The Thames water race was constructed over the period 1872-75 to carry water from the Kauaeranga River to Thames, providing water and energy for gold mining operations and the town's domestic water supply. The design was known as an “open” race; that is, it was not totally enclosed by a pipe, which meant the survey and engineering had to be very precise, to prevent water spilling over the sides.
Water first flowed down the race on 14th January 1876, and it provided the town's water supply needs until it was replaced by a pipeline and finally decommissioned in 1947. Historical research and a field survey of what little remains of the race and its infrastructure were conducted over the period December 2008 - May 2009. Portions of the race still remain, and are readily accessible, although some are on private property, and permission should be sought before entering.
The Thames goldfield was opened on 1st August 1867, and the population of Thames quickly swelled to around 18,000. It soon became apparent that the majority of the gold to be found in the area was not alluvial, but was bound up in quartz rock and required intensive crushing and refining operations to extract from the rock. There was an obvious need for an extensive water supply for the town - for processing the quartz, to provide power for the crusher batteries, and for domestic consumption. This could not be met from the small streams that flowed through the town, particularly on account of their seasonal flows. The most likely source was the Kauaeranga River, which had sufficient flow and was not significantly affected by summer drought conditions.
The idea of a race to convey water from the upper reaches of the Kauaeranga was mooted as early as 1968, and in 1868-69, an 18-month survey was done by a Mr Coates. The Daily Southern Cross of 10th June 1869 reported that: “Mr Coates has returned to Shortland from his survey of the Kauwaeranga [sic] river, and reports favourably upon the practicability of the Thames water supply scheme.” However, nothing more was done until gold production peaked in 1871, and calls were renewed for the (then) provincial government to do something about an appropriate water supply for the town. In 1871, another survey was conducted by a Mr J.J. O'Neill (Isdale 1977, Isdale 1982).
From 1872, a series of contracts were let for the construction of the race. According to the Daily Southern Cross (Unknown correspondent 1876a), four contracts were undertaken, for different sections of the race, over a period of what turned out to be about five years. The first was by a Mr Heron to construct the head works (intake) and the first 1800 feet, of which approx 600 feet was a tunnel through solid rock. The second contract was by brothers R.N. and A. Smith involving seven and a half miles, from the end of Heron's section to the Parawai area. This included 1200 feet of tunnelling and the construction of a massive trestle over the Mangakirikiri Stream. A reservoir for town supply was also established in the vicinity of the Waikiekie stream.
The third contract was to extend the race from Parawai, through the eastern outskirts of Thames, to the Karaka Stream. The fourth contract was to build a new reservoir in the Waiokaraka valley and to extend the race to that point. (It is not clear who won the third and fourth contracts.) A fifth contract was contemplated; to extend the race to the Waiotahi and Moanataiari valleys. This was never completed, because gold production slumped after 1871, despite a few short periods of resurgence up until about 1915, when mining effectively ended (Berry 2002, Berry 2007).
Water first flowed down the race on 14th January 1876; from the intake, and directly into the Karaka Stream, as the race extension to the Waiokaraka and the reservoir had not been completed by then. Local and Auckland newspapers all recorded this momentous event.
The Thames Advertiser of Sat 15th January 1876 (Unknown correspondent 1876b) reported that:
“Yesterday the water from the head works was turned into the race, and we are glad to find that as it is constructed, everything is perfectly satisfactory. There is a little to do yet before it is quite finished, some leaks to stop, and some work to complete, but it conveyed the water from the Kauwaeranga [sic] to the Karaka in splendid style. The whole of the water available, for which the race has the capacity for carrying, was not turned in. It is capable of delivering about 20,000,000 gallons per day, and the quantity which it carried yesterday was about 6,000,000. The effect on the Karaka Creek was remarkable. It increased its volume to a marked extent and the battery-owners on the Karaka below the point of delivery were not slow to avail themselves of the water thus supplied. So far, therefore, we may look upon the race as finished as far as the Karaka Creek. It is finished but practically useless. We really cannot understand the reason for the delay on the part of the government in not letting the contract for the construction of the [Waiokaraka] reservoir.”
The [Auckland] Daily Southern Cross of Monday 3rd April 1876, provided extensive engineering information about the race, as follows:
“The total length of the race is nine and three-quarter miles. It is composed of open earth cuttings extending 26,000 lineal feet, of fluming in iron troughs 21,000ft., and of 4,000ft. of tunnelling, in all 51,000 lineal feet. The iron in the fluming is one-eighth of an inch thick, three sheets rivetted together forming a semi-circular trough 5ft. wide and 2ft. 9in. deep. The open ditching is 9ft. wide at the top, 4ft. at the bottom, and 2ft. deep. The race has a fall of 5 1/4 ft. per mile, which rate of fall is preserved with almost strict mathematical accuracy all through. The rate of flow of the water is two miles per hour, and, as we have stated, the quantity the race is capable of discharging amounts to the liberal sum of 20 millions of gallons per diem ; and this water is capable of being used for motive power, besides the supply for domestic purposes, to the extent of 350 horse power [261 kW]. In crossing some of the branch creek valleys which intersect the course of the race the fluming is supported on trestle work reaching a height ranging from 50ft. to 70ft.”
