River Spean

The river looks pretty benign today but the washed up debris tells a story. That this section of river exists in a broad channel but can yet have huge limbs of trees deposited so far from the main channel conveys a scary scene. Such flow is probably the result of both dams upstream (Laggan and Treig) spilling, sustained heavy rain run off from mountains and perhaps some snow melt in the mix. Every construction development we see these days seems forced to address the flood risk from the 1 in "x hundred year event" plus another percentage safety margin.
If you build on flood plain and occupy storage volume where water could otherwise wait then a compensatory void (hole) must be created elsewhere nearby. Bridge openings, narrow gorges can have a restrictive effect on water escape in the severe situation and may cause flooding upstream and mitigate downstream. Our survey software has special export filters pandering to the specialists who can make use of our survey data for flood modelling.
I am often surprised to later learn the results, that an apparently safe site may well flood when the data is analysed.

This survey wasn't for FRA.