' travel times are used to calculate the distances between the scanner and the points to determine elevation. From these data, the USGS produces a bare earth Digital Elevation Model (DEM) by removing any points from structures and vegetation. The USGS is replacing legacy DEMs with lidar DEMs. Figure I. Examples of Lidar Bare Earth and Point Cloud Data, Region in Olympia, WA Source: Vicki Lukas and Vanessa Baez, 3D Elevation Program-Federal Best Practices, USGS, USGS Fact Sheet 2020-3062, 2020. Notes: Top: bare earth digital elevation model from lidar (color shading shows elevation from low [green shades] to high [brown shades]) for a region in Olympia, WA. Middle: colorized point cloud data of the same region as the top (colors are estimated based on what a person might see in this region). Bottom: lidar point cloud profile of the vegetation (color shading shows elevation from low [blue shades] to high [red shades]) along the white dotted line shown https://crsreports.congress.gov