Medlow Dam | NSW Environment & Heritage

Culture and heritage

Heritage

Medlow Dam

Item details

Name of item: Medlow Dam
Other name/s: Medlow Bath Dam, Lake Medlow Dam, Adams Creek Dam, Medlow Bath Reservoir
Type of item: Built
Group/Collection: Utilities - Water
Category: Water Supply Reservoir/ Dam
Location: Lat: -33.6583270012 Long: 150.2993227930
Primary address: Beauchamp Road, Medlow Bath, NSW 2780
Parish: Blackheath
County: Cook
Local govt. area: Blue Mountains
Local Aboriginal Land Council: Deerubbin
Property description
Lot/Volume CodeLot/Volume NumberSection NumberPlan/Folio CodePlan/Folio Number
PART PORTION253 DP979433
PART PORTION274 DP979433

Boundary:

SCA owned land in vicinity of dam wall and operating envelope.
All addresses
Street AddressSuburb/townLGAParishCountyType
Beauchamp RoadMedlow BathBlue Mountains BlackheathCookPrimary Address

Owner/s

Organisation NameOwner CategoryDate Ownership Updated
Water NSWState Government 

Statement of significance:

The Medlow Dam was the first of the water supply dams built as part of the development of the Upper Blue Mountains and is an important example of the "Wade" series of dams erected in NSW between 1890s and early 1900s for NSW country town water supplies which utilised a concrete arch wall. It is associated with the NSW Department of Public Works and its design is a product of the work of two of Australia’s leading engineers, L.A. B. Wade and C.W. Darley. The Medlow Dam was a world leader in the development of thin-walled concrete arch dams and created considerable controversy when completed, reputedly having the thinnest wall of any comparable dam in the world. It remains a textbook example of this form of design and construction. The completion of the Medlow Dam was a significant step in the process of providing a reliable water supply for Medlow Bath, Blackheath and the surrounding areas.
Date significance updated: 26 Aug 09
Note: The State Heritage Inventory provides information about heritage items listed by local and State government agencies. The State Heritage Inventory is continually being updated by local and State agencies as new information becomes available. Read the OEH copyright and disclaimer.

Description

Designer/Maker: NSW Department of Public Works
Builder/Maker: NSW Department of Public Works
Physical description: Medlow Dam is a small water storage dam which utilises a thin-arch concrete wall under high stress. Its design capacity for the reservoir is 304.5Ml (67 million gallons), with a wall height (maximum) of 20.6m (65ft). The radius of curvature for the dam wall is 18.5m (60ft), the length of the wall is 38.2m (124ft) and the thickness of the wall at its top is 1.1m (3.5ft). It remains in everyday use for the purpose for which it was designed. It is built of concrete (not reinforced), curved in plan, with reliance for stability being placed only on the capacity of the material in the wall and sides of the valley to resist compression.

Associated with the dam is a small corrugated iron clad pumping shed, which contained three pumps. In 1993, these were rated as being of some significance, with two dating from 1927 and the third from the mid-1930s.
Physical condition and/or
Archaeological potential:
Good
Date condition updated:24 Sep 08
Modifications and dates: 1993 - Calcite deposits were removed from the downstream face using high pressure water jets.
2008 - Trunnion winch was replaced and the original winch moved to the side of the carpark for interpretive purposes.
Current use: Water supply
Former use: Water supply

History

Historical notes: Medlow Dam is a thin-wall arch concrete dam constructed by the Public Works Department of NSW in 1907, for water supply to nearby townships and possibly also for ornamental purposes. Control was vested in Municipality of Blackheath in 1940, then transferred to the MWS&DB in 1980. Water supply was first furnished to Medlow Bath in 1907 and subsequently extended to Blackheath, Megalong and Mount Victoria.

Medlow Dam is one of the series of so-called ‘Wade Dams’, constructed in the late years of the nineteenth century and the early years of the twentieth century by the NSW Public Works Department under the supervision and/or design of Mr L.A.B. Wade, for water supply to country towns. They were remarkable in pioneering the general use of thin-arch concrete walls under high stresses. It is claimed that this dam, when constructed, was the thinnest of its type in the world and the basic design attracted grave misgivings in the engineering world.

Both this dam and a similar example at Lithgow are recognised in the standard engineering work "A History of Dams" as world leaders in dam design and construction and they excite continuing engineering interest for the thinness of their wall section. It is stated in the 1909 Institution of Civil Engineers paper that Mr C.W. Darley, Engineer in Chief of Public Works, was responsible for initiating the construction of this type of dam in Australia and for the completion of the earlier structures. The paper’s author (L.A.B. Wade) acted under Mr Darley as Supervisor of Works and subsequently succeeding to the latter's position, was responsible for the design as well as construction of the Lithgow No. 2, Katoomba and Medlow dams.

