Stormwater Runoff Calculations

The video tutorial explains how to calculate stormwater runoff for a site, using a four-acre farmland behind a high school as an example. It covers both pre-development and post-development scenarios, focusing on the impact of adding a 30,000 square foot parking lot. The tutorial details the use of formulas to determine peak stormwater runoff rates, considering factors like runoff coefficients, rainfall intensity, and drainage area. The goal is to assess the additional burden on the storm sewer system due to the new development.

What is the primary concern when adding a parking lot to the farmland?

• Increased traffic congestion

• Increased noise pollution

• Higher stormwater runoff

• Decreased property value

Which formula is used to calculate the peak stormwater runoff rate?

• Bernoulli's Equation

• Darcy's Law

• Manning's Equation

• Rational Method

What is the average runoff coefficient for farmland?

• 0.05

• 0.5

• 0.3

• 0.175

How many square feet are in one acre?

• 60,000

• 50,000

• 43,560

• 30,000

What is the calculated acreage of the parking lot?

• 0.5 acres

• 0.689 acres

• 1 acre

• 2 acres

What is the runoff coefficient for asphalt?

• 0.3

• 0.5

• 0.825

• 0.95

How is the composite runoff coefficient calculated?

• By weighting the coefficients by area

• By multiplying the coefficients

• By averaging all coefficients

• By dividing the total area by the coefficients

What is the new runoff coefficient after development?

• 0.9

• 0.7

• 0.5

• 0.199

What is the increase in stormwater runoff due to the parking lot?

• 3 cubic feet per second

• 1 cubic feet per second

• 0.4 cubic feet per second

• 0.1 cubic feet per second

What is the final calculated runoff rate after the parking lot is added?

• 2.5 cubic feet per second

• 3.4 cubic feet per second

• 4 cubic feet per second

• 3 cubic feet per second