What is hydraulic head?

Hydraulic head is the total mechanical energy per unit weight of groundwater (elevation plus pressure head). Groundwater flows from high to low hydraulic head; the head gradient, not pressure alone, drives flow.

What is hydraulic conductivity?

Hydraulic conductivity K measures how easily water flows through a porous medium. It varies by 10 orders of magnitude from gravels (highly permeable) to clays (nearly impermeable), controlling where groundwater flows.

What is a cone of depression?

When a well is pumped, hydraulic head drops in a cone-shaped pattern around the well. The cone expands until pumping rate equals inflow from the surrounding aquifer, determining the sustainable yield of the well.

Home▸Geology & Earth Science▸Groundwater Flow

💧 Groundwater Flow

Simulate groundwater flow using Darcy's law q = −K·dh/dl. Visualise confined and unconfined aquifers, equipotential lines, streamlines, and well drawdown cones interactively.

Geology & Earth Science3DEasy60 FPS💧 Water 🌍 Earth

About this simulation

This simulation visualises groundwater movement through porous rock under Darcy's law, q = −K·(dh/dl), where K is hydraulic conductivity and dh/dl the hydraulic gradient. Three settings — unconfined, confined and regional flow — show the water table or piezometric surface responding to recharge and pumping. Switching on a well draws head down into a cone of depression sized by the Dupuit–Thiem equation, whilst seepage velocity is Darcy flux divided by porosity.

🔬 What it shows

A cross-section with the water table for unconfined conditions, a dashed piezometric surface under an aquitard when confined, or two layers with regional flow arrows. Equipotential lines and moving particles trace flow direction; clicking the canvas adds a well whose cone of depression bends the head surface and particle paths towards it.

🎮 How to use

Choose Unconfined, Confined or Regional Flow from the tabs, then click the canvas to place or remove a pumping well. Adjust Hydraulic Conductivity K (0.1–100 m/d), Hydraulic Gradient i (0.001–0.1), Pumping Rate Q (0–3000 m³/d), Porosity n (0.05–0.50), Aquifer Thickness b (5–60 m) and Recharge (0–800 mm/yr) to watch the Darcy flux, head difference, drawdown, seepage velocity and radius of influence readouts respond live.

💡 Did you know?

Hydraulic conductivity spans roughly ten orders of magnitude between materials: clean gravel can conduct water at up to 1000 m/d, whilst intact clay conducts less than 0.0001 m/d — deciding whether ground makes a productive aquifer or a barrier to contaminants.

Frequently asked questions

What is Darcy's law and how does the simulation use it?

Darcy's law, published by Henri Darcy in 1856, states flow through a porous medium equals −K·(dh/dl): hydraulic conductivity K multiplied by the hydraulic gradient, with the minus sign showing flow runs from high head to low head. The simulator uses this relation directly for the Darcy flux readout and to drive the seepage velocity and particle motion for whichever aquifer type is selected.

What's the difference between the confined and unconfined settings?

Unconfined, the aquifer has a free water table that rises and falls, drawn as a solid blue line. Confined, an impermeable aquitard sits above it, so pressure is carried instead by a dashed piezometric surface that can rise above ground level under artesian conditions. The regional flow tab shows two stacked layers exchanging water between shallow and deep flow paths.

How is the drawdown around the well calculated?

Once a well is placed, the simulation applies the steady-state Dupuit–Thiem solution: drawdown grows with pumping rate Q and shrinks with hydraulic conductivity K and aquifer thickness b, following a logarithmic profile in distance from the well out to a fixed radius of influence. This produces the visible cone of depression and the drawdown figure s_w shown in the stats row.

What effect does the recharge slider have?

Recharge represents rainfall reaching the water table, entered in millimetres per year. In the unconfined and regional settings it lifts the water table into a gentle mound between the domain edges, competing with the hydraulic gradient and any pumping well to shape the overall head surface, much as recharge competes with abstraction in a real aquifer.

What do the seepage velocity and radius of influence readouts mean?

Seepage velocity is the Darcy flux divided by porosity n, the true average speed of water moving through the connected pore spaces rather than the bulk flow rate. The radius of influence is the distance from the well at which drawdown becomes negligible; in this simulator it is fixed at 200 m, so conductivity, thickness and pumping rate change how deep the cone reaches within that boundary.

⚙ Under the hood

Pump a well in a confined or unconfined aquifer and watch Darcy's law draw down the water table, with conductivity setting the cone of depression.

groundwaterDarcy's lawaquiferwell drawdownhydraulic conductivityhydrogeologyconfined aquiferunconfined aquiferearth

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install