Sump Pit or Rain Catcher

220 mm/h equals 2200 cubic meter of water per hour per ha (100m x 100m).

More detail is required

You do not indicate your location. From the very limited description you have provided, and assuming the basement is not dedicated to other purposes, you might want to consider using it specifically as a cistern to accumulate rain water for human consumption. Unless you live in a heavy metropolitan area with a lot of air pollution. Even here in Panama, with some areas registering over 400 inches of rain a year, catching and storing rain water is becoming more and more critical...

you'll need a pump - and back-up power. check www.onstatpower.com

If you have an area that is lower than the sump you can install a "French Drain" to conduct water to that area. If not, you will have to pump it to somwhere that IS lower. Water only flows down-hill. Unless, of course, you can convince B.P. to share the technology they used to "siphon" fluids one mile up-hill.

I would let the sump pump specifications dictate the sump size. It must be deep enough to prevent the pump from creating a whirlpool and cavitating, but still keep the motor dry. It should hold enough water for the pump to have a duty cycle that is not too short. You don't want your pump short cycling, the motor will overheat.