Part 3 - Groundwater Basics

Hydrology

What is GROUNDWATER?

Water beneath Earth’s surface (Around soil/sediment/rock)

What is POROSITY?

How much space there is for water

What is PERMEABILITY?

How easily water flows through rock/sediment

Why might water NOT FLOW EASILY through PORE SPACES?

The spaces may not be well connected.

Why does groundwater MOVE SLOWLY?

It follows winding paths & experiences friction → (rubbing that slows things down)

What is a RESERVOIR?

A place where FLUID COLLECTS

What is an AQUIFER?

A layer of rock/sediment that LETS WATER FLOW EASILY.

What is an AQUICLUDE?

A layer of rock/sediment that RESTRICTS WATER FLOW!

What is the UNSATURATED zone?

Area ABOVE water + pore spaces NOT COMPLETELY filled with water.

What is the WATER TABLE?

Boundary BELOW + pore spaces filled with water

What is the SATURATED zone?

Area BELOW water + pore spaces are COMPLETELY filled with water.

What are the TWO main types of AQUIFERS?

Unconfined & Confined

What is an UNCONFINED aquifer?

ABOVE the water table + NO blocking layer above it

What is an CONFINED aquifer?

UNDERGROUND layer that is TRAPPED between layers

What AFFECTS the water table?

TOPOGRAPHY (Shape + Elevation) + amount of RECHARGE

Why can groundwater be an ANCIENT RESOURCE?

Can travel LONG DISTANCES underground (LARGE-SCALE)

What is HEAD?

Water pressure (helps groundwater move)

What is HYDRAULIC GRADIENT→ (slope)

The slope (change) in water pressure over a DISTANCE.

What CAUSES groundwater to flow?

Differences in head (water pressure)

How can RECHARGE affect a DRY AREA?

Recharge ELSEWHERE can INCREASE water pressure in the dry area.

What are SPRINGS & SEEPS?

Places where groundwater flows OUT ONTO the surface.

How can spring & seeps flow CHANGE?

It can change depending on the SEASON!

What is groundwater OVERDRAFT?

More groundwater is PUMPED OUT than is replaced by recharge. (PUMPING > RECHARGE)

What happens DURING groundwater overdraft?

The water table DROPS.