Factors Influencing the Hydrological System (Edexcel A Level Geography): Flashcards

Wetlands help by reducing flooding, lowering air temperatures and improving water quality.

True.

Drying of wetland soils speeds up decomposition, which can release more carbon dioxide and contribute to climate change.

Over-abstraction of surface water and groundwater aquifers lowers water stores, making regions more vulnerable when rainfall is below average.

Climate change, deforestation, overgrazing, over-abstraction for irrigation and very high per capita water use all intensified the Millennium drought impacts.

Physical atmospheric processes such as intense storms, prolonged rainfall, and snowmelt that create surplus water in the hydrological system and trigger flooding.

Intense storms produce precipitation rates that exceed infiltration rates, causing rapid surface runoff, a short lag time, and rivers quickly exceeding their bankfull capacity.

During monsoon conditions, soil becomes saturated so infiltration cannot increase, leading to more surface runoff.

Rapid snowmelt over frozen or impermeable soil prevents infiltration, so surface runoff rises quickly and river discharge increases sharply.

The removal of forest vegetation, which reduces interception and infiltration, increases surface runoff, shortens lag time, and raises peak discharge in rivers.

In overgrazing, animals compact soil, reducing infiltration and increasing surface runoff.

Urbanisation adds impermeable surfaces, culverts, bridges and ramps, which reduce infiltration, speed runoff into rivers, and often build on natural floodplains.

False.

Channelisation can lower flood risk locally but often displaces high flows downstream, increasing silting or flooding in other locations.

If embankments or levees are breached, the scale of flooding is often much greater.

Consequences of flooding for people and the economy, including loss of life, property damage, disrupted infrastructure, loss of income, and long-term psychological effects.

Environmental impacts include loss of habitats and pollution of waterways, but also soil replenishment and groundwater recharge in some cases.

False.

Natural systems often benefit from moderate flooding through nutrient redistribution, wetland recharge, and triggering breeding or migration.

In the UK, extreme weather events are four times more likely than in 1970, increasing flood risk.

A hydrological store is a part of the water cycle where water is held for a period, such as ice, oceans, soil, or groundwater.

Climate change is expected to reduce stores like ice and groundwater and increase flows such as runoff and streamflow, though there is still uncertainty.

Higher temperatures create a negative mass balance in glaciers, shrinking them and reducing water available for people.

Warming oceans may see increased evaporation and more intense tropical cyclones.

Climate warming melts permafrost, releasing methane, which strengthens the greenhouse effect and alters tundra ecosystems.

Evapotranspiration is the combined loss of water vapour from evaporation at surfaces and transpiration from plant leaves to the atmosphere.

Warmer air holds more moisture, so rainfall intensity and frequency increase in tropics and high latitudes, while 10°–30° north and south may see decreased precipitation.

False.

Soil moisture may increase where rainfall rises and decrease where it falls, so overall climate change impacts on soil moisture are uncertain.

In many northern regions, snowfall is increasingly replaced by rain due to warming.

Water security is reliable access to sufficient, safe water for health, livelihoods and ecosystems, while managing water-related risks such as droughts and pollution.

Rising land and sea temperatures could make ENSO cycles more frequent, creating more unreliable rainfall, floods, droughts and possible monsoon failures.

True.

Reduced snow and glacier melt threatens downstream communities, especially in mountain regions, by cutting a vital dry-season water supply.