2016-10-08_REVISION - M1977300 - Laserfiche WebLink

Home Browse Search

Comment No. 3 - Sheet 3. The features labeled as "Sheet Runoff energy Dissipaters" must be re- designed as stormwater diversion channels with the capacity to safely convey the peak flow from the 100-year, 24-hour design precipitation event, with adequate freeboard. This channel design should include depth(with freeboard), side slopes,bottom width, riprap size and gradation. Comment No. 4 - Sheet 4. The features labeled as "Sheet Runoff energy Dissipators" must be re-designed as stormwater diversion channels with the capacity to safely convey the peak flow from the 100-year, 24-hour design precipitation event, with adequate freeboard. This channel design should include depth(with freeboard), side slopes, bottom width, riprap size and gradation. Response to Comments I -4: As previously stated in our response to Comment No. 19, Cotter is no longer using energy dissipaters. Attachment C, Sheets xxx include designs of the drainage channel for the WRPs. These designs satisfy the concerns addressed in items 1, 2, 3, and 4. Comment No. 5 - Sheet 5. The following need clarification: a. The "Profile" for the Check Structure is too vague on what constitutes the "Buffer Zones". The 15-foot dimensions do not coincide with any visible feature in the detail. Please clarify the buffer zones. BUFFER ZONES RALSTON CR. in 2 14 IN a PROFILE 1 in. =20 ft. b. Note 2 discusses "Riprap Slope Protection". However,there is no gradation, size or even a detail as to how this riprap is to be constructed, only a vague location. Additional details for construction are necessary. c. Note 4: States "RIPRAP SHALL BE ANGULAR, DURABLE QUARRY ROCK MEETING THE FOLLOWING GRADATION:" No gradation is provided on the drawing. Please provide gradation for the riprap. The Division also has concerns with respect to the survivability of the check structures as 2016-1 1-07 Response to TR23 Adequacy Review 10