Hong Kong Water Supply – The Aberdeen Reservoirs Scheme
Tymon Mellon: The year of 1921 was a good year for the growing population of Hong Kong Island; it would be the last year[i] until 1982 when there were no more water shortages[ii]. With the completion of the Tai Tam Tuk reservoir in 1917, doubling the total water capacity, the Colonial Government was confident there would be a sufficient water supply for many years to come. Yet within 12 years, in 1929 Hong Kong Island suffered the worst water shortage in its history. New sources of water were required.
In January 1928, the Governor of Hong Kong, Sir Cecil Clementi wrote to Secretary of State for the Colonies, Leo Amery regarding the water supply situation for Hong Kong Island[iii]. The majority of the water for the city was supplied by the Tai Tam reservoirs and transferred to the city by tunnel and the Bowen Road conduit. This arrangement had a capacity of around seven million gallons a day, yet in hot weather, the demand could rise to eleven million gallons per day. The small Pok Fu Lam reservoir had to make up the shortfall. Given the limited capacity of Pok Fu Lam, the reservoir would become quickly exhausted and water restrictions had to be introduced.
An exhaustive investigation had been undertaken to locate new sites for reservoirs on Hong Kong Island[iv], but which were mostly rejected for a number of reasons, these include:
- New reservoirs in the Tai Tam Valley, above the existing reservoirs, being in the same catchment as the existing structures they would not represent a new source;
- A new reservoir below Tai Tam Tuk with a capacity of 700 million gallons, but previous investigations had shown the geology to be unsuitable;
- New reservoir below the existing Pok Fu Lam reservoir with a capacity of 78 million gallons, but would require the resumption of Hong Kong Dairy Farm and considered un-desirable;
- A 2,500 million gallon reservoir at Shouson Hill, requiring two dams across the valley with the water having to be pumped over the hill to Victoria, the scheme considered to costly;
- Two new reservoirs with a combined capacity of 114 million gallons in the Tai Koo catchment on the slopes of Mount Butler. However the water rights were held by Messrs Butterfield and Swire who used the water for the Taikoo Sugar Refinery and Dockyard; and
- Aberdeen scheme requiring the resumption of the existing reservoir (Aberdeen Lower reservoir) from the Tai Shing Paper Manufacturing Company and construction of a new reservoir higher up the valley with a capacity of 175 million gallons.
The Aberdeen scheme was endorsed by Legco on the 2nd May, 1928.
The Aberdeen Scheme
Mr R H Henderson, was the engineer in charge of water works during this period and in August 1926 he published a report on the partial and complete development of the Aberdeen Valley. As reported by the Director of Public Works, Mr H T Jackman in 1927, it was decided to proceed with the full scheme, as this would “prove the mores satisfactory scheme”[v].
The proposal was to acquire the existing reservoir, constructed in 1890 for the paper works, and construct a new reservoir higher up the valley. The water would then be piped to a new pumping station at Sandy Bay, pumping the water over the hill to the Elliot filter beds.
The Aberdeen scheme, would cost $2.7 million[vi] to be financed by a loan to the Colonial Government.
The Aberdeen Lower dam and storage reservoir was originally constructed in 1890 by the Tai Shing Paper Manufacturing Company. The original dam had a maximum height of 12m, retaining 42 million gallons for a cost of $24,000. In 1899 the height of the dam was raised a further 5m and strengthened with ten concrete buttresses giving a dam length of 142m and increasing the storage capacity to 92 million gallons at an additional cost of $48,000.
The dam was constructed using a cement lime concrete core backed with rubble concrete and faced with granite. Mr Henderson described the structure as, “The structure while apparently well built is constructed of poor materials and is a good example of what might be termed cheap construction”. The option to replace the dam was considered but it was concluded that the best arrangement would be to strengthen and upgrade the existing structure.
As part of the Crown lease terms, Tai Shing was to supply the Aberdeen and Ap-Lei Chauvillages with 60,000 gallons of water a day. In 1897 the Government constructed a small covered service reservoir and three filter-beds to improve the quality of the water supply.
Following the approval of the Aberdeen scheme in May, 1928, the Government resumed the reservoir at a cost of $525,000. The company was granted 183 days, commencing on the 20th July 1928 to use up the remaining water before the Government took possession.