The race provided water for mining operations until mining effectively ceased around 1915, and domestic water supply for the town until 1947. By this stage, the race was expensive and difficult to maintain, and slips on the hillsides it traversed caused increasingly more frequent damage. Also, hygiene issues associated with an open race were of concern (there were reports of dead animals being taken from the race during routine maintenance). The race also represented a human safety hazard, with drownings frequently being reported. During the mid-1940s,the town water supply was progressively converted to a pipeline and the race was eventually decommissioned and demolished in 1947 (Williams and Williams 1994).
An interesting aside is that after mining operations ceased c. 1915, there was surplus water available from the Waiokaraka reservoir, and this was used to power a pelton wheel and electricity generator in the basement of the old Bella St pump house. This was Thames' first electricity supply and was used until the town was joined to the national grid in the 1920s. Thereafter, it was used as a backup supply, until about the 1960s. The pelton wheel and generator still exist, and can be viewed at the Bella St museum.
It is also noteworthy that there were (at least tentative) plans to build a second water race from the Kauaeranga Valley to Thames. A report to the Undersecretary of Mines (Perham 1898), discusses a planned “low level” race (i.e. with an intake lower in altitude than the original one) which was to run from the vicinity of “Stephen's hotel” (the Kauaeranga Hotel - from 1882-1909, the proprietors were members of the Stevens family) to a new reservoir, to be built on the Karaka Stream. This project was never undertaken.
Numerous visits to various features and sites associated with the Thames water race were conducted over the period December 2008 - May 2009. This section describes the various significant sites, organised in order of the geographical layout of the race, from the intake near Hoffmans Pool to the Waiokaraka reservoir, which was the final storage site associated with the race. (The planned extension to the Waiotahi and Moanataiari valleys was never built.)
Survey maps of the race (SO 7105 Sheets 1-8 1895) show “feeder” races joining the main race from the Mangarehu and Mangakirikiri streams. No firm historical evidence was found as to whether or not these were actually built; however, archaeological evidence obtained during the survey confirmed they were. The locations surveyed are indicated on the TUMONZ map below. GPS waypoints are listed in the relevant sections.
This can be accessed from the nature walk loop track that is signposted from both the Hoffmans pool end and the western end, although the intake structure is only a few minutes walk from the western end. There is a stone wall remaining, with intake vents, but the valve mechanism is no longer apparent. There is a good interpretation panel and a viewing platform at the site. Apparently, the intake was designed to cope with flood conditions, as well as normal river flows. Some of the flood conditions would have been man-made, as kauri logs were driven down this section of the river (to the Parawai booms) until around 1910.
A concrete control gate with diversionary and stop valve functions is clearly visible, with interpretation panel, next to the track leading to the model kauri dam from the KVC building. Approx 200m further on, after crossing the model dam, a section of water race in-ground channel with some iron fluming fragments, can be seen. It is possible to follow this channel west, for approx 200m before it peters out.
Site record T12-1209 (NZMG 2742690E 6449970N), submitted by Warren Gumbley in Feb 2004, records two sections of in-ground channel on the true right bank of the Mangarehu Stream, and some notches cut into the bank which may be holes associated with a trestle that carried the race across a side stream. This area was revisited in January 2009 and again in April 2009, when data from the original survey plans (SO 7105 Sheets 1-8 1895) was available in NZMG format. This data shows that the main race crossed the Mangarehu about 20m upstream from where the existing Kauaeranga Valley road currently fords the Mangarehu, and is approx 300m downstream from T12-1209.
Remains of a channel were seen on the true right bank of the Mangarehu in several places between the site where the main race crossed the Mangarehu, and the point marked as the start of the feeder race (which is adjacent to the second ford on the current Mangarehu road, heading upstream). There were well-defined sections of channel at WP 460 (2742541E 6450146N) and WP 461 (2742546E 6450379N). The notches reported by Warren Gumbley were not observed, but no great effort was made to locate them, as there was thick undergrowth and leaf litter in most places along the true right bank. There were no signs of an intake at the location indicated on the survey plan.
A search was also conducted in the vicinity of the current Kauaeranga Valley Rd ford over the Mangarehu. Remains of an in-ground channel were found on the true left bank of the Mangarehu, approx 15m upstream from the ford. This is approx 1m deep and runs east, parallel to the existing road, for approx 200m where it peters out (i.e. merges with the road). Following the line of this channel towards the Mangarehu stream, some piles of rocks can be found on both banks, in the approximate location where the trestle would have been built, but there were no signs of concrete or other foundations. On the true right bank of the Mangarehu, approx 50m west along the Kauaeranga Valley Rd and approx 20m into the bush line to the north, a pile of iron fluming was found. This was spread over an area of approx 30 sq m, and looks as if it would have been all, or most, of the fluming associated with the Mangarehu trestle.
