None of those are a problem if you're talking about building a canal. From my previous experience, 80% to 90% of the cost of building a fiber network is constru

None of those are a problem if you're talking about building a canal. From my previous experience, 80% to 90% of the cost of building a fiber network is construction, especially digging ditches, hanging poles, etc. Materials account for the remaining 10%-20%. RoW costs are not included. IIRC, the materials cost for building long haul fiber is a couple dollar per meter or less, especially in China. If you're already building a massive structure like a canal, embedding conduits into the infrastructure is a tiny marginal cost. And Fiber maintenance is very, very low in protected environments (such as the electric-fence protected canal). Not only that, you could easily build two conduits, one on each side of the canal, creating route diversity. So for laying hundreds of miles (let's say 1000km) of fiber where construction is already happening, the total cost would be a few million USD.