A carbon footprint is the amount of carbon dioxide (CO2) released into the atmosphere as a result of a construction activity. It includes emissions from construction equipment and vehicles that are affected as a result of traffic jams created by road closures due to construction projects taking place in the area. Trenchless construction methods such as horizontal directional drilling (HDD), horizontal auger boring (HAB) and microtunneling utilize sub surface drilling techniques that result in lesser carbon emissions than traditional open-cut methods.
An open-cut method of pipeline installation requires a lot of digging and moving of cut earth and asphalt. The dug up area is much larger than the pipe diameter in order to allow for easy installation resulting in the need for many truck loads of dirt to be moved away. After pipe installation the trench needs to be backfilled and the road has to be paved again. The entire process utilizes a lot of energy in the form of fuel resulting in greater carbon emissions.
Trenchless methods such as HDD, HAB and microtunneling on the other hand only require minimal digging at the entry and exit pit for the sake of launching and retrieving machinery and pipe. The entire length of pipeline excavation is carried out underground and the excavated mud is slightly more than the pipeline diameter. In addition to this there is no need for backfilling of trench or paving asphalt as the surface is relatively undisturbed. Carbon emission in the case of trenchless construction methods is much lower than that in open cut method.