1. What is Groundwater Gradient?

The groundwater gradient (i) represents the slope of the water table or potentiometric surface, indicating the direction and rate of groundwater flow. It's a fundamental parameter in hydrogeology for understanding groundwater movement.

2. How Does the Calculator Work?

The calculator uses the groundwater gradient equation:

Where:

• \( i \) — Hydraulic gradient (dimensionless)
• \( \Delta h \) — Head difference between two points (meters)
• \( \Delta L \) — Distance between the two points (meters)

Explanation: The gradient is calculated by dividing the difference in hydraulic head between two points by the distance between them.

3. Importance of Gradient Calculation

Details: The groundwater gradient is crucial for determining flow direction, estimating flow velocity (when combined with hydraulic conductivity), and modeling contaminant transport in aquifers.

4. Using the Calculator

Tips: Enter the head difference (Δh) in meters and the horizontal distance (ΔL) in meters. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical groundwater gradient value?
A: Most natural gradients range from 0.001 to 0.01, with steeper gradients in mountainous areas and flatter in plains.

Q2: How does gradient relate to flow velocity?
A: Actual flow velocity is calculated using Darcy's Law: v = Ki/n, where K is hydraulic conductivity and n is porosity.

Q3: Can the gradient be negative?
A: The absolute value is typically used, but negative values indicate flow in the opposite direction of measurement.

Q4: How many measurement points are needed?
A: Minimum two points for simple gradient, but more points give better representation of complex flow systems.

Q5: Does this work for confined aquifers?
A: Yes, but use potentiometric surface measurements instead of water table for confined aquifers.