Siting and impact studies for the construction of a gas pipeline

Siting & Permitting Industries Turkey

Context and challenges

Extending for 1850 kilometers with 56” diameter pipes, Trans-Anatolian Natural Gas Pipeline is the longest and largest-diameter natural gas pipeline in Turkey, the Middle East and Europe. It passes through 20 provinces, 67 districts and 600 villages. The construction of the project was initiated in 2015. In 2018, gas transmission started.

This client, an oil and gas company, is to carry an annual volume of 6 billion cubic meters of Azeri natural gas to Turkey via South Caucasus Pipeline (SCP), and it is to form the Southern Natural Gas Corridor with the Trans-Atlantic Pipeline (TAP) to deliver 10 billion cubic meters of gas per annum to Europe.

The transmission capacity of the pipeline is capable of increasing to 24 billion cubic meters, and then to 31 billion cubic meters upon realisation of additional investments in 2026.

This client has appointed Assystem Envy to perform site surveys (siting and impact studies) including physical and ecological monitoring and environmental samplings.

Project scope

The site surveys include physical and ecological monitoring and environmental sampling (physical studies, air quality, water quality, soil quality). In this scope, Assystem conducted the following activities:

  • Environmental monitoring surveys for:
    • Air quality and water quality measurements at 6 stations of the client
    • Monitoring of forestation areas
    • Monitoring concerning the rehabilitation of some locations which have erosion risks
  • Ecological monitoring on:
    • Critical habitats (terrestrial flora, terrestrial fauna on critical habitats and freshwater aquatic fauna on river crossings)
    • Important species, vegetation & species diversity surveys in 67 critical habitats

Environmental and ecological monitoring of camp sites and pipe stock areas


  • Reduction of potential risks during pipeline operation
  • Visibility and transparency related to project advancement thanks to monitoring of achievement progress in relation with post-construction goals with on-site tracking
  • Rehabilitation of all areas in time (campsites and stock) thanks to monitoring the progress of actions on-site, which includes delivery of reports to the client
  • Effective protection & monitoring of species conservation concerned (endemic flora species, fauna species under risk or that have the potential to be under risk) and critical habitats defined in the Biodiversity Action Plan of the client thanks to surveys performed
  • Compliance with Equator Principles, World Bank, MIGA(1), IFC(2) and EBRD(3) international environmental standards

(1)Multilateral Insurance Guarantee Agency, (2)International Finance Corporation, (3)European Bank for Reconstruction and Development

in figures


Assystem Envy collaborators involved


professors from universities