Michael Brown — no, not the D.C. Councilmember, or the Shadow Senator, but the County Manager of Arlington — has resigned this morning, according to TBD’s Rebecca Cooper. Cooper reports that Deputy County Manager Barbara Donnellan will assume Brown’s position. Brown reportedly resigned to tend to family issues. Donnellan has experience with the position, having served as County Manager for seven moths prior to Brown’s appointment in May. Arlington County Manager is not an elected position; rather, the Manager is appointed by the five-member County Board.