Water Systems and Pollution

Test Review

What are the percentages of available water on the planet?

• Saltwater: Approximately 97%

• Freshwater: Approximately 3%

How is the world's freshwater distributed?

• Glaciers and Ice Caps: Approximately 68.7%

• Groundwater: Approximately 30.1%

• Surface Water and Other Freshwater: Approximately 1.2%

  • This includes lakes, rivers, and atmosphere.

What is freshwater used for and what are the approximate percentages of each water use?

• Agriculture: 70%

• Primarily used for irrigation and livestock.

  • Industry: 20%

• Used for manufacturing, power plant cooling, and processes.

  • Domestic households: 10%

• Used for drinking, sanitation, and lawn maintenance.

How does the water cycle impact available freshwater?

• Renewal: It continuously replenishes freshwater sources through precipitation.

• Purification: Processes like evaporation and soil infiltration naturally filter contaminants out of the water.

• Redistribution: It moves water from the oceans to land, making it available for terrestrial ecosystems and human use.

What is an aquifer?

A body of permeable rock, sediment, or soil that contains or transmits groundwater. It acts as an underground reservoir where water can be extracted using a well.

What is groundwater recharge?

The hydrological process where water moves downward from the Earth's surface into the subsurface. This is the primary way that water reaches and refills an aquifer.

What factors impact groundwater recharge?

• Soil Permeability: Sandy soils allow for faster infiltration than clay-based soils.

• Land Use: Urbanization and impermeable surfaces (like concrete) block water from entering the ground.

• Vegetation: Plants slow down surface runoff, providing more time for water to seep into the soil.

• Topography: Flat land promotes infiltration, while steep slopes cause more surface runoff.

• Climate: The amount, timing, and intensity of precipitation determine how much water is available to soak into the earth.

What is a watershed?

An area of land that channels rainfall and snowmelt into specific creeks, streams, and rivers, eventually flowing to a common outflow point such as a lake, bay, or ocean.

Why is understanding the watershed / river basin concept important?

• Resource Management: It allows for better planning of water usage and conservation.

• Pollution Control: It helps trace the source and spread of contaminants moving through connected water systems.

• Ecosystem Protection: It helps communities recognize that actions upstream directly affect the health of the environment downstream.

What is the difference between lentic and lotic water bodies?

• Lentic: Refers to still or standing water ecosystems.

• Examples: Lakes, ponds, and wetlands.

  • Lotic: Refers to flowing water

How can we increase the supply of available freshwater?

• Desalination: Removing salt from seawater to make it potable.

• Wastewater Reclamation: Treating sewage or greywater for reuse in irrigation or industry.

• Rainwater Harvesting: Collecting and storing rain for non-potable or treated potable use.

What major issues impact our available freshwater?

• Pollution: Chemical and biological contaminants from industry and agriculture.

• Over-extraction: Pumping groundwater faster than the recharge rate.

• Climate Change: Changing weather patterns that cause severe droughts and alter the water cycle.

• Population Growth: Increasing demand for domestic and agricultural water.

How does agriculture impact groundwater and surface water resources?

• Consumption: Uses 70% of global freshwater, often leading to over-pumping of aquifers.

• Runoff: Fertilizers and pesticides leach into groundwater and run into surface water, causing eutrophication.

• Erosion: Poor land management leads to sedimentation in rivers and streams.

How does the average US citizen's water use compare to the rest of the world?

• High Consumption: The average U.S. citizen uses 80−100 gallons per day.

• Global Context: This is significantly higher than many developing nations, where use can be as low as 5−13 gallons per day.

What are ways that people can conserve water or reduce their water use?

• Household Efficiency: Fixing leaks, using low-flow faucets/toilets, and taking shorter showers.

• Landscaping: Using xeriscaping (drought-tolerant plants) instead of lawns.

• Consumer Choices: Reducing consumption of water-intensive.

What is water scarcity?

Water scarcity is the lack of sufficient available water resources to meet the demands of water usage within a region.

Which regions of the world face water shortages?

Regions facing water shortages include parts of Africa, the Middle East, and South Asia, where drought, overuse, and pollution contribute to limited water availability.

How can we solve water scarcity problems locally and regionally?

Solutions to water scarcity include implementing water conservation practices, improving water management, investing in water recycling technologies, and enhancing infrastructure for water distribution.

How do water treatment plants work?

Water treatment plants purify water by removing contaminants through processes such as coagulation, sedimentation, filtration, and disinfection to make it safe for consumption.

What are the major steps in wastewater treatment?

Major steps in wastewater treatment include preliminary treatment (screening), primary treatment (sedimentation), secondary treatment (biological processes), and tertiary treatment (advanced filtration and disinfection).

What is a septic tank and how does it work?

A septic tank is an underground chamber that treats wastewater from a household by allowing solids to settle at the bottom and liquid effluent to flow out for further treatment in the drain field.

How does groundwater withdrawal impact ecosystems?

Groundwater withdrawal can lower water tables, reduce surface water levels, and negatively affect wildlife habitats, aquifers, and the overall health of ecosystems.

What are the major sources of water pollution?

Major sources of water pollution include agricultural runoff, industrial discharges, sewage, and plastic waste.

What are two methods to assess water quality?

Two methods to assess water quality are chemical testing (measuring pollutants) and biological assessments (evaluating the health of aquatic organisms).

What is BOD?

BOD, or Biochemical Oxygen Demand, is a measure of the amount of oxygen that microorganisms will consume while decomposing organic matter in water.

What is eutrophication?

Eutrophication is the process where water bodies become enriched with nutrients, leading to excessive growth of algae and depletion of oxygen, harming aquatic life.

What is the source of human-caused eutrophication?

Human-caused eutrophication primarily results from agricultural runoff containing fertilizers, sewage discharge, and industrial effluents that introduce excess nutrients into water bodies.

What are the major US laws addressing water pollution?

Major US laws addressing water pollution include the Clean Water Act and the Safe Drinking Water Act, which regulate discharges into water bodies and ensure safe drinking water standards.

What is the state of global fisheries?

Global fisheries are in decline due to overfishing, habitat destruction, and climate change, leading to reduced fish populations and biodiversity.

What can be done to help global fisheries?

To help global fisheries, measures such as sustainable fishing practices, habitat restoration, and enforcement of fishing regulations can be implemented.