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<br />construction fill material or used in site reclamation to build slope <br />gradients. <br />As portions oP the site become available for reclamation, the slopes will <br />be plated with topsoil out of the topsoil storage berms. The progression <br />will be that the soil in the north berm will be used first, as the eastern <br />berm is to remain until operations are completed at this site. <br /> 3. A portion of the site as it now exists is in the 100-year flood plain. <br /> Please see the revised Mining Plan maps where the 100-year flood plain is <br /> delineated. <br />a ,~' ~,' The elevation at this site is practically uniform at 4,600'. According to <br />1 <br />.~ <br />~ z''+' <br />o q ~.' <br />v Mesa County Engineering Staff Engineer Jaci Gould, P.E., the 100-year <br />-,d ~ ~y7, <br />~,i flood plain elevation at this site is 4,599'. Storm waters should not <br />qf~ ~ A <br />, <br />~„~" enter the site with the construction of the berms that are discussed in <br />:i '!`~ Item No. 4. The berm will be built to an elevation of 9,602' minimum <br />{4"~ ~'~ ' <br /> <br />'. elevation which will give 2 <br />freeboard in the event of a 100-year flood <br />~ <br />:~ ;~ <br />.4 occurrence. <br /> <br />~ . ~ ~ <br />A~p1' ~ <br />'~ Included are maps obtained from the Mesa County Engineering Office <br />~ <br />` <br />~Mn supporting this information. <br />1 <br />L <br />T <br />V <br />1 <br />, <br />~, <br />'y~ <br />' <br />,I„ 4. The 100 <br />greenbelt area that is adjacent to the Colorado River is to be <br />~ measured from the edge of the river channel to the top of the slope. The <br /> slope ratio at this section of the excavated area is planned to be to a <br /> finish grade of 5:1. <br />+(~j'+"~ Additionally, as addressed in Item No. 2, an earthen berm will be <br />. 'i~ ~ constructed to provide for a minimum of 1' freeboard above the 100-year <br />~~ Y ''~ ~ ~~--)" flood level. The existence of these two features should make this section <br />'~"''~ hv+~"'jn reasonably sound. The additional height of the compacted berm and the <br />~jd~ ~,r~+~'~ y thickness of the section should mitigate the concerns of instability. <br />Mesa County officials have evaluated the bank along the subject property <br />and for a reasonable distance upstream (east). Their appraisal is that <br />the bank is structurally sound along this stretch, giving consideration to <br />the angle and direction of the stream flow. The flow is parallel to the <br />bank for several hundred feet and shows no inclination to desire to <br />rebound off the north shore in this area. <br />There is a section of approximately 10' in length that displays potential <br />weakness. United Companies has been directed by Mesa County to place rip- <br />rap in this section to provide adequate stability. This requirement is a <br />stipulation in our local approved permit. <br />The area that is being discussed here is all above the waterflow line and <br />will not require a 404 Permit from the Army Corps of Engineers - per Grady <br />McNure of the Corps in Grand Junction. Regular inspections of the site <br />will be conducted, and the integrity of the 100' berm will be maintained <br />as far as is possible. In the event of major maintenance that would <br />involve buffering of the bank to or below waterline, the Corps of <br />Engineers will be consulted and appropriate measures will be taken. <br /> <br />