Laserfiche WebLink
<br />199B. Colorado Flood Hazard Mitigation Plan (409J <br /> <br />The causes of floods relate directly to the accumula- <br />tion of water from precipitation or the failure of man- <br />made structunes such as dams or levees. Floods <br />caused by precipiiation are further classified as com- <br />ing from: <br /> <br />. Rain in a general stonn system <br /> <br />. Rain in a localized intense thunderstorm <br /> <br />. Melting snow <br /> <br />. Rain on melting snow <br /> <br />. Ice jams <br /> <br />Rainfall and melting snow in the mountains feed four <br />major river systerns with headwaters in Colorado. <br />These are the. Missouri, Arkansas, Rio Grande, and <br />Colorado River basins. These basins encompass <br />many small streams and rivers as shown in Figure <br />2.2. <br /> <br />Precipitation in each basin is related to the seasons <br />and two major sources of moisture. Summer showers <br />and thunderstorms that occur from June through <br /> <br />September primarily are caused by moisture from the <br />Gulf of Mexico or the Pacific Ocean. During the fall, <br />occasional general rainstorms and thunderstorms 0c- <br />cur from wet and warm cyclonic air masses, which <br />move in from the southern Pacific Ocean. Winter and <br />spring rain and snow storms are generally a result of <br />moist air masses which originate in the cooler northern <br />Pacific Ocean and move inland across the Pacific <br />Northwest <br /> <br />Floods caused by failure of man made structunes are a <br />resu It of: <br /> <br />. Hydrologic deficiencies <br /> <br />. Structural deficiencies <br /> <br />. Improper Operation or Sabotage (1 case in CO) <br /> <br />Each of these causes results in floods, which have <br />distinct characteristics relative to rate of rise, volume, <br />duration, and flood season. <br /> <br />,,,. 101" IllS" 101' ,or <br />.il. -.- n' <br />0 <br /> I <br /> , <br /> \1 c <br /> I <br /> REPUBLICAN I <br /> ... <br /> <br /> <br />31' <br /> <br />\09' <br /> <br />\08' <br /> <br />'.7' <br /> <br />...'-..-..;.__......_.:-.'"-'.._---"'" .__--'--...~_. ..~__ ..___,.,__, ."...'-.>._."-._,_."._.:....:"'-""'-.:..:~__,...;._,.:.c ,;:;,,",,-::,,::,--:-;'.;..;.:.;.-,--,-,,'-,_.~;,;,:.__~.,,,-,;'., ,:...;'..:.:.....-,:;;.::..~~~,,~:,.;;~'.::. <br /> <br />FIgute 2-2 <br /> <br />F/Ie~ <br /> <br />.------ <br /> <br />1116" <br /> <br />'OS' <br /> <br />.01' <br /> <br />Inr' <br /> <br />Chap1er 2 . 2 <br /> <br />11UIIS 6:14 AM <br />