OCR Text |
Show 85 * * The ( extent ext6iit ) of the erosive action of ( the t116 ) 6tei is ( 'evidenced evidenced ) by the fact that only remnants of ( tlie Ilib ) Colorado River plateau remain . Each gully , % Vashy and canyon , is ( mute ninte ) evidence of erosion and ( topo- topo ) graphic features of all grades show the influence of aridity . . Besides the material brought into the river by side tributaries or blown in by the wind ( Photo ( Ex Ex' Ex ) _ hibit 20 ) , the ( river's rivers ) own powers of erosion are a ( 'source source ) of sediment supply caused by gradually wearing away their rock ( walls valls ) or undermining their banks . As a result of these conditions the Colorado River system carries more suspended matter per square mile of drainage area than any other river in the ( United 'United United ) States . ( Denudation by R . B . Doyle and JJ . Stabler , pages 78 to 93 , ( TJ U ) . S . Water Supply Paper No . 234 , Government Printing Office , 1909 . ) The following testimony all based ( 011 on ) ( actual actnal ) ( obser- obser ) vations made since 1909 ( when vhen ) Water Supply Paper No . 234 was prepared is a partial indication of the actual amount of ( suspended siispended ) matter carried by these streams . ( G-reen Green Green ) River ( -According According ) to Fortier and Blaney ( Exhibit 68 , page 17 ) as digested by Hoyt ( ( Ex- Ex ) ( hibit bibit ) 75 , pages 76 , 77 ) , the amount of silt carried past Green River in suspen , sion during the 12- month period August , 1914 , to ( July Iuly ) , 1915 , was 8,332,900 tons . This is ( exclusive -exclusive exclusive ) of sediment brought in by Saleratus Wash and San Rafael River and includes no ( led bed ) load . |