1.3

• What are the three main pathways precipitation can take in the hydrological cycle?

  Precipitation can follow three pathways: infiltration (water soaking into the ground), overland flow (surface runoff), and evaporation. It may also be intercepted by vegetation or buildings before evaporating or infiltrating. Infiltrated water can percolate through rocks and be stored as groundwater in aquifers.
• What is a drainage basin and how is it different from the global hydrological system?

  A drainage basin, also called a catchment area, is the land area drained by a river and its tributaries. It’s an open system, meaning inputs like precipitation are not directly linked to outputs like runoff, evaporation, or percolation. As an open system, a basin can lose more water than it gains.
• What natural factors influence water movement in a drainage basin?

  Solar energy and gravity drive the movement of water, but factors like relief (height and slope), geology (rock permeability), climate (rainfall and temperature), vegetation, land use, and drainage density (network of rivers/streams) determine how precipitation behaves when it reaches the land.
• How does rainfall vary across the UK, and what are the consequences for drainage basins?

  The UK has three main rainfall types: orographic (relief), frontal, and convectional. Western basins get more rain due to moist Atlantic air hitting high ground (orographic), while eastern basins are drier due to being in a rain shadow. In summer, eastern basins may get flash floods from convectional thunderstorms due to hot, dry ground.
• How do human actions affect drainage basins and the local hydrological cycle?

  Human impacts include over-abstraction, which depletes groundwater and can dry up rivers. Deforestation disrupts interception and infiltration, especially in tropical forests where thin soils rely on tree cover to regulate water movement. Urbanization also increases impermeable surfaces, speeding up runoff and reducing infiltration.