The United States and Canada independently developed their own suite of hydrographic datasets using different standards and approaches. Containing mapped rivers, lakes, and watershed boundaries, these national datasets stopped at the international border and often did not line up, leaving an area of uncertainty about how the water behaved. This lack of data continuity proved to be a challenge for managers, planners, and scientists using this data. These environmental systems do not know political boundaries, and a proper understanding of them is vital to assess issues like ecosystem health, flood and drought risk, as well as water resource management.
Realizing the challenges of inconsistent data and the potential advantages gained by a better alignment of geospatial hydrographic datasets along the international border, the International Joint Commission (IJC) convened the Transboundary Hydrographic Data Harmonization Task Force (DHTF) in 2008. This project was designated as a strategic priority for the IJC under the International Watersheds Initiative (IWI), a 21st century initiative that recognizes that environmental systems function as whole entities and should be managed as such, rather than being bound by traditional political boundaries. Harmonized data is vital to the success of the initiative’s watershed-based and local participatory approach.
Background / The issue
A digital geospatial hydrographic dataset contains information about an area’s surface water, including its rivers, streams, canals, lakes, ponds, glaciers, dams, coastlines, and watershed boundaries. The United States and Canada each independently developed their own suite of hydrographic datasets using different standards and approaches. From the Canadian federal and provincial perspective, these fundamental hydrographic datasets translate to Canada’s National Hydrographic Network (NHN) and the working version of Canada’s Fundamental Drainage Areas (FDA). From the U.S. federal and state perspective, the geospatial datasets include the U.S. National Hydrography Dataset (NHD) for surface water and the U.S. Watershed Boundary Dataset (WBD) for drainage areas. These national datasets stopped at the border, thereby preventing a seamless transboundary exchange of data and water-related information. The mapped rivers, lakes, and watershed boundaries were often offset where they met the international border, leaving an area of uncertainty about how the water behaved. In addition, the scales of the data, the names of the waterbodies, as well as other information associated with them were inconsistent.
As a result of these hydrographic inconsistencies, federal, state, provincial, local, academic, and private users were developing their own interpretations of surface water maps in the transboundary region. In addition, differences in how each country presented the data made interpreting or connecting study results from each side of the border about environmental and ecological issues in transboundary watersheds complicated. For example, the word ‘basin’ does not mean the same thing in North Dakota as it does in Manitoba. This disconnect in the way hydrography is described and quantified was apparent along the entire boundary region.
One consequence of these disparities was that large portions of drainage areas were often overlooked. Drainage areas, or watersheds, represent the topographically-defined area of the landscape that drains to a common outlet or outlets. Without a uniform dataset, these areas could not be accurately defined, and they often stopped at the international border. These environmental systems do not know political boundaries, and a proper understanding of them is vital to assess issues like ecosystem health, flood and drought risk, as well as water resource management. It was clear that there needed to be a way to align the watersheds on each side of the border to enable a seamless interpretation of their water flow and physical characteristics between the United States and Canada by the agencies that oversee them.
Realising the challenges of inconsistent data, and the potential advantages gained by a better alignment of geospatial hydrographic datasets along the international border, the IJC convened the Transboundary Hydrographic Data Harmonization Task Force (DHTF) in 2008. This group’s goal was to develop a binational and coordinated approach to the harmonization and long-term stewardship of hydrographic datasets, covering a “swath” of binational drainage areas along the international boundary. By harmonizing binational data, this team is furthering cooperation, and enhancing decision making with information and common understanding on each side of the border.
This project was designated as a strategic initiative for the IJC under the International Watersheds Initiative, a 21st century initiative that operates on an ecosystem focus, recognizing that environmental systems, in this case watersheds, function as whole entities and should be managed as such, rather than being bound by traditional political boundaries. Harmonized data is vital to the success of the initiative’s watershed-based and local participatory approach.
The regions of focus for the DHTF are referred to as the “swath”, shown in Figure 2.0 as the polygons in two shades of blue. These areas represent the more than 10,000 nested binational drainage areas along the international boundary. The Swath represents the areas where harmonization activities occurred. The mapped areas in grey represent the complete or “contributing” drainage area of the river systems that cross the international boundary. Partners in the states and provinces along the boundary were kept informed of data harmonization activities that occurred within the Swath.
