Since the route design phase and given that the pipeline intersects 19 rivers and 8 drainage canals, TAP identified the steep mountainous terrain and the major river crossings as the main construction challenges in Albania.
The Seman and Osumi Rivers are the two main rivers crossed several times by TAP. The Seman River (281 km long and up to 200 m wide) is crossed twice, while the Osumi River (161 km long) is crossed 12 times. The longest pipeline crossing has been completed across the Osumi River, near Çorovoda, where the stream is 1.3 km wide. River-crossing operations are carried out hundreds of meters from each side of the river.
TAP used micro-tunnelling technology for five of the longest and most complex crossings of the Osumi River. A tunnel boring machine excavated under the river bed followed by concrete lining in segments. Following this step, the welded pipes were pulled through the tunnel.
TAP carried out the crossings of the two longest segments of the Seman River using Horizontal Directional Drilling (HDD). This method uses progressive drilling probes to bore underneath the river bed. The welded pipe is then pulled through the tunnel.
Underground tunnels have also been bored for the pipeline to cross less complex rivers and small canals, without any impact on river stream or ecosystem.
As for the entire pipeline construction process, TAP has applied the highest international standards and used state-of-the-art technology for the river crossings. All river crossings have been carried out under the surveillance of TAP and its contractors’ environmental experts.