NamWater’s Calueque in troubled water
Repairs to a vitally important pump at the Calueque Dam in southern Angola will take four weeks and not two as was said earlier, NamWater has announced.
29 December 2017 | Infrastructure
Emergency repairs to two crucial pipelines from Angola’s Calueque Dam, which have jeopardised NamWater’s ability to supply water to north-central Namibia, will be completed in about four weeks.
In a letter dated 22 December and addressed to minister of agriculture, water and forestry John Mutorwa, NamWater CEO Vaino Shivute confirmed that a contractor had been appointed to fix two pumps that had been “leaking heavily.”
Shivute’s letter assured the minister that the Calueque scheme, which is the main source of water to north-central Namibia, was “currently vulnerable, but not under critical threat”.
He said contractors were working around the clock and were expected to conclude the repairs in the next four weeks.
Shivute said damage to the pumping lines from two raw-water abstraction pumps had minimised water supply and caused a lot of water wastage, which was seeping back into the pumps and switchboard building, while some was “collecting into pools outside”.
Shivute emphasised the urgency of the repairs, noting they were needed “before it gets worse and compromises the integrity of the pumping scheme and supply of raw water.”
He estimated that the Calueque scheme provides raw water to a “population that exceeds 50% of the country’s population during the festive season.”
As a result of the pumping line damage, NamWater’s supply from Calueque has been halved in recent weeks, Namibian Sun reported more than a week ago.
Apart from water supply to the Omusati, Ohangwena, Oshana, Kunene and Oshikoto Regions, water is also supplied to the Ruacana hydroelectric power station and one of the biggest green schemes, the Etunda Irrigation Project.
As a means of boosting water supply, NamWater used the backup reservoir at Olushandja Dam, which has pushed many crop farmers there to the brink and forced some to shut down operations and cut jobs.
Extracting water from the dam has “negatively impacted” the small-scale irrigation farmers around Olushandja Dam, which has been “depleting due to the augmentation and boosting of the canal,” NamWater acknowledged.
Moreover, the prevailing natural conditions of drought and increased evaporation have “additionally drained the dam,” the letter stated.
In addition, the supply has put pressure on providing sufficient water to the Etunda Irrigation Project.
With repairs ongoing, NamWater informed Mutorwa that supply to their purification plants currently was dependent on one pump at Calueque, which has an output of 1.8 cubic litres per second.
This output is shared with the Etunda irrigation scheme, which “siphons about one third of the total water abstracted,” Shivute explained.
Etunda management and AgriBusDev were warned that they might face rationing if supply to NamWater production plants came “under threat,” he added.
The letter further cautioned that the pipes being repaired are located 12 metres below ground and the repair work is “being conducted within the pipe underground, creating uncertainty in the smoothness of successful execution of the project.”
Mutorwa was informed that a NamWater team was on standby to provide support and monitor progress of the repairs.
Namibian Sun previously reported that at the beginning of 2017 NamWater announced that the Angolan government had spent about N$2.7 billion to rehabilitate the Calueque Dam in the Cunene River Basin in southern Angola for the benefit of Namibians.
The rehabilitation included the installation of three new water pumps and other state-of-the-art facilities to increase water supply to a population of about two million people in southern Angola and northern Namibia.
The rehabilitated dam is an 18-metre-deep composite structure with earth-fill flanks and a central mass concrete spillway.
It has a pump station, situated on the southern bank of the Cunene River, which supplies a peak flow of 7.4 cubic metres per second - of which 1.4 is intended for new Angolan irrigation projects, while the rest is allocated for use by Namibia.