Sue Water Purification Plant Slow Filtration Treated Water Collecting Well

At the End of the Axis

The Sue Water Purification Plant Slow Filtration Treated Water Collecting Well (末浄水場緩速浄水集合井, Sue Jōsuijō Kansoku Jōsui Shūgōsei) is a single-storey reinforced concrete building constructed in 1930 at the Sue Water Purification Plant in Suemachi, Kanazawa City, Ishikawa Prefecture, and was registered as a national Registered Tangible Cultural Property on 28 August 2001. It stands at the western edge of the site, at the head of the central walkway between the six slow sand filters, with a building area of 26 square metres.

A collecting well brings together the water cleaned in each filter. Output from the clear-water wells of filters No. 1 to No. 6 joins a pipe under the walkway and flows in here. The building covers the point where the whole slow-filtration line becomes a single stream.

The Kanazawa City Public Enterprise Bureau dates its completion to June 1930, a year before the filters themselves were finished in June 1931, so the western anchor of the plan was in place first.

From Circle to Oval

The criterion applied is that the building serves as a model of design. Most of the basins and filters were registered for their place in the landscape; the Sue Water Purification Plant Slow Filtration Treated Water Collecting Well, like the Former Receiving Well House, was registered for its architecture.

According to the Agency for Cultural Affairs, the plan was first drawn as a circle. When a larger well area was called for, the circle was stretched into an oval. The change was made to hold the combined output of six filters, a case of function setting the form.

The building closes the supply axis that runs due west from the pavilion in the front garden. If the pavilion is where that axis begins, the collecting well is where it ends. Three well houses on each side of the walkway and the collecting well at the far end show how closely the engineering plan and the landscape design were worked out together.

Three Arches and Carved Circles

Along its sides run three semicircular arches, one large and two smaller, the larger apparently set between the others.

The roughly triangular space between the curve of an arch and its neighbour is called a spandrel. Here each spandrel carries a relief based on the circle. The bureau notes that the spandrel began as an accidental gap and over time became an indispensable place for ornament.

An oval plan means walls that curve as they turn. Arches cut into those curved walls, with circles in relief between them: circle, half-circle and oval are the only shapes the elevation needs.

The bureau's web page also shows the design drawings. Set beside the building, they show how the spacing of the arches and the reliefs was carried through.

Seeing It

The Sue Water Purification Plant Slow Filtration Treated Water Collecting Well stands at the western edge of the site, well away from the front garden that is open without booking, and published sources do not say whether it can be seen from there.

The water facilities are shown on pre-booked group tours, which the bureau says cover the treatment process and the sedimentation basins and filters. Whether the collecting well is included is not stated, so ask when applying. Tours are for groups such as local governments and community associations, and applications are due two weeks ahead.

Nothing is published on photography, so ask the guide. Directions and garden hours are on the Sue Water Purification Plant page.