2011-09-09_REVISION - M1981185 (43)

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Mr. Wallace H. Erickson Response to August 22, 2011 Cazier Memorandum September 9, 2011 Page 4 BMP #12 Rip Rap Rip rap material is readily available on site. Rip rap will be produced during road construction. D50 riprap, as designed, will be sized using portal crushers and screened as necessary. Crushing and screened activities will be located such that BMPs can be in place to prevent materials from eroding into streams or sensitive areas. Sized materials will be used in place, stored in designated areas (staging, rock storage areas) or piled within the area where the materials will be used as road base or as stone filter. Rip rap as specified will be used for channel aprons (including flare) and channels that extend up the banks and to the height of the maximum depth of flow for the design storm. The maximum riprap diameter size will be dmaX 1.5 d50. The apron thickness will be equal to 1.5 x d The upside end of the apron adjacent to the pipe will have a width three times the diameter of the pipe. The apron will be constructed with no overfall at the end. As necessary, fugitive dust will be controlled using water. Wildcat intends to analyze the gradation, density and shape of riprap created during crushing and screening operations to confirm the riprap specified in the Stormwater Management Plan is appropriate for design conditions. Wildcat will also commit to meeting the design specifications set forth in Section 506 of the CDOT Standard Specifications for Road and Bridge Construction (2011). In order to clarify this intent, Wildcat will add the following bullet after the third bullet in the Pre - Construction Activities section on Page 5 of Attachment D -1 (New Access Road Construction Work Plan): • Perform laboratory testing and visual inspection on terrace rock which will be crushed and screened for use as riprap to determine density and conformance with Section 506 of the CDOT Standard Specifications for Road and Bridge Construction (2011); Wildcat will also add the following sub - bullet to the existing fourth bullet in the Pre - Construction Activities section on Page 5 of Attachment D -1: • Criteria for the design of riprap as specified in work plans and the Stormwater Management Plan; Finally, Wildcat will further clarify its intent by adding the following bullets after the fifth bullet of the Pre - Construction Activities section on Page 5 of the New Access Road Construction Work Plan: DEN 97,591,786v1 9 -9 -11 GREENBERG TRAURIG, LLP • ATTORNEYS AT LAW • WWW.GTLAW.COM