trazor said:
driving a fork in will compress soil around the tines, making it more resistant to drainage, long term[/quote
^thats the funniest thing i read all day
I suggest you do some research. The act of driving a fork/spade into soil "smears" the earth together, making it resistant to water, more so in clay based soils.Ask any green keeper.
The depth that a fork will get to will do nothing to help drainage, including filling with sharp sand.
Are you seriously trying to lower the water level in his garden with a fork......