Bruce Comfort
on Google Maps
I'm a retired engineer. I ride a 400cc Suzuki Burgman motorscooter and I live in Oamaru, South Island of New Zealand. I have two adult daughters. My interests (if you haven't worked it out) include New Zealand's heritage of engineering works, snapshot photography of the built environment and recording pastoral farming activities around here. ---------------------------------------------------------------------------------------------------------------------- PLEASE NOTE THAT MANY PHOTOGRAPHS ON THIS PANORAMIO SITE HAVE BEEN TAKEN BY ACCESSING HERITAGE BUILDINGS, STRUCTURES, AND ENGINEERING ARTIFACTS WHICH LIE ON PRIVATE LAND. PUBLICATION OF PHOTOGRAPHS ON THIS SITE DOES NOT IMPLY ANY PUBLIC RIGHTS OF ACCESS. ---------------------------------------------------------------------------------------------------------------------- PLEASE ALSO NOTE THAT A FEW PHOTOS ON THIS SITE ARE NOT MINE, AND THAT MANY ARE TAKEN INDOORS AND ARE OF MACHINERY AND THAT THIS APPARENTLY CONTRADICTS THE TERMS OF USE OF THE PANORAMIO WEBSITE. I HAVE HAD THE SITE MODERATORS' APPROVAL FOR USING THE SITE THIS WAY AS ALL SUCH PHOTOS LINK IN SOME FASHION TO MY OWN PHOTOGRAPHS OF PLACES IN NEW ZEALAND WHERE ARTIFACTS OF ENGINEERING OR PASTORAL OR INDUSTRIAL HERITAGE CAN STILL BE FOUND. ---------------------------------------------------------------------------------------------------------------------- MY INTENTION IS NOT TO USURP THE RIGHTS OF THE HISTORIC PHOTOGRAPHERS NOR OF COPYRIGHT OWNERS, AND CREDIT IS GIVEN WHERE I CAN. I have made an endeavour to contact copyright holders of material published on these pages and where appropriate, permission is still being sought for these items. Where replies were not received, or where the copyright owner has not been able to be traced, or where the permission is still being sought, I have decided, in good faith, to proceed with publication. I would be happy to hear from copyright owners at any time to discuss usage of item. IF YOU GO TO THE PLACES WHERE MY OWN PHOTOGRAPHS HAVE BEEN ACCEPTED BY THE MODERATORS TO BE IN THE PHOTOS LAYER ON GOOGLE EARTH, MY HOPE IS THAT THE OTHER HISTORIC PHOTOGRAPHS (which will not have been accepted by the moderators of Google Earth but which appear on these pages) WILL STIMULATE YOU TO THINK ABOUT THE ENGINEERS, ENTREPRENEURS, INVESTORS, THE WORKERS AND OPERATORS AND ALL THE PEOPLE, NOW GONE, WHOSE LIVES WERE INEXTRICABLY TIED TO THESE PLACES AND THESE ENDEAVOURS. ---------------------------------------------------------------------------------------------------------------- MY E-MAIL ADDRESS IS AND I WELCOME INPUT INTO THIS WORK -----------------------------------------------------------------------------------------------------------------

Bruce Comfort's conversations

Built 1871-1872 this earth dam incorporated the very best practice. It had a puddled clay core for which a pug mill was imported and used, and it had no "breaches"

Following the experience of the failure of Bilbery Dam in the UK, this dam had no culvert through it at its base - not even a de-watering sediment scavenging pipe. The only breach is a high level sluice at its Eastern end - used in advance of predicted flood flows to drop the level. The spillway over the crest and the wave protection barrier are both concrete (normal practice was for the upstream facing (wave protection) to be rip-rap but Wellington city has no hard rock sources or quarries (still) the nearest then being at Horokiwi in the Hutt Valley. All of Wellington's accessible rock, including in the valley of the Kaiwharawhara Stream is deeply oxidised and weathered Greywake which is soft.

The valve tower access footbridge jets from the East embankment and not from the dam itself as would have been much more commonly seen.

