United StatesEnvironmental Science

Unit 5: Land and Water Use

17 dot points across 17 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

Can farming fish take the pressure off wild stocks, or does it just create new pollution problems?

Topic 5.16 Aquaculture: describe aquaculture and explain its benefits and environmental costs compared with wild fishing.
A focused answer to APES Topic 5.16, covering aquaculture (fish farming), its benefits as a protein source, and its environmental costs including water pollution, disease, escaped fish, habitat loss and reliance on wild fish for feed, with a worked feed-conversion calculation.
9 min answer →

Why is removing every tree at once the cheapest way to log a forest but also the most damaging?

Topic 5.2 Clearcutting: describe clearcutting and explain its environmental consequences for soil, water and ecosystems.
A focused answer to APES Topic 5.2, covering clearcutting as a logging method, its economic appeal, and its consequences for soil erosion, water temperature and quality, flooding, habitat loss and biodiversity, with a worked erosion comparison.
9 min answer →

How much of the planet does it take to support one person's lifestyle, and why do some people need far more than others?

Topic 5.11 Ecological Footprints: define the ecological footprint, explain what it measures, and compare footprints between countries and lifestyles.
A focused answer to APES Topic 5.11, covering the ecological footprint, what it measures, the factors that raise or lower it, biocapacity and overshoot, comparison between countries, and how to interpret footprint data, with a worked footprint calculation.
9 min answer →

How do tilling, fertilizing and grazing the land slowly wear it out?

Topic 5.4 The Impact of Agricultural Practices: explain how tillage, fertilizer use, overgrazing and other farming practices degrade soil and water.
A focused answer to APES Topic 5.4, covering how tillage, fertilizer use, overgrazing, and confined animal feeding degrade soil and water through erosion, nutrient runoff, salinisation, desertification and waste, with a worked nutrient-loading calculation.
10 min answer →

What does digging minerals out of the ground do to the land and water around the mine?

Topic 5.9 Impacts of Mining: compare surface and subsurface mining and explain their environmental consequences, including acid mine drainage and tailings.
A focused answer to APES Topic 5.9, covering surface mining (strip, open-pit, mountaintop removal) and subsurface mining, their environmental consequences, acid mine drainage, tailings, habitat destruction, and reclamation, with a worked overburden calculation.
10 min answer →

Why have so many fisheries collapsed, and how can fishing be made sustainable?

Topic 5.8 Impacts of Overfishing: explain how overfishing depletes fish stocks, describe destructive fishing methods, and explain sustainable management.
A focused answer to APES Topic 5.8, covering overfishing, fishery collapse, bycatch, destructive methods such as bottom trawling, the tragedy-of-the-commons link, and sustainable management through quotas and sustainable yield, with a worked sustainable-yield calculation.
10 min answer →

How can a farmer control pests with the least possible pesticide and still protect the crop?

Topic 5.14 Integrated Pest Management: describe integrated pest management (IPM) and explain how it combines biological, cultural, mechanical and limited chemical control.
A focused answer to APES Topic 5.14, covering integrated pest management (IPM), its combination of biological, cultural, mechanical and limited chemical controls, monitoring and economic thresholds, and its advantages over relying on pesticides, with a worked threshold example.
9 min answer →

What does it actually mean to use a resource sustainably, and how do we measure whether we are?

Topic 5.12 Introduction to Sustainability: define sustainability and sustainable yield, and explain the indicators used to assess whether resource use is sustainable.
A focused answer to APES Topic 5.12, covering sustainability, sustainable yield, the difference between renewable and non-renewable resources, indicators of sustainability (biodiversity, soil, water, productivity), and the link to natural capital, with a worked sustainable-yield calculation.
9 min answer →

Which way of watering crops wastes the least water, and why does irrigation sometimes ruin the soil it feeds?

