Imbe Water Purification Plant No. 2 Filtration Pond

A Filter Bed Added in 1929

Imbe Water Purification Plant No. 2 Filtration Pond (忌部浄水場二号濾過池) is a concrete slow sand filter bed completed in 1929 at the Imbe water treatment plant in Higashi-Imbe-cho, Matsue City, Shimane Prefecture, and registered as a Registered Tangible Cultural Property of Japan on 18 April 2008. It is the second of six beds counting from the west, built to the same size and pattern as its neighbour, No. 1.

It covers 683 square metres. Granite coping stones run along its rim, and a regulating well sits at the centre of its north side. The well is round, 1.8 metres in radius, and topped by a small housing in reinforced concrete. The bed itself is a sunken tank of water; the housing is what gives it a face.

Finished in a Drought Year

The Imbe Water Purification Plant No. 2 Filtration Pond came out of Matsue's first waterworks expansion. Within ten years of water arriving in 1918, the city was attracting a silk mill and building new offices and schools, and the original four beds could not keep up. Approval came in November 1927, and the work ran as a three-year programme.

In August 1929, the final year of construction, Matsue had to restrict supply because of drought. The two new filter beds were finished three months later, in mid-November. The whole programme is recorded as costing 400,000 yen.

The registration criterion is contribution to the historic landscape of the country. Together with No. 1, this bed shows how the city raised its capacity by following the founding design rather than departing from it.

The Pillared Housing

The thing to look at is the front of the well housing. According to the Agency for Cultural Affairs, it has square pillars and corner pillars, each with a simplified capital and base, and a dense row of pilaster forms along the top.

Capitals and bases come from classical architecture, but here they are reduced to outline. Stacking the pillar motif in two tiers gives the No. 2 housing a look unlike any of the other five, and the Agency singles it out as distinctive.

Because the housing is low, you need to stand square in front of it to read the detail. Raking light, early or late in the day, brings out the rhythm of the pilasters at the top.

Visiting

The Imbe Water Purification Plant No. 2 Filtration Pond is inside an operating treatment plant and is not open to the public. Visits depend on whether the Matsue City Water and Sewerage Bureau is accepting them, so check in advance.

On a visit, look for the regulating well at the centre of the north side. Whether you can approach the rim or take photographs is up to the staff on the day.