If you look at this Panoramio photograph by the very productive Eva Kaprinay

you can see the two reservoirs in their beautiful native bush setting, and so close to Wellington City.

The Upper Karori Reservoir is partially drained - exposing half the height of the upstream wall of the dam. Its water surface is now at 160MASL and it would have been at about 180MASL when it was operational.

The Lower Karori Reservoir (pictured here) has a water surface at just on 150MASL and this has always been its operating height.

Before the dam was completed in 1878, water from the Kaiwharawhara Stream (which the two dams impound) was sent through a short tunnel into the Aro Valley to a holding reservoir (now filled in) and water was piped into the city by 1874.

The use of flowing water, in streams and rivers, to power machinery and replace human and animal power in agriculture (grain milling and irrigation) and processing (spinning, weaving and other activities where rotation energy was needed) is as old as civilisation, however the utilisation of the fall in rivers and streams was generally dependent on the processing facilities being located at the river and at the place where the fall (the drop = waterfall usually) actually occurred.

So we see the famous river mills of the UK, such as those along the River Severn, being built right beside the natural waterfalls. Even if a dam or some other impoundment was required to increase the flow or capacity of the river, the impoundments comprised only low bunds or small stone dams.

The technology of dam construction was not as well developed as the technologies of the mechanical devices spawned by the Industrial Revolution and Karori's Lower Reservoir and dam is a very early example (worldwide) of a properly constructed waterproof and durable dam, built in response to some notable dam failures in the UK - one of which, the Bilbery Dam failure of 1852 in which 80 lives were lost, set the pattern for properly engineered work of this type.

It is interesting to contemplate the fact that we couldn't build safe earth dams in the 1850s and yet British engineers were capable of building durable and spectacular canals which had the need for water tight embankments and suspension bridges and aqueducts to speed the flow of goods and services around Britain by the 1790s!

On completion, and once water was piped into Wellington City, the town had access to clean water in almost unlimited volume (or so it seemed at the time) and at a pressure that must have been in the range of 100 -150psi. With the reservoir surface at 150MASL the theoretical water pressure in the supply piping at sea level would have been roughly 250 pounds per sq inch. Pressure reducing valves must have been fitted?? to make the mains pressure safe and protect the pipe works from damage, but I haven't researched the details of the network that was installed.

When the Lower Karori Reservoir was built, people were already utilising the power of the Kawharawhara Stream and in fact a grain miller low down on the run of the stream successfully sued the Wellington City Council when he lost his run-of-the-river water supply/flow, but in general and world wide, the power of flowing water was what was harnessed in all devices and systems to extract energy from rivers and streams.

All the devices that were used, such as water wheels and most of the things we now class as turbines, needed water flow and water at significant flow, to extract power from natural or modified water bodies. When early water power engineers looked at a river, even one that was steeply graded and although the height difference between the top (high regions) of the river and the bottom (lower reaches) was obvious and obviously the "source" of the river's energy (through gravitational fall which was well understood since Newtons work in about 1665) they didn't see pressure in a stationary water column of the same differential height, as a source of energy.

It was not until the work of Sir William Armstrong in the 1840s that this potential was realised.

The 1879-1880 (approx) reservoir at the termination of Timaru's public water supply race.

Like many towns in the dry regions of New Zealand, Timaru was forced to create a public water supply system early in its development and before the rating base could fully support the expenditure. Early Timaru obtained its domestic water from drilled/dug wells, but they were generally unreliable and the water table fell below usable height whenever deep droughts struck.

The citizens of Timaru were engaged in a debate over the years of about 1868 to 1874, through their Borough Council and through newspapers (letters to the Editor) seeking the most cost effective way of building a permanent water supply. The centre of Timaru had been burned to the ground in an disastrous fire in December 1868 and it was clear that a reticulated water supply and a fire brigade was an essential for a growing township.

The council eventually decided to pursue a gravity driven water race from the Pareora River - an idea that had been floating around for ages.

Generally too, it seems that the people and the council were sure that the race was not so complex an undertaking that it couldn't be designed "in-house" (the council had a Chief Engineer of its own - Henry Wigg possibly as a result of the need for design of harbour works?) and built by a digger - being a man (or company) with the experience of digging water races for goldfield sluicing.

