Retreat of Lakeshore Bluffs

Three basic criteria are used in the design of lock filling and emptying system: (1) Lockages must be accomplished in the shortest possible time; (2) disturbances in the lock chamber must not endanger craft in lockage; and (3) the cost of constructing the hydraulic system must satisfy the customary requirements of economic justification. Foundation and site conditions generally dictate the adoption of one of three basic types of filling and emptying systems: (1) end, (2) wall port and culvert, or (3) bottom diffuser. Details of the respective types may be varied to satisfy specific design requirements for each project. In low-lift locks in which wall culverts are not feasible, or in locks subject to reversal of head, end filling systems may be required. The bottom diffuser system is usually adopted for large or high-lift locks of modern commerical rank. Being somewhat more economical to construct than the latter, wall culverts and ports are commonly used in intermediate-lift locks in which the minimum depth of water prism in the chamber is adequate to provide satisfactory stilling action during the filling process.