Discharge ratings for control gates at Mississippi River Lock and Dam 14, Le Claire, Iowa

The water level of the navigation pools on the Mississippi River are maintained by the operation of tainter and roller gates at the locks and dams. Discharge ratings for the gates on Lock and Dam 14, at Le Claire, Iowa, were developed from current-meter discharge measurements made in the forebays of the gate structures. Methodology is given to accurately compute the vertical gate openings of the tainter gates. Discharge coefficients, in equations that express discharges as a function of tailwater head, headwater head, and vertical height of gate opening, were determined for conditions of submerged-orifice and free-weir flow. A comparison of the rating discharge to the hydraulic model rating discharges is given for submerged orifice flow for the tainter and roller gates. (Author 's abstract)