Protecting the Highway Infrastructure from Flooding

Depletion of ozone layer and greenhouse effect as a result of high level of carbon emission in the air present a serious global threat.

Warming of climate is evident from increases in global average air and ocean temperatures, widespread melting of snow and ice, unprecedented flooding around the world and rising global mean sea level. We have already started seeing and might see more in future, falling crop yields in many areas, particularly in developing regions, depleted water reservoirs, sea level rise threatening many cities, very high intensity of storms, forest fires, droughts, flooding and heat waves.

The increased frequency of flooding is raising the public awareness of the importance of effective surface water drainage and the need for greater protection of property and life.

The role of engineers in protecting environments and ensuring sustainable infrastructure development is very important because engineers can use creativity, technology, and scientific knowledge to solve practical problems. Engineers seek to minimize adverse impact on the environments during construction as well as operation phases.

Heavy rainfall and high floods in the rivers are playing havoc with the highway infrastructure along with the widespread devastation of lives and properties. A few impacts on highway infrastructure are:

• Premature failure of highways
• Greater build-up and mobilisation of surface pollutants in the summer
• Increased likelihood of erosion at the road edge or in the associated drainage system
• Higher groundwater levels resulting in more road pavement failures or landslips
• Greater quantities of vegetation that may block or fill drainage systems.

Potential Solutions for Protecting Highway Infrastructure

To address these impacts planners, engineers and technicians will need to develop highway drainage systems that accommodate the increased demands of the climate. Potential solutions include:

• Undertaking flood risk assessment of all highway infrastructure development schemes
• Provision of reasonable allowance for global warming/climate change in the drainage design
• Keeping the level of highways embankment adequately above the expected highest flood levels
• Adequate protection of berms and batter slopes
• Providing greater numbers of rainfall collection units
• Increasing the size of pipes, culverts and ditches to reduce the likelihood of their capacity being failed
• Assessing the combined capacity of the road and drainage systems to accommodate extreme storm events
• Greater use of porous/pervious surfacing materials
• Attenuating and controlling flows in highway drainage systems
• Providing additional balancing ponds-attenuation facilities adjacent to the highway.
• Provision of Sustainable Drainage Systems (SuDS) on highways