NewburyportNews.com, Newburyport, MA

March 1, 2013

The ebb and flow of Plum Island

Bill Plante's North Shore
Newburyport Daily News

---- — Friend Gene Smith called to tell me on Wednesday that northeast winds were beating the bejabbers out of Plum Island once again; and after we hung up, I was reminded of that old truism that the more things change, the more they seem to stay the same.

Seems so in the lifetimes of those who have spent much of their lives at Plum Island, but ...

The ocean has been beating up on it since it was formed following the retreat of an Ice Age that began some 12,000 years ago. It’s not just an island. It’s a barrier island, and that makes for problems for those on and behind them at risk.

That took some making over centuries, because if what I have been led to understand is accurate, what passed for the coastline then was more than 20 miles seaward at Stellwagen Bank.

It’s fair to say that northeasters beat up on whatever the shorelines were up and down the East Coast before the barrier beaches of Salisbury and Plum Island we know today were formed.

Be that as it may, we tend to respond to what we live with and I have been doing that here for just short of a century.

One of the things I was able to do by way of my time with The Daily News was to call our then Congressman William H. Bates shortly before he died in office to ask for help regarding the need for an engineering study concerning the relevance of the Merrimack River’s relationship to Plum Island’s erosion problems.

I had been playing with the idea that if the rock bed in the river at Ben Butler’s Toothpick were removed, perhaps the outward river current would not be diverted toward Plum Island, thereby keeping the river channel between and beyond less prone to buildup.

That call would have been during the time relating to the rebuilding of the jetties, accompanied as always by differences of opinion relating to the why and wherefore of their relationship to beach erosion.

The congressman did as I asked, and some weeks later, I received a telephone call from the Army Corps of Engineers regional commander asking what I had in mind. I told him what was needed was research relating to the river’s currents and their effects under all conditions as related to the shorelines at the river’s mouth and the beaches beyond.

He said that calls for study instead of reconstruction was considerably different from the usual kind of request for definitive action to overcome a problem.

Just as we were about to end our discussion, he surprised me by asking whether I had been a Corps of Engineers platoon commander at Ft. Belvoir early in our Second World War. I said I had been, and the conversation took a less technical and more warming tone because it turned out that he had been a trainee in my platoon and I had recommended him as an officer candidate. He was chosen and made his service a lifetime career.

The fruit of all that transpired is contained in a Corps of Engineers report of the “Newburyport Harbor Design for Hydrodynamics, Salinity, and Sedimentation by virtue of a Hydraulic Model Investigation.”

What follows is an excerpt from the initial navigation project that began in 1880 and the details of the study of the 1960s.

The short of it is that “extensive data of currents, water depths, erosion and all related issues” was gathered. Two hydraulic models of the river were then constructed and tested at the U.S. Army Engineer Waterways Experiment Station in Mississippi to study plans designed to eliminate or minimize problems.

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.

Nature, of course, knows no limits. Our resistance to its attacks is to do what can be done by government and hope for the best. Property owners put their money down on that, and cities and towns do what they can to help, but it’s an uncertain grind.

What’s going on now is the third major contest with nature at Plum Island of my lifetime.

The difference has been the upscaling of the island’s residences. Dwellings up to and even beyond World War II were modest. Most no longer are.

Newburyport, Newbury and Salisbury have benefitted by increased tax revenues as property values have increased. Plum Islanders now have city water, so concerns regarding them are no longer just those of residents.

This season’s storms have shaken us. All things considered, they won’t be the last. Meanwhile, the south jetty is in the process of repair, but the north jetty isn’t. That will change something, but we won’t know what for some time.

That takes a lot of grit along with the expense for those most at risk. It always has been, but more is at stake this time than it was a half century ago.

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Bill Plante is a Newbury resident and staff columnist. His e-mail address is plantejr@comcast.net.