Stormwater drainage is a system that manages stormwater flow from impervious surfaces like rooftops, sidewalks, and roads in urban and residential areas. Stormwater originates from precipitation (storm), including heavy rain, hail, and snow.

In essence, stormwater drainage is piping that carries and stores runoff to prevent flooding and direct excess water away from buildings and other structures. 

The Importance of Stormwater Drainage

Stormwater is the runoff from rain that’s usually absorbed by the soil and plants. However, those aforementioned impervious surfaces can get in the way and prevent the runoff from absorbing back into the land. When this happens, the excess water can cause problems for us and the environment.

The pollutants that stormwater collects can eventually end up in the lakes, rivers, and streams that supply us with drinking water. Large quantities of excess water also cause flooding, erosion, and structural damage to homes and properties.

An effective stormwater drainage system can prevent flooding, protect water quality, and minimise environmental impact.

Components of a Stormwater Drainage System

Stormwater drainage systems are made up of many components, including:

• Gutters: These channels direct stormwater runoff to the inlets.
• Inlets/Drains: The openings in the curb or sidewalk that collect stormwater runoff.
• Pipes: Directs stormwater runoff to a treatment facility or discharge point.
• Treatment facilities: Removes pollutants from stormwater runoff before it is discharged to a waterway.
• Discharge points: The locations where stormwater runoff is released into a waterway.
• Catch basins: Underground chambers that are located along the pipe network. They serve multiple purposes like allowing heavier materials such as sand or debris to settle out of the water, regulating the flow rate of stormwater entering the pipe system, and capturing specific pollutants before they enter the main pipes.

How Does Stormwater Drainage Work?

Rainwater that doesn’t soak into the ground becomes runoff as gravity pulls the water down into the stormwater drains and gutters on the street. These drains are managed by your city or local council and they all connect to form bigger channels that collect runoff from a wider area.

Special underground chambers catch debris and slow things down to prevent floods. Eventually, all this water joins in bigger pipes and large open channels known as trunk drainage and is carried to its final destination which could be a treatment facility, river, lake, or ocean.

Types of Stormwater Drainage Systems

There are many different types of stormwater drainage systems, such as gravity-fed and pump-based systems. The choice between these two systems depends on the landscape, how much water there is, and the budget.

In a gravity-fed system, the pipes are installed in a way that uses gravity and the natural downhill motion to move stormwater through pipes. The size of the drain pipes varies, depending on the intensity of the precipitation and the size of the area from where the rainwater is collected.

In flat areas or areas where water needs a lift, pump-based systems are key. Pump-based systems are necessary if gravity isn’t enough to feed the water to the drainage system. These pumps keep the flow going even when gravity can’t, pushing the water uphill or over long distances. Pumps can also be installed in homes with a rainwater tank to direct the water to the tank.

Stormwater Detention and Retention

Runoff can overwhelm drainage systems and cause flooding. Stormwater detention and retention are two ways to combat this. Detention temporarily holds rainwater and releases it slowly to prevent flooding. Retention allows rainwater to soak into the ground over time.

An example of stormwater detention is the use of detention tanks. Detention tanks soak up extra rainwater during a storm and slowly release it later to prevent overwhelming the drainage system.

Rain gardens are landscaped areas with special soil that soak up rainwater and let it slowly seep into the ground to help replenish groundwater and reduce runoff. Unlike a detention tank, a retention basin or rain garden is designed to permanently hold water.

Stormwater vs. Sewer Systems

This may sound like an obvious question to some, but it is important to know the difference between the two.

Stormwater drains collect runoff from roofs, roads, and sidewalks after it has rained. The water usually flows directly into waterways such as rivers, lakes, or oceans.

A sewer system, on the other hand, collects wastewater from homes, businesses, and other infrastructures. This includes water from the toilet, sink, dishwasher, washing machine, etc. Sewage is transported to a treatment facility after collection to be cleaned before it is either discharged or reused.

Sewer and stormwater systems are separate from each other and are used in different ways to carry water from different starting points to endpoints.

Innovative Solutions in Stormwater Management

There have been several modern advancements in and approaches to stormwater management. Two ways to change stormwater into a resource include sustainable urban design and green infrastructure.

Cities are getting more proactive about their sustainable urban design layouts. Low-impact development practices include features like permeable pavements and rainwater harvesting into new developments, effectively reducing the need for traditional stormwater infrastructure and promoting a more water-friendly urban landscape.

Concepts like urban forests naturally filter and absorb stormwater, and smart technologies like sensors and data analytics allow for real-time monitoring of water levels that can adjust the drainage system and prevent overflow.

Green Infrastructure adds vegetation and soil into stormwater management in the form of rain gardens, bioswales, or green roofs.

Instead of letting rainwater run off, stormwater management, sustainable urban design, and green infrastructure mimic nature’s way of catching and reusing it to bring back a healthy water cycle for our cities.

Stormwater Drainage and Environmental Impact

Stormwater management is mainly concerned with retaining stormwater and removing pollutants. When done properly, the environmental impact of stormwater plumbing can result in:

• Flood prevention
• Water quality protection
• Soil erosion prevention
• Reduced pollution
• Safer rivers, lakes, and oceans
• Lessening the spread of contaminants and debris
• Reduced damage to properties and the environment

Let Us Help! 

Stormwater drainage is a specialised field that requires extensive knowledge, training and experience. At Good Hands Plumbing, our expertise lies in stormwater drainage solutions.

Having been operating since 2016 and with over 35 years of combined experience, we are your trusted Inner West plumbing partners.

Contact us online today or give us a call at 02 9195 6989 to get a quote for all your drainage and stormwater needs.