Hirase Water Purification Plant Former Katayama Tunnel Lower Portal

The Town End of the Katayama Tunnel

The Hirase Water Purification Plant Former Katayama Tunnel Lower Portal (平瀬浄水場旧片山隧道下口) is a stone conduit portal completed in 1913 at 1715 Nashinoki, Haguro-cho, Kofu, Yamanashi Prefecture, and was entered on the national register of Registered Tangible Cultural Properties on September 2, 1998. It marks the downstream end of the Katayama Tunnel, which carried treated water from the Hirase plant to the city.

The Agency for Cultural Affairs describes a plain masonry body with an arched, iron-doored opening. Inside, an iron pipe runs through a passage cut into the bedrock, and a nameplate above the arch reads Katayama Zuidō, Katayama Tunnel. The upper end of the same tunnel survives in Hirasecho as the Former Katayama Tunnel Upper Portal, built to the same pattern.

The published dimensions disagree. The Agency's structural entry and the waterworks bureau's list both give 4.7 metres wide by 3.4 metres high, while the Agency's descriptive note puts the masonry body at 6 metres wide by 5 metres high. The first figure may refer to the registered portal and the second to the whole masonry mass, but the available sources do not settle it.

Why It Was Registered

The Hirase Water Purification Plant Former Katayama Tunnel Lower Portal was registered for its contribution to the historic landscape, and the Agency adds that it is valuable for understanding how the plant was laid out. It stands outside the plant, in Haguro-cho, yet it carries the plant's name, which says a good deal about how the whole system was viewed.

It was registered on September 2, 1998, the same day as the Former Intake Gate inside the plant, so the gate that took river water in and the tunnel mouth that sent clean water out joined the register together. The upper portal followed on October 9 that year.

Once a water main leaves a treatment plant it usually vanishes from view. Leaving a stone portal and a nameplate at the tunnel's exit gave the buried delivery line a visible marker above ground.

The Arch and the Nameplate

The things to look for at the Hirase Water Purification Plant Former Katayama Tunnel Lower Portal are the arched opening and the Katayama Tunnel nameplate above it. The Agency's note on the upper portal mentions no nameplate, so on the record it is the lower end that announces the tunnel's name.

Behind the iron door, the bedrock passage holds an iron pipe. That arrangement suggests the tunnel was built as a protected route for a pipe rather than as an open culvert with water flowing freely through it.

The two portals share one design, with the lower end described as the slightly larger. Matching the ends while giving the town-side portal the name suggests that the tunnel's public face was meant to look toward the city.

Visiting

The Hirase Water Purification Plant Former Katayama Tunnel Lower Portal is outside the Hirase plant grounds, at 1715 Nashinoki, Haguro-cho. It is not part of the waterworks bureau's plant tours, and no public access has been announced.

Official sources do not say whether the portal can be seen from a public road. If you want to see it, contact the Water Purification Division of the Kofu City Waterworks and Sewerage Bureau, which owns it, in advance. The published guidance does not mention photography.