4.3. ERMUSR 06-16-2015 - Laserfiche WebLink

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. . . .. art.... flood preparation at Elk River Dam. The City should also coordinate efforts with the National Weather Service and local agencies (sheriff, city and state police, radio and television stations) in disseminating flood information to residents in the flood plain. GATE OPERATION This section describes the radial gate operation plan during • flood or other periods of high water elevation. The gates should always be operated in general accordance with the operation plan described here. During extreme floods, some deviation from the operation plan may be required. Such deviation should only be permitted when the reservoir water surface rises very rapidly and normal gate operation proce- dures are impractical. • Figure 2-1 shows the gate operation curve related to spillway • discharges and reservoir water surface elevations. Figure 2-2 shows the anticipated reservoir response to an approximately 10- and 25-year flood. A complete description of the gate operation plan is presented below: • o Always clear the downstream area of any personnel at or near river level before opening a gate. o When the reservoir level reaches elevation 875.0 feet and rising, open Gate No. 2. (middie gate) approximately 6 feet. - To open the gate 6 feet, the electrical • operator should be engaged for approximately 8 to : . 9 minutes. the gates can also be opened manually with the handwheel : 670 rotations of the' stem nut . will open the gate approximately 6 feet. The amount of gate opening can also be estimated by . visually observing the takeup on the wire cables on the drum hoist. When the gate is open 6 feet, . the top of the gate will be approximately 1 foot lower than the top of the operation deck. o if the water surface elevation rises to 875.5 feet, maintain Gate .NO. 2 at 6 feet and open Gate No. i (south gate, farthest from the main weir) 6 feet. • Close the Main Street Bridge to all traffic except . emergency vehicles if this has not already been done. .. o If the water surface elevation rises to 876. 2 feet, . maintain Gates Nos. 1 and 2 at 6 feet arad 'open Gate No. 3 (north gate, nearest to-the main weir) . • to the full open position. (All gates are equipped .. with switches that will automatically shut off . when the gate reaches its full open position. ) Close the Main Street Bridge to all traffic if this has not already been done. 2-2 S 205 ..