3DHP Datasets

The 3DHP datasets will include a 3D hydrography network generated from and integrated with 3DEP elevation data to better represent stream gradients and channel conditions, along with waterbodies, hydrologic units, hydrologically enhanced elevation and other surfaces, and more consistent and accurate attributes (fig. 2). The 3DHP datasets will be built on high-quality, standardized 3DEP data to ensure spatial and temporal consistency across all derived products. This integration can increase usability of 3DHP datasets for applications like flood modeling and prediction, culvert and bridge engineering design, and stormwater management.

The 3DHP datasets will inherit key attributes of the NHD, WBD, and NHDPlus HR, and they also will include new attributes and links to other data such as the NWI, groundwater data, and information from engineered hydrologic systems such as stormwater networks.

The modernized 3DHP data model includes both the stream network and hydrologic units with more robust logic rules to ensure data quality. The data model would be able to store a highly detailed and accurate set of derived stream network features, as well as attributions for generalizing the stream network and hydrologic units. The features in the stream network can be connected such that flow models will work correctly across the entire network. The 3DHP stream features are expected to be less than 1 meter below, and within 2 meters horizontally, of the water surface where depicted in a high-accuracy elevation surface; these standards greatly improve the positional accuracy of features compared to the accuracy of existing hydrographic data. Improved spatial accuracy can also make the new hydrography data more consistent with other data such as transportation networks and other infrastructure.

A snapshot of all 3DHP data is planned to be made available annually as a national dataset release with a persistent Digital Object Identifier (DOI) to support citations in scientific research. These annual snapshots will be archived so that users may reference older versions as needed. The most current data will be available as individual data layer downloads and accessible as map services between annual data releases. Open data standards will be considered in developing 3DHP datasets.

The 3DHP datasets are planned to be an integrated data stack that includes the following:

3DHP Infostructure

The 3DHP will be designed to provide a set of open and interoperable web-based tools, maps, and data catalogs, creating a robust system for users to reference their information about water; the system elements are collectively referred to as the “infostructure.” The infostructure can support discovery of data based on the stream network; examples of user data include water levels at streamgages, water temperature, and the health of fish and aquatic life in a stream. The 3DHP and the infostructure are being designed to provide a foundational geospatial underpinning for the Internet of Water, a community-based effort to modernize tools and technologies to share water data.

The 3DHP hydrographic addressing tools can enable users to link water data to create and share the information as authoritatively managed observations and data linked to the 3DHP network. These tools are planned to provide reference locations on the stream network, similar to street addresses, that can be attached to a user’s data records. The 3DHP search and discovery tools can locate data within the stream network, and these tools can also help users to understand relationships among different records or observations at different locations, such as the distance between water-quality observations or possible effects of obstacles to fish passage, such as dams, on spawning or the spread of invasive species. Any kind of water-related information can be given an address on the stream network, including hydrology, geomorphology, water quality, biology, regulations, or public access points (fig. 3).

3DHP Lifecycle

Because of the large volumes of data to be acquired in the first several years, and the expectation that acquisitions would decline to a maintenance level later in the 3DHP, much of the work to delineate the stream network from elevation can be completed by the private sector for the USGS or partner organizations. The USGS will ensure that all acquired data meet published specifications (U.S. Geological Survey, 2022) regarding the derivation of hydrography features from 1-meter digital elevation models (DEMs) derived from light detection and ranging (lidar) data for the conterminous United States and Hawaii and 5-meter DEMs derived from interferometric synthetic aperture radar (IfSAR) data for Alaska. The USGS will be responsible for data validation prior to accepting data into national data holdings. Once in national data holdings, individual errors within the 3DHP datasets discovered by the USGS or reported by users can be corrected by USGS data editors; a 3DHP maintenance goal will be to correct errors 1–2 months after they are reported. The stream network is planned to be reviewed on a regional basis every 4–5 years, and regional updates are planned to be applied as needed. In the future, change detection based on either the elevation data or hydrography may trigger updates to 3DHP data.

The USGS will also be responsible for producing data related to the stream network, such as hydrologic units and some attributes, as well as the general management and delivery of data to the public. The planned datasets include hydrologic features such as those described in box 2. The USGS will maintain an enterprise system to manage the 3DHP datasets and infostructure. The 3DHP infostructure will be developed, tested, and operationalized to use the 3DHP datasets as the geospatial foundation.

