Definition of watershed in US English:



  • 1An area or ridge of land that separates waters flowing to different rivers, basins, or seas.

    • ‘O'Grady and Geslin were still in the lead, some hundred miles into the stage, when the peloton climbed steadily into the area known as Le Forez, the watershed between the rivers Saone and Rhone.’
    • ‘Besides being a watershed, a hill area impacts a much larger area in the plains below.’
    • ‘The slopes of the hill on the northern and eastern sides descend sharply into the river valleys draining from the mountain watersheds of Avgo and Ayios Niketas.’
    • ‘In the Marin watershed on Pumpkin Ridge, Davidson showed me a site where Rizzo and other scientists had injected some healthy coast live oaks with P. ramorum.’
    • ‘These included aggregations sampled along parallel watersheds in the Madawaska Highlands for examining fine geographic scale population structure.’
    1. 1.1 An area or region drained by a river, river system, or other body of water.
      • ‘Then, about 13,000 years ago, the southern edge of the ice sheet retreated past the divide that separates the Mississippi watershed from areas that drain northward.’
      • ‘An overpopulated forest, he insists, is an ecosystem gone wrong - a disaster for wildlife and plant diversity, a drain on watersheds, and a firestorm waiting to happen.’
      • ‘The city council voted unanimously in July to make the entire watershed an ecological reserve.’
      • ‘What are the practices that work best within specific watersheds and regions?’
      • ‘The Penobscot River drains the largest watershed in Maine and is the U.S. Fish and Wildlife Service's flagship river for the restoration of Atlantic salmon in the country.’
      • ‘Opponents of the project worry the resulting salty waste water will find its way into the local watershed and into river systems leading south into Montana.’
      • ‘Bailey Woods drains southward into the Yocona River watershed.’
      • ‘During the last 10 years he has moved on to restoring the entire watershed.’
      • ‘We can do this while protecting critical watersheds, forest aesthetics and wildlife.’
      • ‘The objective of this study was to characterize the vegetation of forested floodplain wetlands along a 66 km stretch of river within the upper Passaic River watershed.’
      • ‘Since so little was known of the species' ecology or distribution, work concentrated in the central piedmont, especially the Broad River watershed.’
      • ‘The ecosystem analyses have since expanded to look at regions - the Chesapeake Bay watershed, Puget Sound, and the Denver / Front Range area.’
      • ‘The proximity of the Passaic River watershed to major urban centers has led to rapid urban and suburban expansion in this region that creates increased potential for these wetlands to be further degraded.’
      • ‘It is the largest river between the great Niger and Congo rivers, and its watershed drains the whole of Gabon.’
      • ‘These sources are particularly important because the rivers drain watersheds that don't receive much summer rainfall and where rates of evaporation are relatively high.’
      • ‘The Pearl River watershed includes an area containing one-eighth of mainland China's population.’
      • ‘Benefit the environment by protecting watersheds and enhancing wildlife habitats and biodiversity.’
      • ‘The site encompasses an entire watershed and thus provides a unique educational opportunity.’
      • ‘My family has continuously resided in the Sun River watershed since the 1870s.’
      • ‘During this period of joint occupation in the Columbia River watershed, neither Great Britain nor the United States had a governmental representative in the area.’
  • 2An event or period marking a turning point in a course of action or state of affairs.

    ‘these works mark a watershed in the history of music’
    • ‘In mythic terms, though, the destruction of the Second Temple was a watershed event in Jewish history - the most decisive since Moses came down from Mt. Sinai.’
    • ‘The Kosovo War was a watershed event that profoundly changed the political situation.’
    • ‘The decade of the 1960s marks a watershed in the history of American ethnic relations.’
    • ‘Well, I think it was a historic watershed.’
    • ‘The Year of the Four Emperors marks a real watershed in the history of the Empire.’
    • ‘This election could prove to be a watershed in modern Canadian politics.’
    • ‘This essay starts from the observation that the 1993 general election marked a major watershed in Canadian party politics.’
    • ‘They mark 1973 as the watershed year in American economy, when the U.S. started lowering import tariffs from 40 per cent to the current average of five per cent.’
    • ‘The arrival of mass consumerism is perhaps the major watershed in European social history between the middle and end of the twentieth century.’
    • ‘Arnold's response to that question was a watershed moment in his political life.’
    • ‘For the last week or more, Taiwan has been in the throes of the early stages of a major, perhaps a watershed, political scandal.’
    • ‘Earle thinks this fall's election will be a watershed in civic politics.’
    • ‘The 19th Century marked a watershed in the art history of India.’
    • ‘The cabinet meeting tonight marks something of a watershed for all involved in the Lydiard Park restoration project because at one stage it looked as if it would stutter to a halt.’
    • ‘The Toronto meeting, attended by 48 nations, was the major political watershed.’
    • ‘Publication of this story marks a watershed in American political history.’
    • ‘This article argues that the 1997 crisis signifies an important watershed in modern Korean economic history.’
    • ‘The year 2000 is shaping up to be another historic watershed.’
    • ‘Naturalization rates increased during the 1920s, but the next decade was marked by a political watershed.’
    • ‘We serve in our military today at a watershed event in the history of modern warfare.’
    critical moment, decisive moment, crossroads, crisis, climacteric, moment of truth
    View synonyms


Early 19th century: from water + shed in the sense ‘ridge of high ground’ (related to shed), suggested by German Wasserscheide.