Imbe Water Purification Plant Former Valve Chamber and Receiving Well

Where the Water Comes In

Imbe Water Purification Plant Former Valve Chamber and Receiving Well (忌部浄水場旧弁室及び着水井) is a concrete structure built 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. Raw water piped down from the Senbon reservoir meets it first when it enters the plant.

It stands at the western edge of the site, about 500 metres northeast of the dam, and covers only 34 square metres. There are two parts side by side. The valve chamber on the west housed the valves that controlled the inflow. The receiving well on the east took the incoming water, let it settle its force, and passed it on.

The receiving well carries a measuring notch, a cut in the lip over which the water spills. Read the depth of water passing over it and you know the rate of flow. This was where the plant first learned how much water it was being given.

Built for the First Expansion

The Agency for Cultural Affairs describes the Imbe Water Purification Plant Former Valve Chamber and Receiving Well as a remnant of Matsue's first waterworks expansion. Approved in November 1927, that project planned for 55,000 people at up to 198 litres each per day. Alongside two extra filter beds, its main works included new supply and distribution mains and the fitting of water meters.

Going from four filter beds to six changed both how much raw water came in and where it had to go. A structure that measured the inflow and let operators adjust it belongs naturally to that moment.

The registration criterion is contribution to the historic landscape of the country. Taken with the eight other registered structures on the site, it means the whole route from raw water to filtered water survives in physical form, and this is the first link in it.

What to Notice

The structure is low and barely rises above the ground. Look instead at the granite coping stones along its top edge, the same finish used on the rims of the filter beds. Even the humble intake was given a stone border, which says something about how carefully the plant was put together.

The measuring notch is the other detail particular to this spot. It is easy to miss the thin sheet of water sliding over it, but once you know flow was read here, it becomes the most telling feature on the site.

From the east side of the receiving well the conduit channel runs straight on. Standing at this western end, you can read the whole axis of the plant: where the water goes next and where it is divided.

Visiting

The Imbe Water Purification Plant Former Valve Chamber and Receiving Well lies inside an operating treatment plant and cannot be visited freely. Access depends on whether the Matsue City Water and Sewerage Bureau is accepting visits, so check before planning a trip.

If you do get inside, this is the natural place to begin, since it marks the start of the water's route. Follow the conduit east toward the row of filter beds and the purpose of each structure falls into place. Follow staff instructions on photography.