An existing levee has a top width of 10 feet, a top ele- vation of 10 feet above the base, and 3: 1 (horizontal: vertical) slopes on both sides. if the levee is to be raised to an ele- vation of 15 feet and must meet new standards requiring a 12-foot top width, how much additional land space (in ft2) will be needed for the base of the levee per mile of levee length? assume side slopes remain 3: 1. show all work, and support your answer with appropriate drawings and schematics