A ford-bridge is a combination of ford and bridge; it works like a bridge during dry weather and like a ford during infrequent floods.
In a wide ephemeral stream, a ford-bridge looks like a ford, but it has a relatively small bridge designed to pass the mean annual flood. The ford-bridge can span the entire width of the river. There is no need to constrain the river in any way and there are no bridge piers to scour during floods. Yet, most of the time, usage of the ford-bridge will be similar to that of a small bridge. Essentially, the ford-bridge looks like a ford only when needed; at other times, the focus is on the bridge. Thus, for wide ephemeral streams in arid regions, the ford-bridge concept offers a unique combination of functionality and economy.
Given the right set of conditions, the ford-bridge affords a practical and useful alternative to a bridge or ford. It is applicable to wide ephemeral streams, particularly in rural areas, where traffic is light and resources may be limited. Its design optimizes the occurrence of hydrologic loads, using the bridge for floods up to 2-yr frequency and the ford for floods of 100-yr frequency and larger. Thus, the ford-bridge concept is a sustainable economical solution to stream and river crossings in arid regions.