The thirteen dams of this type were built of concrete (not reinforced), curved in plan, reliance for stability being placed only on the capacity of the material in the wall and sides of the valley to resist compression. In designing these dams, the complex question of the exact stresses that may occur and the assistance that may be afforded by the weight of the wall was disregarded; as it was considered that all practical requirements would be met if in theory the dams were treated simply as sections of rigid cylinders subject to exterior water pressure. The radius of this cylinder depended upon the natural features of the sites, it being stated elsewhere in the paper that the use of such curved walls was restricted to comparatively narrow valleys and gorges.

This local (and as it turned out, entirely successful) design followed an earlier and perhaps even bolder 1884 precedent at the Bear Valley Dam in California but it led, as had the Californian work, to a storm of criticism from the engineering profession of the day, not least, because it had proved to be successful in the face of orthodox theory, which at that time concentrated on gravity dam walls.

Comments of members of the Institution in 1909 included:
Walter Hunter: Looking at the cross sections, he would feel a little nervous if he had to sleep on the down-stream side of one of the dams.
Mr CE Jones: His fears were aroused and he thought a dangerous point had been reached. He felt very much concerned about the engineers who had charge of the dams described in the Paper, and he thought that the responsible engineers in Australia might at times pass sleepless nights.
Mr Reginald E Middleton: ‘admired the pluck’ of the designers.
Col J Pennycuick: ‘did not know that any engineers had the courage of their opinions until the NSW works were constructed’.

Even the eminent Sir Alexander Binnie, Past President of the Institution, was moved to remark that ‘to look at the cross sections produced a blood-curdling sensation’. He went on, however, to support the design as a practical achievement: it was not a matter of cavilling at theory or formulas; the dams were built and were standing. The problem that now arose was for mathematicians to show how the strains were accommodated in such apparently narrow walls. The entire justification of this then-daring and unorthodox design was economic. As stated by its originator, Mr Darley: small towns could not afford expensive gravity dams, and therefore it was a case of either building a cheap dam or not giving a water supply.

Historic themes

Australian theme (abbrev)New South Wales themeLocal theme
3. Economy-Developing local, regional and national economies Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings Landscapes of scenic beauty-
3. Economy-Developing local, regional and national economies Technology-Activities and processes associated with the knowledge or use of mechanical arts and applied sciences (none)-
3. Economy-Developing local, regional and national economies Technology-Activities and processes associated with the knowledge or use of mechanical arts and applied sciences Technologies of dam and weir building and maintenance-
3. Economy-Developing local, regional and national economies Technology-Activities and processes associated with the knowledge or use of mechanical arts and applied sciences Technologies for reticulated water supply-
4. Settlement-Building settlements, towns and cities Utilities-Activities associated with the provision of services, especially on a communal basis (none)-
4. Settlement-Building settlements, towns and cities Utilities-Activities associated with the provision of services, especially on a communal basis Providing drinking water-

Assessment of significance

SHR Criteria a)
[Historical significance]
The Medlow Dam was the first of the water supply dams built as part of the development of the Upper Blue Mountains and was an important example of the "Wade" series of dams erected in NSW between 1890s and early 1900s for NSW country town water supplies which utilised a concrete arch wall. It was designed by the NSW Department of Public Works and its design is a product of the work of one of Australia’s leading water supply engineers, L.A. B. Wade, who carried on the earlier work of C.W. Darley, President of the Metropolitan Water and Sewerage Board from 1893. The Medlow Dam was a world leader in the development of thin-walled concrete arch dams and created considerable controversy when completed. It remains a textbook example of this form of design and construction. The completion of the Medlow Dam was a significant step in the process of providing a reliable water supply for Medlow Bath, Blackheath and the surrounding areas.
SHR Criteria c)
[Aesthetic significance]
The Medlow Dam is a simple and attractive construction, located in a picturesque setting. It is an excellent example of a thin-walled concrete arch dam. The thinness of the wall sections provides a spectacular appreciation of the engineering behind the design of the dam.
SHR Criteria d)
[Social significance]
The Medlow Dam is of significance to the engineering profession, as evidenced by its listing in the Engineering Heritage Register of NSW (1994).

