The historic flooding that occurred in 2011 in central Thailand revealed fierce struggles over flood protection, which were made particularly complex because of the unruly nature of water itself. The interplay between two forms of infrastructure, each of which shape the flows of water coursing through the Chao Phraya Delta, is key to understanding this complexity. As an ambiguous place in between the sea and land, a delta environment can be seen alternatively as an extension of the sea or as reclaimable land. Constructing infrastructures based on either of these views remakes the landscape accordingly—thus making the landscape more terrestrial or more aquatic. In the Chao Phraya Delta, the terrestrial infrastructure, which consists of road networks and land-based urban living, has been overlaid on a pre-existing aquatic infrastructure characterized by canal transport and flood adaptive architecture. Mainly due to state interest in facilitating water transport, the aquatic infrastructure organized the landscape of the delta until the mid-twentieth century. However, since then the introduction of modern irrigation has progressively rendered the delta landscape more terrestrial. Dry land created by the irrigation system made modern forms of agriculture, commerce and industry possible. While this terrestrial trend seemed to take over the entire delta, the terrestrial infrastructure did not eliminate the aquatic one. Instead it created a dynamic interplay between different forms of infrastructure. The 2011 flood foregrounded the centrality of this interplay in flood protection and sheds new light on the role of the aquatic infrastructure.