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• Minimal impact to ad j cent ditch i.e., 211 grading wort was toward the levee from the <br />ditch edge) <br />Is Use onsite raining operations rock stockpiles to the extent possible for the riprap facing <br />One of the primary tans of the design was to inventory the locations, quality, gradation, and <br />quantity of on -site rock, both stockpiled m ite and salvageable from the existing levee <br />riprap slope. This material was generally the 12- to -inch diameter rock which was left <br />over from reining operations because it was not easily handled by en -site aggregate minin <br />processing equipment, consequently it was generally st ip_ raded, missing a sufficient <br />quantity of the - to -inch rock sizes. Handling this rock had introduced sufficient sand size <br />and smaller material. One of the stockpiles was rumored to contain some a nthropogenic <br />debris arid, although it was not noticeable this source was not considered for use. Other <br />than this one source, it was concluded that the on --site rock could be converted to an <br />acceptable type L/M riprap by mixing it on a :1 retie with imported type VL angular <br />riprap. Since the resulting quantity was insufficient to face the entire levee slope, this <br />composite riprap was placed in the higher water v elocity reach and imported type L riprap <br />was used on each end. Since the largest rock needed was D, = 177 mm and type L is <br />D 50 = 229 mm, the composite riprap and type L riprap were more than adequate in size. <br />Since there were portions of the levee which needed to be reshaped, raised and existing <br />riprap rock salvaged before riprap could be placed and because an adequate toe protection. <br />had to be constructed, the project tool, on an earth - moving compon nt that preceded riprap <br />placement. This meant a two phase design /construction process was necessary. The first <br />phase involved designing the accessary earthwork to create a proper structural surface <br />from which to build the second phase. The second phase was fire grading, excavating, and <br />constructing the toe protection and placing the riprap slope protection. <br />In order to minimize the `Impact on the existing irrigation ditch and to not move the <br />embankment, a vertical structural tee wall was designed as the toe protection adjacent to <br />the ditch and conventional 18-inch thick riprap constructed on a :1 dope above the toe <br />protection. The toe wall was designed as an 18-inch vide VL type grouted riprap wall with <br />fibermesh reinforcement and it was constructed as a 12-inch wide fiberme h reinforced <br />concrete wall. <br />CONSTRUCTION <br />The first stage of construction was the regrading, raising, and otherwise completing all the <br />basic earthwork associated with levee rehabilitatian. This was accomplished by Western <br />Mobile for Flatiron with conventional earthmoving equipment which was already on site for <br />the mining reclamation activity. Work was complete by approximately November 10, 1997. <br />Immediately thereafter November 20), when weather permitted, L & M Enterprises began <br />the final subbase preparation, final grading; then constructed the riprap embankment as <br />designed and as shown on the completed as-- constructed Drawings. Work was complete an <br />February 16, 1998. <br />Ayres Associates <br />