Stormwater Management Concepts

This video tutorial covers storm water management, focusing on the importance of managing storm water pre- and post-development. It explains the rational method for calculating runoff, using the stormwater technical standards manual, and provides detailed steps for calculating pre- and post-development runoff. The tutorial also guides on estimating the volume and area of a retention pond, using a rule of thumb and basic area equations.

Why is storm water management important?

• To increase water flow to rivers

• To eliminate water flow

• To reduce water quality

• To manage water quantity and quality

What does the rational method calculate?

• Soil erosion

• Runoff rate

• Air quality

• Water temperature

Which section of the stormwater manual is used for hydrology?

• Section 400

• Section 100

• Section 200

• Section 300

What is the unit of rainfall intensity in the rational method?

• Cubic feet per second

• Inches per hour

• Acres

• Gallons per minute

What is the runoff coefficient for a meadow in pre-development?

• 0.10

• 0.25

• 0.50

• 0.75

How is the area of a site measured in the rational method?

• Acres

• Square feet

• Square meters

• Hectares

What is the average runoff coefficient for asphalt?

• 0.95

• 0.825

• 0.70

• 0.50

How do you convert square footage to acres?

• Multiply by 43,560

• Divide by 43,560

• Multiply by 10,000

• Divide by 10,000

What is the rule of thumb percentage for estimating retention pond volume?

• 10%

• 15%

• 20%

• 25%

If a pond is circular, which formula is used to find the radius?

• Area = πr²

• Diameter = 2r

• Volume = πr²h

• Circumference = 2πr