Numerical Type 3 Chapter 5 - Ground Water and Well Hydraulics - Water Resource Engineering 1

TL;DR

This video discusses numerical problems related to groundwater, specifically calculating specific yield, porosity, transmissibility, and drawdown in wells.

Transcript

hello everyone in this video we are going to discuss the third type of numerical based on the chapter of the groundwater so let's start now the first of the problem it says that in a certain alluvial basin of 100 square kilometer area 90 cubic millimeter of the ground water was pumped in a year and because of that the ground water table that has dr... Read More

Key Insights

• 🔇 Specific yield is the volume of water pumped out divided by the total volume of the aquifer, while specific retention represents the volume of water retained.
• 🔉 Porosity describes the total volume of voids in the medium and is calculated by summing specific yield and specific retention values.
• ✖️ Transmissibility is determined by multiplying the coefficient of permeability by the width or depth of the aquifer.

Questions & Answers

Q: How is the specific yield of the aquifer calculated?

The specific yield is calculated by dividing the volume of water pumped out by the total volume of the aquifer from which it was extracted.

Q: What is the formula for calculating porosity?

Porosity is calculated by summing the specific yield and specific retention values, which represent the volume of voids in the medium.

Q: How is the transmissibility of an aquifer determined?

The transmissibility is determined by multiplying the coefficient of permeability by the width or depth of the aquifer.

Q: How is the drawdown in the main well calculated?

The drawdown in the main well can be calculated using the same formula as for other observation wells, but with modified values for h1 and hw.

Summary & Key Takeaways

• The first problem involves calculating the porosity of a soil based on specific yield and specific retention values.

• The second problem focuses on determining the transmissibility of an aquifer by using the Thiem's equation and given drawdown data.

• The third problem involves calculating the drawdown in the main well by using the Thiem's equation with modified values.