[Lake Berryessa, the Monticello Dam, and the largest drain, or spillway, in the world.]
Prompted by an excellent text entitled “Three Doors to Other Worlds” by Andrew Crompton in the JAE from last November, we are following him down the rabbit hole. (Get the complete PDF here.) Crompton positions architecture within the cognitive sciences with a fancy for the grotesque / Baroque. In this particular text Crompton is seeking to chart and qualify architectures that elude description through drawing or photograph, instead requiring something more, err, cognitive. A tall order, and possibly one that were it actually taken to task would be a very short list in architecture, though maybe longer in art and media, and surprisingly engineering. One case in point in Crompton’s search is the architectural equivalent of a black hole. It is a bellmouth spillway. In particular Crompton refers to the Ladybower bellmouth constructed in 1935 near Sheffield, UK.
[The spillway at the Monticello Dam, near San Francisco, CA.]
Unable to evaluate whether the bellmouth truly qualifies for its ineffable status having not seen them in person, it is easy to note in photograph the surreal nature by which the weighty mass of water at once appears as a single surface folding in on itself. Or as Crompton writes: It is easy to overlook its obvious purpose and see instead an object of sinister artistry. Simply speaking, the spillway is a massive drain for the reservoir. It prevents water from rising above a certain level and spilling over the dam or lake shoreline. The bellmouth at the Monticello Dam is the largest in the world at a diameter of 87 feet narrowing to 27 feet and can drain off 367,500 US Gallons per second. Gulp.
Spillways serve to regulate reservoir levels and maintain two states; (1) in use they disappear and are minimally obscured by flowing water, (2) not in use they are sculptural oddities hovering ambiguously above the water line. In use the spillway is pure negative space, a void; not in use, they are solid, positive space. Aside from Crompton’s observations on the black hole condition, we would add the potential for contradictory phase change to its ineffability. The spillway swallows its own description as it imbibes water through Klein-bottle-like inversions.
[Section of the Morning Glory Spillway of the Val Noci Dam in Montoggio, Italy showing revisions made to the design for increased performance.]
The nomenclature behind the bellmouth spillways further its reading as a massive engineered earthen orifice. The mouth, the throat, the shaft. In refining the engineering behind the bellmouth for the Val Noci Dam in Montoggio, Italy a throttle and air supply was added to accelerate the spillways ability to process extreme flow and turn a 90 degree corner. In other words, to keep the bellmouth from choking on itself in grew a tongue.
[Studies of the flow for the Morning Glory spillway for Val Noci Dam.]
[The massive High Island Reservoir, created in 1978 near Hong Kong on the Sai Kung Peninsula, is serviced by this bellmouth.]
[The steeped edges of the Ladybower bellmouth prevent the surficial reading found in the smooth flow of the bellmouth at Monticello Dam.]
[Peering into the ineffable, the Ladybower bellmouth spillway.]
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Via InfraNet Lab