Program Scenarios

The HRBS highlighted the need for a modernized, 3D-enabled hydrography program to support emergent user and stakeholder applications. To help define a modernized program, three scenarios created from the HRBS were considered. Each scenario included the cost of developing the source data, the time required to build the national dataset, and the potential benefits enabled by the data produced as documented in the HRBS. The National Geospatial Program (NGP) consulted extensively with stakeholders and users of hydrography data through both public presentations and smaller venues to gather feedback on the potential program directions.

Scenario 1 (status quo) continues management of the current hydrography data with minimal incremental improvements. While the USGS would make general progress to update the NHD by using current technologies, continued local maintenance programs with a variety of funding sources and priorities would continue to decrease national consistency of the datasets over time.

Scenario 2 replaces all existing hydrography over a 9-year period with data derived from 3DEP-quality lidar data for the conterminous United States and Hawaii or IfSAR-derived data for Alaska. This scenario includes improvements supported by the HRBS, such as improved accuracy, accounting for more components of the hydrologic cycle, and more effective maintenance of data.

Scenario 3 is similar to Scenario 2, except the source data would be 0.5-meter DEMs created from Quality Level 1 (QL1) or better 3DEP lidar data. For a description of topographic data quality levels, please refer to https://www.usgs.gov/3d-elevation-program/topographic-data-quality-levels-qls. Scenario 3 meets more user requirements and provides more benefits, but at a substantially greater cost than Scenario 2. Currently, QL1 data are not readily available across the country, making this scenario difficult to achieve, but it may be a viable program in the future.

The USGS vision for the 3DHP is based on Scenario 2. A comparison of the three implementation scenarios (fig. 4) shows that the new benefits compared with program costs provide the greatest value in Scenario 2. This scenario would meet most mission-critical activity needs identified in the HRBS and has the potential to achieve more than $1.047 billion in annual benefits.

3DHP Potential Community-Wide 9-Year Costs

The 3DHP program of work projects that the 9-year effort will begin in fiscal year 2024 (FY 2024), will have moderate growth for FY 2025, and will grow primarily through partnerships in subsequent years. Investments by Federal, State, Tribal, Territorial, and local government entities and private partners in lidar and IfSAR data collections through 3DEP have made it possible to derive 3DHP features from elevation data for a substantial portion of the Nation. For the proposed operational program to be fully realized, a similar community-wide investment of $685 million ideally would occur within the first 9 years; the timeframe includes 1 year of preparation, 6 years of delineating hydrography data from 3DEP elevation data, and 2 additional years to complete data validation, processing, and publication after the acquisition period. The length of the 9-year timeline may change, depending on available funding.

Just as 3DEP was successful in building community partnerships with government agencies and private organizations to fund data acquisition, the 3DHP plans to follow a similar collaborative funding model that would benefit from investments by partner organizations for shared data acquisition costs. For example, approximately 62 percent of the total funding that has come to 3DEP has been from partnerships (please refer to https://usgs.gov/3DEP/numbers for more information).

Data maintenance and distribution costs, as well as data contracting, validation, and processing expenses would be included in the core USGS budget for the 3DHP. The cost-sharing model (fig. 5) is one potential model and is not intended to allocate cost shares to any organization or to individual government sectors. The actual funding model is expected to evolve and change in the program operations plan.

Leadership and Governance

Governance of the 3DHP will be led by senior executives from cooperating agencies through the 3D Elevation Federal Interagency Coordinating Committee (FICC) that is being established by the U.S. Department of the Interior as required by the National Landslide Preparedness Act (Public Law 116–323). The committee will oversee the formulation and approval of policies and priorities recommended by the 3DEP and 3DHP Working Groups. The National Hydrography Infrastructure (NHI) Working Group, created in 2018 as a forum for Federal agencies, has transitioned to become the 3DHP Working Group (3DHP WG). The 3DHP WG will provide input and collaboration on the development of the 3DHP datasets and infostructure and will take on new responsibilities for prioritizing and coordinating data acquisition. The structure and next steps for the FICC are being determined by the U.S. Department of the Interior’s Assistant Secretary for Water and Science.

