Yes, 2011/12. The problems then were not so much to do with the sea-level than forced water release from the dams within the Chao Phraya river basin system after months of extra high rainfall from a strong SW Monsoon, as well as tropical depressions delivering even more rain late in the season. Earlier release of reservoir water would have helped but then there is a risk of not having enough water reserved for the following year, if there is no late rain.
The Chao Phraya does not drain well due to sandbars near Bangkok, and is tidal up to just past Ayutthaya so drainage slows or stops as the tides flood. Spring high tides can cause local flooding in any case.