Introduction

Inland flooding, sea-level rise, and pollution pose challenges for Maine’s infrastructure and natural resources. A highly detailed, three-dimensional (3D) model of the Earth’s surface is allowing the State of Maine to address these challenges and opportunities in an increasingly comprehensive and timely manner. In addition, highly accurate elevation data facilitate land development, forest management, agricultural practices, and wildlife conservation, all of which are key pillars of Maine’s economy.

The Maine Library of Geographic Information (2019, p. 10), in its annual report for 2018, states that “elevation data are having a transformative effect on land development costs for private and public sectors in Maine’s economy.” Critical applications that meet the State’s management needs depend on light detection and ranging (lidar) data that provide a highly detailed 3D model of the Earth’s surface and aboveground features.

The 3D Elevation Program (3DEP; see 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 Maine. The status of available and in-progress 3DEP baseline lidar data in Maine 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 $4.7 million in new benefits annually to the State. The top eight Maine business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown in table 2.

Flood Risk Management

Many documented business uses benefit from increasing the availability of and access to highly accurate lidar data in Maine. For example, the Maine Floodplain Management Program works with individuals, communities, and flood-plain management professionals to reduce the risk of flooding by directing development outside of flood zones. More than 9,000 flood insurance policies are in effect in Maine, with coverage totaling over $1.9 billion for property deemed at risk (Maine Department of Agriculture, Conservation, and Forestry, 2021). Accurate lidar data could improve community flood maps (fig. 2), enable a better assessment of properties at risk, and possibly reduce insurance rates.

Natural Resources Conservation

Forty-eight percent of the water consumed by the public in Maine comes from surface-water utilities (Maine Division of Environmental and Community Health, 2023). Organizations responsible for the quantity and quality of the State’s water supply have the potential to make better watershed delineations and decisions using lidar data. Accurate watershed delineation is required for estimating stormwater runoff in small urban watersheds and for defining and managing point and non-point sources of pollution. Lidar increases Maine’s ability to protect natural resources and to steward related recreational opportunities.

Coastal Zone Management

The fishing industry in Maine is reliant on long-term coastal zone management. Mapping intertidal zone elevations, sea-floor bathymetry, and upland topography, coupled with a seamless integration of these data, is vital for effective management of the coastal zone. In 2017 the lobster industry supply chain contributed $1 billion to the State’s economy, and the total value of landed lobsters was $433 million (Island Institute, 2018). Lidar has the potential to improve coastal hazards modeling, identification and analysis of impervious surfaces, and development of resiliency plans and storm response plans, all of which protect Maine’s shoreline and the fishing industry.

Forest Resources Management

The forest products industry is a direct beneficiary of the widespread availability of public lidar data. A 2016 Maine Forest Products Council report (Crandall and Anderson, 2016) estimated the statewide annual economic impact of the forest products industry to be $8.5 billion in sales output and $1.8 billion in labor income, with 33,538 supported full- or part-time positions. Three-dimensional lidar point clouds are used by foresters to calculate biomass, differentiate tree types, and map terrain suitable for wildlife habitats, such as deer wintering areas. Management of forest activities also requires change detection in aboveground vegetation and wet-area mapping, which are greatly enhanced with accurate digital elevation models and classified lidar point clouds.