Crystal Brook History Group, Water Supply

The dam is 32.8 m high, has a crest length of 140 m (not including the spillway) and has a capacity of 3200 ML (megalitres; 1 ML = 1000 KL). Its catchment area is 48 km². It is a curved concrete gravity dam consisting of 43 400 m² of concrete.

At the time of construction it was the largest concrete dam in the southern hemisphere.

The dam is on the Crystal Brook, about 15 km upstream from Crystal Brook township.

Beetaloo Dam Construction

Click on the photos with a bright outline to see a larger copy

	These men are excavating the area where the dam is to be built. This was necessary to produce a watertight foundation for the dam. The photo is dated 1889.
	This rare photo shows part of the construction township beneath the dam wall, whose steel reinforcing rods can be clearly seen. The photo was taken in 1889 or 1890.
	The village photographed sometime between 1887 and 1891. This was copied from an old print that had been torn in two. You can see that quite a substantial little town was built for the men who constructed the dam. Note that there is another photographer, with the large black bag used to exclude light while composing his view, in the foreground.
	An insight into the life of the Beetaloo Dam construction workers. One supposes that this was following a very successful hunt held on the worker's day off. The man on the left is holding what look like a couple of possums; is his hat made of possum skin? Note the tent accommodation and the stone and kerosene tin chimney. The photo is dated 1891.
	The entrance to this tunnel can still be seen just below the dam wall. I think that it was used to divert the water around the dam site while the wall was being constructed (this should be checked). The outlet pipes now pass through this tunnel. The upstream end is, apart from the pipes, blocked by a large concrete plug. The photo is dated 1989.
	Building one of the silt-trapping weirs. I'm guessing, but perhaps the very heavy wooden framework would have been dragged one way or the other over the weir as needed by a teem of horses. Few stone could have been layed with the framework in any one place, and dismantling and rebuilding it would have been very time-consuming.
	The first time Beetaloo Reservoir filled, 1893. Because of the relatively dry climate of the catchment area, the reservoir does not often fill. Note that the spillway is higher than it is today.

Raising and lowering the spillway

	Water flowing over the spillway; date not recorded. The height of the spillway has been changed several times. It was raised by 740mm in 1927 to increase the capacity of the reservoir, and lowered by 300mm in 1979 after a hydrological study and dam stability analysis. Note that there is a walkway over the spillway in this photo. In 1975 the reservoir was full when a major flood occurred. It was reported that the area between the spillway crest and the walkway became partially blocked with logs causing the water to pass 75mm deep over the main dam.
	By 1986 the concrete of the dam wall had become porous and there were leaks through cracks. Holes were drilled from top to bottom along the length of the wall and cement grout was pumped in, and the spillway was lowered by a further metre.
	The new spillway has concrete blocks to slow the water and reduce erosion. Part of the old, higher, spillway can be seen on the far left of this photo.
	Overflowing after the spillway had been rebuilt. The gully seen in this photo was eroded out sometime during the life of the dam.
	Apparently taken at the same time as the photo above. This was taken from closer to the spillway.

Beetaloo Dam: Historical Background

The first reference to the Beetaloo works appeared in early 1885 in an article written for the South Australian Register. This article must have created a great deal of interest, because after publication a deputation was sent to the Commissioner for Public Works, to lobby for a water supply to Yorke Peninsula. The Commissioner in turn instructed the Hydraulic Engineer (Mr. Mestayer) to conduct a survey of the Beetaloo Springs area and then to prepare a report.

The survey was commenced in May 1885 and the report (parliamentry Paper No. 100-1885) was tabled in September. The report was not optimistic, for although the geology of the area was suitable, (Government Geologists Report P.P. 100-1885) it appeared from the small number of gaugings taken that the flow in the creek would not be sufficient to fill a reservoir of more than 350 ML. However the report did say, that if a further supply could be obtained, then the dam would be quite feasible. This further supply must have been quickly found, because before the end of 1885 the construction of the dam had been approved and the Resident Engineer (Mr. Christopher Jobson) arrived at Laura on the 28th December 1885.

