Environmental Insight with a Touch of Real Science

by Don Flora (a real scientist)

Some More Things We All Knew, But Apparently Didn’t

We’ve been told and told again that floats and docks and stairs and bulkheads out on the beach are deadly for the health of Puget Sound in general and our nearshores in particular.  Very persuasive, what with pictures of sunsets and all.  We’re so sure it’s true that we’re spending hundreds of millions of dollars and volumes of rules and endless hours of ‘education’ to stop these lethal degradations.  The badness is there, widely proclaimed, and we shall smite it.

Last month’s article pointed off in a different direction.  Some new information, from the shores of Easterly Kitsap and Bainbridge Island, covering more than 200 sections of nearshore, indicates that shore-protecting bulkheads have no discernable effect on nearshore habitat for forage fish, eelgrass, inter-tidal seaweeds, kelp, and geoduck beds.  An index of habitat welfare that includes all of these factors has almost no correlation with the extent of bulkheading. That conclusion was demonstrated with a diagram.

The same data sources are the basis for some more no-harm conclusions.  One is that bulkheads that protrude onto the beach are as benign as bulkheads flush against the bank.

Another is the effect of docks and floats on habitats. The analysts didn’t rate docks, presumably because of their low impact.  However, floats and ramps were given scores.  Are these over-water structures associated with habitat harm?  NO.

Yet another is that the total of a whole group of seemingly stressful human-installed fixtures (over-water structures, groins, ramps, floating structures) plus human-created conditions (dredging, bare backslopes, impervious upland), does not explain the variation in habitat conditions.

An index of nearshore habitat welfare is plotted against a composite rating of stressors nearby.  Each point reflects a beach segment on Bainbridge Island. The graph looks much like last month’s dealing with bulkheads.  A narrow band of dots, running from upper left to lower right would indicate negative correlation between stressors and habitat.  But there is wide scatter and no trend, hence no correlation.

As with bulkheads, these conclusions are supported by statistical analysis, and they are startling.

  • First, they suggest that natural, not human-caused factors drive the welfare of nearshore habitat.
  • Second, they raise serious questions about the relevance of restoration. Return of shorelines to some presumed historic character is high-order business to the Department of Ecology, to be implemented by local shoreline plans. Restoration implies removal of harmful structures and conditions, but apparently they aren’t harmful at all.
  • Third, no net loss of shoreline functions, an admirable if simplistic goal, appears irrelevant if shoreline activities and structures are benign.
  • Fourth, equally irrelevant are human-caused ‘cumulative impacts’ if no impacts are occurring.
  • Fifth, lack of correlation between ‘stressors’ and habitats mean that adding cultural features doesn’t hurt.  Neither does it help habitat. I’m not sure where this leads, but it clearly shows that if the natural world is hurting itself, healing will require something other than tearing out bulkheads and other useful structures.  We may be looking for creative ways of protecting parts of the natural world against their own self-injury.

In any case, here we are, discovering that some nearshore doctrines we were sure of, to the point of making policy about them, are rather dubious.

Editor’s Note:  There is a related story by Christopher Dunagan in the November 20 edition of the Kitsap Sun. The article entitled Corps of Engineers to Begin Devising Ways to Restore Nearshore Habitats, deals with ongoing effort by the US Army Corps of Engineers. It is interesting to note that this effort appears to be in progress paralleling, but separate from, the planning effort being completed by Puget Sound Partnership.

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