Laserfiche WebLink
<br />1 <br /> <br />) <br /> <br />r <br /> <br />CHAPTER 1 <br /> <br />STREAK AND WATER RESOURCES <br /> <br />Stream Water Resources <br /> <br />Water is by far the single most abundant substan,:e in the biosphere. <br />It forms a major part of the earth's continents, ocea12s, ice caps", <br />glaciers, streams, lakes, and wet lands. ror ,pr8,cti~,:~ ~rpos.!~!lr"t. h., I <br />considered to be .tored in three reaervoin:" the _..'"hJ.~ contd" 97 <br />percent, the continents'lthich contain 2.8 percent, (.."....ty fl~e' percelK of <br />whicb 18 locked up in tlie polar ice cap. and in Blacillra>, and the <br />at.o.phere containing 0.0001 percent. ,Thus euch less than one percent is <br />divided between groundwater, lakes, streallS, and atmol.pheric water vapor. <br />Lakes contain only 0.009 percent of the total and at'ILOY given - thlll only <br />0.0001 percent of the water i. in stre.. channels (Leelpold et al. 1964). <br />In addition to the tiny amount of water being carried by streams (in <br />comparison to the total), the total worldwide surface area of streams is <br />only about 0.1 percent of the land surface" Nevertheless, streams annually <br />carry about 37,000 cubic kilollletera of water to the se,a, which is <br />equivalent to about 25 centimeters (9.84 ill.) of rainfall spread evenly <br />over the entire land surface (Hynes 1970). <br /> <br />Historically, strealllS have been thought to be major features of the <br />landscape because of their sharp contrast with the terrestrial and aerial <br />environments. The continued constt'Uction elf highways, roads, and trails <br />along streams provides increasing visibility that tends to give the false <br />impression of an infinite resource. However, when one considers the total <br />stream IIlilage, stream size (i.e., small, medium, and large), tempE,rature <br />regime (i.e., warllUater or coldwater), flOlol' regimes (i.e., intermlttent and <br />interrupted strealllS), and IIlJltitude of hU"'1I demands and activities <br />concentrated on the remaining stream IIlilage, it beco... clear that: tbe <br />resource ia finite, that no more atre... are being created, and that long <br />reaches are being changed and degraded at an ever incr.easing pace. It is <br />hoped that the following synthesis of published scientific information will <br />contribute to the wise use and rational management of this priceless <br />resource. <br /> <br />Drainage Bas!n <br /> <br />Even a cursory examination of a physiographic map of the conterlll1nous <br />United States illustrates the dramatic contrast betwee'l land, drainage <br />basins and water resources (Figure 1). From west to e.lst the continental <br />United States extends from the Pacific Ocealll to the Atlantic Ocean and is <br />bounded on the south by Mexico and the Gulf of Mexico .rod on the north by <br />Canada. It lies more or less centrally in the temperal:e zone of the <br />Northern Hemisphere. The prinCipal geographic featurell are the mountains, <br />valleys, plains, and drainage basins. 'Especially conal,icuoull are the (1) <br />mountainous region covering approximately the western l:hird of the country, <br />