A subsurface detention basin is installed beneath a street to help prevent flooding. Water from the rain is chanelled into the basin and begins to infiltrate into the ground when it reaches 1ft. The water table sits 29ft beneath the bottom of the basin and the soil in that distance consists of urban fill. The hydrauic conductivity of the soil is 139ft/day and the dimensions of the tank is 78ft by 13ft. What is the infiltration rate? How long will it take to empty the tank?