17. How many gallons of water fall on a flat 1-acre campus from a 0.6-inch rainstorm? Convert this amount to liters. (Hint: 1 cubic inch = 0.017316 quart, 144 square inches I square foot, I acre = 43,560 square feet.) %3D 18. A certain amount of the precipitation will infiltrate into the ground, some may evaporate, and the rest will flow as stormwater runoff. (See Figure 1.2 for an illus- tration of precipitation infiltration and runoff.) a. What factors influence the degree of ground infiltration? b. Estimate the percentage of your campus that has impervious surfaces (parking lots, sidewalks, roofs, etc.). Evaporation and transpiration Precipitation 100% Precipitation Evaporation and 100% transpiration 40% 25% 10% Surface runoff Surface runoff (Includes storm sewer runoff from roads and buildings) 43%. Groundwater 50% 32% Groundwater elesn Preurban Urban (a) (b)