$**$SOLUTION $=1\mathrm{.}36\%**$ The approaching velocity head is often assumed to be negligible when computing the discharge of overflow spillways. Is this a reasonable assumption? Even on a small dam, it is not unusual for the spillway width to be at least $20$ ft and the spillway approach channel to be $10$ ft deep not including the static head. Using a typical discharge coefficient of $3\mathrm{.}5$ and $3$ ft of static head, determine the percent error in the calculated discharge that occurs when the velocity head is ignored. $($Note: Use the discharge from the solution ignoring approach velocity to determine the approach velocity head.$)$