Stream Restoration: A Source of Liability?
In a lawsuit recently filed in Whatcom County Superior Court, Washington, property owners allege that a project on an adjoining property is causing increased flooding. While the suit is in early days, with only a complaint and one answer filed to date, and with the factual situation not yet entirely clear (at least to me), I think it worth following for those involved in restoration work.
Streams and rivers are fickle beasts with minds of their own. Stream flow is the architect of its own channel, to paraphrase the great geomorphologist Luna Leopold.
In Shuksan v. Whatcom Conservation District the complaint alleges at paragraph 10 that "[a]n important feature of the new channel was that it was designed to convey 'bankfull' flows but not higher flows." The answer of the conservation district is, in part, that "[t]he District admits that paragraph 10, provides a generally accurate description of design specifications that speak for themselves."
It is generally thought that "bankfull" discharge will occur about once every two years in a natural channel whose bed and banks are composed of materials that the stream flow has transported in the past and will transport again in the future. So, if one sets out to restore a channel to its natural condition, one would most likely seek to recreate a channel sized to just carry "bankfull" discharge. If so sized (and much effort has been expended in how to determine this size by folks doing restoration work), that stream channel will flood over its banks every couple of years.
Now there are almost certainly complicating issues in Shuksan that the highly accomplished attorneys involved will suss out to great effect. This writer takes no position on who will or should prevail in this suit. The point for me is the more general issue: a stream restoration is not essentially a flood-control project. Flooding can be an issue with a restoration project.
Updates will follow as warranted.