The people and industries of Manitoba as in all areas of North America are demanding more and more electrical energy every year. The demand in Manitoba has more than doubled in the last decade (Figure 1) and there is reason to believe that it will double again in the next 10 years. In parallel with the accelerating demand for electrical energy, there is an ever increasing awareness of the need to preserve Manitoba's natural environment and to allocate its natural resources with a view to benefiting Manitobans now and in the future. Satisfying the demands of Manitobans for electrical energy and for environmental quality requires advance planning and compromise. The Government of Manitoba decided in 1966 to proceed with developments to harness the potential energy of the Nelson River and to add to that potential by diverting a major part of the Churchill River flow into the Nelson River. The hydroelectric development program included a generating station at Kettle Rapids, a high voltage transmission line from the Nelson River to Winnipeg, regulation of the outflow from Lake Winnipeg and diversion of substantia l flow from the Churchill River into the Nelson River. The Kettle generating station and the transmission line have been completed. The Lake Winnipeg regulation and Churchill River diversion projects are under construction. The governments of Canada and Manitoba, recognizing the overall interest and conflict over the use of the water and related resources, initiated the Lake Winnipeg, Churchill and Nelson Introduction Rivers study. The study was intended to determine the effects which the regulation and diversion projects are likely to have on other water and related resource uses, to indicate ways in which the projects may prove beneficial to such other uses, to recommend modifications in the design and operation of the works, and to recommend remedial measures where considered necessary to lessen undesirable effects. The study took over three years to complete at a cost of $2,000,000. It involved many experts from federal and provincial agencies, universities and consulting firms representing a variety of disciplines. The salient aspects of the study, including the social, economic and environmental conditions in regions affected by the regulation and diversion projects, are summarized in this report along with the antiCipated implications to the people and the environment. Opportunities for increasing overall benefits and lessening harmful effects are also outlined. Further details of the study are to be published separately in the Technical Report. The study was authorized under a joint Canada-Manitoba agreement entered into on August 24, 1971. A sixmember federal-provincial board, established under the agreement, directed the study. A study office was set up in Winnipeg and a four-member technical advisory committee was appointed. The complete study agreement and the study organizational chart are included at the end of this report The study agreement esta blished the objective, terms of reference and administrative framework for the conduct of the study. Funding for the study was shared equally between Manitoba and Canada. The Board was required to report to the Minister of Environment Canada, to the Minister of the Manitoba Department of Mines, Resources and Environmental Management, and to Manitoba Hydro. The objective for the Lake Winnipeg, Churchill and Nelson Rivers study was defined in the agreement as follows : .. . to determine the effects that regulation of Lake Winnipeg, diversion from the Churchill Riuer and deuelopment of hydro-electric potential of the Churchill Riuer diversion route are likely to have on other water and related resource uses and to make recommendations for enhancing the overall benefits with due consideration for the protection of the environment.