How are pipelines built under rivers?

 The pipeline installation companies that transport oil and gas throughout the country sometimes have to cross rivers. During pipeline installation, pipeline companies are aware of the importance of protecting these rivers. Advanced technology methods are used to drill a path under the rivers. In order to effectively implement a project of this scale, many factors must be considered, such as marine ecology, geological hazards, and environmental impacts.

Following should be considered before installing a pipeline under the rivers:

Route survey - Facts need to be gathered including topological surveys.

Transporting material on-site - Identifying ways to transport the pipes and fittings.

Strength of the seabed - The pipeline may bend of the riverbed is uneven. If it’s not too strong the pipeline may sink. Similarly on a rocky riverbed, trenching would be expensive.

Leakage or repairs - It is important to check for any underground pipeline leak at the joints. Also restoring the land post pipeline installation.

Other environmental concerns can be 

Landslides caused by earthquakes

Tides and waves can cause trouble in laying the pipes

Issues related to the ice like stamukhi and strudel can remove the soil and make the structure vulnerable

The under river pipes are designed to accommodate fluids at very high temperatures and pressures. Trench-less technology is used to provide riverbank stability. 

Here are the steps involved in installing pipelines under rivers.

Step 1: Transporting the equipment - Temporary bridges might be required to be built to transport material to the other side. The refueling activity must take place at a distance from the river bed to avoid contamination of water. Once the pipelines are installed the same need to be removed.

Step 2: Clearing vegetation - In order to build bridges or install pipelines the vegetation around the river bed must be removed. In the case of a rocky riverside, blasting must be done to remove the rocks so that they do not cause an underground pipeline leak.

Step 3: Flume pipes - Installing enough flume pipes of adequate size in the stream to handle the highest anticipated flow.

Step 4: Building a dam - Creating a dam by placing sandbags at each end of the proposed trench isolating the water from the construction site.

Step 5: Trench - Once the area is dry, the trench will be dug.

Step 6: Restoration - Once the trench is ready the riverbed will be restored with its normal flow. 

Step 7: Horizontal Directional Drilling (HDD) - The drilling process has three stages.

Pilot hole drilling - Preparing a directional path by drilling a pilot hole. Monitoring systems are used to track and direct the drilling string's path. 

Enlarge the pilot hole - The enlargement will ensure that the pipe fits the hole. This is done with the help of hydraulic cutting and hydraulic motors.

Size correction - HDD unit pulls pipe through the hole.

Adopting the above method for pipeline installation, companies can minimize the impacts of sedimentation. However, post installing the pipelines, the pipeline installation companies must ensure to maintain the pipelines. Over a period of time, these pipelines can get affected therefore timeline monitoring for any underground pipeline leak should be done. Raci provides services to keep track of these pipelines. One can not zero down the impact of the whole exercise on the water body or the aquatic life, but using the above method helps in minimizing the impact.