An overhead view of Arsenal Park. The long red building is the Arsenal Mall, and to the left is the Commander’s Mansion and the Arsenal on the Charles complex. A public-private partnership between the Town of Watertown and the developers of Arsenal Yards, which was to speed up renovation of part of Arsenal Park, has ended, Town Manager Michael Driscoll announced Tuesday night. A disagreement over a construction management fee that Boylston wanted to charge the Town to oversee the construction was the main sticking point, according to Driscoll, who read from a letter from the Town’s attorney Mark Reich of KP Law. “Of particular concern, and the primary impetus for this letter, is the insistence of Mr. (William) McQuillan that the Town pay Boylston Properties a 5 percent construction management fee as part of the proposed public-private partnership,” the letter reads.