Before the Storm: Clear Stormwater Inlets to Minimize Flooding

Throughout the year, leaf litter, yard waste, trash, and eroded soil from surrounding properties tends to slowly gather on top of these drains. Overlooked long enough, this debris builds up to the point where it can block inflowing stormwater when a big rainstorm happens.

You may not give them much thought, but if you live in a city or suburban area, the stormwater inlets in your community are most likely part of a large runoff water management network that includes underground pipes, open ditches, infiltration basins, and stormwater ponds. Working together, all this infrastructure ultimately has one very important task, moving stormwater to nearby streams before it causes street flooding and basement backups.

Stormwater inlets are easy to spot once you know where to look.  Most often they are located next to street curbs but sometimes you can find them in the middle of parking lots and other low places where stormwater collects. Inlets come in different shapes and sizes, but three common types include those consisting of just a heavy metal grate set at street grade, those with a narrow vertical gap cut into the curb itself, and those that combine both types of openings. If we could peer below the surface of the street, we would see how the inlet sits above a water-tight chamber constructed out of precast concrete. These catch basins range from only a few feet deep to over 20 feet deep, but somewhere inside they will have at least one side outlet connected to a drainage pipe.  In most storm sewer systems, these pipes eventually drain stormwater into local waterways.

You can help reduce flood risks where you live by inspecting the stormwater inlets on your street to make sure they are free of leaves, branches, trash, and other debris. The best time to conduct these checks is before heavy rain or major snowmelt is predicted to happen. If an inlet is covered, or there is a pile of debris next to it, fixing the situation usually takes just a few tools and some elbow grease. Using gloves, a flat-tipped shovel, and a stiff broom, scoop up the offending material and place it in a bucket or garden cart. Soil and organic material can be disposed of with regular yard waste, and trash can go in the garbage or be recycled. If you discover the chamber below the inlet is filled with soil or trash, don’t try to remove this material yourself. Instead, call your local municipality to report the problem. And most important, don't try to clear a storm drain after it's flooded. The water may be deeper than it appears, the grate may be missing, and there could be sharp objects or other hazardous material in the floodwater. Stay safe, wait out the flood, and make a mental note to inspect your local stormwater inlets before the next storm arrives.