In December 1931 a small contract was awarded to Messrs Foo Loong & Co to demolish and reconstruct part of the dam to investigate the structure and support preparation of the reconstruction. On the 4th April 1932 a contract was awarded to Messrs Kin Lee & Co for $93,834 for the reconstruction of the dam. This included cutting away parts of the old buttresses and filling the space in between to provide a uniform appearance. A new overflow was constructed with 25 rectangular openings with a decking above for a new road.
Once the reservoir had been drained it was found to be heavily silted up and had to be removed to ensure the integrity of the dam and pumps. An initial 8,500m3 of material was removed, followed by 16,700m3 during the reconstruction of the dam. A further 15,000m3 was sluiced through the washout valve at the bottom of the dam.
With good progress of the works, impounding of the reservoir commenced on the 23rd September 1932 with around 12 million gallons collected by the end of the year. The new reservoir had a capacity of 107 million gallons.
Construction work on the new upper dam commenced in October 1929[vii] with the award of a contract to The Hong Kong Excavation and Pile Driving Company for $604,066. Works commenced immediately with construction of the access road, catchwaters and dam foundations. A good rock foundation was identified and placing of the dam concrete commenced in May, 1930[viii].
The dam was faced with concrete blocks with a casting yard located close to the former paper mill, the blocks being delivered to the site using a 1100m cable way. The core of the dam utilised concrete, mixed in a batching plant at the south end of the dam and delivered to site using a chute system fed from a 30m timber tower. The block delivery system was commissioned in August 1930 but problems with the wooden tower disrupted the delivery of concrete until the problems were resolved by the end of the year. The use of these new methods of material delivery were a first for Hong Kong and represented a significant step forward for this and future dam construction. Good progress was made and by October 1931 the dam was substantially complete.
In variance to the original plan, two pumping stations were constructed; one was constructed below the lower dam, pumping the water from the lower dam to the upper dam or to the Elliot Filter Beds. The facility consisted of a single story brick building with a concrete roof. Divided in to two rooms, one section housed the electric motor and centrifugal pump with the other half used as a store and sleeping accommodation for the pump attendant. The pump house was completed in October 1931 and was used to pump out the former paper works reservoir to allow removal of the silt.
The second pumping station was constructed to the east of the former Aberdeen docks, in a reinforced concrete frame building with brick infill. The ground floor was divided in half, with the electric motor and centrifugal pump in one half, and an office with a store in the other half. The upper floor contained staff accommodation, served with a kitchen, bathroom and toilet at the back of the building.
The design of the supply pipe allowed for a gravity water supply to the Elliot filter beds of up to 2 million gallons a day, to be supplemented by the pumping station when the water level in the upper reservoir dropped below the Elliot beds discharge level.
A contract was awarded on the 13th March, 1930 for the installation of 8km of water supply pipes between the new reservoir and Elliot treatment plant to The Lai To Construction Co for $39,085. The works scope included all the trenching, 450mm diameter steel pipes and driving a short length of tunnel at Sandy Bay Gap. By July, 1931 the pipe works was complete and the system commissioned.
The new dam was 122m long and 42m at the highest point, impounding 175 million gallons of fresh water. The dam was faced with concrete blocks with a concrete core providing stability and water tightness. Sixteen arched bays form the overflow and carry a roadway above, and a bridge structure near the base carried the reservoir discharge pipe. Establishing a style that would be adopted for later dam construction. Construction of the dam used 20,000m3 of concrete and 16,000 concrete blocks. With the completion of all works associated with the scheme in 1934, the total cost of the project was published as $2,555,702, under the original budget.
In addition to the dam, an east catchwater, extending 1,500m around the slopes of Mount Cameron was complete for the opening, and was further extended to 1,770m in 1933. The west catchwater of 1,900m long around the southern slopes of Mount Gough, was completed in 1932 and extended a further 2,500m in 1933. A pair of catchwaters around Bennetts Hill was constructed in 1932.
Impounding of water in the new upper dam commenced in July 1931 and the reservoir entered into supply on the 1st August 1931. A formal opening ceremony was held on the 15th December 1931 when the Governor Sir William Peel along with guests formally opened the new reservoir[ix].
