The Poddle, which once supplied water to the medieval city and filled the moat of Dublin Castle, has been culverted and buried for much of its course. But in 1990, excavations along its east bank turned up something that quietly rewrites the texture of everyday medieval life: a length of post and wattle revetment, over eleven metres long and roughly sixty centimetres high, constructed directly on the surface of the river silt.

A revetment, in this context, is a retaining structure built to stabilise a riverbank and prevent erosion or collapse into the water. What makes this particular example notable is the method and the moment. Rather than being driven into the ground in the conventional manner, the structure was built free-standing, sitting directly on the silt of the Poddle's east bank. Dating to the thirteenth century, it represents a period when Dublin was expanding rapidly under Anglo-Norman administration, and managing the watercourses that ran through and around the city was a practical necessity. The post and wattle technique, familiar from domestic building of the same period, was here applied to infrastructure. At some point, the wattle structure was replaced by a stone wall, suggesting the site saw continued investment in bank management over time. The details were published by Walsh in 1997 and remain the primary record of the find.

There is nothing to see above ground today. The Poddle runs underground through this part of the city, and the excavated revetment itself is long since recorded and gone. What a visitor can do is trace the river's approximate route through the south city, where its presence occasionally surfaces in street names, in the topography of older laneways, and in the slightly sunken quality of certain ground. The area around Dublin Castle and the Coombe sits above this buried drainage network. For anyone interested in how medieval cities actually functioned, the Poddle's management, the channelling, the banking, the periodic upgrading of its edges, is a reminder that urban infrastructure in the thirteenth century required the same kind of incremental, practical problem-solving it always has.