Developing Tools for Assessing the Impacts of Water Withdrawals in the Great Lakes-St. Lawrence Basin

Background
Limno-Tech, Inc., an environmental engineering and science firm, has developed a prototype modeling tool to assess the ecological impacts of withdrawals and diversions for a Great Lakes watershed. As one of a series of projects supported by the Great Lakes Protection Fund, including the Great Lakes Commission’s project on water conservation, it provides practical and scientific support to the governors’ and premiers’ commitments under Annex 2001 of the Great Lakes Charter (www.cglg.org/1pdfs/Annex2001.pdf).

The Annex outlines a framework for a set of guiding principles to review proposals for new and increased water withdrawals in the Great Lakes basin. The principles apply to withdrawals from all waters of the Great Lakes basin (groundwater, tributaries, inland lakes), not just the Great Lakes themselves. The implementation of the Annex calls for the development of a decision support system to ensure the best available information to make decisions on large-scale water withdrawals/diversions. Additionally, the Annex calls for further commitment to improve the sources and applications of scientific information regarding the water resources of the Great Lakes basin and the impacts of the withdrawals on the ecosystem. As guidance for the implementation of these provisions, the development of this prototype model provides insight on the challenges and opportunities in developing models to assess water withdrawal impacts for other watersheds in the Great Lakes.

This modeling project builds upon the work that Limno-Tech, Inc.completed for the Great Lakes Commission’s Water Resources Management Decision Support System Project (www.glc.org/wateruse/wrmdss/). Based on an inventory of models relevant to assessing ecological impacts of water withdrawals, Limno-Tech found that existing models generally address only part of the overall problem, such as watershed hydrologic response, channel hydraulics, sediment transport, water quality or ecological effects. No existing model by itself directly links a water withdrawal to ecological responses. Furthermore, no existing model addresses the broad range of potential ecological responses resulting from water withdrawal scenarios. This project addresses these gaps in modeling by constructing a prototype applicable to the riverine watersheds of the Great Lakes basin.

Working documentation (PDF) is now available. For more information, please view the project factsheet.