Former Ominato Water Source Waterworks

Former Ominato Water Source Waterworks: Tohoku's First Modern Water Supply

The Former Ominato Water Source Waterworks (旧大湊水源地水道施設) are a former naval water-supply system built between 1902 and 1910 in Udacho and Sakuragicho, Mutsu City, Aomori Prefecture, and designated a national Important Cultural Property in 2009.

The Agency for Cultural Affairs says the system was planned and designed by the building section of the Yokosuka Naval District's accounts department, mainly to supply water to warships. The designation covers three structures, the No. 1 Intake, the Settling Pond Dam and the Otsu Water Tank, and according to Mutsu City the Ko Water Tank and the Ochikagawa Intake are included as attached items. The waterworks belong to Mutsu City.

Aomori Prefecture notes that the system passed to Ominato Town in 1946 and supplied drinking water until 1976. The site is now Suigenchi Park, where the structures serve as its centrepiece.

Why It Was Designated

The Agency values the Former Ominato Water Source Waterworks as the first modern waterworks built in the Tohoku region, of high importance in the history of modern water supply. It adds that the No. 1 Intake and the Settling Pond Dam are finely crafted stone structures, each built by a distinctive method, that show the level of late Meiji stone river engineering.

The three structures are: the No. 1 Intake of 1902, a square stone chamber of 9.18 square metres; the Settling Pond Dam of 1909, a gravity-arch stone dam 27.5 metres long and 9.0 metres high; and the Otsu Water Tank of 1910, a brick tank with a roofed shelter, which Mutsu City gives as 2.5 metres across and 3.9 metres deep.

Aomori Prefecture describes the dam, which holds back the Uda River flowing from Mount Kamafuse, as small but the first thick-arch stone dam attempted in Japan. The prefecture gives it as 7.9 metres high and 26.5 metres long, figures that differ from the Agency's.

What to Look For

The dam wall is the thing to see. Aomori Prefecture says its 4 spillway openings form elegant segmental arches, and the sight of water falling through them is special. Stand in front to take in the curve of the finely laid stone and the row of arches.

The No. 1 Intake and the shelter over the Otsu Water Tank also survive in the park, so compare brick tank with stone dam. According to the Aomori tourism site, the park has about 200 cherry trees and 300 azaleas, blooming from late April to early May and from late May to mid-June respectively.

Visiting the Former Ominato Water Source Waterworks

The waterworks stand in Suigenchi Park (21-25 Udacho, Mutsu), which Aomori Prefecture lists as open to the public; no admission fee is mentioned. Free parking is available at the north car park (18 cars), the Kaibokan car park (21 cars and 4 coaches) and the south car park (23 cars).

By public transport, take a bus bound for Wakinosawa from JR Ominato Station to the Kaijo Jieitai-mae stop, about 10 minutes, then walk about 5 minutes. Enquiries go to the Mutsu City tourism section via the city office on 0175-22-1111.