Goblin siege, my goblin traps (square constructions filled with stone traps and kittens, abusing goblin hatred of all things cuddly) wiped out the southern and western groups, leaving the large groups from the north and northeast, which met up and formed a giant goblin horde. Opened the door to my cistern , they thought they could get in the fort through the escape stairway but I also opened some floodgates to shunt the water from a few less than necessary pools to flood it to 7/7 as they entered. Sealed it off, good thing I have a secondary cistern because this one is about to get tainted.
A small cluster of goblins ran, launched ballista down predictable one tile wide escape path, three goblins down and xp for siege operator, VICTORY! Also uncovered a bituminous coal vein while strip mining the last chalk lair I have, probably the last one I'll find in this fort.
Next plan is to start constructing a large watchtower over my bigger cistern complex, going to pump some water up in it and make a level devoted to a retirement center for my Dwarven Veteran's Association, gotta keep the royal guard healthy. Will also install a recruit barracks and an archery range below the top, which will be converted into my primary ammo stockpile. After this is set up the barracks areas in my main fort are going to become high income housing, storage space, dining areas, and shops. Ideally the tower will let my military dwarves be almost entirely self sufficient, with my militiamen haulers bringing food and other supplies during peacetime.