The Problem and the Fix
Made up of representatives from both governments, the DHTF set out to address the lack of seamless transboundary hydrography and drainage areas (hydrologic units). The DHTF set up two binational technical groups, one focused on hydrography and the other on drainage areas, to make sure that the two countries’ respective national datasets were aligned within the Swath.
A Phased Approach / Current Status
The IJC binational hydrographic data harmonization initiative was completed in phases, as follows:
Phase III: Creating new higher resolution “harmonized” drainage areas at the U.S. WBD 10- and 12-digit hydrologic unit level (which are two new drainage area levels in Canada).
Phase IV: Assigning hydrographic names and codes (attribution) to the Phase III new higher resolution drainage areas.
The Phase III and IV harmonized data has been made available to the public via the WBD.
The harmonized data has been completed for all phases and is available within each source dataset. These datasets are considered “living” and will continue to be improved and updated as new methods and base data become available.
Applications, Outcome, and Future Directions
Harmonization of hydrographic and watershed data in the Swath has opened doors for a range of binational activities that require seamless applications and analysis. This has promoted and broadened data development and discovery through a range of projects built on top of the DHTF’s efforts.
Harmonized drainage areas provide the water-resources community with a common framework for reporting information and defining study areas for water-related investigations. The harmonized drainage area information allows IJC Boards and other organizations like the Saint-Francois River Watershed Governance Council (COGESAF) to provide integrated watershed management within a standard recognized drainage area.
Geospatial hydrography data includes functionality that creates a network that enables up and downstream tracing. This functionality allows water-related information such as the location of hydrometric stations, diversion structures, water quality samples, or dams to be associated with the network and used for analyses, water management, hazard mitigation, and water quantity or quality models.
The harmonized data also is the foundation for applications like StreamStats and modeling systems like SPARROW. StreamStats is a USGS web interface that allows on-the-fly watershed delineation, calculation of selected basin characteristics, and calculation of predicted streamflow at any point on streams. StreamStats for the binational Rainy River Basin is the first international implementation of the web interface and is built on the harmonized hydrography data. SPARROW is a modeling system developed by USGS to estimate the transport of nutrients or other constituents in watersheds. SPARROW models built on the harmonized hydrographic data are part of the International Watersheds Initiative. The harmonized data and partnerships built between Canadian and U.S. resource agencies have also allowed USGS to develop NHD Plus High Resolution (NHDPlus HR) for drainage basins across the international boundary. NHDPlus HR is an application-ready framework that underpins hydrographic analysis and models like SPARROW and StreamStats.
In addition to improvement and enhancement of water resources models, analysis, and data discovery, the harmonization effort has helped the DHTF partners to develop shared standard practices for managing and maintaining geospatial data, improved collaboration, and strengthened partnerships between the agencies involved in the work.
The roles of the DHTF included data, oversight, communications, and facilitating stewardship.
Data: The DHTF’s roles included the harmonization of water-related geospatial datasets. It is important to ensure that these data products provide stakeholders a standardized system of transboundary drainage areas and hydrography together for real world applications and analysis. To ensure that the benefits are felt everywhere the DHTF is facilitating the incorporation of the harmonized data into the participating agencies' geospatial programs.
Oversight and communications: The DHTF provided oversight to the Hydrography and Drainage Area Harmonization technical groups. This included communication, interaction, and coordination, as well as receiving feedback from the hydrography and drainage area groups to help continually refine the approach and recognize and measure success.
In addition, the DHTF strengthened and formalized federal, regional and local stakeholder participation, and raised awareness in both governments that consistent institutional support is critical for the long-term evolution and sustainability of this effort.
Beyond the data, binational harmonization requires collaboration.
Without partners, Transboundary Hydrographic Data Harmonization could not be accomplished. The IJC’s unique role in Canada-U.S. water-resource relations allowed the Transboundary Hydrographic Data Harmonization Task Force to facilitate direct collaborations amongst those agencies responsible for water-resource management in Canada and the United States.