Partnering To Acquire Data

To be successful, the 3DHP can build on existing relationships to establish a systematic and unified process for data acquisition partnerships. The 3DHP intends to use a partnership-based acquisition model, in alignment with the one used for 3DEP data acquisition (fig. 6). When USGS funding is available, partners will be able to propose acquisition projects that use the USGS Geospatial Products and Services Contracts (GPSC) or their own contracts to acquire data that meet the 3DHP specifications. Organizations may also contribute data that meet 3DHP specifications and that were acquired independently; the USGS will implement a standard procedure for reviewing those datasets for inclusion in the 3DHP.

The USGS will facilitate the sharing of partner mapping requirements to help identify common areas of interest and leverage funds. The strategy would help prioritize acquisitions where there are multiple requirements and a high potential for leveraging funds. Data acquisition is planned to take place by whole hydrologic units, with an emphasis on collection through multipartner and multistate funding coalitions.

Collaborating To Build the Internet of Water

Community collaboration and cooperation are core components of the 3DHP, the 3DHP infostructure, and the Internet of Water. While the USGS and partner agencies will provide the overarching structure and functionality of the 3DHP infostructure, the data searchable through it will be managed by the datasets’ authoritative producers. This federated structure gives data producers control over their information while sharing it with the broader community. In turn, the community of users can efficiently search and access the most authoritative data.

Outreach and Communications

Outreach will be an important aspect of the program because the success of the 3DHP is dependent on a broad base of support and participation from Federal agencies, State and Tribal governments, and other stakeholders. Outreach will continue to be directed toward growing a user base for 3DHP products and toward gathering feedback to ensure that the 3DHP is responsive to the needs of government and private sector users. Equally important is a focus on building support and a community-wide funding base to move the program forward.

Roles and Responsibilities

The whole water-resources community has a role to play in the 3DHP, from partnerships, to data development, to creating new and unimagined applications (fig. 7). Today, States are major contributors of data and often lead statewide acquisition and maintenance programs through stewardship agreements with the USGS. The 3DHP will not include a formalized stewardship program. Rather, the 3DHP will focus on cooperative community data acquisition and on building and responding to a network of users with local knowledge who improve 3DHP data by reporting errors. Iterative improvements to the 3DHP datasets to support local needs and requirements will be identified jointly, and the 3DHP infostructure will be developed to empower users to manage their water-related data to promote sharing and new and emerging applications.

Milestones

The project milestones shown in figure 8 represent major and time-sensitive accomplishments that can lead to the successful implementation of the 3DHP. The schedule is based on assumptions of successfully securing community-wide funding and additional assumptions of products and services as described in the figure. A critical transition occurred during 2023, when maintenance on the legacy datasets—NHD, WBD, and NHDPlus HR—was brought to a close, and data acquisition and production shifted to the 3DHP. Static versions of the legacy datasets have been published and continue to be available to support existing applications while 3DHP data are acquired, validated, and published.

Research Requirements

The 3DHP planning process identified numerous issues or questions for which additional assessments, evaluations, and research would be beneficial. A 3DNTM research plan that addresses both 3DHP and next generation 3DEP research needs is expected to be completed by the end of FY 2024. Operational development will be undertaken by the USGS National Geospatial Technical Operations Center. More fundamental geospatial and hydrological research will be carried out by the USGS Center of Excellence for Geospatial Information Science; the USGS Water Resources Mission Area, particularly the Integrated Modeling and Prediction Division; and the broader community of researchers and users. The near-term and immediate research requirements have been identified, and the research agenda will be managed as a cohesive activity by the USGS through the NGP. As the 3DHP develops to include additional functionality, such as incorporating linkages to surficial geology, research is planned to include an expanded set of organizations with appropriate subject matter expertise, such as the National Cooperative Geologic Mapping Program.

To address emerging needs and to test emerging technologies, the development strategy for the 3DHP infostructure calls for an iterative evolution of products and services. Development teams will advance a core functionality, and through feedback from the community, the 3DHP infostructure can be improved. User community input and collaboration will also be provided by the 3DHP Working Group. Over time, the 3DHP infostructure will evolve to improve functionality and grow additional partnerships through the community.