Make it flood.
Build a storm hydrograph from rainfall, soil and concrete; push sediment along a drifting coast; and watch a city grow its own heat island.
Build a storm hydrograph
FIG. 01 · WATER CYCLE · DRAINAGE BASINS · 3.1.1Total depth over the whole basin. Depth is not the same as intensity — that is the next slider's job.
Same rain in half the time doubles intensity — and intensity is what beats infiltration capacity.
How wet the basin already was. Saturated soil has almost no storage left, so rain becomes overland flow.
Tarmac, roofs and drains. They remove infiltration and shorten the route to the channel.
Interception storage and stemflow delay water; roots keep infiltration capacity high.
0 = long and thin (tributaries arrive one after another). 100 = circular (they all arrive at once).
Why this is worth your time. Hydrograph questions are pure AO2: you are handed a graph and asked to explain the shape, not describe it. Every mark comes from linking a basin characteristic to lag time or peak discharge — and then to the risk downstream. Move one slider at a time and write the sentence you would use in the exam before you move the next.
Longshore drift, and the bill downdrift
FIG. 02 · COASTAL SYSTEMS · SEDIMENT BUDGET · 3.1.3Angle between the wave crest and the coastline. Transport peaks near 45° — head-on waves move almost nothing along the shore.
Stand-in for fetch and wind. Transport rises steeply with height, so a handful of storms can do a year's work.
Cliff erosion and rivers feeding the cell. Dam the rivers or armour the cliffs and this is the number that falls.
Hard engineering across the drift. Each one traps sediment on its updrift side.
The exam point. A sediment cell is a system with inputs, stores, transfers and outputs, and the whole of coastal management is an argument about whose part of the budget you are allowed to spend. Groynes do not create sediment — they move where it sits. Terminal groyne syndrome (accelerated erosion immediately downdrift) is the standard evaluation point for any hard-engineering answer.
The city makes its own weather
FIG. 03 · URBAN CLIMATE · HEAT ISLAND · 3.2.6Deep street canyons trap long-wave radiation at night and cut the sky view factor, so heat cannot escape upwards.
Evapotranspiration spends energy as latent rather than sensible heat. Parks show up as cool islands inside the warm one.
Vehicles, industry, air conditioning and bodies. A direct energy input the countryside does not have.
The heat island is strongest on calm, clear, anticyclonic nights. Wind mixes it away — and smears what is left downwind.
What the mark scheme wants. "Describe the shape" is worth almost nothing on its own. The credit is in the sequence: surface property → energy balance → temperature → consequence for people (heat stress, air quality, energy demand). The plateau, the cliff at the urban edge and the park dips are the three features worth naming by name.