1. What is Hydraulic Gradient?

The hydraulic gradient (i) is the change in hydraulic head per unit distance of flow. It represents the driving force behind groundwater flow and is a fundamental concept in hydrogeology.

2. How Does the Calculator Work?

The calculator uses the hydraulic gradient equation:

Where:

• \( i \) — Hydraulic gradient (dimensionless)
• \( \Delta h \) — Head change (m)
• \( \Delta x \) — Horizontal distance (m)

Explanation: The equation calculates the slope of the hydraulic head, which determines the direction and rate of groundwater flow.

3. Importance of Hydraulic Gradient

Details: Hydraulic gradient is essential for understanding groundwater flow direction, calculating flow rates using Darcy's Law, and assessing contaminant transport in aquifers.

4. Using the Calculator

Tips: Enter head change (Δh) in meters and horizontal distance (Δx) in meters. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical range for hydraulic gradient?
A: In natural systems, gradients typically range from 0.001 to 0.01, but can be higher in steep terrains or near pumping wells.

Q2: How does hydraulic gradient relate to flow velocity?
A: According to Darcy's Law, flow velocity is proportional to the hydraulic gradient (v = Ki, where K is hydraulic conductivity).

Q3: Can hydraulic gradient be negative?
A: Mathematically yes, but physically it just indicates flow direction opposite to the coordinate system orientation.

Q4: How is hydraulic head measured in practice?
A: Head is measured using piezometers or wells, calculated as the elevation of water above a datum plus the pressure head.

Q5: What's the difference between hydraulic gradient and slope?
A: Slope refers to land surface elevation change, while hydraulic gradient refers to water pressure potential change in the subsurface.