No abstract

No abstract

Ihatcom Coimty is on th© international border in the extreme northwestern part of the State of Washington. The western pert ef the county is a lowland area .of about 3SO square mlcii that extends eastward froia Fuget SoAind to the footliills of the Cascade? fountains* The area, knusm as the 7;hatco5i B^sin, consists of loir, glacially smoothed. till plains rising to an altitude of 200 to 600 feet above broad river valleys to which they are connected by gentle slopes and. terrace lands. '?he major drainage sj-3tea in the area is that of the Foo&sack River; some scalier stream drain local degressions. The firea has an equable oceanic climate. The precipitation is about > 3k inchesj, occi^rring mostly as rain in the winter months. The lowland is underlain largely tjjr imeonsolidsted deposits of Pleisvocene and Recent age. The bedrock that cosmoses the foothills of the-''. '-' " ' '< Cascade Kounteins protrudes through the unconsolidated i^aterial in a fear places around the margins of the Iceland. Tlieae consolidated rocks are indxrrated continental-type sediioentary rocks of lower Eocene ago and coiisist of sandstones, shales, conglonorates, and coal having a total thickness of acre tlian 10,000 feat. The Tortiary rocks are underlain by pre~Tertiary iaetacK>rph3.c recks that are exposed at a £enr places in wast»em Whatcoa County. Prioi1 to the fathon glac5,ation in lata Ploistocene time the Puget *?ro«gh wap f L13.ed to a pcint noi^ abora se^ Iev3l vith clays, sands, and fjio^e source ^7^3 probsb3.y the "xi'dsi-ing mountain ratiges. Subssi.V.esa unconsolidated deposits-r'?.r-deeply entrenched "by foiind j?t d^otbu of 1-0 f^et or wore Ln rao rloistoceno aj;d E'3ce.it dspoaits. Ground iwater furnishes the principal domestic, industrial, and public isater mipply for-pestem Tftiatcorj Count./ outsida th© cfty of Belliftghaau An estimated 15COO acres of farm land aro irrigated with gronnd water. Approximately 3,000 dug-srells, U?5' drilled wells, 300 driven irslls, and 100 springs yield about 6^ gi.llion gallons of trater per d.ay. Water ;*i»crt arasu sro found chief3.^ in p:-.?ts of tbe upland areas. rrhere peru^eablc strata ere licking i:r IPTICI-C tha till cappimj prevents n.dsc[ue.te recharge, and in arsas where the Tertiary rocks lie at shallow depth b@ti££&h ct.her :xaterial3 of ICT; pcomcc.bility. VIII

Tacoma-_________ 45 25. Flood-stage frequency curve, Green River near Palmer.-.___ 47 26. Flood-stage frequency curve, Green River near Auburn._____ 27. Stream discharge and sediment load, Green River near Palmer_ 28. Particle-size distribution of suspended-sediment samples analyzed in dispersion medium, Green River near Palmer. _ 29. Cumulative frequency curve of water temperature, Green River near Palmer, 1950-55__________.

Acknowledgments _____________________________________________ Previous investigations.________________________________________ Geographic setting___________________________________________ Well-numbering system ________________________________________ Geologic setting_______________________________________________ Climate and vegetation_______________________________________ Agriculture and industry.. _____________________________________ Definition of terms. ___________________________________________ Hydrology_ _ ____________________________________________________ Surface water.________________________________________________ Ground water_________________________________________________ Storage reservoirs____________________________________________ Ground-water basins.__________________________________________ History of streamflow measurement____________________________