Complex sentence: In dry weather, drivers become aware of a ford by crunching across outwash detritus on the roadway, and a Bailey bridge off the main line of the road to carry emergency traffic during high water.
Split into simpler sentences: In dry weather, drivers become aware of a ford by crunching across outwash detritus on the roadway. A Bailey bridge may be built off the main line of the road to carry emergency traffic during high water.