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-10- d. Engineering design - The diversion must be designed by or under the supervision of a qualified registered professional engineer. The applicant has previously submitted a map showing the location of the diversion, Hydrology Ifap, sheet 2 of the response, a longitudinal channel cross-sections for the 100-year design flood as calculated by the G.E.C, SOAP contractor (submi.tted PSarch 22, 1982). This information should be assembled into a detail plan, and certified by a cualified registered professional engineer as required under Rule (2.05.3(4)). The plan should describe the transition from the natural drainage to the diversion channel. This point should be clearly identified on the plan view and channel profile (sheet 4). The applicant should show how flows are diverted from the natural channel into the diver- sion. Provide design details for any structures used. For each segment of diversion channel, the applicant should provide the flow velocity, identify the material into which the channel is excavated, and identify when channel protection would be required. The applicant should show on the plan view and in profile (sheet 4) all areas where riprap is used. The applicant should provide discussia and calculations showing riprap sizing, gradation of the riprap, nature of the filter blanket used, method of emplacement, and the method used to determine durability. An unnamed tributary enters the permanent d_'ve rsion at station Ff on the profile. The applicant should show all modifications to the tributary and the diversion to accommodate this confluence. (The tributary is much steeper than the diversion channel. Would the break in slope cause a fan to form at the mouth of the tributary?) e. Responsibility for~the inlet and outlet portions for the Diversion - Upstream, the culvert under County Road 92, is undersized and does riot meet performance standards. It is. uncertain who is responsible for the culvert. If the culvert is installed in an undisturbed portion of the stream, it is the county's responsibility and we would have no jurisdiction. If, however, the culvert was installed when the channel was realigned for the Magpie Creek diver- sion, Dorchester should install a culvert sufficient to pass the 100-year event. Responsibility for the culvert must be confirmed. If the culvert is the responsibility of Dorchester, designs to meet the performance standards of Rule (4.05.3). Do~,mstream,~ the diversion passes through G,E .C.'s permit area. i The riprap in this section has only been sized for the 10-year, 24-hour event. Therefore, after G.E.C. reclaims its property, will Dorchester reconstruct this portion of the diversion to meet the permanent standards? 2. Diversions Around the [9aste Pile Diversions around the waste pile will drain areas of Less than one square mile and must be permanent. Attachment I, Figure 8 of the original application, has calculations fora diversion, but the location could not be determined. All waste Wile diversions must be revised and must meet t-he requirements of Rule (4.05.3).