How the stormwater system works during heavy rain

Summary

This video script explains Adelaide's urban stormwater management, detailing how rainwater is collected and transported through 'minor' underground pipes and 'major' overland road systems. It highlights the challenges during heavy rainfall, such as blockages and potential street flooding, and emphasizes the importance of not driving or walking on flooded roads. The script also touches on the impact of tides on coastal stormwater systems and the ongoing efforts by councils to improve infrastructure and prepare for flooding.

Takeaways

• 💧 Councils manage stormwater infrastructure in Adelaide.
• 🌧️ Urban stormwater systems consist of underground 'minor' pipes and overland 'major' road systems.
• 🏡 Rainwater from roofs and surfaces is collected in kerb and gutter, then flows into side-entry pits.
• 🚧 The minor system handles smaller storm events, while major roads become the overland system during heavy rainfall.
• 🍂 Debris like leaves and rubbish can block stormwater drains, especially in autumn and winter.
• 🌊 Flooding can occur when the underground system is overwhelmed during heavy storms.
• 🚫 Avoid driving or walking on flooded roads due to hidden hazards and the risk of creating bow waves.
• 🏡 Properties on lower ground are at a higher risk of flooding compared to those on higher ground.
• 🌊 Tide levels can affect the drainage of stormwater systems, especially along the coast.
• 🔄 Creek and river levels can rise during heavy rains, preventing the minor systems from draining and causing upstream flooding.
• 🔨 Councils are working on improving stormwater systems and preparing management plans to mitigate flooding risks.

Q & A

What is the primary responsibility of councils in managing stormwater in Adelaide?

Councils are responsible for managing much of the stormwater infrastructure across Adelaide.

How does rainwater typically flow from roofs to the street?

Rain runs off roofs, through down-pipes, and out to the street.

What are the two parts of a typical stormwater system?

A typical stormwater system has two parts that work in tandem: the underground 'minor' pipe system and the overland 'major' road system.

What is the purpose of the underground minor stormwater system?

The underground minor stormwater system transports stormwater during smaller storm events that typically occur once every two to five years.

How is rainwater collected and directed into the stormwater system?

Rainwater is collected in the kerb and gutter, which then flows into drains called 'side-entry pits', and then through a network of pipes.

What can happen to stormwater drains during autumn and winter?

During autumn and winter, there is an increase in the amount of leaf matter on roads and footpaths, which can be washed into and block stormwater drains.

What occurs when the underground stormwater system reaches its capacity during heavy rainfall?

When the underground stormwater system fills and reaches its capacity, stormwater in the gutters may start to rise, potentially leading to the road becoming submerged.

Why is it dangerous to drive or walk on flooded roads?

It's dangerous to drive or walk on flooded roads because you cannot see the condition of the road underneath or if there are any obstacles, and driving through can create bow waves that push water into properties.

How does the landscape and environment affect where stormwater flows?

The flow of stormwater depends on the lay of the land, landscape, and the environment. Properties on the lower side of the street may be at greater risk of flooding compared to those on higher ground.

How do coastal stormwater systems differ from those inland?

Some urban stormwater systems along the coast are influenced by tide levels. Major rain events that coincide with high tides or ocean storm surges impact the minor stormwater system's ability to drain out to sea.

What actions are councils taking to improve stormwater systems?

Councils are continuing to improve the stormwater systems, including preparing stormwater management plans and upgrading stormwater infrastructure.