What is storm water management?
Storm water management is the practice of managing the quality and quantity of storm water to avoid the unfavorable effects of massive storm water or surface runoff.
What is stormwater?
Stormwater is water that comes from the atmospheric process of precipitation (e.g. rain, snow, sleet, hail, graupel). When stormwater is not absorbed by the ground, the portion that is not used by the plants becomes stormwater or surface runoff that will later find its way into storm sewers and surface waterways and will eventually empty out to surface waters like rivers and lakes.
Why is stormwater cause for alarm?
When we create and build new surfaces like impervious surfaces (e.g. roofs, residential driveways, parking lots) on an existing landscape, these impervious surfaces prevent stormwater from being distributed evenly across the ground. This will eventually increase the amount of stormwater or surface runoff that carries pollutants derived from the surfaces it passed through. These pollutants come in the form of fertilizer, pesticides, sediment, automobile fluids, pet waste, etc., and all of these go straight to the nearest bodies of water.
What are the dangers of stormwater?
- The pollutants in the stormwater or surface runoff that are deposited into the bodies of water can have adverse effects on the wildlife and water quality.
- The increased volume of stormwater can cause erosion to the stream banks and hillsides.
- Aside from the usual pollutants, debris can also be carried away by stormwater or surface runoff and this can possibly clog storm drains and eventually cause flooding.
How to prevent the dangers of massive stormwater or surface runoff?
Through residential stormwater management and effective and efficient implementation of BMPs (Best Management Practices), the adverse effects of stormwater or surface runoff can be prevented. BMPs are the engineered or structural control devices and systems used to treat polluted stormwater, and the operational or procedural practices utilized in reversing and preventing the effects of stormwater.
Here are some examples of BMPs (Best Management Practices).
- Reduce the pollutants present in impervious surfaces that can be carried away by stormwater or surface runoff.
1.1 If you are using commercial fertilizer on your garden or lawn, resort to organic fertilizer or use compose.
1.2 If you have grease or oil stains on your driveway, remove them immediately before the rain washes it away.
1.3 If you have pets, dispose of their droppings properly by either flushing the wastes down the toilet or by burying them underground.
- Landscaping and site management.
By altering the impervious surfaces and the landscaping of your garden or lawn, stormwater or surface runoff and the pollutants that come with it can be reduced.
2.1 Direct downspouts away from concrete pavements and towards your garden or grassy lawn.
2.2 You can use a rain barrel to catch stormwater by placing it under a downspout.
2.3 If you are thinking of building a new structure, consider constructing a green roof.
This type of roof can directly and rapidly absorb stormwater.
How Large Should the Tank Be?
The size of the retention or detention tank will depend on the local council requirements and the size of the building’s roof area and hard surfaces. Most council’s who require storage and slow release of storm water provide guidelines on what is required for each site.
Storm water tanks can be designed with fittings that facilitate both applications.
The placement of the detention or retention tank will be determined by the size and slope of the site along with the requirement to catch the maximum amount of water from the site. Often more than one tank maybe required as there will be more than one point of capture on site. In some case there may be a requirement for an underground tank which will be required to harvest water at ground level and the water is then pumped back into the water drainage system.