The Governor turned a valve, opening the water supply to the Aberdeen filter beds while a second valve was opened to fill the dry stream-bed with water[x].
A speech was given by the Director of Public Works, Mr Creasy, noting that “while Kowloon consumes 20 gallons per head the Island consumes 33.75 gallons per head”. He noted that this difference was due to water wastage on the Island, “particularly in the rider main districts where there is normally an unlimited free supply”. The introduction of universal meterage was needed to prevent the wastage of water.
In his opening speech the Governor congratulated Mr Creasy and his ‘lieutenants’, Mr Henderson responsible for the site supervision, along with Captain B Montague Ede the Managing Director of the main dam contractor. He noted that this was “probably the last reservoir of any considerable size which will be built on the Island”[xi]. He also referenced the comments made by his predecessor, Sir Henry May at the opening of Tai Tam Tuk dam, “he read a homily on the evils of intemperance. I do not know how it was justified, but judging by the increase in water consumption, it looks as if his advice had borne fruit”. Referencing the difference in water consumption between the Island and Kowloon, he noted “Whether the people in Kowloon are what are called ‘harder cases’ or whether they prefer their whiskey less diluted, I am not prepared to say. I fancy however that the Club bar receipts in both places show considerable reduction.”.
It was recognised that the Aberdeen scheme would not solve all the water problems for the Island. However, the construction of the Shing Mun Scheme would address many of the shortfalls, or as the Governor put it, “The scheme is vital to the Colony, and should not be delayed”.
Aberdeen Filter Beds
With the original dam, a small filter plant was constructed in 1896 with a capacity of 100,000 gallons a day. Following the construction of the new reservoirs, the existing facility was unable to support the needs of the growing population, thus a new facility was constructed in 1939. The new facility consisted of four slow sand filter beds, each with a capacity of 100,000 gallons a day, along with a covered service reservoir of 400,000 gallons. The works were let to Messrs Hoo Cheong & Co for $67,663 and work commenced in August of the same year.
The filter beds were in operation until 2000 when they, along with the service reservoir, were converted to sea-water storage to supply street fire hydrants and toilet flushing.
The Tai Po area was supplied with either fresh water from wells or water “from sources of doubtful purity”[xii]. In August 1921 it was decided to install a water supply to Tai Po and Tai Po Market, with the scope extended in February 1922 to include the surrounding area. A large stream crossed the Tai Po Road near the 17th Mile Stone and this would be the new source for the area. An intake structure was constructed in the stream at the 120mPD level, with a strainer tank 10m lower down. A 100mm wrought iron pipe then carried the water into Tai Po Market where a 75mm pipe distributed the water to other districts.
To ensure the quality of the water, all cultivated land above the intake structure was resumed and the catchment area made into a forestry reserve. Construction works commenced in August 1922 and was substantially complete by the end of the year for a cost of $19,856. By 1929 the scheme was supplying 40,000 gallons a day. A detailed location has not been identified but it is likely to be the stream passing through Tai Po Kau reserve.
In October 1920 the Royal Hongkong Golf Club entered into an agreement with the Government to take over the existing water supply system constructed by the club and upgrade the system to supply the links, club-houses and nearby private residential development. Obtaining water from a stream to the west of the club, probably the Sheung Yue River, a new intake structure and 1,400m of 100mm of wrought iron pipe and 2,000m of 75mm was laid along with the re-laying on a new alignment of 1,200m of 75mm pipe. A new system was installed for water supply to the second nine-holes of the Relief Course[xiii]. The total cost of the works was around $27,000 with the Club paying 5% of the Government’s outlay and paying for the water at 25cents per 1,000 gallons. Works commenced in December, 1920 and were completed by March, 1921.
The Government reserved the right to right to supply other customers and in 1922 the supply main was extended to supply houses on Castle Peak Road and Kam Tsin Villages[xiv]. By 1929 the scheme was supplying around 17,000 gallons a day.
