（28/2/2021）去年年底主教山地下配水庫曝光後，一眾民間保育人士、建築師、水務專家、城市研究學者，研究大量歷史文獻及整合民間流傳的配水庫資料，完成「地水重光 — 主教山配水庫文物價值評估報告」，引證配水庫具有極高文物價值，值得列為法定古蹟。
主教山配水庫為1902年啟動的「九龍重力自流供水系統」（Kowloon Waterworks Gravitation Scheme）的重要一環，目的是改善九龍供水系統，解決食水供應不足的危機。主教山配水庫作為二十世紀九龍供水設施的起源，開創了九龍水塘供水的先河，亦見證了九龍半島由泵井供水到水塘供水的轉變，而推動改變的正正是香港的城市化進程。
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Group advocates monument status for Bishop Hill service reservoir
(28/2/2021) A group of heritage conservationists, architects and urbanists today called on the heritage authorities to declare the Bishop Hill service reservoir a monument, following a study that established its exceptional heritage value. The Bishop Hill Service Reservoir Heritage Assessment is the result of a crowdsourced research effort. Since the century-old underground facility came to light late last year, the team had extensively studied historical records as well as a large amount of relevant information circulated online.
The assessment follows the six criteria the Antiquities and Monuments Office uses to evaluation historic buildings, namely, historical value, architectural value, authenticity, rarity, group value, and social value.
1. Historical value
Bishop Hill service reservoir (hereafter “Bishop Hill reservoir”) is a key part of the Kowloon Waterworks Scheme. Launched in 1902, the scheme modernised Kowloon’s water supply in bid to solve a water shortage crisis. Rainwater is collected in Kowloon Reservoir at the heart of the scheme, replacing well water and subterranean water pumped out by the Yau Ma Tei Pumping Station. The underground facility up Bishop Hill served the public by distributing treated water across Kowloon. It witnessed not only the beginning of a new water supply system for Kowloon in the early 20th century, but also the forces of urbanisation that brought about the momentous change in the first place.
Several notable figures in Hong Kong’s architectural history were involved in the building of Bishop Hill reservoir. They include Lawrence Gibbs, the Kowloon Waterworks Scheme engineer, and the Ng brothers of Tung Shing Construction Co, a well-known contractor of government building projects at the time.
2. Architectural value
Bishop Hill reservoir is a stunning sweep of red brick arches carried on granite columns. It is the only service reservoir in Hong Kong that combines granite columns, red brick arches, and barrel vaulting, sidewalls and floor of concrete. Before the use of reinforced concrete became common, this unique combination of building materials effectively spreads weight across the underground structure in a marriage of art and science. The reservoir construction was also a daring use of concrete in early 20th century Hong Kong, signalling the modernisation of engineering and architecture in the city.
Hong Kong Museum of Medical Sciences and Western Market, two red-brick buildings completed in 1906 and after Bishop Hill reservoir, were declared monuments in 1990.
Over the past 116 years, Bishop Hill reservoir has largely kept its architectural character. In 1952, a concrete wall was added, and a waterproofing material of rock asphalt was applied. The alterations reduced the reservoir capacity, while 30 of the 108 columns were embedded in the compacted earth area behind the concrete wall. However, the original structure of the reservoir was not affected.
In December 2020, the reservoir was damaged by Water Supplies Department works. However, an estimated 90% of the reservoir was not affected and remains intact. Existing building plans and field surveys should provide adequate information for future restoration.
Bishop Hill reservoir is unique among all pre-WWII service reservoirs because of its circular design.
In addition, it is the only service reservoir in Hong Kong that is built of granite columns, red brick arches, and barrel vaulting, sidewalls and floor of concrete. This unique construction method reflected the modernisation of civil engineering in Hong Kong. It is also a special case that captured a moment of transition in local architectural history in the early 20th century.
Bishop Hill reservoir is one of at least five remaining pre-WWII service reservoirs in Hong Kong. It is the second oldest known service reservoir in Kowloon.
5. Group value
Bishop Hill reservoir was directly linked to five historic structures of Kowloon Reservoir: main dam, main dam valve house, spillway dam, dam recorder house, and recorder house. Built between 1901 and 1910, the five structures were declared monuments in 2009. Together with the former Yau Ma Tei Pumping Station (Grade 1 historic building), these century-old waterworks represent the start of Kowloon’s modern water supply system.
6. Social value
In providing a more hygienic and economical source of water supply to the public, Bishop Hill reservoir transformed the water supply system in Kowloon and significantly reduced the risk of epidemics. The reservoir construction also marked the first time the government hired a local company for public works projects – an important development in the local building industry. Though the reservoir was retired in the 1970s, Bishop Hill has in recent years become an important public space in Sham Shui Po and Shek Kip Mei. Local residents have turned the site into a popular recreational hub by installing basic playground fixtures and fitness facilities.
Bishop Hill reservoir is a most special heritage structure that can powerfully tell Hong Kong’s water supply history. The authors of the Bishop Hill Service Reservoir Assessment call on the Antiquities and Advisory Board to duly declare the century-old facility a monument at its upcoming meeting on 11 March 2021.
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The Bishop Hill Service Reservoir Heritage Assessment is the product of crowdsourced knowledge, collective energy, and savvy in gathering historical information scattered online. The assessment provides a solid and thorough knowledge base for the community to evaluate official heritage decisions. The hope is that this innovative exercise in community engagement can provide a model for even more public participation in future heritage debates.