Water good enough to drink so don’t raise a stink: City

THE flow of sewer water at several points along Windhoek’s rivers poses no threat to the City’s water supplies, according to the Municipality.

Angered by a media report that an overflow of sewage caused by flooding in the capital three weeks ago has affected the quality of water consumed by residents, the City has given an assurance that drinking water is safe. “It can be stated that the water quality is of a high standard and there should be no concern that any contaminated water could have entered the system,” said the City’s Public Relations Officer, Ipupa Davids, in a specially issued statement.”The water distribution system is under high pressure and it is not physically possible for contamination to enter from a riverbed into the distribution system”.While acknowledging that the damaged sewers were of concern in light of the potential to contaminate storage dams downstream, the City said its boreholes south-east of the capital were not threatened by the situation.Whereas water distribution pipes might have been damaged in a polluted riverbed, the City says great care was being exercised to isolate and disinfect such areas.In its damage assessment report this week, the City’s Department of Infrastructure, Water and Technical Services said that where possible it was using manholes to stem the flow of sewer water to riverbeds, and that pumps were also being used to rid the river of pools of sewer water.The City of Windhoek said that to date all testing at its supply sources, reservoirs and the water distribution system for faecal pollution had proved negative.Chlorine levels were also being measured daily to ensure that water flowing into the distribution system was disinfected if necessary.Over and above this, tests were being conducted across the City at more than 50 places where shoppers gather.A City statement said yesterday: “Water quality is monitored both at source and in the distribution system and any change in condition of our drinking water will be communicated to our customers without delay”.Half of Windhoek’s water supply comes from the Von Bach Dam, but none of the rivers currently polluted from sewer-water drains into the dam.The New Goreangab reclamation plant supplies 30 per cent of the City’s water and underground sources another 20 per cent.The Goreangab plant, which treats water from its dam, was shut down almost two weeks ago for repair work expected to last at least till the end of this month.The City says the shutdown was planned in November and was unrelated to the post-flooding situation.Under normal operating conditions, it is also against municipal policy to use water from the Goreangab Dam after heavy rains because of the large amounts of organic material accompanying the inflow which makes the water difficult to treat.Increased urbanisation around the dam has also contributed to higher pollution levels.For this reason the Municipality says water from there is treated in the same way as wastewater effluent from the Gammams Water Care Works.The Department of Infrastructure, Water and Technical Services says it is concentrating all its efforts on repairing sewerage pipes but that it is too soon to have detected all the damage: this may become apparent only once the upstream sections have been replaced.Much of the reticulation system is filled with sand and rocks, and a high-pressure jet machine provided by the Walvis Bay Municipality is being used to free up the system.Along the Klein Windhoek River, about 550 metres of sewer line and 14 manholes were swept away.The extent of the damage between the Mission Road Bridge and the drift at Nelson Mandela Avenue is still not fully determined.In this section 18 manholes were washed away, some of which had to be pumped free of sand.Along the Gammams and Arebbusch rivers, more than 300 metres of pipeline were destroyed.Tenders have also now closed for the reconstruction of a 60-metre stretch of the aqueduct that carried semi-purified sewage from Gammams Water Care Works to the Goreangab Reclamation Plant across the Goreangab Dam.This repair work is estimated to cost about N$1 million.”It can be stated that the water quality is of a high standard and there should be no concern that any contaminated water could have entered the system,” said the City’s Public Relations Officer, Ipupa Davids, in a specially issued statement. “The water distribution system is under high pressure and it is not physically possible for contamination to enter from a riverbed into the distribution system”. While acknowledging that the damaged sewers were of concern in light of the potential to contaminate storage dams downstream, the City said its boreholes south-east of the capital were not threatened by the situation. Whereas water distribution pipes might have been damaged in a polluted riverbed, the City says great care was being exercised to isolate and disinfect such areas. In its damage assessment report this week, the City’s Department of Infrastructure, Water and Technical Services said that where possible it was using manholes to stem the flow of sewer water to riverbeds, and that pumps were also being used to rid the river of pools of sewer water. The City of Windhoek said that to date all testing at its supply sources, reservoirs and the water distribution system for faecal pollution had proved negative. Chlorine levels were also being measured daily to ensure that water flowing into the distribution system was disinfected if necessary. Over and above this, tests were being conducted across the City at more than 50 places where shoppers gather. A City statement said yesterday: “Water quality is monitored both at source and in the distribution system and any change in condition of our drinking water will be communicated to our customers without delay”. Half of Windhoek’s water supply comes from the Von Bach Dam, but none of the rivers currently polluted from sewer-water drains into the dam. The New Goreangab reclamation plant supplies 30 per cent of the City’s water and underground sources another 20 per cent. The Goreangab plant, which treats water from its dam, was shut down almost two weeks ago for repair work expected to last at least till the end of this month. The City says the shutdown was planned in November and was unrelated to the post-flooding situation. Under normal operating conditions, it is also against municipal policy to use water from the Goreangab Dam after heavy rains because of the large amounts of organic material accompanying the inflow which makes the water difficult to treat. Increased urbanisation around the dam has also contributed to higher pollution levels. For this reason the Municipality says water from there is treated in the same way as wastewater effluent from the Gammams Water Care Works. The Department of Infrastructure, Water and Technical Services says it is concentrating all its efforts on repairing sewerage pipes but that it is too soon to have detected all the damage: this may become apparent only once the upstream sections have been replaced. Much of the reticulation system is filled with sand and rocks, and a high-pressure jet machine provided by the Walvis Bay Municipality is being used to free up the system. Along the Klein Windhoek River, about 550 metres of sewer line and 14 manholes were swept away. The extent of the damage between the Mission Road Bridge and the drift at Nelson Mandela Avenue is still not fully determined. In this section 18 manholes were washed away, some of which had to be pumped free of sand. Along the Gammams and Arebbusch rivers, more than 300 metres of pipeline were destroyed. Tenders have also now closed for the reconstruction of a 60-metre stretch of the aqueduct that carried semi-purified sewage from Gammams Water Care Works to the Goreangab Reclamation Plant across the Goreangab Dam. This repair work is estimated to cost about N$1 million.