Dam Tailwaters - Hydro-Environmental Analysis: Freshwater Environments - page 505

Q air

Q water

FIGURE 18.11 Illustration of a high-pressure gated conduit.

to cause TDG problems. Examples of aerating weirs include linear, labyrinth, and infuser weirs. A
labyrinth weir is shaped like a series of “Ws” in the channel. The infuser weir may have an equivalent
waterfall length to the labyrinth weir using a slotted decking or grates to create a series of waterfalls,
but it is more compact (Hauser and Brock nd). Examples of the three weir types are illustrated in
Figure 18.12, and a photograph of a labyrinth weir on the Brazos River, Texas is shown in Figure 18.13.

(a)

(b)

(c)

FIGURE 18.12 Comparison of conventional linear (a), labyrinth (b), and diffusing weirs (c) used for aera-
tion. (From WES, The Handbook on Water Quality Enhancement Techniques for Reservoirs and Tailwaters ,
U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS, 1998.)