Waterproof walls will be set up outside pits for the construction of new subway lines as authorities in Beijing brace for a possible repetition of last year’s floods that killed 77 people.

In a regulation issued on Thursday, the Beijing Municipal Commission of Housing and Urban-Rural Development ordered that all the 307 construction pits must have waterproof walls to ensure the safety of current subway lines.

“Last year’s floods were a benchmark and this year’s flood prevention standards can only be higher,” said Wang Gang, deputy director of the commission.

The city’s construction pits withstood tough tests in last year’s floods, as rainwater from all parts converged into them, threatening the operation of subway lines.

The commission has already embarked on a renovation program of 20 low-lying overpasses on the major ring roads that circle the city, including a project to build water storage ponds next to overpasses.

In last year’s floods, the overpasses proved to be a major area for rainwater convergence, which led to damaged roads and the death of one driver.

"The flood last year taught us lessons the hard way. This year, things will be different as we know what to expect in the worst-case scenario and we know we should be prepared,” Wang added.