Voclanic ash was removed from this drainage canal at Clark Air Base in the Philippines to permit the free flow of water. The 1980 eruption of Mount St. Helens demonstrated the importance of preventing as much ash as possible from entering storm drainages and sanitary sewers in order to limit ash from invading waste-water treatment facilities. Residents must help in preventing ash from entering the hundreds or thousands of storm sewers, "manhole" covers, and storm-drainage systems in their community, especially during clean-up operations.