Infrastructure for Good: Construction projects that help the environment and the economy
New infrastructure can deliver environmental as well as economic gains. In the seventh edition of our construction magazine Building Sight, we look at how the construction industry is tackling environmental issues and aiding countries to reduce emissions and meet ambitious targets.
Multilateral development banks and infrastructure investors are starting to prioritize sustainable and resilient infrastructure that helps to slow climate change and protect communities from natural disasters.
It’s not just about doing the right thing: Switching to a more sustainable development model could be worth at least US$26 trillion by 2030 compared to business as usual, found a 2018 report by New Climate Economy.
“We are moving towards a new climate economy,” says Ken Chee, vice president in the Marsh JLT Specialty Construction Practice in Kuala Lumpur. “Moving forward, we need robust ways to evaluate new infrastructure projects within these emerging models.”
Here are three notable infrastructure projects from around the world:
SMART Tunnel, Malaysia
Malaysia’s SMART (Stormwater Management and Road Tunnel) tunnel in Kuala Lumpur truly deserves its name.
The 11.5 kilometers-long, 13.2 meter-diameter structure is the world’s first and longest dual-purpose traffic and storm water storage tunnel. It was constructed after conventional flood alleviation measures, such as channel widening and deepening, were no longer effective in a city that suffers regular flash floods.
As well as helping to divert floodwater away from the confluence of two rivers, a three-kilometer section of the tunnel doubles as a two-deck motorway at the main southern entrance to the city, cutting journey times into the center from 20 to 8 minutes.
When rainfall is low, water doesn’t need to be diverted into the tunnel, but in moderate storms, water flows into a bypass tunnel in the lower section of the motorway tunnel, which remains open to traffic.
In heavy storms, the road tunnel section is closed completely and, as part of the larger Kuala Lumpur flood mitigation system, the tunnel directs huge volumes of water to a storage system that can hold up to 3 million cubic meters of water.
Before the watertight gates are opened in the tunnel during a severe storm, a system of 200 CCTV cameras linked to a central control room ensures no vehicles are left inside.
After flood events, the motorway is cleaned with high-pressure water jets and can reopen within 48 hours.
Completed in 2007, SMART cost US$515 million to build but, over the 30-year concession period, it is expected to generate savings of US$1.58 billion by preventing possible flood damage, and another US$1.26 billion in savings from traffic congestion.
The tunnel diverts around 30,000 cars a day from the city center.
Mi Teleférico, Bolivia
At more than 3,650 meters above sea level, La Paz in Bolivia is one of the highest cities in the world. Its suburb El Alto sits even higher, at 4,000 meters.
Their altitude, combined with the congested, winding roads linking El Alto and La Paz presented a particular transport challenge: despite their centers sitting only 19 kilometers apart, road journeys can take hours.
To combat this problem, the Bolivian government announced the creation of the Mi Teleférico project, the world’s highest cable-car system, launched in 2014.
It currently consists of 23 kilometers of lines with 20 stations along six routes, and will eventually be expanded to at least 34 kilometers of cable with five more lines and a total of 30 stations.
Capable of transporting 230,000 passengers a year, the network is open 17 hours a day with cars departing every 12 seconds.
Aside from offering a far more efficient, quicker means of transport, the new lines are also sustainable. They have helped to alleviate pressure on the public transport system between La Paz and El Alto, which is dominated by buses, taxis, and minibus services negotiating narrow streets, creating high levels of noise and air pollution.
By contrast, the cable car system uses electrical power for its main drive and has won praise from the Bartlett Development Planning Unit, part of University College London, not just for its speed and relatively low cost of construction, but the fact that it emits low levels of particulate emissions.
Mi Teleférico has also proved a benefit for people with impaired mobility, who find the accessible system easier to use than more traditional forms of transport such as the bus network, which lacks dedicated stops.
Built by Austrian-Swiss company Doppelmayr Garaventa Group, the project has been funded by the Bolivian government and runs without the need for a grant or government subsidy.
In 2018, it reported an operating surplus of US$5.8 million.
DC Water, US
Washington D.C. has embarked on a huge US$2.6 billion infrastructure program to rid its rivers of raw sewage.
The city’s waterways are suffering as a result of its antiquated “combined sewer systems” that collects rainfall and sewage in the same pipes.
During heavy rainfall, the systems become overwhelmed and combined sewer outflows (CSOs) find their way into the local Potomac and Anacostia rivers, adversely affecting water quality. Around 1.3 billion gallons of diluted sewage was estimated to flow into the Anacostia River in an average year.
The solution was to start constructing four huge underground tunnels used to store the CSOs until they can safely be treated at wastewater treatment plants.
The project is due for completion in 2025; the Anacostia river tunnel, funded by US$1.4 billion from rate payers and government funds, has already been completed.
The CSO discharge rate is expected to fall in volume by around 80% in an average year of rainfall.
That will rise to 98% with the completion in 2023 of the US$580 million Northeast Boundary Tunnel segment, which will connect to the Anacostia River Tunnel.
Once the final two tunnels — designed to protect the Potomac and Rock Creek — are finished, average-year discharges into the Washington D.C. waterways are expected to drop by 96% overall.
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