North Wasco County School District 21 officials are examining how much damage was suffered when a broken gasket in the sprinkler system forced closure of The Dalles Middle School gymnasium.  The break occurred on Friday afternoon.  D-21 Superintendent Candy Armstrong says the district’s facilities personnel is looking over the situation, noting they think the break occurred when a ball hit a sprinkler head.  The Dalles Middle School gym has been closed to all activities and events until further notice.