You could probably bury a cistern and pump it in there for use with a sprinkler system...you could run the overflow to your drainage easment, if it ever filled up. You really should consider making sure that the soil slopes away from the house for at least the first 6' or so. If you did that, you might slow down the flow into your sump. Also, run your gutter downspouts away from the house. Maybe also put in dry wells or run them to your cistern, if you decide to put one in. Make sure the tank doesn't leak, or you may end up pumping thatwater many times over...my unprofessional opinion.