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to be designed to limit the amount of erosion along the Swale, and because of the steepness of the quarry access road, check structures would be required at frequent intervals to limit the degradation of the Swale as it approaches the 54/30-inch culvert. The amount of sediment available for transport to downstream property would probably not be decreased compared to the existing condition. Option 2: This option is very similar to the Option 1, and does not address the concern of flow diversion. Using th,= Cedar Heights Drive street section to convey the runoff ori~3inating from the HR-6 basin to the existing culvert under Cedar Heights Drive will cause sediment to be routinely deposited in th~a street section. This would appear to increase the maintenance responsiblity of the Cedar Heights property owners. As in the case of Option 1, the 54/30-inch culvert would be overtopped in 100-year event or in the event the HR-6 culvert became plugged. Option 3: This option does not effectively solve the concerns pointed out in the above discussion. In fact, of thc~ three options discussed thus far, Option 3 increases the fJ.ow and sediment transport (relative to options 1 and 2), to the' 54130- inch culvert and thereby creating the potential for even greater damage to the quarry access road and to Black Canyon Road. Options 4 and 5: These options propose that all of ttie flow originating from basin HR-6 be diverted to the HR-7 ba_cin and eventually to the 54/30-inch culvert. This option in our opinion is unacceptable and creates the potential for even greater liability to the quarry operator. If these options are pursued, the quarry operator would have to make provisions for the handling of overflows onto the public portion of Black. Canyon Road which would involve concurrence from either the County and/or the City of Manitou Springs. Removing the section of 30- inch culvert from the 54/30-inch system would increase the capacity sufficiently to prevent overflow on to Black Canyon Road. Design of the roadside swales would have to be completed by the quarry operators. Option 6: This option in our opinion if the most acceptable of the alternates .identified thus fay. The construction of a 100- year capacity culvert at the outfall point of the HR-6 basin would prevent the diversion of flows to other basins and thereby relieve the concerns caused by such diversions. This option would also eliminate the need for hold harmless provisions necessary to implement an~• of the diversion schemes discussed above. The quarry operator should also be responsible for removing and/or otherwise stabilizing the area at the inlet of the HR-6 culvert so as to prevent sediment deposition along the natural Swale and within Cedar Heights Drive. Though a 100-year U ~~ 4I Q p! ~ i n~~Jsht `Q~~~'r i ~"`~, N Pao,~~ ^; u~ r o~ 1S 3