When a federal agency threatened to do what no storm has managed in 375 years — wreck Portland’s working waterfront — local officials and members of Congress pushed back.

Now that it seems their effort has paid off, and the Federal Emergency Management Agency appears ready to redraw its flood maps allowing development on both sides of Portland Harbor. That’s good news, but the question remains why FEMA needed so much pressure in the first place.

FEMA is engaged in redoing its flood maps for portions of the East Coast to better protect life and property. While that is a valuable goal it initially wanted to put Portland Harbor in a “V” or velocity flood zone, which would have prohibited new construction and made it nearly impossible for existing structures to get flood insurance, all but ending investment in improvements. The working waterfront would be left to wither and die.

U.S. Rep. Chellie Pingree wrote a letter to the head of FEMA in August, making an important point. “Portland Harbor is not on a barrier island nor is a community built on shifting sand or even one walled off from the sea by levees,” she wrote. “(It) is a waterfront community with hundreds of years of history and development.”

Sen. Susan Collins, who serves on the committee that oversees FEMA, also used her influence.

Portland’s planning director, Penny St. Louis Littell, and Fire Chief Fred LaMontagne provided important information that has apparently made FEMA officials re-think part of their designation for Portland, but the question remains: Why is this powerful federal agency relying on municipal officials to show them where they went wrong?

Even a postcard from Portland would show that it is a city built around its harbor, and it has been here for quite a long time. Local officials should keep working on these negotiations, and FEMA authorities should try to use a little more common sense when they make designations that would have such a powerful impact on Maine’s biggest municipality.