The Medlow Dam is of significance to the community of NSW, as evidenced by its inclusion in the National Trust of Australia (NSW) Register (1985).
SHR Criteria e)
[Research potential]
The Medlow Dam represents the thinnest thin-walled concrete arch dam erected in Australia and both individually and collectively, as one of a number of dams built in NSW in the early twentieth century which utilise a similar design and similar materials, it provides continuous data as to the long-term performance of this type of dam construction.
SHR Criteria f)
[Rarity]
The Medlow Dam was the first of the water supply dams built as part of the development of the Upper Blue Mountains. The Medlow Dam was a world leader in the development of thin-walled concrete arch dams and had the thinnest wall of any comparable dam in the world at the time that it was built.
SHR Criteria g)
[Representativeness]
The Medlow Dam is representative of the "Wade" series of dams erected in NSW between 1890s and early 1900s for NSW country town water supplies which utilised a thin concrete arch wall, although it is a notable example of that set.
Integrity/Intactness: The Medlow Dam is intact and in good condition
Assessment criteria: Items are assessed against the PDF State Heritage Register (SHR) Criteria to determine the level of significance. Refer to the Listings below for the level of statutory protection.

Recommended management:

Recommended Management: Manage the place and its components in accordance with the NSW Heritage Office Management Principles and Guidelines for NSW Agencies including the Minimum Standards of Maintenance and Repair. Recommended Management: Prepare a Conservation Management Plan for the site to guide future management. Recommended Management: Undertake environmental impact assessment (EIA) when planning works on the site (refer to SCA's EIA Policy). Prepare a Statement of Heritage Impact and gain S60 or S140 Heritage Office approval prior to undertaking any non-exempt works on the site. Recommended Management: Carry out annual condition inspections and report condition in SCA annual report. Recommended Management: Consult experienced heritage practitioners and the SCA's Planninig and Assessment Team during the preparation and execution of works to the place. Recommended Management: Prepare a maintenance schedule for the item(s) in Maximo.

Procedures /Exemptions

Section of actDescriptionTitleCommentsAction date
57(2)Exemption to allow workStandard Exemptions SCHEDULE OF STANDARD EXEMPTIONS
HERITAGE ACT 1977
Notice of Order Under Section 57 (2) of the Heritage Act 1977

I, the Minister for Planning, pursuant to subsection 57(2) of the Heritage Act 1977, on the recommendation of the Heritage Council of New South Wales, do by this Order:

1. revoke the Schedule of Exemptions to subsection 57(1) of the Heritage Act made under subsection 57(2) and published in the Government Gazette on 22 February 2008; and

2. grant standard exemptions from subsection 57(1) of the Heritage Act 1977, described in the Schedule attached.

FRANK SARTOR
Minister for Planning
Sydney, 11 July 2008

To view the schedule click on the Standard Exemptions for Works Requiring Heritage Council Approval link below.
Sep 5 2008
21(1)(b)Conservation Plan submitted for endorsementConservation management Plan for Medlow Dam submitted for comment/endorsement by Sydney Catchment Authority. Mar 10 2011

PDF Standard exemptions for works requiring Heritage Council approval

Listings

Heritage ListingListing TitleListing NumberGazette DateGazette NumberGazette Page
Heritage Act - State Heritage Register 0136618 Nov 99   
Heritage Act - s.170 NSW State agency heritage register 120317   
National Trust of Australia register      

Study details

TitleYearNumberAuthorInspected byGuidelines used
Sydney Water Heritage Study1996120317Graham Brooks and Associates Pty LtdGRAHAM BROOKS AND ASSOCIATES PTY LTD 1 JULY 1996 Yes

References, internet links & images

TypeAuthorYearTitleInternet Links
PhotographDepartment of Commerce2008SCA Trunnion Winches Medlow Bath, Middle Cascade and Greaves Creek Dams - Archival Photographic Documentation of trunnion winches prior to their replacement.
WrittenDepartment of Commerce2007Statement of Heritage Impact Replacement of Trunnion Winches.
WrittenEngineering Heritage Committee Sydney Division, Institute of Engineers1994Medlow Dam, Medlow Bath
WrittenJagger, B.1986Conference Paper; IEA Engineeering Heritage Conference
WrittenPublic Works Department1908Annual Report 1907-1908
WrittenRobert Kable1998Lake Medlow Dam: Nomination for Listing on the Register of the National Estate
WrittenSmith, N.1971A History of Dams
WrittenYeaman, John1975Historic Blackheath

Note: internet links may be to web pages, documents or images.

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Data source

The information for this entry comes from the following source:
Name: Heritage Office
Database number: 5051465
File number: H07/00038, 120317


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