According to a quote on this Dailymail article the pipelines are 70-90 meters deep. A workable depth for professional divers with proper equipment. Supposedly they can also be fixed in a week. Feel free to find better sources, but it sounds like this may not be as complex as CRP suggested.
https://www.dailymail.co.uk/news/ar...uffer-unprecedented-damage-start-leaking.html
https://www.dailymail.co.uk/news/ar...uffer-unprecedented-damage-start-leaking.html