Swimmers have been banned from Al Bateen beach after raw sewage spilled into the sea. Health chiefs also advised against fishing and other recreational activities in the waters off the beach, in the south of Abu Dhabi island. The beach reopened to the public only last month. It had been closed for two years for work on a 700-metre waterfront redevelopment project, and the first 200 metres were unveiled in December. The problem began last week when a building contractor broke a main sewer pipe in the area of Mohammed Bin Zayed City, east of Musaffah, carrying outflow to the treatment plant at Al Wathba. The pipe had to be closed, increasing pressure on the rest of the network. At peak times it could not cope, and sewage spilled into the sea through outflow pipes at Al Bateen, and off the Mangrove Corniche in the north-east of the island, where fishing has also been banned until further notice. \"When something like this happens there is no capacity to hold the sewage. It has to go somewhere,\" said an official at the Abu Dhabi Sewerage Services Company. The damaged pipe has since been repaired and the network is fully operational. It is not clear how much sewage ended up in the water. Some sources have suggested that up to 20 per cent of Abu Dhabi’s sewage outflow ended up in the Gulf at peak times, but the ADSSC official denied that. “We have not calculated it but it is minimal compared to the normal sewage flow,” he said. Muhra Al Muhairi, the beach section head at Abu Dhabi Municipality, first heard of the sewage leak on Thursday morning. “We had an environmental engineer check it and we asked them to investigate,” she said. As a precaution, the municipality activated its emergency plan for Al Bateen beach and temporarily banned swimming. Ms Al Muhairi stressed that the main Corniche beach was unaffected, but the waters off Al Bateen beach will remain off limits until further notice. The Environment Agency – Abu Dhabi (EAD) said yesterday it was closely monitoring the affected areas. Experts were performing visual surveys from boats and taking water samples that were sent to laboratories for testing. A water quality expert said that while it was difficult to define the exact impact of the pollution, the situation did not call for any measures beyond those the Government had already taken. To determine the precise effect on human health and the environment it was necessary to know exactly how much sewage ended up in the water, and to have access to a dispersion model – a computer simulation of conditions in the Gulf in the affected area. “I am not aware of a detailed model for the seabed around Abu Dhabi island,” the expert said. Although repulsive, sewage contains mostly organic material that is degraded by nature and is less harmful than industrial waste. “My general feeling is, it will soon go away in a matter of days – three, four, five days – thanks to the sunshine of Abu Dhabi and the wind,” the water quality expert said. “I do not really see a big risk there unless someone is subjected to this water directly, for example if they happen to be swimming where the outflow is. “Some of the classic, old waste water treatment is about dumping the water in a lagoon and just waiting, and the sun and mother nature do the job,” he said. However, frequent discharges of sewage in the ocean can increase the amount of nutrients in the water and cause algal blooms that can destroy other marine life and sea creatures by blocking out sunlight. The expert said avoiding such incidents in the future required more control over contractors. “It is not like the pipe collapsed by itself,” he said. “Contractors working in public places should be made aware of the location of important infrastructure.” Better policing of the rules that govern contractors and marking posts to indicate the locations of important services should also be considered by the authorities, he said.