Since the 1950s,the International Joint Commission (IJC) of Canada and the United States has issued water regulation and management plans for Lake Ontario and the St. Lawrence River. Changes in recreational, environmental, navigational and other uses of the water system have prompted the IJC to consider replacing the current water regulation plan in operation for more than 40 years. IJC's goals for a replacement plan include sound scientific foundations, public participation, transparency in plan development and evaluation, and inclusion of environmental considerations. To help develop and select the new plan, the IJC supported a 5-year, $20 million Lake Ontario-St. Lawrence River Study (LOSLR Study). The LOSLR Study uses models to compile and integrate data gathered from a series of commissioned studies of wetlands, species at risk, recreational boating, fisheries, coastal erosion and flooding, commercial navigation, hydropower, industrial, municipal and domestic water intakes, public information and education, and hydrologic modeling. This report reviews a portion of the study that focused on wetlands and species at risk and three of the models that were used. The report finds that the overall breadth of the LOSLR study is impressive, and commends the scale and inclusiveness of the studies and models. In terms of informing decision making, however, the reviewed studies and models show deficiencies when evaluated against ten evaluation criteria, including treatment of uncertainty, quality control/quality assurance, thorough documentation, and empirical foundations. Among the report's recommendations is a need for more thorough documentation of study methods and findings, stronger and more consistent quality control, and more attention to how uncertainty should be addressed to better inform decision making. This NRC study was conducted in collaboration with the Royal Society of Canada.

Fluctuating flow and water levels in the St. Lawrence River, whether natural or human-induced, are of concern to the various stakeholders (government organizations, research scientists, industries and the general public) that have been involved for several years in managing water resources and their use, and in maintaining the physical chemical and biological integrity of the ecosystem. Such concerns are particularly justified in the current context of climate change, which is likely to significantly influence socio-economic and environmental policy decisions. In recent years, Environment Canada research scientists have been studying the problem of fluctuating flows and water levels in the fluvial portion of the St. Lawrence. Much of their research has been carried out in the context of the work of the International Joint Commission and, more specifically, the International Lake Ontario-St. Lawrence River Study Board, which has a mandate to evaluate the procedures and criteria used to regulate outflows from Lake Ontario and manage water levels in Lake Ontario and the St. Lawrence River. This document is the product of the work of several of the above-mentioned Environment Canada research scientists. It is a synthesis of the current state of knowledge and of certain recommendations relating to the possible impacts of fluctuating flows and water levels on various environmental and socio-economic factors.

Water resources systems provide multiple services and, if managed properly, can contribute significantly to social well-being and economic growth. However, extreme or unexpected hydroclimatic conditions, such as droughts and floods, can adversely affect or even completely interrupt these services. This manual seeks to provide knowledge, resources and techniques for water resources professionals to manage the risks and opportunities arising from hydroclimatic variability and change. Managing Climate Risk in Water Supply Systems provides materials and tools designed to empower technical professionals to better understand the key issues in water supply systems. These materials are part of a suite of resources that are developed to share climate risk knowledge related to a range of sectors and climate-related problems. The text motivates students by providing practical exercises and it stimulates readers or workshop participants to consider options and analyses that highlight opportunities for better management in the water systems in which they are stakeholders. Managing Climate Risk in Water Supply Systems provides a hands-on approach to learning key concepts in hydrology and climate science as they relate to climate risk management in water supply systems. The primary audience is technical professionals in water resources management and provides a practical approach to training. Editors: Casey Brown, University of Massachusetts at Amherst, MA, USA and M. Neil Ward, Independent Consultant, New Jersey, USA

Fluctuating flow and water levels in the St. Lawrence River, whether natural or human-induced, are of concern to the various stakeholders (government organizations, research scientists, industries and the general public) that have been involved for several years in managing water resources and their use, and in maintaining the physical chemical and biological integrity of the ecosystem. Such concerns are particularly justified in the current context of climate change, which is likely to significantly influence socio-economic and environmental policy decisions. In recent years, Environment Canada research scientists have been studying the problem of fluctuating flows and water levels in the fluvial portion of the St. Lawrence. Much of their research has been carried out in the context of the work of the International Joint Commission and, more specifically, the International Lake Ontario-St. Lawrence River Study Board, which has a mandate to evaluate the procedures and criteria used to regulate outflows from Lake Ontario and manage water levels in Lake Ontario and the St. Lawrence River. This document is the product of the work of several of the above-mentioned Environment Canada research scientists. It is a synthesis of the current state of knowledge and of certain recommendations relating to the possible impacts of fluctuating flows and water levels on various environmental and socio-economic factors.

Many challenges, including climate change, face the Nation¿s water managers. The Intergovernmental Panel on Climate Change (IPCC) has provided estimates of how climate may change, but more understanding of the processes driving the changes, the sequences of the changes, and the manifestation of these global changes at different scales could be beneficial. Since the changes will likely affect fundamental drivers of the hydrological cycle, climate change may have a large impact on water resources and water resources managers. The purpose of this interagency report is to explore strategies to improve water management by tracking, anticipating, and responding to climate change. Charts and tables.