As climate change continues to wreak havoc, and freak climate incidents like the 2021 Sydney rainfall floods become more and more common, mitigating strategies like stormwater management planning, and useful tools like stormwater drainage systems also become more and more important. 

Stormwater drainage systems can not only help fight evils like stormwater pollution at community levels, but can also be major life-savers at individual levels by protecting the integrity of home foundations, roofs, and other load bearing structures. 

As such, it is important to understand questions like what are stormwater drainage systems, and what are types of stormwater drainage systems.  

What is stormwater drainage?

A storm water drainage system is an infrastructure system designed to take the excess stormwater from impervious surfaces and deposit it to particular water bodies like lakes and reservoirs, through an interconnected system of channels, in order to prevent the pooling of water, and harmful effects of stormwater pollution.

They are usually present at the side of highways and road, at the base of buildings, or roof tops, and other impervious surfaces. Impervious surfaces are those that do not allow water to pass through them.

Most of our roads, buildings, rooftops, and most surfaces in the Urban infrastructure are made up of impervious materials.

While the water is absorbed into the ground in natural environments, in case of impervious surfaces, it pools up in. This, unabsorbed and pooled up water, can cause structural damage if not allowed an outlet.

This outlet also has to be well planned as undirected runoff water can result in stormwater pollution. Click here to learn more about what is stormwarter?

Parts of a storm water drainage system

A storm drainage system majorly consists of three parts:

• Inlet: It is the mouth or opening of the storm water drainage system. It is the opening through which water enters the drain, and it mostly determines the type of the drainage system depending upon its position. The opening of the inlet can be open, such as in French type drains, or with a grated lid, such as in American type drains.
• Piping: This consists of the interconnected network of channels that carry the water load from the collection point i.e inlet to the deposit point i.e. outlet. Pipings are made from different materials which may be steel, plastic, etc.

• Outlet: The outlet is the deposit end of the drain. It normally open up into a sewer system or another larger water body.

Types of storm water drainage system:

There are different types of storm water drainage systems available which are determined by the position and structure of the drain. One must be familiar with all types and specifications in order to judge which type will be most suited to one’s needs.

• Surface Drainage System:  These drains have their inlets on the surface. They are present on flat grounds and require a few ditches to be dug which can act as funnels for excess water. The area around the drain may also be sloped to allow easier flow of water towards the inlet. 

These drains thus send the water away from the home to prevent any flooding or pooling of water. These drainage systems can be used for walkways and driveways as well.

• Subsurface Drainage System: These drainage systems, which are also known as French drains, are buried beneath the top layer of the soil. One needs to  dig ditches to install the pipes of subsurface drains. 

They function by removing the excess water that pools up underneath soil, thus  they not only help get rid of excess water, but also help plants and trees as trapped water can be harmful for them.

• Slope Drainage System: Slope drainage systems are designed in such a way that water moves in a downward direction along a slope. This is achieved by using pipes, the same as was in French drains; the difference is, instead of being buried underground, these pipes are installed on an incline. 

This means that water naturally moves in a desired direction along the slope. The pipes can be made up of different materials such as concrete, steel, or plastic and are wrapped with a protective layer.

• Downspouts and Gutter Systems: This type of system is mostly used to remove rainwater from rooftops. Accumulation of rainwater on rooftops can cause serious damage to the property as it can cause water logging in the walls, and leaking so extensive as to cause flooding in the basement on occasions. 

This is why a downspout and gutter system is so important. A downspout is a pipe for carrying rainwater from a rain gutter. The purpose of a downspout is to allow water from a gutter to reach the ground without dripping or splashing down the building structure.

Why we need of a storm water drainage system:

Storm water drainage systems are necessary to protect us from the harms of stormwater runoff. Stormwater runoff is water that reaches the surface as a result of precipitation (rainfall or ice-melts). 

Water from other minor sources, such as hoses, overuse of sprinklers, etc can also be considered to fall under the same umbrella for the sake of convenience. This water can have the following harmful effects:

• When pooled: Storm water normally pools near the base of the buildings or on rooftops. This way it can cause extensive damage to the foundation or the building or its roof. Both of them are load bearing structures and cause extreme problems if compromised.

They are also extremely expensive to get repairs on due to the labour-extensive nature of the repairs.

• When allowed to run off uncontrolled: In a natural environment, the majority of the water gets absorbed, and the rate of waterflow is also controlled and predictable. But due to impervious surfaces, the water is not stored at all and either there is a complete dearth of water flows, or there are rapid water flows in large quantities.

Also, as water occupies these and flows over these impervious surfaces, it picks up debris, sediment, nutrients, bacteria, and other pollutants that eventually flow, untreated, into creeks, streams and rivers. 

Omega Project Services:

We, at Omega Project Services, take great pride in our position as one of the finest civil engineering service providers in Australia with more than 35 years in the field of Structural, Construction Management, Civil/Stormwater Engineering. Contact us with confidence for any of your stormwater drainage system needs and queries.