WATER CYCLE & GROUNDWATER

TYPES OF SOIL MOISTURE

1. GRAVITATIONAL WATER

2. CAPILLARY WATER

3. HYGROSCOPIC WATER

1. GRAVITATIONAL WATER

Type of Soil Moisture

Water draining DOWNWARD from GRAVITY

2. CAPILLARY WATER

Type of Soil Moisture

Water held in TINY soil SPACES

• IMPORTANT for plant growth

3. HYGROSCOPIC WATER

Type of Soil Moisture

Water held in TIGHT soil PARTICLES

EVAPOTRANSPIRATION (ET)

COMBINES 2 ways water RETURNS to ATMOSPHERE

EVAPORATION

Evapotranspiration (ET)

Water turns into VAPOR

• Soil, lakes, surfaces

TRANSPIRATION

Evapotranspiration (ET)

PLANTS release VAPOR

• Leaves

POTENTIAL EVAPOTRANSPIRATION (PET)

How MUCH water COULD evaporate and be RELEASED by plants

• Energy, temperature, sunlight, & wind

ACTUAL EVAPOTRANSPIRATION (AET)

How MUCH water ACTUALLY evaporates and is RELEASED by plants

• Available energy & water supply

1. AET APPROACHES PET

Factors Controlling AET & PET

• WARM

• SUNNY WEATHER

• PLENTY OF WATER

2. HIGH PET, AET DROPS

Factors Controlling AET & PET

• WARM

• SUNNY WEATHER

• DRY SOIL

3. LOW PET

Factors Controlling AET & PET

• COOL WEATHER (less available energy)

WATER DEFICIT

Water DEMAND is GREATER than AVAILABLE water

WATER DEFICIT PROCESS

PET > AET

1. TEMP & SUNLIGHT INCREASES

2. PET RISES

3. NOT ENOUGH RAINFALL = DECREASED SOIL MOISTURE

4. PLANTS CANNOT RELEASE WATER

5. AET FALLS BELOW PET

GROUNDWATER PROCESS

1. INFILTRATION

2. PERCOLATION

3. RECHARGE

4. GROUNDWATER FLOW

5. DISCHARGE

1. INFILTRATION

Groundwater Process

RAINWATER enters SOIL

2. PERCOLATION

Groundwater Process

PROCESS of Water moving DOWNWARD through SOIL & ROCK from gravity

3. RECHARGE

Groundwater Process

Water SATURATES & REPLENISHES groundwater

4. GROUNDWATER FLOW

Groundwater Process

Water moves through CONNECTED PORES & CRACKS in SOIL & ROCK

5. DISCHARGE

Groundwater Process

Groundwater EMERGES

• Springs, rivers, lakes, & oceans

FACTORS CONTROLLING GROUNDWATER MOVEMENT

• POROSITY

• PERMEABILITY

• WATER TABLE (top of saturation)

• AQUIFER

• IMPERMEABLE LAYER (dense clay/rock)

POROSITY

Factors Controlling Groundwater Movement

How MUCH EMPTY pore space

• Water storage

PERMEABILITY

Factors Controlling Groundwater Movement

How EASILY water moves through CONNECTED spaces

AQUIFER

Factors Controlling Groundwater Movement

Layer of PERMEABLE ROCK/SEDIMENT

• Stores/transmits usable groundwater

1. EFFECT OF LOW PRECIPITATION

LESS water enters SOIL

2. EFFECT OF DECREASED SOIL MOISTURE

LESS water available to PLANTS

3. EFFECT OF LESS WATER RECHARGING GROUNDWATER

GROUNDWATER levels FALL

• Recharge stays below discharge/pumping