A rainstrom lasts for 90 min at a constant intensity of 3.2 in/hr over a five acre parking lot. a detention pond is used to store all of the runoff from the parking lot and cannot be deeper than 2 ft. how many acres should the detention pond be to store the runoff from the parking lot. assume it takes 0.1 inches of rain to coat the parking lot surface, there is no inflitration from, or puddles on, the parking lot. Hint: set up a continuity expression for the pond with a variable surface area and solve for area.