NAVI MUMBAI/MUMBAI: With the water level rising to the overflow mark following incessant rain, the century-old Ilthanpada dam in Digha , near Kalwa , has developed three cracks near its top edges and started leaking. As a result, thousands of slum-dwellers residing downstream are living in fear of flooding.The cracks have developed in the concrete layer built a few decades ago to extend the dam’s height by around one-and-a-half-feet.The Navi Mumbai Municipal Corporation has passed the responsibility to railways in case of any tragedy, saying it is under the Central Railway. And railway officials say the structure is stable and their engineers have been monitoring the dam regularly.Thousands of shanties—four major slum pockets of Ilthanpada, Yadav, Nagar, Subhash Nagar, Kanheiya Nagar—have mushroomed near the dam over the years. So, the downstream has been squeezed, posing danger of possible flooding. “The slums have encroached upon the hillside, which may cause a landslide,” said Santosh Patil, an environmentalist. Om Prakash Yadav, a slum-dweller, said, “We saw cracks and leakage from the extension built over the original dam. Hardly any maintenance has been carried out in the past several years.”Sanjay Desai, executive engineer of NMMC, said, “We are worried about the residents living near the dam. Considering the condition of the dam, we approached the Central Railways, urging them to hand it over to us for proper maintenance and beautification of the area. The response has been negative as the railways seems interested in keeping its ownership.”Ravinder Goyal, CR divisional railway manager, said, “The century-old stone structure still stands strong. Our engineers are monitoring the dam site. However, I will instruct the department concerned to take stock of the fresh development like leakage from multiple spots.”Meanwhile, thanks to the bountiful downpour this month, city has already received the average rainfall for July, with still a week remaining.Between July 1 and July 23, the India Meteorological Department ’s Santacruz observatory recorded 838.6mm rain — way above the average of 799.7 mm. The Santacruz weather station is considered to be indicative of Mumbai.In June, the observatory recorded 523.2 mm rain, a little above the average of 523.1mm for the month. It has recorded 1361.8mm rain from June 1 to July 23.K S Hosalikar, deputy general, western region, IMD, said, “The July rainfall has already crossed its average. However, the rainfall activity may witness a reduction in the coming week. We have issued warnings for the next two days after which there are no major warnings given.”