This is in considerable contrast to the Oamaru Borough Council which was embarking on a water supply project at the same time. They had decided that their supply (water race) was so complex that it was essential that it was designed in detail and by an engineer engaged solely for that task.

I haven't researched this Borough Race as comprehensively as I have the Oamaru Borough Race, however it is clear from the collection of drawings in South Canterbury Museum under the care of Tony Rippin, that when the race was approved, its design (layout and route) was at least the subject of a proper survey by a competent surveyor a John Thomas Thompson. To the extent that the route and elevations were defined, the race was designed. Whether or not he designed the water race structure (cross sections, siphons, aqueducts and tunnels etc.) is unclear because no drawings have been preserved, but it is possible he contributed to the detailed work of the Borough's Chief Engineer, as only a competent surveyor would have been able to transpose information on the feasible route into civil works that could be built at sustainable cost. The "idea" "to bring water from the Pareora River and deliver it to a reservoir in the downlands close to and above town" would probably have been well understood for decades beforehand and well recognised as being generally feasible.

Thompson's "survey design" is encapsulated on [extant] a about four large sheets of plan drawings and one elevation drawing rendered on linen reinforced paper (which is itself unusually thick) These drawings are dirty and somewhat distressed at the edges but very readable and useful. They are inscribed by Thompson and signed by him. They are dated around 1878.

They are in red and black Indian Ink and are colour washed to highlight the features shown. They are very complex with a large number of dimensions - some drawn in font so small that it is hard to visualise what sort of pen was used.

They define the easement (described as a right-of-way which it legally is/can be called) at about a Chain or 22 feet wide) with the general line of the race itself superposed by a central thick black line.

The history of the survey of the race includes this interesting report on the visit of Henry Wigg to see the Chief Surveyor of Canterbury and the Commissioner of Crown Lands in order to get the acquisition of the easements lands which were needed, settled.

Apparently reserved lands along at least a major part of the race had been set aside for some time and fencing along the boundaries of these reserved lands had been erected by adjoining landowners to the traditional "put-and-take" standards which practical men had been using for fencing legal boundaries for centuries - and still do. The fences follow the boundary closely or precisely or a feature of the landscape in the general sense of the boundary where adhering to the defined legal boundary would make it impossible to actually erect a fence.

The need for a two chain wide easement was generally established in New Zealand for such purposes, but Wigg was keen to not have to survey such a prosaic acquisition from scratch and to exactly two chains - there were unsurveyed sections where he acknowledged that a new survey to dimension was possible [his report advises that this is over about five miles] and appropriate, but over the bulk of the race he wanted to argue that a survey of existing fence lines was "good enough"


The following report of the Borough Engineer Mr Wigg was read at last Wednesday evening's meeting of the Borough Council.

4th February, 1878.

  1. In accordance with a resolution of the Council, I proceeded to Christchurch on the 28th ult. in order to consult with the Chief Surveyor as to the best mode of having the land reserved for water-race purposes granted to the Council at the earliest date. I took with me all the plans, sections, field-books, and detailed mathematical reductions of the numerous surveyed lines, and laid the same before the Chief Surveyor. "

  2. Interviews between myself and the Chief Surveyor took place on the 29th and 30th ult., and likewise with the Commissioner of Crown Lands on the latter date; both gentlemen giving to the subject matter much consideration and attention.

  3. The result of these interviews has been as follows: The Chief Surveyor has consented that all the lands reserved for water-race purposes which lie between the reservoir and section 23541 (about 5 miles from Pareora Gorge) are to be granted to the Council, according to the lines as they appear on the Government plans, without requiring me, as was first proposed, to reduce their bearings so as to agree with the lines of true meridian as lately established by the Surveyor-General's department. The Chief Surveyor, however, conceives it necessary that through all the lands which have not been surveyed by the Survey Department, extending from section 23544 to the head of the water-race (a distance of about. 51/2 miles) the lines which are finally to bound the reserve to be granted to the Council, should be laid out on the ground and surveyed on the true meridian, and for this purpose requires them to be connected with the lines of some trig, stations whoso distance and bearings have been recently determined by the officers of the Survey Department.