The dam originally envisaged by Mr. Mestayer was to be of masonry construction with a large bywash cut through the right abutment, but after seven quarries had been opened up no suitable stone had been found that could have been quarried cheaply. Even though there was considerable pressure to build a masonry dam (because of high unemployment among masons) it was decided to use concrete. It was a large and ambitious project being the largest concrete dam built in the southern hemisphere. Because the project was such a departure from previous works, both in design and materials, no suitable machinery was available so the machinery and plant were designed and made by the Waterworks.

By the time the Resident Engineer arrived at the site no final drawings had been prepared as the project had been commenced quickly in an effort to help unemployed labourers. This was possible because the initial work of clearing foundations, building catch dams and clearing the reservoir area required only preliminary sketches.

During 1886 work commenced on clearing the foundations and sinking trial shafts, with the main effort being concentrated on clearing the reservoir area and building silt trap dams. These small dry rubble masonry dams were built with the base of the dam 1.6 metres above full supply level of the reservoir and were on the twenty main creeks emptying into the basin. Two earthern catch dams were built, one in Walters Gully and one on Crystal Brook. These were connected with a water race. Catch drains were cut 3 metres above full supply level and these discharged into the catch dams. These catch drains and dams were constructed in an effort to protect the works from flooding and also to provide the water needed for the construction of the main dam. The overflow from the Walters Gully dam was diverted past the main dam excavation by means of a race, which effectively kept the dam foundations dry.

Water was scarce during 1886 and soon after their completion the catch dams were used to supply Bute via 80 kilometres of temporary main. The only interruption to this supply occurred in November 1886 when a heavy storm brought 65 mm of rain in 2 hours accompanied by hailstones about the size of tomatoes. After about 20 minutes the creek came down and for a while the catch dams held. However, when the hail melted the flow increased dramatically and the catch dam on the main creek was washed away. During this flood a man named Wilson attempted to cross the creek from one camp to another using only a rope and was washed away and drowned. His body was recovered about 1 1/2 hours later having been washed 5 kilometres downstream.

During 1887 most of the preparations for the mixing and placing of the concrete were completed with all the machinery in place and tested. Stone was broken and stockpiled, tramlines laid and wood stacked to be used later to fuel the steam powered machinery. The casks of cement were brought from Port Pirie and stored in the sheds so that by the end of 1887 all was in readiness for the pouring of the concrete which began on February 28th 1888. Concrete was poured continuously until May 1889 when the non-arrival of cement stopped pouring until the end of July 1889. The work then proceeded satisfactorily until October 1890 when the dam was finally completed.

When the dam was built it was expected to collect sufficient runoff to fill the reservoir once annually (3600 ML). This later proved to be over optimistic as there was only sufficient water to fill it each year. An all year round supply of spring water supplements the runoff from the catchment. The main sources being in Norman's Gully where a shaft and cross-cut were excavated in 1930 and Mary Springs where a tunnel was excavated in 1899 to intercept the springwater. In 1936 a graded earthenware pipe was constructed along the creek bank to carry the spring water from Mary Springs to the reservoir. During a major flood in 1975 a section of the pipe was washed away and remains in disrepair.

Beetaloo-Copper Triangle Pipeline

	The photo shows steam traction engines that were used to power the pumps that lifted water from the Broughton River at Merriton into the Beetaloo to Kadina pipeline. This took place some time in the 1890s when Beetaloo reservoir went dry. One of the most interesting points about this operation is that, in recent times, the water in the Broughton River at Merriton is so saline that it would be of little use for a town water supply; as shown on the graph below.
	The graph shows the salinity of a number of water samples taken from the Broughton River. Most of the samples having low salinities were taken when there were high rates of flow in the river. The River is generally at about its most saline when its flows are at the lower limits. In summer, in the last twelve years, the salinity has typically been 4500 to 8000 milligrams of salt per litre of water. This is too salty for human consumption. Of course, when the Beetaloo reservoir is dry, one would expect flows in the River to be very low. So, in the 1890s, when Broughton River water was pumped to Kadina, Wallaroo and Moonta, was it less saline than it has been in recent years, or was it just that the situation was so desperate that they had to have salty water to wash in, and get by with what rain water they had for drinking?

Bundaleer Dam