Beijing learns a soggy summer lesson

Tough tests

The Beijing climate center predicts the municipality could face a summer with the same amount of rain as last year, as spring was mainly dry.

After 13 years of dry summers, the city has entered another cycle of rainy years, meteorological experts told the Beijing Times.

The center predicts that this year the capital could face five to eight days of rainfall as heavy as last year's.

The downpour on July 21, and ensuing floods, exposed a series of vulnerabilities in the city's flood prevention plan. These included weak prevention infrastructure, inadequate facilities and materials, lack of an early warning system, and weak safety awareness among residents faced with natural disasters, according to the municipal government.

As last year's downpour showed, such weather can cripple the road network, with rainwater forming on overpasses, submerging vehicles and threatening drivers' lives.

It can also threaten the lives of thousands of migrant workers living in the basements of high-rises and people living in dilapidated houses on the municipality's outskirts.

And with Beijing surrounded by mountains to the north and southwest, there is also the chance of landslides in heavy rain.

Fangshan district in the southwest of the city was hardest-hit last year, with 40 residents killed and mudslides destroying homes, roads and bridges.

Ongoing work on new subway lines also poses problems during rainy weather, as water can gather quickly at the construction pits.

Most severe

Since last year's deluge, work has started on improving the city's infrastructure to prevent flooding.

This involves a project to renovate 20 overpasses on the capital's ring roads, which saw the most severe cases of water convergence last year. The work includes building pumping stations and digging water storage ponds alongside bridges. When there is heavy rain, the ponds will take water pumped from the roads by drainage workers.

The two water storage ponds built near Fengyi bridge on the southwest Third Ring Road can store a total of 11,000 cubic meters of water.

All renovation work on the 20 overpasses will be completed by July 20 when the main rainy season begins, according to a statement from the Beijing Drainage Group. The work is expected to raise flood prevention standards on 12 of the overpasses to resist levels of rain that occur once every 10 years and on eight overpasses to withstand levels seen once every five years.

The group has also completed the dredging of 2,061 km of drainage systems in the municipality and installed safety nets for 36,000 manholes ahead of the rainy season.

To ensure that subway lines continue to operate, the Beijing Municipal Commission of Housing and Urban-Rural Development has ordered that all 307 construction pits must have waterproof walls. For those pits close to subway lines that are operating, water pumps must be installed and waterproof walls built inside the subway, the commission said.

Meanwhile, as blockages on river channels in the city have reduced their efficiency to discharge floodwater, dredging work has been continuing at 34 channels since Sept 1.

As of May 31, some 905 potential blockages in the rivers, including rural houses, dams and greenhouses, had been removed to increase their flood discharge capacity, the Beijing Water Authority said on its micro blog.

In Fangshan district, which saw the severest infrastructure damage last July, nearly all the bridges damaged in the deluge have been repaired, the Beijing Municipal Commission of Transport said on May 29.

The district has also set up warning lights at key bridges and crossroads, while commuters will receive timely warnings of heavy rain from information screens at roadsides.