Numerical Type 1 - Hydrology - Water Resource Engineering 1

TL;DR

Estimating the peak of a unit hydrograph and calculating the base width using given data on storm duration, discharge values, and catchment area.

Transcript

hello everyone in this video we are going to discuss the first type of numerical which is based on the conversion of the flood hydrograph into the unit hydrograph so let's start the first problem it says that the peak of a flood hydrograph due to three hours storm in a catchment area is 270 cubic meter per second that is the peak discharge given fo... Read More

Key Insights

• 💐 The process of converting a flood hydrograph into a unit hydrograph involves subtracting the base flow and calculating the effective rainfall depth.
• 💐 The base flow represents the constant flow in the catchment area unaffected by the storm event.
• 🔇 The runoff volume is determined by multiplying the area of the direct runoff hydrograph segment by the effective rainfall depth.
• 🙊 The unit hydrograph peak can be calculated by dividing the peak of the direct runoff hydrograph by the effective rainfall depth.

Questions & Answers

Q: What is the difference between a flood hydrograph and a unit hydrograph?

A flood hydrograph represents the discharge values over time for a specific storm event, while a unit hydrograph is a scaled down version of the flood hydrograph and represents the discharge values for a unit depth of rainfall.

Q: How is the base flow accounted for in the calculations?

The base flow is subtracted from the flood hydrograph values to obtain the direct runoff hydrograph, which is used to calculate the unit hydrograph. The base flow represents the constant flow in the catchment area unaffected by the storm event.

Q: How is the runoff volume calculated?

The runoff volume is calculated by multiplying the area of the direct runoff hydrograph segment by the effective rainfall depth. The effective rainfall depth is the portion of rainfall contributing to surface runoff after accounting for infiltration losses.

Q: How do you determine the base width of a triangular hydrograph?

The base width of a triangular hydrograph can be calculated by dividing the runoff volume by the unit hydrograph peak. The unit hydrograph peak is obtained by dividing the peak of the direct runoff hydrograph by the effective rainfall depth.

Summary & Key Takeaways

• The video discusses the process of converting a flood hydrograph into a unit hydrograph using numerical calculations.

• It explains how to estimate the peak of the unit hydrograph and calculate the base width of a triangular hydrograph.

• The video also provides step-by-step calculations for two different problem scenarios.