Increasingly, local, state, and federal governments all around the world are requiring residents, businesses, and cities to have comprehensive stormwater management systems in place. These are usually well thought out plans that start at the source of the problems and follow them through, cleaning, sorting, and filtering all along the way to the local stream. It’s important to point out that, in nearly every case, preventing pollution at its source is the preferred tactic. Here are some examples.

It Takes Boots On The Ground

It’s one thing to sit at a collection pond and sort through all of the garbage, litter, pesticides, and other contaminants and try to treat them all. Each will need a specific treatment that may take time, money, and experimentation.

On the other hand, it’s far better to walk through every neighborhood, industrial site, retail parking lot, on every street and locate the sources of the pollutants before they enter the system. That could entail requiring some industrial sites to cover toxic heavy metal, pesticide, or oil residue areas until they have a cleanup plan started.

Places like wrecking yards have long been dumping grounds for oil, gasoline, and antifreeze, now they remove those contaminants before the cars are parked on-site. This is just one example of a change that prevents toxins, oils, and other types of contaminants from reaching the rivers.

Fast food sellers may be required to put more outside garbage cans, post signs encouraging proper litter disposal, and regularly clean out the stormwater grates in front of their businesses. The point is, the first step in stormwater management systems is to prevent the contaminants from ever entering the system at all.

Stormwater Catch Basins Are Next

Many larger sites, and even plenty of residential neighborhoods are now being required to have their own rainwater runoff catch basin on-site. This helps to regulate the heavy flows of water during the hardest rainfall periods. It also allows the local rains time to soak back into the ground which is by far the best solution.

Any extra water can siphon off into the local stormwater system but it will have deposited most of the silt, litter, pesticides, and oils in the catch basin. There these pollutants can be cleaned regularly on dry days to prevent their further travel into the system.

The Next Step Is Separation And Filtration

There are several different types of stormwater separators each having its own statistics as to which types of pollutants it’s best at removing. Hydrodynamic separators are an excellent example in that they remove over 80% of most pollutants just by using gravity and the swirling motion of the water. Light objects are jettisoned into one chamber and heavy objects, silt, and rocks are allowed to settle into the middle.

Each step of the way different stormwater filters can be applied based on the projected amount of each kind of pollutants. Careful examination of the stormwater is needed in advance to determine which filters and separators will work best in each situation.

The object is to have as much of the water soak back into the ground as it would naturally. This helps replenish the ground water and it is naturally filtered by tons of soil, sand, and gravel. Then the remaining runoff can be allowed into the creeks nearby, but the water will be cleaned and filtered so as not to kill local fish and other wildlife each time there is a hard rain.