It is important to acknowledge the effort and in-kind time of all partners and their contributions to jointly participate, review, and correct hydrography geospatial data issues within the shared binational basins. The DHTF spends a substantial amount of time and effort on coordination which has been the key for successful hydrographic data harmonization. Following is a partial list of the partners who have contributed to the harmonization effort.
- Environnement Yukon (lien français)
- Manitoba Sustainable Development
- Manitoba Infrastructure and Transportation
- Natural Resources Canada
- New Brunswick Department of Environment and Local Government
- Ontario Ministry of Natural Resources and Forestry (English link)
- Ontario Ministère des Richesses naturelles et des Forêts (lien français)
- Quebec Ministry of Energy and Natural Resources (MERN) (English link)
- Québec Ministère de l'Énergie et des Ressources naturelles (MERN) (lien français)
- Quebec Ministry of Sustainable Development, Environment and the Fight against Climate Change (English link)
- Québec Ministère du Développement durable, de l'Environnement et de la Lutte contre les changements climatiques (lien français)
- Saskatchewan Water Security Agency
- Service New Brunswick (English link)
- Service Nouveau-Brunswick (lien français)
- Yukon College
- Yukon Department of Environment (English link)
- Yukon Geomatics
- Maine Office of GIS
- Minnesota Department of Natural Resources
- Minnesota IT Services
- Montana State Library
- New Hampshire Department of Environmental Services
- North Dakota Department of Health
- U.S. Army Corps of Engineers
- U.S. Bureau of Land Management
- U.S. Fish and Wildlife Service
- U.S. Forest Service
- U.S. Geological Survey
- U.S. National Oceanic and Atmospheric Administration
- U.S. National Park Service
- U.S. Natural Resources Conservation Service
- University of Alaska Anchorage
- University of Michigan
- Vermont Department of Environmental Conservation
- Vermont Agency of Natural Resources
- Washington State Department of Ecology
- Commission Mixte Internationale(Lien français)
- International Joint Commission (English link)
- Lake Champlain Basin Program
- Red River Basin Commission
- Skagit Environmental Endowment Commission
- Yukon River Inter-tribal Watershed Council
- Hydrographic map
The mapped representation of surface waters including streams, rivers, lakes, and other water features, from the U.S. National Hydrography Dataset (NHD), and the Canada National Hydrographic Network (NHN).
- Watershed / Drainage Area
A topographically defined area of land with surface runoff that drains to a common outlet or outlets (the SSDA/FDA and WBD).
- International Watersheds Initiative (IWI)
Incepted in 1997, the International Watersheds Initiative (IWI) is an approach to resolving transboundary water issues grounded on the belief that local communities, given appropriate assistance, are best placed to achieve solutions. This approach operates on an ecosystem focus, recognizing that ecosystems function as whole entities and should be managed as such, rather than being bound by traditional political boundaries.
- The “Swath”
Transboundary watersheds along the Canada – United States International Boundary that define the hydrographic data harmonization project area.
- National Hydrographic Network (NHN)
Geospatial digital dataset that represents the water drainage network of Canada with features such as streams, rivers, lakes, etc.
- National Hydrography Dataset (NHD)
Geospatial digital dataset that represents the water drainage network of the United States with features such as streams, rivers, lakes, etc.
- Hydrologic Unit (HU)
A single HU represents all or some portion of the extent of surface water drainage to a selected stream outlet. A system of HU is organized in a nested, hierarchical system which creates a baseline drainage area framework that can be used for the analysis and reporting of water resource information. The selection and delineation of drainage area boundaries are based on hydrologic principles.
- Sub-sub Drainage Areas (SSDA) and Fundamental Drainage Areas (FDA)
Canada’s geospatial digital dataset containing information about the country’s drainage areas in four hierarchically nested levels. The SSDA and FDA provide the geometry and attribution for HUs within Canada.
- Watershed Boundary Dataset (WBD)
The United States’ geospatial digital dataset containing information about drainage areas in eight nested levels. The WBD provides the geometry and attribution for HUs within the United States.