Problem $1\mathrm{.}5.$ A paved parking lot section has a uniform slope over a length of $100$ m $($in the flow direction$)$ from

the point of a drainage area divide to the inlet grate, which extends across the lot width of $30$ m $.$ Rainfall is occurring

at a uniform intensity of $10c\frac{m}{h}r.$ If the detention storage on the paved section is increasing at the rate of $60\frac{m^3}{h}r,$

what is the runoff rate into the inlet grate?