Out-foxing a digging dog

Angel has a habit of digging.  I don't really care that she digs.  I do care *where* she digs.  The particular hole in question is just off the patio, in direct line of the patio door.  If the grass around it gets long, which it is wont to do, then it is hard to see there is a foot long, 3 inch deep hole in the ground as you step off the patio slab. 

I realize that it is a tempting spot to dig.  When it does rain, the water sluices off the patio roof right onto this spot, making it soft and squishy.  Even without rain, water pools in the hole from the sprinklers when the grass is watered.  No digging-inclined dog can resist the temptation.  And she doesn't resist.

Angel isn't the only canine resident with a fondness for holes.  I have never caught him actually digging.  And there are no dirty paws to incriminate him.  But I have seen Rags with his face down in the hole, lapping up the muddy water.  I yell.his name.  He lifts his head and looks at me with muddy water dripping from his beard.  What?  Did you want something? 

I've filled the hole a couple different times.  Angel was thrilled with the soft new dirt that scattered so easily.  I've even sprayed the ground with No Digg.   This actually works for a short while, until the water from the sprinklers dilutes it. 

This last time I filled the hole and covered it with a piece of wire fencing, anchored down with long hooks pounded into the ground.  I am hoping once the grass takes hold, I can remove the fencing.  If not, well it's green and should blend in.

So far Angel has not attempted to pull up the fencing.  She has chosen a new, safer spot to dig.