We can’t control the weather but proper drainage can facilitate the rapid removal of storm water from airport surfaces. Although some conditions are regional or seasonal, effective drainage prevents standing water which can ultimately delay and cancel flights.
Of course, the more surface area there is, the greater the amount of rainwater that is displaced. It all has to go somewhere that is practical and doesn’t create residual issues such as erosion or unplanned ponding areas.
County airports support small single and twin prop aircrafts. Pre-sloped 4” wide trench drain systems are found on taxiways and in front of the hangar doors. Loads are light (Class D) so these drains tend to use ductile or cast iron grates without reinforcement.
Municipal airports are a little bigger with aircrafts that may include some light commercial crafts. Hangar doors will use 4” wide trench drain but will require reinforcement. Along the taxiways, 8” and 12” wide pre-sloped drains with Class D and E grating is recommended.
International airports deal with heavy equipment and acres of concrete surfaces that need to be drained quickly in the event of a storm. Drainage systems usually have Class E or F load ratings and grates with 2-point lock down systems. Trench drains designed for large flow capacities use grates with a high percentage of open area along with wider trench dimensions; it is not uncommon to see 12 inch wide trenches that reach 3-to-4 feet deep.