Immediately after Sandy two years ago, newspapers and elected officials suggested that the region should build a massive barrier across New York Harbor to prevent the next big storm from causing havoc.

These gates had been built in the Netherlands, England, Russia — and even Stamford, Conn., and Providence, R.I. But the idea has gradually lost favor.

First, then-Mayor Mike Bloomberg deemed it too difficult to build and recommended instead a sweeping suite of other protections such as temporary flood walls and salt marshes.

Now comes the U.S. Army Corps long-awaited $19.5 million comprehensive study of the Northeast Coast, first commissioned in the federal Sandy aid bill. It did not address the harbor-wide, storm-surge barrier explicitly, but in a matrix it gave gates low marks for their ability to adapt to sea level change (e.g. to grow higher over time). It also said barriers do not do anything to help with erosion, and have few ancillary benefits, such as developing fish and wildlife.

By contrast, even though the Army Corps is often criticized for favoring hard engineering over natural solutions, the report gave favorable mention to strategies such as oyster beds and wetlands restoration.

The multi-volume report, however, is not the final word. Instead, it is a document meant to guide future study and collaboration with state and local governments. It also mentioned several instances where smaller storm surge barriers are being proposed — across the Gowanus Canal and the mouth of Jamaica Bay, for example. And the same study did note the barriers’ ability to prevent flooding is much higher than those natural solutions.

“There is no magical silver bullet," said Joe Vietri, the planning and policy chief for the Army Corps’s North Atlantic Division. “None of them by themselves are really the correct answer. It’s really a combination of things. And depending on where you are, the combination of things may shift.”