In a mere four years after the completion of the Van Stadens Waterworks Scheme in 1885, the town was once again faced with the prospect of being short of water. How had this situation arisen and what solution did the Council propose?
Main picture: The Upper Van Stadens Dam
Causes of the shortfall
The overarching reason for the shortage of water was prevarication on the Council’s part. The Van Stadens Waterworks Scheme had first been raised in 1861 when the surveyor, Robert Pinchin, had submitted his treatise “Oude Van Staaden” to the Town Council. This proposal had gathered dust for 16 years before the mayor, Mr Henry William Pearson, announced at a Council meeting that it would present a Bill to the Cape Parliament requesting that it be given the power to expropriate land on which the pipeline would be laid as well as the power to issue Debentures to cover the capital cost of the project. Finally water would only flow in Main Street in September 1880. However the official opening was only held in June 1881 as household connections still had to be made.
Furthermore, the other reasons for the water shortage were due to the fact that 1885 was a dry season and as the intake weir possessed no storage capacity, the offtake was limited to the inflow to the weir.
Unlike 1861 when Pinchin had to goad the Council to take action, this time the Council was proactive. Accordingly, the Town Council commissioned the Consulting and Hydraulic Engineer, Mr Thomas Steward, then working from No.16 St. George’s Chambers in Cape Town. Amongst his responsibilities were to investigate, design and prepare contract drawings with specifications for the construction of
- Storage dam
These artefacts were to be located upstream from the existing weir in the Van Stadens River which had been constructed by Wicksteed.
On the 22nd July 1890, Steward finalised the designs and the specifications for both contracts and submitted them to be advertised for public tender with the closing date being the 9th February 1891. On the recommendation of Steward, on the 19th September 1890, the Council awarded both contracts to Messrs. Dollery & Fettes of Port Elizabeth with the stipulation that they would be completed within 18 months.
The construction of the weir and the dam would comprise the following contracts:
Integral to this contract was the use of large volumes of cement. As none of the contracts deals with the supply of cement, the presumption is that it was a free issue supply by the Council to the project. The cement was supplied from England in wooden casks, shipped to Algoa Bay where, on arrival, samples were subject to tests for “spoiled weight, breaking strain and fineness.” Certain tests revealed that the cement was too quick-setting for use on the works. In addition, there was doubt too about other properties of the cement such that Thomas Steward in 1892 notified the Town Clerk, William Pillman Pin that:
“Portland cement of great strength could be obtained by using large amounts of chalk in the manufacture, but unless the cement was burnt thoroughly it would contain lime in such a form that mixed with water it slaked and swelled , afterwards constricting and causing haircracks. He further advised that if the cement of that quality were exposed to the air, the lime would become partially harmless.”
The cement supplied and shipped by the vessels Killeena and Lismore Castle contained free lime and was not suitable for use on the works until it had been exposed to the air. After extensive tests and manipulation in the storage shed it was, finally, accepted by Steward.
David Raymer states that “In another report dated February 1892, Steward advised Pinn that the whole of the soft ground for the new storage dam had been excavated and the rock exposed across the valley. The exposed rock was found to be full of cavities with numerous cracks. The composition of the rock being variable, moreover, it required treatment before the foundation of the foundation of the dam could be cast. At the time, during 1892, the contractor experienced difficulties in engaging a bricklayer to work on the caretaker’s cottage. As a consequence, it was decided that the external and partition walls of the building be constructed of concrete by the masons on site. Unfortunately before construction of the dam commenced, a serious landslip occurred at the recently completed upper intake weir which almost filled the weir with sand and rubble. However the debris in the pool area of the weir was soon cleared by the workmen on site.”
Furthermore, David Raymer noted that “construction of the new weir, storage dam, filter beds and caretaker’s cottage was completed in November 1893. On completion, the Van Stadens Dam had a splendid wall, 15.2m in height and between 30 and 40 feet at the base, built right across the valley. In the centre of the dam wall was the valve tower used for regulating the escape of water and a little beyond was the sill [spillway] over which the water passed when it reached a critical level. The storage dam was 34 feet deep at the sill. 14 feet from the sill was the upper bell mouth intake and 28 feet down, the lower mouth intake. These were the two levels at which the water could be drawn for use. The remaining 6 feet was reserved for the settling of sediment. At the bottom of the valve tower was a 400mm scour pipe for drawing off impure water from the lower depths.”
The new Van Stadens Dam had a storage capacity of 138,380 kl.
Finally David concludes that “Immediately below the dam wall on the down stream side were four large filter beds, each about 20 square yards. The water, after leaving the valve tower in the storage dam, passed into the four filter beds, each of which was capable of filtering 1140 kl of water daily. From the filter beds, the water entered the recently completed section of 12-inch cast iron pipeline and gravitated to the service reservoir – the Fort Nottingham Reservoir – off Cape Road, where it was measured through two large meters.
Streams of Life: The Water Supply of Port Elizbeth and Uitenhage by David Raymer (2008, Express Litho Printers)