Locks - Navigation Facility

The layout, mechanical systems, and operational procedures of lock and dam projects are diverse. Some differences are due to the historic development of lock design technology. Most differences, however, are due to project-by-project hydrologic constraints and commercial navigation needs. The following four examples of lock variations highlight differences in design and operation.

1. The high-lift lock shown in (Figure 11) is located adjacent to flood control, river regulation, and hydropower structures as well as other salient features (e.g., fish passage facilities). The project accommodates a lift (the difference between extreme upper and lower pools) of 32 m. The gates used to close the chamber during filling and emptying are an upstream submersible tainter gate and an extremely high downstream miter gate. The chamber has clear dimensions of 26 m wide and 206 m long. Flow into and out of the lock chamber is through a complex hydraulic system that includes intakes with trashracks, culverts, valves, manifolds, ports, and baffles.

2. The high-lift (21-m) lock shown in (Figure 12) is located in a channel that bypasses river-regulation and flood-control facilities. Miter gates are used upstream and downstream to close the chamber. The chamber has clear dimensions of 34 m wide and 183 m long. Flow into and out of the lock chamber is through a complex hydraulic system that includes intakes with trashracks, culverts, valves, manifolds, ports, and baffles.

3. The medium-lift (6-m) locks shown in (Figure 13) accommodate a relatively large volume of commercial traffic. Thus, the project includes a large main lock (34 m by 366 m) and a smaller auxiliary lock (34 m by 183 m ft). The hydraulic system includes components similar to the first two examples, but is less complex and has lower flow velocities than the high-lift locks. In fact, many low-to medium-lift locks do not include manifold systems on the chamber floor. Instead, ports lead directly from the wall culverts into the chamber and are termed side-port systems (large ports) or multiport systems (many small ports).

4. The low-lift lock shown in (Figure 14) is a relatively low-cost lock that fills and empties using flow through the upstream and downstream gates (sector gates), respectively. The sector gates are structurally designed to operate under reverse as well as normal lift conditions and are therefore often, but not always, used in tidal areas.

Zebra mussel infestation can interfere with operations at lock and dam projects in many ways. Clogging intake screens and roughening smaller flow passage surfaces (decreasing hydraulic efficiency) are examples. The large scale of navigation projects tends to preclude the physical clogging of most lock valves, gates, culverts, and other appurtenances. However, secondary problems dealing with paint, corrosion, instrumentation, cleaning, and disposal can be significant.

Navigation Facility Components at Risk

Control Methods by Facility