翻訳と辞書 Words near each other ・ Perenjori, Western Australia ・ Perenna Kei ・ Perennation ・ Perenni ・ Perennial (disambiguation) ・ Perennial calendar ・ Perennial candidate ・ Perennial crop ・ Perennial Divide ・ Perennial Favorites ・ Perennial grain ・ Perennial philosophy ・ Perennial Pictures Film Corporation ・ Perennial plant ・ Perennial rice ・ Perennial stream ・ Perennial sunflower ・ Perennial vegetable ・ Perennial veldtgrass ・ Perennial water ・ Perennialism ・ Perennibranchiate ・ Perenniporia ・ Perenniporia fraxinea ・ Perenniporia fraxinophila ・ Perenniporia medulla-panis ・ Perenniporia nanlingensis ・ Perenniporia piceicola ・ Perenniporia podocarpi ・ Perenniporia subacida Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Perennial stream ： ウィキペディア英語版 Perennial stream A perennial stream or perennial river is a stream or river (channel) that has continuous flow in parts of its stream bed all year round during years of normal rainfall.〔 Water Supply Paper 494.〕 "Perennial" streams are contrasted with "intermittent" streams which normally cease flowing for weeks or months each year, and with "ephemeral" channels that flow only for hours or days following rainfall. During unusually dry years, a normally perennial stream may cease flowing, becoming intermittent for days, weeks, or months depending on severity of the drought. The boundaries between perennial, intermittent, and ephemeral channels are indefinite, and subject to a variety of identification methods adopted by local governments, academics, and others with a need to classify stream-flow permanence. As stream flow decreases in dry weather, visible flow above the stream bed may not be readily evident, especially in streams with coarse substrate (gravel and rocks), where water is flowing beneath and between these particles (hyporheic flow). From a biological perspective, a stream may be considered flowing if sufficient water is available to support flow-dependent aquatic life, including fish and gill-breathing amphibians, benthic insects, crustaceans, and mollusks, many of which survive in shallow hyporheic flow beneath rocks or logs. This extreme low flow may not be detectable on typical USGS stream-flow gages, but is vital to stream ecology. ==See also== * Winterbourne, a stream or river that flows only in winter. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Perennial stream」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.