  4. To this requirement I have consented, subject to the approval of the Council but, in doing so, I have got the important permission that I need not confine the lines of fences to one chain on both side of the centre of the present tortuous race, but may lay out lines which may now, or afterwards, form those of the fences, and be in as long straight lengths as the nature of the ground will permit, which,in so broken a district, I think will be found a matter of great convenience, a saving of considerable trouble, and some extra expense in the fencing which would otherwise occur.

  5. As laying out the fences is a process that may, under any circumstances be gone through, it is far better to deal with this length of about 51/2 miles as early as may be convenient.

  6. When tho survey of the fence lines has been made under the conditions named above, the Chief Surveyor will accept the survey and adopt it as showing the lines defining the land to be granted to the Council, and no further survey of this length of reserve will be necessary for the purpose of passing the land under the Transfer Act so that I recommend the Council to adopt the suggestion of the Chief Surveyor and Commissioner of Crown Lands, the former having undertaken to furnish me with the bearings (from the true meridian) of trig stations in the neighbourhood of the proposed survey.

  7. With this report I lay before the Council, three sheets of drawings of special castings which will be required in conjunction with straight pipes numbered from 2 to 4 drawings in detail of proposed dam at lit ad of race numbered 5 design for the covered reservoir numbered 7 and also a list of the hydrants and valves which will be required for the whole Borough. "

  8. The sewer now being constructed in, the Great South Road is, of necessity, progressing slowly. In consequence of the fineness of the gravel used in the concrete, a longer time to set is required, than when the material is larger and more exposed to the free action of the atmosphere.

I am etc.

Henry Wigg, C.E. Board and Waterworks Engineer. 

In the absence of any existing complete and complex race construction drawings (such as were produced by Donald McLeod for the Oamaru Borough Race) it could be surmised that the contractors Black & Black, were simply commissioned to build the race to a general fixed dimension, with tunnels and aqueducts where set out and of these [there were just a few - two tunnels and possibly three or four smallish aqueducts] to "standard design"

Evidence in the form of existing sections of the race show it was small in cross section - and not unlike a gold miners' race with tunnels just big enough to crawl through (I leave it to the reader to consider how these tunnels were excavated and made durable!) in places it was formed with stonework and plaster and there was one section made in concrete, but over the bulk of its length it appears to have been just a small trench.

Although the race has been filled in in many places in the downlands, it is still quite clear in the Pareora Gorge and can be walked along - on parts of the easement (waterworks reserve) around Evans Crossing, land still in the ownership of the Timaru District Council.

Much of the detailed design of fixtures and fittings and of the reservoirs themselves (quite substantial structures) clearly fell to Henry Wigg who was the Chief Engineer of the Borough of Timaru and a surveyor also.

These items were comprehensively designed, as was a reservoir keepers' cottage and the valve and screen chambers but not everything got built to plan - it's common with civil works of this sort that the designer's dreams get squeezed into the budgetary reality of the day - and anyway, sometimes the things that get put on paper are not the best solution to what is encountered when the shovels hit the dirt.

So, we see in the collection of drawings, a design for the valve tower, valve chamber and connecting bridge of the conventional type, out in the lake, of which Oamaru's Ardgowan Reservoir, Wellington's Lower Karori Reservoir and Dunedin's Ross Creek Reservoir have extant and very good examples.

Timaru's one however was never constructed, and the valve chamber was built into the bund in the centre of the east bund and covered by a prosaic little corrugated iron shed.

Drawings are also there for a second structure, a covered reservoir - with vaulted brick chambers and roof, a huge Gothic structure partly underground and partly above with multiple courses of brick in the walls and an arched roof in three long rectangular sections of brick and concrete. Of course covered reservoirs were being built like this in bigger cities in the world and some may even have been built in New Zealand by this time (1880) but clearly the scale and complexity was outside Timaru's budget and the drawings never translated into civil works.

Just the one open bluestone lined reservoir was built. A second reservoir was not added until 1910-11.

