Rainwater Harvesting Math: the Runoff Coefficient

The video tutorial explains how to assess rainfall and calculate runoff on different surfaces. It covers the steps to estimate water infiltration and runoff for paved and earthen surfaces, highlighting the importance of understanding surface characteristics like soil compaction and slope. The tutorial also discusses the impact of organic matter on reducing runoff and enhancing water infiltration.

What is the typical range of runoff percentage for a paved surface?

• 50 to 70%

• 80 to 95%

• 30 to 50%

• 100%

How do you calculate the exact amount of water running off a surface?

• By measuring the total rainfall

• By checking the soil type

• By using a runoff coefficient

• By estimating the wind speed

What percentage of rain typically runs off a bare earthen surface?

• 10 to 20%

• 35 to 55%

• 60 to 80%

• 90 to 100%

Which factor does NOT affect the amount of water runoff on an earthen surface?

• Soil looseness

• Color of the soil

• Soil compaction

• Slope of the soil

How does organic matter affect water runoff on a pathway?

• It increases runoff by making the soil less compact

• It has no effect on runoff

• It decreases runoff by absorbing more rainfall

• It increases runoff by making the soil more compact