Matsumoto City Waterworks Bureau Shiroyama Water

Matsumoto Waterworks Joyama Old Distribution Reservoir

Stand on the grass at Joyama, on the hill northwest of Matsumoto's castle, and you are standing on the roof of a structure of 1,518 square metres. There is soil under your feet, and under the soil a vaulted concrete lid, and under the lid two basins that once held the drinking water of an entire city.

The name is a small puzzle before the building is even reached. Its official title runs Joyama haisuichi kyu-haisuichi, which sounds like a stutter and is not one. The first haisuichi is written with the character for ground, meaning the distribution site as a whole. The second uses the character for pond, meaning the reservoir basin itself. Two identical sounds, two different words: the old reservoir of the Joyama distribution grounds.

The reservoir is the reason the whole system exists in the shape it does. Springs at Shimauchi, beside the Naraigawa on the far side of town, gave up their water to a collection well. Pumps in the engine house lifted it about 600 metres to this hill. It arrived first at the junction well next door, then filled these basins. From here it needed no more machinery. The city lay below, and water runs downhill.

That is the entire principle of a gravity distribution system, and it is why the engineers went to the trouble of pumping water uphill in the first place. Lift it once, store it high, and the pressure in every tap in Matsumoto comes free thereafter. The laying of the network was completed in 1924, and modern piped water in Matsumoto began.

The reservoir has been out of service for some time now. The basins are empty. The structure remains.

How It Is Built

Concrete, buried, with earth heaped over the roof. The insulating logic is obvious once stated: covered water stays cool, stays dark, and stays clean.

The roof is vaulted, which is how the concrete carries the weight of all that soil. Down the centre runs a management passage, entered through brick pavilions, and the passage divides the volume into two basins. Internal walls stand at intervals of roughly four metres inside them.

Where the covering earth would otherwise spill away, brick walls rise to hold it. Here the sources part company. The Agency for Cultural Affairs record places these brick retaining walls on the north and south faces. Matsumoto City's own description places brick walls on the east and west faces. The national database is the authoritative record and this article follows it, but a visitor comparing the two accounts will find they do not match, and the point is unresolved.

The dimensions carry a smaller discrepancy of the same kind. The national record gives the reservoir as 35 metres by 42; the city gives roughly 36 by 42. The registered area of 1,518 square metres divides by 42 to give about 36.1, which sits closer to the city's figure. The gap is a metre and it is not important to a visitor, but it is there.

At the north and south ends of the central passage stand the entrance pavilions, and they are the part of the reservoir that anybody photographs. They are brick, and they are Art Deco.

Why a Water Tank Was Given a Style

Brick in 1923 was not the cheap option. Matsumoto's own account of the registration calls it the finest building material of the day, and it was chosen for structures that spend most of their existence unvisited, holding water in the dark.

The Art Deco treatment runs across the group. The entrance pavilions here, the brick covering house over the junction well beside them, and the old engine house back at Shimauchi share a design language of geometric ornament. The engine house and the junction well both carry the emblem of the Matsumoto waterworks above their openings.

Something in that is worth sitting with. A municipal utility in a provincial city, in the years after the First World War, decided that the machinery of clean water deserved to look like an achievement. The people who built it were not wrong. Matsumoto had burned repeatedly, and a piped supply under pressure was among the more consequential things that had ever happened to the town.

The project drew on two engineers of national standing in the early construction of Japanese waterworks: Sano Tojiro, who surveyed the sources, and Takechi Shojiro, who did the design. Their names are part of the case Matsumoto made for registration.

Registration, and What Has Been Lost

Registration and designation are separate instruments in Japanese heritage law. Designation, the older and heavier one, produces National Treasures and Important Cultural Properties under strict control. Registration, established in 1996, was aimed at the enormous stock of Meiji, Taisho and early Showa structures disappearing faster than anyone could evaluate them. It relies on notification rather than permission, keeps its regulatory touch light, and is designed to work quickly.

This reservoir was the first of the Matsumoto waterworks structures to attract attention. A comprehensive survey of modern heritage by the Nagano Prefectural Board of Education in fiscal 2007 and 2008 identified the old Joyama reservoir and its junction well as candidates. An inspector from the Agency for Cultural Affairs came in September 2013 and advised something broader: the Joyama structures and the Shimauchi source facilities were one system, and should go on the register together. Matsumoto submitted its formal opinion at the end of September 2014, and six structures were registered on 4 August 2015, in the eighty-first round. The reservoir carries registration number 20-0485, entered as a structure contributing to the historic landscape of the nation.

Registration did not arrive early enough to protect everything. Construction of new plant has substantially altered the northeastern corner, and half of a staircase has been broken. The doors of the entrance pavilions have been remade in recent years. Matsumoto's assessment is that beyond these losses no major alteration is evident, and that the reservoir survives largely in its original form.

The honesty of that account is itself useful. Working infrastructure does not stop working because it becomes a cultural property, and a utility that must keep water flowing to a whole city will sometimes build where a heritage structure stands.

Seeing It

The interior is not normally shown. Matsumoto's waterworks bureau has published a video that explains the purpose of the reservoir and how the water moved through it, and includes footage from inside, which for most people will be the only way to see the vaults and the central passage.

Guided visits do exist. The city accepts applications through its Demae Koza outreach programme, submitted to the Lifelong Learning Division via the municipal electronic application system. Season and ongoing engineering work both affect what can be arranged.

Joyama itself is worth the walk regardless. The hill sits northwest of the castle, and the city the reservoir once served spreads out below it, which is exactly the point.