Let’s get this out of the way first. Plastic waste doesn’t CAUSE flooding. Rain causes flooding.
Discarded plastic bags and plastic bottles DO impact the efficiency of flood control systems in several ways. Besides the obvious potential for clogging drains, plastic waste can also take up a lot of the volume in detention ponds. These problems are either dealt with using taxpayer funded labor and equipment, or they can be ignored with the hope that it never rains all that much. The danger presented by an accumulation of plastic trash in an urban storm drain can prove deadly after days of heavy rain.
Photo credit: bjornmeansbear
Plastic bags were made the scapegoat during a particularly deadly monsoon season in Mumbai in 2005. Plastic bags did clog the system. The system was very old and not designed to deal with the massive population that live in shanties clustered around the city center. The system was also poorly maintained. The system was built before plastic bags were imaginable. Laws against plastic bags had been imposed before the 2005 floods that killed over 1000 people.
At the opposite end of the spectrum, we have places like Salt Lake County, Utah. It’s not a place where you expect to hear about deadly floods. It’s infrastructure is not particularly ancient or under funded. Plastic garbage does accumulate in the drainage system. Draper is a city of just under 40,000 people and it employs 3 people full time to clean the trash and debris from the drains. There are almost 14 million people in Mumbai. I don’t know if they have 1,000 people cleaning out the storm sewers, but that’s how many people it would take to be proportional to Draper. Littering is more prevalent in the developing world, so Mumbai should probably have several thousand people cleaning out the storm drains. They do have a squad of Plastic Bag Police.
Making an individual choice to use less plastic won’t do much to prevent floods, but if everyone made the same choice it could make a huge difference