This area was also visited in January 2009 and again in April 2009 when survey data was available in NZMG format. The site of the Mangakirikiri trestle was located, by means of a GPS waypoint which was based on the interpolated survey data. A careful search of the stream bed in the vicinity of the waypoint revealed the remains of the trestle foundations.
A search was conducted above the foundation on the true left bank, by climbing the cliff (which is very steep and not recommended, without appropriate safety gear). A considerable quantity of iron fluming was found scattered over about 30 sq m approx 15m (vertically) above the stream bed. Following the line of the trestle to the top of the cliff leads to a spot approx 15m inside the front gate of an existing house. A clearly defined in-ground channel runs from the lip of the escarpment east across the farm for approx 200-300m before it meets up with the Kauaeranga Valley Rd and peters out.
The survey map shows a feeder race with its intake approx 800m further up the Mangakirikiri from the trestle. There is a channel leading towards the main race that meets the Kauaeranga Valley Road and peters out approx 200m south west of the existing road bridge over the Mangakirikiri. It is possible to follow this upstream, parallel with the road, for approx 100m before it detours off over private property. This provides archaeological evidence that the Mangakirikiri branch race was actually built. Above the bank, where the channel meets the main road, there is a culvert that looks as if it was associated with the race (i.e. provides a crossing-point over the branch channel), but it could be more modern.
These areas were sample-searched along the various side roads joining Kauaeranga Valley and Parawai Rds, based on the predicted route of the race as per the topographic map below. The following roads were searched: Mangotahi Rd, Packtrack Rd, the two access roads (un-named on the TUMONZ map) opposite the Kauaeranga Christian Camp in grid square 4046, Te Ana Rd (and its extension, Bliss Way), Booms Ave, Waikiekie, Reservoir, and Grafton Rds, Herewaka St, and Mountsea Rd. In many places, the route the race would have followed was apparent, but modification due to farming and urban development has removed virtually all traces of it.
This was surveyed and recorded as T12-1263 in 2006, but has since been destroyed. It was similar in form and function to the control gate near the KVC but was in a better state of preservation, and there were crumpled remains of iron fluming on the ground approx 20m from the control gate. There was also an iron rod approx 3m long, with a screw mechanism, which appears to be part of the control gate opening/closing mechanism. The author recalls visiting this control gate and a section of fluming carried by a trestle, leading north to the tunnel under Hauraki Terrace, while living in the area as a child in the 1950s and 1960s. There was also an in-ground channel heading roughly south from the control gate, towards Mountsea Rd. It was possible to follow this, although badly overgrown, for approx 80m until it petered out. The vegetation clearance for the Korokoro subdivision made this channel quite easy to see, but it was destroyed later, during site earthworks.
This facility, located at the northern end of The Terrace, was built c.1920 to pump water from the race up the hill to the Block 27 reservoir, at the northern end of Hill St. The reservoir still exists but is no longer used. The pump house is used as a garage and storage shed by the current owner of the property.
From the end of Waiokaraka Rd, proceed directly up the stream bed. After approx 100m, the earth wall of the old reservoir dam is reached. This is approx 80m wide (from bank to bank) and estimated to be 12-15m high (above the original stream bed). Along the true right bank of the dam wall, there is a trench, approx 2m wide and 2m deep, leading north-west on to some private property, where it peters out. This could have been part of the planned extension of the race to the Waiotahi and Moanataiari valleys, which was never built.
In the middle of the dam, upstream from the wall, the remains of the outlet pipe and its control structure can be found. Downstream from the dam wall, a section of the pipe leading to the Bella St powerhouse can be seen, including a gate valve.
In the old Bella St building, the pelton wheel and generator used to provide the original Thames electricity supply (used from c.1915 until the 1960s) can still be seen. This was powered by water from the Waiokaraka reservoir, which was surplus to town supply requirements after gold production declined in the late 1800s.
Berry, A. (2002). The Centenary of the Kauaeranga Hall, Goldfields Print, Paeroa, NZ.
Berry, A. (2007). The Kauaeranga Valley, Allan Berry, Thames.
Isdale, A. M. (1977). Collected Notes: The Kauaeranga River, Thames.
Isdale, A. M. (1982). The Kauaeranga Water Race, Thames.
Perham, T. (1898). Thames County Low-level Water Race, Wellington.
SO 7105 Sheets 1-8 (1895) Water race to be taken under the Public Works Act Thames County, Borough, Survey District Blocks V, VI and VIII
Unknown correspondent (1876a). Thames Water Race, Daily Southern Cross, Monday 3rd April, Auckland, PAPERSPAST
Unknown correspondent (1876b). Untitled, Thames Advertiser, Sat 15th January, Thames
Williams, Z. and Williams, J. (1994). Thames & the Coromandel Peninsula: 2000 Years, Williams Publishers, Thames
