Hirase Water Purification Plant Former Katayama Tunnel Upper Portal

The Upper Mouth of the Delivery Tunnel

The Hirase Water Purification Plant Former Katayama Tunnel Upper Portal (平瀬浄水場旧片山隧道上口) is a stone conduit portal built in 1913 at 2903 Hirasecho, Kofu, Yamanashi Prefecture, and was entered on the national register of Registered Tangible Cultural Properties on October 9, 1998. It is the portal at the upper end of the Katayama Tunnel, part of the line that carried treated water from the Hirase plant down to Kofu.

It measures 4.6 metres wide and 3.4 metres high, with an iron door across the opening. The tunnel's other end survives as the Former Katayama Tunnel Lower Portal at 1715 Nashinoki, Haguro-cho, also registered. According to the Agency for Cultural Affairs the two were built to the same pattern, with the upper one slightly smaller; the lower portal is recorded at 4.7 metres wide and 3.4 metres high.

Two of the other Hirase structures, the No. 2 Tunnel portal and the Former Intake Gate, belonged to the conduit that brought river water in. The Katayama Tunnel worked the other way, sending clean water out, and this portal sits at its plant end.

Why It Was Registered

The Hirase Water Purification Plant Former Katayama Tunnel Upper Portal was registered for its contribution to the historic landscape. The Agency describes it as one of the facilities essential to understanding the history of Kofu's water supply.

Both ends of the tunnel date from the same 1913 works, yet they were registered separately and a little over a month apart: the lower portal on September 2, 1998, the upper on October 9. Each is a registered property in its own right.

Registering a portal located away from the plant shows that the heritage value of Hirase was not confined to the treatment site. The whole route, from intake to delivery, was treated as a record of the founding waterworks.

Matching the Lower Portal

What rewards a look at the Hirase Water Purification Plant Former Katayama Tunnel Upper Portal is how closely it follows its partner while trimming the dimensions slightly. Both ends set an iron-doored opening in a stone frame, which suggests the builders wanted the tunnel's entrance and exit to read as a pair.

The iron door protected the tunnel, but it also gives the portal its face. Stone surround and iron leaf are a typical material combination for waterworks of the early Taishō era.

The Agency records a nameplate reading Katayama Zuidō above the lower portal's opening but mentions no such plate for the upper one. If you ever see both ends, compare them on this point.

Visiting

The Hirase Water Purification Plant Former Katayama Tunnel Upper Portal is outside the Hirase plant grounds, at 2903 Hirasecho. 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.