Dhanbad: An accident was averted at Maithon dam on Wednesday after a tourist boat carrying around a dozen passengers from Majumdar Nivas to Sabuj Deep began sinking following collision with a submerged rock. Tajuddin, 27, a speedboat operator from Babu Boat Ghat, rescued all passengers.Witnesses said the boat struck a large rock mid-reservoir. The impact severely damaged the lower portion of the vessel, triggering panic among passengers as it started sinking.Tajuddin noticed the vessel and immediately steered his speedboat towards it. He then rescued the stranded tourists one by one. Locals credited his courage, presence of mind and swift response for ensuring that no lives were lost.Rajesh Sahni, 40, a boat operator, said the water level in Maithon dam has been steadily declining over the past few weeks, exposing several large rocks that are serious hazards to navigation.Sources attributed the sharp fall in water level to the heat, water release for hydel power generation and maintenance work being carried out by Damodar Valley Corporation (DVC). The receding shoreline has also affected boat operators, vendors and others dependent on tourists.The decline has raised concerns over the Maithon-Dhanbad water supply scheme, which serves Chirkunda, Nirsa, Kumardubi and Govindpur areas. DVC project head Subir Saha said the situation remains under control, though municipal and industrial supplies in Jharkhand and West Bengal could be hit if the reservoir level drops below 460 feet.