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i Table G-3 Ditch Summary Bottom 100-hr, 24-hr Channel Name Width Si(H:V) a (�°) (�n) Slope peak Flow Depth Riprap Dso ft H'V) cfs ft 6.7% 2 15 North Channel 20 3:1 272 28% 2 24 10% 2 12 Middle Channel 10 3:1 105 30% 2 21 33% 104 2 24 South Channel 10 3:1 20% 2 21 154 2% 2 12 Lower Channel 20 3:1 25% 443 2 27 Outlet Channel 20 3:1 2% 485 3 21 F— T errace na 2.25:1 2% Up to 20.63 2.0 na • and 10:1 Groundwater Pikeview Quarry is located in northwestern Colorado Springs, where the Rockies rise out of the plains. Predominantly, the quarry has mined the Ordovician Manitou Limestone, a sedimentary formation with occasional thin layers of clayey shale. The limestone dips between 20 and 25 degrees on the floor of the pit to 30 to 45 degrees in the middle and upper slope areas. Mapping suggests the dips may be as high as 90 degrees in the immediate vicinity of the Rampart Range fault. The Manitou limestone has an exposed thickness of approximately 145 feet in portions of the Pikeview Quarry (Morgan, et al. 2003). The base of the limestone is the Cambrian Peerless Dolomite which is approximately 40 feet thick. Underlying the dolomite is the Cambrian Sawatch sandstone, ranging from a glauconitic sandstone near the top to an arkosic sandstone near the base. The Sawatch is approximately 70 feet thick in the quarry. All formations are underlain by the Precambrian Pikes Peak granite which is highly weathered, fractured and jointed at the surface. The quarry is situated in a fault-bounded block related to the Rampart Range Fault. Both the Rampart Range Fault and the unnamed sub parallel fault that is located on the east side of the quarry exhibit west-side-up relative motion. The structural throw on the Rampart Range Fault is estimated to be approximately 4,300 feet (Morgan et al, 2003). Pikeview Quarry Amendment 4 2019 G-7