Introduction

The geographic information system (GIS) community in Vermont has a long history of interdisciplinary and cooperative projects that have facilitated the leveraging of geospatial technology on myriad data acquisitions across the State. High-resolution elevation data are proving to be a resource of great economic value in dealing with many important issues in Vermont. Vermont attained statewide coverage of quality level 2 (refer to table 1) coverage of topographic light detection and ranging (lidar) data in 2019. Having access to elevation data that are exponentially more accurate than what was previously available is enabling GIS professionals to better support and empower decision makers in economically important efforts such as environmental protection, public safety, watershed management and water quality, geology, transportation planning, forest and wildlife management, local planning, and flood plain management. In addition, developing a consistent and seamless statewide topographic framework supplants the traditionally time consuming and costly approach of extensive field data collection by requiring less time and money, therefore adding economic benefits. Critical applications that meet the State’s management needs depend on lidar data that provide a highly detailed three-dimensional (3D) model of the Earth’s surface and aboveground features.

The 3D Elevation Program (3DEP; refer to sidebar) is managed by the U.S. Geological Survey (USGS) in partnership with Federal, State, Tribal, U.S. territorial, and local agencies to acquire consistent lidar coverage at quality level 2 or better (table 1) to meet the many needs of the Nation and Vermont. The status of available and in-progress 3DEP baseline lidar data in Vermont is shown in figure 1. 3DEP baseline lidar data include quality level 2 or better, 1-meter or better digital elevation models, and lidar point clouds, and must meet the Lidar Base Specification version 1.2 (https://www.usgs.gov/3dep/lidarspec) or newer requirements. The National Enhanced Elevation Assessment (Dewberry, 2012) identified user requirements and conservatively estimated that availability of lidar data would result in at least $1.64 million in new benefits annually to the State. The top eight Vermont business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown in table 2.

Status of 3DEP in Vermont

With the completion of the statewide baseline quality level 2 dataset, there is now an emerging need for lidar data of even higher resolution and frequency. Use of existing data suggests that the annual benefits would increase if quality level 1 lidar data were available for critical business uses in Vermont. Statewide quality level 1 lidar data are expected to be available in the third quarter of 2025. In addition, high-resolution bathymetric lidar data are very important for managing Vermont’s waterways. With a surface area of 435 square miles and nearly 600 miles of shoreline in Vermont, New York, and Quebec, Lake Champlain is the most important surface-water feature in Vermont and is an economic driver in the region. For similar reasons, the Connecticut River and the many other lakes and ponds in Vermont would also benefit from high-resolution bathymetric lidar data coupled with the existing statewide quality level 2 lidar foundation.

Geologic Resource Assessment and Hazard Mitigation

Because Vermont contains the headwaters of numerous rivers, the State experiences landslides throughout all its physiographic provinces. Lidar provides detailed bare-earth elevation data, even in densely vegetated areas, that enhances surficial geologic mapping used for the identification of landslides (fig. 2), sinkholes, and blind valleys, and for geologic resource assessments such as the identification of sand and gravel deposits.

Flood Risk Management

Lidar data provide high-quality terrain information as input for more accurate and less expensive hydrologic and hydraulic modeling for flood studies, retention dam design, dam breach studies, and stormwater management and engineering. Lidar data also are useful in identifying vulnerable properties within a flood plain, facilitating better flood-plain management decisions and educating the public on true flood risks, and creating dynamic three-dimensional models to show the potential effects of flooding.

Natural Resources Conservation

High-resolution elevation data enable State, regional, and local governments to effectively implement natural resources conservation practices such as grade stabilization, dam safety oversight, provision of habitat easements, situating of pipelines, terracing, wetland restoration, identification of cultural features and historical (drained) wetlands. Lidar reduces the need for fieldwork, thus saving costs for governments and organizations.

Agriculture and Precision Farming

High-resolution elevation data can provide a more accurate depiction of the terrain and dramatically improve precision farming activities, which can help improve crop yields, prevent soil degradation, minimize groundwater usage, and reduce agricultural chemical runoff—factors that help farmers realize a larger return on their investments. Digital elevation models derived from lidar help with hydrologic and hydraulic modeling to identify fields that frequently flood and require extra care to avoid manure and fertilizer runoff.