This was no Tinker Toy study. The models took place in structures the size of a footfall field, and the reproductions of the river currents included compositions from both salt and fresh water sources, tides and erosion factors that were as close to realities as was possible to create.
Those of us who used the river at the time became accustomed to the evidence of the ongoing study by the presence of information-seeking floating tubes recording data over what I recall to have been more than a year.
What we make of what we see is but part of the whole. Causes are complex, but we seem to have fewer problems at Plum Island and at the river’s mouth when the jetties are solid than when they are not.
What we know of Plum Island’s history is that it is a barrier island, as is Salisbury beach, and barrier islands are restless. What seems to be at the moment is by no means what it is likely to be over time. That is why we, for the first time since the groins were installed in the early 1960s, see the beach at the center as it was then.
What seems to be effective for relatively short-term relief is the restoration of the condition and height of the north and south jetties. What the study produced was data relative to changing conditions that can be used as a base for whatever engineering can do to respond to the realities presented by nature and by ourselves.
What we did not learn was whether the research had modeled the suggestion concerning removal of the rock bed from the river at the Toothpick.
Building on barrier beaches is to likely to assume considerable risk. We forget that during periods when healthy beaches beckon.