Not sure I can agree on that.
But the fact is that area from Tap Sakae to Chumporn and further south is the flooding central every year. As soon as the rain hits the mountain range the runoff cause severe flooding in some areas. Mainly Chumporn.
Here in BS after severe flooding some years back, and due to Royal intervention, they have installed some drainage and additional water runoffs. Of course, being open they were used by Thais as garbage disposal, just like in Bangkok, and now the work is being redone with proper covert culverts and as a bonus they are widening some roads, redoing the surface, installing lights, and central dividers, which I for one do not understand the reason for. Just asking for accidents by all drunks driving at night....
Or perhaps it's in preparation for this Sattahip to Hat Yai car ferry.... One stop on the way was supposed to be Bang Saphan.