Black and white photograph of ten people, eight women and two men, in front of an open arched door. Taken my Merrill while attending the American Society of Civil Engineers conference in New Orleans, Louisiana.

Black and white photograph of a group of people talking in a courtyard in front of a building. Chairs are scattered around the courtyard. Taken my Merrill while attending the American Society of Civil Engineers conference in New Orleans, Louisiana.

Black and white photograph of a group of people walking along a park path lined with metal benches. Taken my Merrill while attending the American Society of Civil Engineers conference in New Orleans, Louisiana.

Black and white photograph of a group of people organizing for a group photo in front of a large building. Taken my Merrill while attending the American Society of Civil Engineers conference in New Orleans, Louisiana.

Black and white close-up photograph of a dam. Taken my Merrill while attending the American Society of Civil Engineers conference in New Orleans, Louisiana.

Black and white photograph of the dredge Empire 5522, taken by Robert Merrill looking west. Lettering is printed along the arm of the dredge reading, "Built by the Marion Osgood Company Marion, Ohio." Water damage is visible on the image, which was…

Black and white photograph of a metal bridge over a dried river bed behind a man-made dam. A building with an American flag raised is visible behind the bridge and an automobile can be seen crossing the bridge.

Black and white photograph of a hydraulic lock in Little Falls, New York.

Black and white photograph of a person standing on a hill of mining spoil in front of several buildings and a smokestack in Little Falls, New York.

Black and white photograph of a partially frozen river in the middle of a city. Buildings are visible on both sides of the river, and there is a bridge across the river in the distance.

Black and white photograph of a lock. A building is next to the lock, and a flagpole and flag are visible in the center of the image. Taken my Merrill while attending the American Society of Civil Engineers conference in New Orleans, Louisiana.

Black and white photograph of a man walking across a street lined with lampposts and trees in front of a large building with hipped roofs, columned porch, and nine visible chimneys. Taken my Merrill while attending the American Society of Civil…