The Narmada's water level has gone past the 31 feet mark due to discharge of over 7 lakh cusec of water from the Sardar Sarovar Dam (SSD) upstream, they said.
The river was flowing at 31.25 feet, three feet above the danger mark of 28 feet, at Golden Bridge that connects Ankleshwar to Bharuch, said Bharuch collector MD Modiya.
"The river has swollen because of the continuous release of water from the Sardar Sarovar Dam in Kevadiya in Narmada district.
"More than 3,900 people were shifted from low-lying areas in Bharuch, Ankleshwar and Jhagadia talukas of Bharuch district during the last three days," said Modiya.
Two teams of the National Disaster Response Force (NDRF) and one of the State Disaster Response Force (SDRF) have been deployed in various parts of the district to shift people living in low-lying areas to safer places, he said.
Meanwhile, the dam's water level touched an all-time high mark of 137.28 metres on Thursday, which is just 1.4 metres short of the Full Reservoir Level (FRL) of 138.68 metres.
The dam has been built on the Narmada river on the Madhya Pradesh-Gujarat border. Most parts of Madhya Pradesh are receiving rains for the last couple of days.
According to the Sardar Sarovar Narmada Nigam Ltd (SSNNL) control room, over 7.73 lakh cusec (cubic foot per second) of water is being released into the river after 23 of the 30 gates of the mega dam were opened.
The dam is currently holding 3.16 lakh mcft (million cubic feet) of water, which is 94.61 per cent of its actual storage capacity, said a Gujarat government release.