Elliot (West Point) Filter Beds
To complement the Tai Tam Tuk scheme, new filter beds and service reservoir were constructed on the site of the former Elliot Battery. Work on the project started in 1911 when it was recognised that a service reservoir and filter bed would be required to serve the western areas of Victoria. The site chosen had also been allocated to the construction of the Hong Kong University. Thus to reduce the space required, a scheme was developed with the filter beds located on top of the service reservoir[xv]. It was recognised that the site within the compound of the proposed university was likely to “hamper the development of that institution”, and work started on exploring land south-west of the Elliott Battery[xvi].
Plans were developed for the site but it was recognised that a superior solution could be achieved if part of the military land could be acquired. Negotiations for the surrender of the military land were concluded in 1914 with the surrender of the land. In September 1914 a contract was awarded for the construction of six filter beds each with an area of 82m2 and a service reservoir of 5 million gallons for a cost of $150,000[xvii].
Construction of the new facility required extensive excavation from the site, necessitating the diversion of Pokfulam Road through the War Department Land, and this proved to be problematic. During 1916 it was discovered that the ground conditions were not as assumed and the design had to be revised, resulting in a change to the structure of the reservoir. Works were substantially complete by 1918, allowing the filter beds to be commissioned and the full scheme completed by April 1914 at a total cost of $387,000[xviii].
In 1921 a committee was formed to look at the use of sea water to supplement the existing supply, and its report[xix] concluded that it was feasible to use sea water for flushing, however it would not be economical:
“The time may come when the limit of the fresh water resources of the Colony has been so nearly reached that it will be more economical to obtain a supply of salt water than to obtain an equal additional supply of fresh water, but it does not appear that that time has yet arrived, and no works which may be carried out now for the use of fresh water will in any way interfere with the use of salt water when its use is found to be more economical”
The situation was reviewed again in 1927, but this time exploring the opportunity to convert sea water into fresh-water use distillation and condensation[xx]. The report concluded that the approximate cost of distilled water would be $2.89 compared to the current supply value of 35 cents. The scheme was therefore not adopted.
[i] Hong Kong in its geographical setting, by Dr S G Davis 1949
[ii] WSD Total water Management in Hong Kong 2008
[iii] Letter, 30th January, 1928, CO129/509 p239-242
[iv] The Colony’s Waterworks, H.E. The Governor, Hong Kong Legislative Council, 5th September, 1929
[v] Aberdeen Valley Catchment Area Development, H T Jackman Director of Public Works, 7th November, 1927
[vi] The Colony’s Waterworks, H.E. The Governor, Hong Kong Legislative Council 5th September, 1929
[vii] Public Works Report 1929
[viii] Public Works Report 1930
[ix] Public Works Report 1931
[x] The Hong Kong Telegraph 16th December, 1931
[xi] Hong Kong Daily Press 16th Dec 1931
[xii] The Colony’s Waterworks, H.E. The Governor, Hong Kong Legislative Council, 5th September, 1929
[xiii] Public Works Report, 1920
[xiv] Public Works Report, 1921
[xv] Public Works Report 1911
[xvi] Public Works Report 1912
[xvii] Public Works Report 1914
[xviii] Public Works Report 1919
[xix] Report Of A Committee Appointed To Consider The Feasibility Of Extending The System Of Water Carriage in the Colony By Pumping Up Salt Water From The .Harbour And The Provision Of Suitable Pipes Therefor, 1st September, 1921
[xx] Report on the cost of converting sweater by distillation and condensation into fresh water for domestic supply purposes, H T Jackman Assistant Director of Public Works 22nd February, 1927
This article was first posted on 19th February 2020.
Related Indhhk articles:
- Hong Kong Water Supply – The Tai Tam Tuk Scheme First Section
- Hong Kong Water Supply – The Tai Tam Tuk Scheme – Second Section
- Hong Kong Water Supply – The Politics of Water Supply and Rider Main Districts (1890-1903)
- Hong Kong Water Supply – Kowloon Reservoir
- Hong Kong Water Supply – Tai Tam Upper Dam (formally Tytam Reservoir)
- Hong Kong Water Supply – Kowloon Peninsula
- Hong Kong Water Supply – Pok Fu Lam Reservoir
- Hong Kong Water Supply – Mint Dam and Other Early Structures
- The Taikoo Sugar Refinery
Our Index contains many other articles about Hong Kong reservoirs and several about Taikoo Dockyard.