Groundwater

🌍 Groundwater Study Guide

💧 What is Groundwater?

  • Groundwater is water found beneath Earth’s surface in soil and rock.

  • It fills the spaces (pores) between particles of soil, sand, gravel, or cracks in rock.

🪨 Key Terms

1. Aquifer

  • An aquifer is a layer of rock or sediment that stores and allows water to flow.

  • Examples: sand, gravel, sandstone

2. Aquitard

  • A layer that slows or stops water flow (like clay).

3. Water Table

  • The top of the groundwater zone.

  • Below it = saturated (full of water)

  • Above it = unsaturated (air + water)

🌊 Types of Groundwater

Unconfined Aquifer

  • Water can flow directly from the surface.

  • Has a water table.

Confined Aquifer

  • Trapped between impermeable layers.

  • Water is under pressure.

🚰 Wells

How Wells Work

  • A well is drilled to bring groundwater to the surface.

Types of Wells

  • Regular well: needs a pump

  • Artesian well: water rises on its own due to pressure

🔄 Groundwater Movement

  • Moves slowly through pores and cracks.

  • Driven by gravity and pressure.

  • Process called percolation.

🌧 Recharge & Discharge

Recharge

  • When water enters the ground (rain, snowmelt).

Discharge

  • When groundwater comes out:

    • Springs

    • Rivers

    • Lakes

🧪 Porosity & Permeability

Porosity

  • How much empty space is in a material.

Permeability

  • How easily water can flow through it.

👉 Example:

  • Clay: high porosity, low permeability

  • Sand: medium porosity, high permeability

⚠ Groundwater Issues

1. Overuse

  • Pumping water faster than it refills → water table drops

2. Pollution

  • Chemicals, fertilizers, waste can seep into groundwater

3. Saltwater Intrusion

  • In coastal areas, saltwater can enter freshwater aquifers

🌱 Why Groundwater is Important

  • Drinking water source

  • Agriculture (irrigation)

  • Supports ecosystems

🧠 Quick Review Tips

  • Aquifer = stores water

  • Water table = top of groundwater

  • Permeability = flow ability

  • Recharge = water going in

  • Discharge = water coming out

✏ Practice Questions

  1. What is the difference between porosity and permeability?

  2. Why are aquifers important?

  3. What causes the water table to rise or fall?

  4. How does pollution reach groundwater?

  5. What is an artesian well?

If you want, I can turn this into:

  • a quizlet-style flashcard set

  • a worksheet with answers

  • or a shorter “test cram sheet” 👍