Water System

I have a unique situation I need some advice on. I have a lake place and pump water from the lake to my house. The house sits about 30 ft above the lake level. I need at least 7 gpm to make my filter backwash work properly. The system I had in place was a 1hp one line jet pump at the house with a 40 gal pressure tank and a ½ hp jet pump on my boat dock with a 8 ½ gal pressure tank that I used as booster. My pump on the dock needs replacing it or replacing this whole system if there is something more efficient. I have only 110 at the dock and am reluctant to put 220 down there. Also the lake board will not allow a submersible pump. Given all this what can anyone suggest?