Despite uncertainty pertaining to methods, assumptions and input data of climate change models, most models point towards a trend of an increasing frequency of flooding and drought events. How these changes reflect water management decisions and what can be done to minimize climate change impacts remains unclear. This paper summarizes and extends the workshop outcomes on ‘Climate Change Impacts on Watershed Management: Challenges and Emerging Solutions’ held at the IWA World Water Congress and Exhibition, Montréal, 2010, hosted by the IWA Watershed and River Basin Management Specialist Group. The paper discusses climate change impacts on water management of freshwater ecosystems and river basins, and illustrates these with three case studies. It is demonstrated through the case studies that engagement of relevant stakeholders is needed early in the process of building environmental flows and climate change decision-making tools, to result in greater buy-in to decisions made, create new partnerships, and help build stronger water management institutions. New alliances are then created between water managers, policy makers, community members, and scientists. This has been highlighted by the demonstration of the Pangani integrated environmental flow assessment, through the Okavango River Basin case study, and in the more participatory governance approach proposed for the Delaware River Basin.

The spill of diesel oil fuel in January 1988 raised a number of technical, legislative, and administrative issues—such as assessing long‐ and short‐term environmental damage, evaluating regulations regarding oil tanks, and examining spill response procedures. An important research need is the development of computer models that can better predict the travel time and the concentration of contaminants should a spill occur.

The Ohio River Valley Water Sanitation Commission (ORSANCO) is an interstate agency created in 1948 to administer a state compact which calls for the abatement of water pollution in the Ohio Valley. Since 1975, ORSANCO has conducted routine monitoring programs to detect the presence of toxic chemicals in the Ohio River and in fish taken from the river. Such information is particularly important as the Ohio River, a major river in the United States, serves as a water supply to over three million people and is used extensively for recreational purposes. The monitoring results have shown several problems: contamination of fish tissue by PCBs and chlordane, concentrations of certain metals which exceed chronic aquatic life criteria in 10 to 25 percent of the samples analyzed, and levels of certain volatile organic compounds which exceeded criteria established to prevent one additional cancer per one million population in almost half the samples analyzed. In 1986, the Commission initiated a Toxic Substances Control Program which was designed to identify sources of the toxics problems and prescribe corrective actions. Because of the multitude of potential sources of toxics along the Ohio, the river was divided into seven segments for intensive study. To date, studies have been initiated on four segments. In addition, special topic studies have been conducted on the river as a whole to address the suitability of the river as a source of drinking water, trends in parameter levels, and the relationship between surface and ground water quality. Findings to date:Point source discharges to the river do not cause widespread toxics problems.Nonpoint sources, including urban runoff and contaminated ground water, are significant sources of toxics to the river.Levels of certain toxics in tributaries are also an important source.Under “normal ” situations (i.e., excluding spills), the Ohio River provides a suitable source water for public supply after appropriate treatment.Levels of many metals and volatile organic compounds have decreased over the past 10 years.

The Ohio River Valley Water Sanitation Commission (ORSANCO), in cooperation with the United States EPA, is completing it role in assisting the Baltic Countries of Estonia, Latvia, Lithuania and Kaliningrad Oblast, Russia with watershed management capacity building demonstration projects under the Great Lakes/Baltic Sea Partnership Program. The Countries of Estonia, Latvia and Lithuania view the skills gained through this program as important to their objective of complying with the European Union's Water Framework Directive and thus facilitating accession into the European Union. The program also addressed Kaliningrad's desire to work cooperatively with their neighboring countries concerning shared waters. Three watershed demonstration projects were designed and implemented, two of which involved joint country efforts: Parnu River (Estonia) modeling for nutrients and bacteria survey; river basin assessment and management planning for the Lielupe Basin (Latvia and Lithuania); and data base development and cooperative water quality survey and analysis for the Sesupe River (Lithuania and Kaliningrad). The benefits of the projects include enhancing the country's technical skills and the forging of relationships, without which achieving effective watershed management will be difficult to achieve.

No abstract