Without knowing the actual local procedures used by the company we can only surmise that having a departure and climbout path that has to cross an arrivals and approach path is not the greatest idea unless you have planned vertical separation as well.
Ie, arriving aircraft stays at 300' until he has positively identified departure aircraft and departing aircraft climbs to 200' until positively clear of the arrival path.
Having no crossing would be ideal but sometimes the wind conditions probably won't allow for that.