Bridge over the Tyne at Bywell - geograph

A flood arch is a small supplemental

arch bridge An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side. A viaduct ...

provided alongside a main bridge. It provides extra capacity for floodwater. The space beneath a flood arch is normally dry and often carries a

towpath A towpath is a road or trail on the bank of a river, canal, or other inland waterway. The purpose of a towpath is to allow a land vehicle, beasts of burden, or a team of human pullers to tow a boat, often a barge. This mode of transport w ...

or similar. In some cases it borders on the shallow edge of a river, but this does not carry substantial flow in normal conditions. A bridge with multiple arches across a flowing river would instead be termed a viaduct. For some bridges, flood arches were added after the first bridge had been constructed, often after initial flooding. Pant-y-Geotre Bridge - geograph

References

Arches and vaults Bridge components {{bridge-type-stub