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<br />PHREATOPHYTES AND WATER SALVAGE <br /> <br />Water exists in three states: <br /> <br />liquid, solid, and vapor. The circu- <br /> <br />lation of water in these three states from the ocean, to atmosphere, to <br /> <br />the land, and back to ocean again by overland and subterranean routes is <br /> <br />known as the hydrologic cycle. Rainfall, surface runoff, ground water re- <br /> <br />charge, evaporation and evapotranspiration are all elements of this cycle. <br /> <br />It is in the broad context that phreatophyte control and water sal- <br /> <br />vage must be viewed. To consider phreatophyte control, or lack of control, <br /> <br />on-a parcel-by-parcel basis or a tributary-by-tributary basis ",ill contri- <br /> <br />bute to ad hoc water management decision making on a case-by-case basis. <br /> <br />An overall plan basis is required for optimum water mamagement. <br /> <br />Evaporation is the subject of special concern in semi-arid regions <br /> <br />where the demand for water greatly exceeds the supply. When water evapo- <br /> <br />rates and escapes into the atmosphere, it temporarily loses its utility for <br /> <br />man; thus, man seeks to keep water in its liquid state. One manner in <br /> <br />which water enters the gaseous state is through the metabOl ic processes of <br /> <br />plants known as transpiration. The combined processes of evaporation and <br /> <br />transpiration are knOl"n as evapotranspiration. The relatively high rates <br /> <br />of evapotranspiration from plants such as phreatophytes are of concern in <br /> <br />dry areas. Phreatophytes in dry areas typically grow in the vicinity of <br /> <br />water-courses ,"here a ready sup~ly of ,'Iater is available, Tile significance <br /> <br />of phreatophytes was commonly realized in the early 1320's when the word <br /> <br />phreatophyte, meaning ,"ell-plant, '"as coined by r.~inzer,.1 <br /> <br />,-. <br />