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Construction Methods <br />i) Earthwork: <br />A) Take advantage of the local topography and engineered features <br />1) natural drainage volume behind haul road <br />2) utilize existing culvert under haul road for overflow of runoff over the stored <br />volume of 40,000 gallons <br />3) compact top surface of retention facility <br />B) Metal work <br />1) clean up (excavate) entrance to culvert <br />2) weld metal extensions that extend 2 feet to either side and 1,5 feet below <br />culvert <br />3) weld metal box to extension plate with outlet aligned with npouth of culvert <br />As-Built Verification <br />Figure 1 documents the as-built dimensions ofthe retention facility. The pictures )n Figure 2 <br />display the fmal as-built facility. The following list describes Figures 1 and 2 in rgore detail. <br />I) Culvert extension <br />A) Meta l Box <br />1) plan dimensions: 4 feet wide by 4 feet long <br />2) metal grate made of %: inch nominal diameter rebar arranged orthogonally <br /> with spacing of 0.8 feet <br />3) vertical dimensions: 8 feet tall <br />4) box extends 0.5 feet above and 1.5 feet below mouth of the b foot nominal <br /> diameter culvert <br />B) Earthwork <br />1) fill placed flush on the down gradient side of [he box <br />2) fill placed at a level approximately 2 feet below box inlet <br />II) Retention facility capacity <br />A) Survey information <br />1) utilized well M-10 as a bench mark <br />2) level information collected on a straight line to survey point .G <br />3) all other survey points referenced from point G <br />4) chained (survey tape) used to measure distances between survey points <br />5) stadia information used to confvm distances measured with Chain <br />6) vertical measurement accuracy to 0.01 feet <br />7) horizontal measurement accuracy of0.1 feet <br />8) vertical verification 0.1% (relative percent difference [RPD]~ <br />9) verification between stadia and chain measurements <br /> i) horizontal verification from M-10 to point G of 0.3°/q (RPD) <br /> ii) horizontal verification from point G to survey points iwithin the <br /> facility of l.l% (average RPD). Chain measurements used <br />]0) survey transposed to site coordinates using AutoCad© and survey <br /> measurements (results shown in Table 1) <br /> i) alignment from M-]0 to point G was measured at 8436'30" W of <br /> magnetic north <br /> ii) declination of magnetic north on day of measurement 10°9' <br />