2012 we bought an orchard property at the end of its useful life 8km from Chanthaburi, reasonably flat at the base of the adjoining rubber tree plantation seen in the background.
Ms P works for a roading engineering company, very useful, and we were able to get advice and planning for development of the area in terms of drainage and suitability for housing, involved bringing the area up to a level 0.5m above the high/mid point of the sealed road across the frontage. First had it brought to level using existing soil - grader and tractor all at minimum cost, compacted, then added a further approx 400 cu. m of clay, again compacted rather than what seems to be the usual 'leave it to settle over two rain seasons'.
Didn't go ahead with the planned house build, had an 'offer we can't refuse' in 2017 and accepted that, bought an existing house instead. While we're not in a flood-prone area the house is on a built-up section, and floor level 0.8m higher, safe enough till Noah floats past in the ark.
Now the former orchard has been subdivided with multiple houses, looks good. It was the right decision for us, as on the 'wrong/inland' side of Sukhumvit Rd.