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 above in two shades of blue. These areas represent the greater than 10,000 nested binational drainage areas along the international boundary. The Swath represents the areas where harmonization activities are occurring. 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 are kept informed of activities in 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 is being completed in phases, as follows: Phase I and Phase II have been completed and are available to the public via the U.S.
Watershed Boundary Dataset (WBD), U.S. National Hydrography Dataset (NHD), and the Canada National Hydrographic Network (NHN).
Phase III and IV are in progress. The harmonized data is being made available to the public via the WBD as it is completed. All of these datasets are considered “living” and will continue to be improved and updated as new methods and base data become available.
If interested in a more detailed outline of each phase, please visit the USGS Confluence Wiki website.
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 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.