Yonai Water Purification Plant Slow Filtration System Receiving Well

The Yonai Water Purification Plant Slow Filtration System Receiving Well

The Yonai Water Purification Plant Slow Filtration System Receiving Well (米内浄水場緩速系着水井, Yonai Jōsuijō Kansokukei Chakusuisei) is a reinforced concrete basin built in 1934 at the eastern edge of the Yonai Water Purification Plant in Kamiyonai, Morioka City, Iwate Prefecture, and listed as a Registered Tangible Cultural Property on 23 August 1999. It is registration No. 03-0012 and covers 17.1 square meters.

A receiving well is the first basin that river water enters when it reaches a treatment plant. The words slow filtration system in the name place it on the plant's slow sand filtration line. Today the Yonai plant runs both slow sand and rapid filtration, and this basin marks the head of the slow line.

Where the Yonai Water Purification Plant Slow Filtration System Receiving Well fits in

The Agency for Cultural Affairs places the well at the eastern end of the plant that began supplying Morioka in 1934. Water drawn from the Yonai River about 1 kilometer upstream first drops its sand in a grit chamber, then flows here. Once it has been metered, it moves on to the sedimentation basin immediately to the north.

That makes the Yonai Water Purification Plant Slow Filtration System Receiving Well the point where the plant first learned how much water it had to work with. Every later adjustment, in the settling basin and on the filter beds, depended on that figure.

It was listed for contributing to the historic landscape of the country, on the same day as the sedimentation basin, the filter, the control houses and the other original structures.

How the Yonai Water Purification Plant Slow Filtration System Receiving Well is built

The Yonai Water Purification Plant Slow Filtration System Receiving Well is a long, narrow basin, 9.5 meters by 1.8 meters and about 2 meters deep, divided inside into three chambers. At 17.1 square meters it is roughly one eighty-fifth the size of the sedimentation basin next door, which covers 1,458 square meters.

According to the agency, the well and the sedimentation basin were built together on a raised terrace on the east side of the grounds. Morioka's first waterworks were designed to move water by gravity all the way from the intake to the distribution reservoir, and setting the receiving basin on high ground fits that scheme.

Unlike the control houses and the outlet well, it has no decorative superstructure. The shape is the point: a slim trough cut into three cells, made to take in water and measure it.

Seeing the Yonai Water Purification Plant Slow Filtration System Receiving Well

The Yonai Water Purification Plant Slow Filtration System Receiving Well is inside a working water plant and the grounds are normally closed. Access comes with the spring cherry blossom opening or the waterworks bureau's tours.

The well lies at the far eastern side, south of the sedimentation basin, so it is easiest to find by locating the large basin first and looking for the narrow trough beside it. How close visitors may go and whether photography is allowed are decided by staff on the day. Directions and opening dates for the plant are on the Yonai Water Purification Plant page.