Topic 5.5 Irrigation Methods: compare the main irrigation methods and explain the problems of salinisation, waterlogging and aquifer depletion.
A focused answer to APES Topic 5.5, covering flood (furrow), spray, drip and other irrigation methods, their water efficiency, and the problems of salinisation, waterlogging and aquifer depletion, with a worked irrigation-efficiency calculation.
10 min answer →

Why does producing meat take so much more land, water and energy than producing the same amount of plant food?

Topic 5.7 Meat Production Methods: compare free-range and feedlot (CAFO) meat production and explain the environmental costs of meat, including its high resource use.
A focused answer to APES Topic 5.7, covering free-range and concentrated animal feeding operations (CAFOs), the resource intensity of meat (the 10% rule), water and land use, greenhouse gas and waste impacts, and trade-offs, with a worked feed-efficiency calculation.
10 min answer →

How can a city be built so that rainwater soaks in and stays clean instead of flooding the streets?

Topic 5.13 Methods to Reduce Urban Runoff: describe methods such as permeable pavement, rain gardens, green roofs and retention ponds that reduce urban stormwater runoff.
A focused answer to APES Topic 5.13, covering methods to reduce urban stormwater runoff (permeable pavement, rain gardens, green roofs, retention ponds, planting trees), how each restores infiltration and filters pollutants, and their benefits, with a worked runoff-reduction calculation.
9 min answer →

Why does spraying more pesticide often make the pest problem worse over time?

Topic 5.6 Pest Control Methods: compare chemical and biological pest control and explain the pesticide treadmill and the evolution of pesticide resistance.
A focused answer to APES Topic 5.6, covering chemical pesticides, their benefits and costs, biological control, the pesticide treadmill, pesticide resistance through natural selection, and broad-spectrum versus narrow-spectrum pesticides, with a worked resistance calculation.
10 min answer →

How can we grow enough food while keeping the soil, water and biodiversity that farming depends on?

Topic 5.15 Sustainable Agriculture: describe sustainable farming practices that conserve soil and water and maintain long-term productivity.
A focused answer to APES Topic 5.15, covering sustainable agriculture practices (crop rotation, contour ploughing, terracing, no-till, cover crops, strip cropping, agroforestry, rotational grazing) and how each conserves soil and water and maintains productivity, with a worked erosion-reduction calculation.
10 min answer →

How can we keep harvesting wood without destroying the forests that produce it?

Topic 5.17 Sustainable Forestry: describe sustainable forestry practices that reduce deforestation while still supplying timber.
A focused answer to APES Topic 5.17, covering sustainable forestry practices (selective cutting, reforestation, controlling pests and pathogens, sustainable yield, certification, reducing demand), how they reduce deforestation, and their benefits, with a worked sustainable-harvest calculation.
9 min answer →

How did new seeds, fertilizers and machines multiply crop yields, and what did that progress cost the environment?

Topic 5.3 The Green Revolution: describe the methods and benefits of the Green Revolution and explain its environmental costs.
A focused answer to APES Topic 5.3, covering the Green Revolution, high-yield crop varieties, fertilizers, pesticides, irrigation and mechanisation, its benefits for food supply, and its environmental costs, with a worked yield-increase calculation.
9 min answer →

Why do shared resources like fisheries and grazing land so often end up overused and ruined?

Topic 5.1 The Tragedy of the Commons: explain how shared, unregulated resources tend to be overexploited, and describe solutions such as regulation and privatisation.
A focused answer to APES Topic 5.1, covering the tragedy of the commons, why individual self-interest depletes shared resources, examples (fisheries, grazing land, the atmosphere), and solutions such as regulation, privatisation and cooperation, with a worked grazing example.
9 min answer →

How does turning land into a city change the way water, heat and pollution move through it?

Topic 5.10 Urbanization: explain the environmental effects of urbanization, including impervious surfaces, runoff, the urban heat island, sprawl and saltwater intrusion.
A focused answer to APES Topic 5.10, covering urbanization, impervious surfaces and increased runoff, the urban heat island effect, urban sprawl, depletion and saltwater intrusion, and the benefits of smart growth, with a worked impervious-surface calculation.
10 min answer →