Inland water

Water on or near the Earth's surface, excluding seawater and water vapor. It accounts for only 2.5% of the total water on Earth. The proportion of land water in the total water is 1.75% in glaciers, 0.73% in groundwater, 0.009% in freshwater lakes, 0.008% in salt lakes, 0.002% in soil water, and 0.0001% in rivers. In addition to surface water such as river water and lake water, land water exists underground as groundwater and soil water, and in solid form as snow and ice. Most of it is freshwater, but lakes in arid regions and deep groundwater often contain large amounts of salt. Unlike other mineral resources, land water is characterized by its cycle, and along with solar energy and biomass (total living organisms), it is a renewable resource that is fundamental to human survival.

[Isamu Kayane]

"Inland Water," edited by Yamamoto Sotake (1978, Kyoritsu Shuppan)" ▽ "The Chemistry of Inland Water, Quarterly Chemistry Review, edited by the Chemical Society of Japan (1992, Academic Press Center)" ▽ "Easy Limnology: Groundwater, River, and Lake Environments," written by Iida Sadao (1993, Bunka Shobo Hakubunsha)" ▽ "The Earth's Hydrosphere: Oceans and Inland Waters," written by Aoki Bin et al. (1995, Tokai University Press)" ▽ "A Guidepost for the Journey to Water: Traveling Through Inland Waters," written by Watanabe Jinji (1996, Kindai Bungeisha)"

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

地球の表面およびその付近に存在する水のうち、海水と水蒸気を除いた水。その量は、地球上の水の総量の2.5％を占めるにすぎない。水の総量に対する陸水の割合は、氷河1.75％、地下水0.73％、淡水湖0.009％、塩湖0.008％、土壌水0.002％、河川水0.0001％である。河川水や湖沼水などの地表水のほか、地下水や土壌水として地中に、また雪や氷として固体の状態でも存在する。そのほとんどが淡水であるが、乾燥地域の湖沼や、深層の地下水には塩類を多量に含む水も多い。他の鉱産資源と異なり、陸水は循環していることが特徴で、太陽エネルギーやバイオマスbiomass（生物体総量）とともに、人類生存の基本となる再生可能な資源である。

［榧根　勇］

『山本荘毅編『陸水』（1978・共立出版）』▽『日本化学会編著『陸水の化学　季刊化学総説』（1992・学会出版センター）』▽『飯田貞夫著『やさしい陸水学　地下水・河川・湖沼の環境』（1993・文化書房博文社）』▽『青木斌ほか著『地球の水圏　海洋と陸水』（1995・東海大学出版会）』▽『渡辺仁治著『水への旅の道しるべ――陸水を旅して』（1996・近代文芸社）』

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例