6.1 Types of Drainage Systems Explained

Key Concepts

• Surface Drainage Systems
• Subsurface Drainage Systems
• Combined Drainage Systems
• Stormwater Drainage Systems
• Sanitary Drainage Systems
• Greywater Drainage Systems

Surface Drainage Systems

Surface drainage systems are designed to collect and remove water from the surface of the ground. These systems typically include gutters, downspouts, and surface drains. They are crucial for preventing water accumulation, which can lead to flooding and damage to buildings and landscapes.

Example: Gutters on a house collect rainwater from the roof and direct it through downspouts to surface drains, which then channel the water away from the foundation.

Subsurface Drainage Systems

Subsurface drainage systems are installed below the ground to remove excess water from soil. These systems often include perforated pipes (French drains) and sump pumps. They are essential for maintaining soil stability and preventing waterlogging in areas with high groundwater levels.

Example: A French drain installed around the perimeter of a basement helps to collect groundwater and directs it to a sump pump, which then discharges the water away from the building.

Combined Drainage Systems

Combined drainage systems integrate both surface and subsurface drainage methods to manage water effectively. These systems are commonly used in urban areas where both surface runoff and groundwater need to be managed simultaneously.

Example: A city may use a combination of storm sewers to handle surface runoff and subsurface drains to manage groundwater, ensuring comprehensive water management.

Stormwater Drainage Systems

Stormwater drainage systems are designed to collect and manage rainwater and melted snow. These systems include storm sewers, catch basins, and retention ponds. They are vital for preventing urban flooding and protecting water quality.

Example: Catch basins installed in parking lots collect rainwater, which is then channeled through storm sewers to retention ponds or natural water bodies.

Sanitary Drainage Systems

Sanitary drainage systems are responsible for collecting and transporting wastewater from homes, businesses, and industries to treatment facilities. These systems include pipes, manholes, and pumping stations. They ensure that wastewater is safely removed and treated before being released back into the environment.

Example: A residential sanitary system collects wastewater from sinks, toilets, and showers, transporting it through pipes to a municipal treatment plant.

Greywater Drainage Systems

Greywater drainage systems collect and treat wastewater from sources such as sinks, showers, and laundry, but not from toilets. This water can be reused for irrigation, flushing toilets, or other non-potable uses. These systems help conserve water and reduce the load on municipal wastewater systems.

Example: A home with a greywater system collects water from showers and directs it to a filtration system, which then uses the treated water for irrigation in the garden.

Examples and Analogies

Think of surface drainage systems as a "water highway" that directs water away from vulnerable areas. Subsurface drainage systems are like "underground rivers" that silently manage groundwater. Combined drainage systems can be compared to a "dual-lane road" that handles both surface and subsurface water efficiently.

Stormwater drainage systems are like "emergency responders" that quickly manage sudden water surges. Sanitary drainage systems are the "garbage collectors" of wastewater, ensuring it is safely removed and treated. Greywater drainage systems are the "recycling plants" of water, reusing treated wastewater for beneficial purposes.

Conclusion

Understanding the different types of drainage systems—surface, subsurface, combined, stormwater, sanitary, and greywater—is crucial for any plumber. Each system plays a vital role in managing water effectively, preventing damage, and ensuring public health and safety.