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Memo to File M-81-302 -3- May 25 , 1997 <br /> minimum design, operation, and maintenance standards for levees . <br /> FEMA accepts determination by other federal agencies as to whether <br /> or not the levees designed, constructed, or inspected by those <br /> agencies meet one percent annual chance flood protection standards . <br /> Protected areas behind levees meeting such standards are shown as <br /> areas of moderate flood hazard (Zone B) on NFIP maps . <br /> III . Reference : Technical Review Guidelines for Gravel Mining <br /> Activities within or Adjacent to 100-year Floodplains, <br /> December, 1987, Urban Drainage and Flood Control District . <br /> Floodway: That area of the floodplain required for a reasonable <br /> passage or conveyance of the 100-year flood and which will convey <br /> the flood flows with not more than 0 . 5 foot rise in the water <br /> surface elevation based on the assumption that there will be an <br /> equal degree of encroachment onto the overbank conveyances on both <br /> sides of the floodplain. <br /> IV. Reference : 4/22/97 letter from the City of Boulder. <br /> The City of Boulder " . . . requests that DMG require Western Mobile to <br /> submit additional detailed information about the land berm and <br /> relevant impacts on the surrounding community prior to any final <br /> determinations concerning the proposed reclamation plan amendment <br /> for the Deepe Farm Pit . " <br /> V. Reference : 10/4/96 Colorado Water Conservation Board letter. <br /> "Should the existing levee fail during a large event (100-year <br /> flood) the hazard to downstream areas could be worse than the pre- <br /> mining condition because the lands within the mined area are up to <br /> 12 feet lower than pre-mining operation elevations . This changed <br /> condition could initiate a change in the direction of floodwaters <br /> during times of high flow and could inundate additional areas along <br /> the left overbank not presently in an identified 100-year <br /> floodplain . Due to this potential floodplain condition, it appears <br /> that it may be in the best interest of the community that the levee <br /> system become a permanent floodplain landform. Without the levee <br /> system, the Love investigations show that larger flood flows will <br /> be experienced at downstream floodplain locations . It should be <br /> noted that a delineated downstream floodplain may include numerous <br /> homes in the floodplain. " <br /> C:\WP51\DEEPEPIT.3 <br />