Stormwater drainage systems are designed to control the quantity, quality, timing, and distribution of runoff. Other objectives in the design of stormwater management systems include erosion control and groundwater recharge.
A stormwater drainage system collects surface runoff via inlets in road pavements and routes it to a treatment unit and/or receiving body of water, usually through underground pipes called storm sewers. In some cases, the surface runoff is discharged directly into a receiving body of water such as a stream, river, lake, or ocean.
An inlet is where the water enters the storm sewer/drainage system. Some common stormwater inlets include:
Swale w/Check Dam
Drop Inlet
•
Swales with Check Dams
•
Drop inlets
• Curb inlets
• Combination inlets
Grate Inlet
An
outlet is where the stormwater exits the storm sewer/drainage system.
Pipe outlets are constructed in numerous shapes, sizes, and materials.
Round and oval pipes made from reinforced concrete, corrugated metal,
or plastic, are most commonly used. Ditches and low-lying or depressed
stretches of land (swales) are also used as outlets to convey stormwater
into and out of the storm sewer system. They usually carry stormwater
from pipes, lack a defined geometry and are often lined with concrete,
rocks, or grass.
Curb Inlet