The stone lined reservoir was designed to be 437' long and 127' wide at the top. This is 131 metres x 40 metres and with its sides sloping in to a floor of 116 metres x 20 metres this reservoir held 5,000,000 gallons of water at a depth of 20' (6.4 metres) That is roughly 25 million litres.

So far I have not located any photographs of the reservoir completed and filled with water - hopefully they exist.

In this telephoto shot you can see the Pareora River Dam and the trace of the old water race across the front of the spur where a walking track now makes the area accessible to the public. The dam is dangerous and as recently as 2005 a young woman was drowned when she was captured by the flow over the dam, in the pool below. At the far right of the pic you can see a section of the race that was lined with/constructed from concrete from its inception. There is an interesting web page at ( on that page a link to a Video made recently by a combined NZHPT and Timaru Museum group - featuring the race. Both the video and the Rootsweb web page perpetuate the impression that the race was something like 27 miles long (the number varies widely!! and often flamboyantly) - it was surveyed at just over 17 miles and will have been as long as it was surveyed - unless the digger disputed the work of John Thomas Thompson, the surveyor.

This cottage, which was made substantially from cob (mud plaster reinforced with straw and forced into a generally wooden formwork, in situ) was burned to the ground in 2008 after being disused and unloved for many decades. Photo courtesy The Timaru Herald. New Zealand.

The Timaru Borough Race only had one raceman who lived in a cottage up in the downlands about halfway along the race, in Adair Road and the flow was not controlled at the intake, consequently the race will have often delivered more water than was needed (at least in its early years as the township population was growing) Good provision had to be made to divert excess water and these structures (which appear to be original ie 1880s) will have been used by the Borough (water supply staff) to divert overflow into a nearby creek or off towards town (straight through after screening) to??? maybe some pasturelands irrigation - as I say not fully researched!

At the left and centre of this pic you can see wastewater channels, but the flow through the concrete structure to the right (a screen chamber?) appears to be piped away. Perhaps to another stream so as not to overload one, or perhaps to be used somewhere as irrigation or process water at no pressure. A little mystery.

One block in the centre of this photo shows drill holes where it was either quarried or split. The material came exclusively from seven or nine small quarry pits in the creek gully which now makes up the Timaru Centennial reserve 300 metres to the North of the reservoir site.

Lava (basalt) from Mt Horrible flowed towards the East and the sea and numerous lava escarpments tower over the creeks and streams running seaward off Mt Horrible. In general, this basalt is columnar crystaline and deeply cracked and weathered making it suitable for quarrying without the need for explosives. In some cases the columns are of very large diameter and rock from these quarries finds use as river and ocean protection works and in other cases the columns are about 400mm "round" These columns will have been sought for lining this reservoir as they require less input to get them to useable size.

Each of the many hundreds of poured in place slabs that make up the protection of this reservoir has been plastered to a fine finish and a thickness of around 30mm. Thousands of hours of plastering and troweling! This reservoir was built about 1911 at the same time that the whole open water race was abandoned and the supply piped to Timaru along the same easement (essentially) and from a source higher up the Pareora River. The water was initially directed to these two reservoirs and the No2 reservoir was still in use in the 1960s but decommission after then (date unknown) The mains supply trunk pipework around both reservoirs is still "live" apparently right up to the shutoff valves.

I'm not sure if the floor of the reservoir is concreted - it may have been just puddled clay (Loess) The extant drawings of the 1910-11 works do not make it clear.

Looking down the screen chamber of the No2 reservoir. The pool at the bottom is at the level of the reservoir floor. I expect that these screens filtered the water moving from right to left and that this and a similar chamber upstream would, when the reservoir was full, have been full to the top with the water just passing through. The filters appear to be perforated zinc in wooden (cedar?) frames. It is interesting to speculate what sort of arrangement of valves and sluices were constructed at the base of this chamber and in others, to allow the water flow to be interrupted and the filters cleaned - as they surely must have been?

Unless it is off site, there appears to have been no sand filter - but this is not a fully researched description of this civil work.


  • loading Loading…


Bruce Comfort's groups