evsc lec 3 deck

% of the earth that is covered in water

71

% of the surface water that is seawater

97

% of the earth's surface water that is freshwater

3

% of the earth's surface water that is usable and available

0.01

Of the 3% of freshwater, what % is in lakes, marshes and rivers

0.26% is in lakes, marshes and rivers

Of the 3% of freshwater, what % is in soil moisture, atmosphere, etc

0.12% is in soil moisture, atmosphere, etc

Of the 3% of freshwater, what % is in ice caps, glaciers & groundwater

99.62% is in ice caps, glaciers & groundwater

Where Vancouver's water comes from

from 3 watersheds

1. Capilano

2. Seymour

3. Coquitlam

Main Storage Components (Elements) of the Water Cycle

1. Land

2. Atmosphere

3. Oceans (water bodies)

Main Interconnections between Elements of the water cycle

1. Precipitation

2. Evaporation

3. Infiltration

4. Groundwater discharge

5. Surface runoff

6. Transpiration

blue water

Water available to humans from surface and groundwater (river flow used as proxy for these sources)

green water

Water available to plants in the rooting zone of the soil and weathered bedrock zone

why was the freshwater planetary boundary updated in 2022 to include green water?

accounts for the hydrological regulation of terrestrial ecosystems, climate, and biogeochemical processes

how is runoff generated

when excess phosphorus (P) and nitrogen (N) from fertilizer application, sewage, wastewater, or eroded soils are washed off farmland and other surfaces by rainfall or irrigation water. This water carries the nutrients into rivers, lakes, and coastal zones, contributing to pollution and eutrophication.

• when there is more water than the land can absorb

What is freshwater?

any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids.

where is freshwater found?

• glaciers

• lakes

• reservoirs

• ponds

• rivers

• streams

• wetlands

• groundwater

where does the most accessible water come from globally

surface water and groundwater

What are the four causes of major regional trends in freshwater storage.

1. water abstractions/diversion

2. water storage/energy

3. land modification

4. climate change

Water abstractions and diversions

1. surface/groundwater extraction

2. stream rerouted to new or different channel

   1. ex. Verde River, USA

water storage/energy

• reduced volumes of surface water, altered flow dynamics

• ex. Tarim River, China

land modification

Greater urbanization and artificial imperviousness

• Changes to land surfaces affect watershed hydrology

• ex. southern and western USA

climate change

reduced precipitation, increased evapotranspiration

• example: Po and Pellice Rivers, Italy