Let’s start with a definition. According to Wikipedia, the term ‘Stormwater’ is (and I quote) “used to describe water that originates during precipitation events” (rain). “It may also be used to apply to water that originates with snowmelt or runoff water from over watering that enters the stormwater system. Stormwater that does not soak into the ground becomes surface runoff, which either flows directly into surface waterways or is channeled into storm sewers, which eventually discharge to surface waters.”
So much for today’s lesson, but Wikipedia goes on to explain the concerns that we should all, as a community, be aware of and vigilant against. Back to Wikipedia quoting mode….
“Stormwater is of concern for two main issues: one related to the volume and timing of runoff water (flood control and water supplies) and the other related to potential contaminants that the water is carrying, i.e. water pollution.”
So there you have it. It’s official – we now know what is meant by the term stormwater and we realize that it is a concern. Now for the management part of the equation.
Obviously pollution prevention is the best pathway to a cleaner environment. If we were to keep the waterways clean we wouldn’t need to remediate the negative effects of pollution. There’s no startling revelation there. But to best understand how we can prevent water pollution we need to look closely at our storm water management strategies.
Stormwater management is the course or act of taking care of the quantity and quality of stormwater. Management of stormwater is crucial, particularly in cities and areas where stormwater runoff is always a problem. You’ve heard of the land of droughts and flooding rains…. It’s true (in Australia)!
Stormwater can be managed through relatively simple (and inexpensive) manufactured products and control mechanisms (such as drain wardens) that are designed to filter the silt, sediment and solids from dirty storm water. It can also be managed through policy and procedural practices.
Unlike soils and sand, impervious areas like parking lots, roads and compacted dirt don’t allow rain to seep into the soil. This is why urban areas generate far more runoff water than rural or forested locations. Not only does this run off water often carry pollutants to other waterways, it prevents the essential replenishment of underground water levels (groundwater).
Rain happens regularly (washed your car lately?). When the runoff comes into contact with the pollutants left by … us, then the bad stuff is transported along with the run off. Guess where to?
Think back to the last time you went to a football game. How did the ground look – around the stands – after the match? Picture that mess being transported by rain water to the nearest drain. Tragic, isn’t it.
In some locations, impure runoff from streets and freeways can be the largest source of water pollution. Then there are the other unwanted effects of polluted storm water – erosion, weed invasion, oil and chemical contamination and litter pollution. A number of stormwater management products are available to help remove impurities from the runoff water before they enter the stormwater system or even groundwater resources.
Management of stormwater may also involve source management. Substances can be controlled to prevent the discharge of impurities into the ecosystem. Soft structures like ponds, swales or even wetlands to work alongside existing or “hard” water drainage systems (like pipes and concrete channels) can also be effective for managing runoffs.
So what should we do – to play our part. It’s important to understand our own impact. What we do truly does make a difference. Whilst there are regulations in place to help, it’s important to teach others of the importance of managing our stormwater systems. Identify what your risks are. Then look for a practical solution.
Put a drain warden in the stormwater pit – to keep silt and sediment from the drains. Use silt socks, or containment booms to control run off. Install an isolation valve in the pit to enable full control in the event of a spill. But along with all of these solutions, train your staff to prevent pollution.