Rivers Unit
9 modules covering where the rain goes. the drainage basin system, the processes that shape a river, its landforms from source to sea, and how people live with rivers — built for the 2027 cambridge igcse syllabus
Your route through the unit.
Start anywhere — M1 is the gentlest way in.Module 1
The Water Cycle & Drainage Basins
Where does the rain go? The drainage basin as an open system inside the closed global water cycle — and the one decision every drop makes when it lands, which decides how fast the river responds.
Module 2
River Processes
A river breaks rock, carries it, and drops it. Erosion, transportation and deposition are not three topics — they are three answers to one question: does the river have enough energy for this particle?
Module 3
The Long Profile & the Bradshaw Model
The slope gets gentler all the way to the sea — so why does the river get faster? Six things you can measure in a channel, one you can only calculate, and an idealised model of what changes downstream.
Module 4
Upper Course Landforms
Six landforms, one contest: the river’s cutting energy against the resistance of the rock. It is WHERE the resistant rock sits — the geometry — that decides which one you get.
Module 5
Meanders & Ox-bow Lakes
The middle course, where the river starts to swing. Why the fastest water drifts from bank to bank, how a river cliff and a slip-off slope grow as a pair, and how a bend migrates until the river cuts it off as an ox-bow lake.
Module 6
Landforms of the Lower Course
The river has almost no slope left to fall down — so how does it build the biggest landforms on its whole journey? One sorting rule, applied three times: floodplains, levées and deltas.
Module 7
Living with Rivers — Opportunities & Hazards
Millions of people choose to live beside rivers that flood — why do they stay? Opportunity and hazard are not two lists: they are the same process seen from two sides, and the balance does not fall the same way for everybody.
Module 8
River Floods & Management — Bangladesh
A flood is a river event; a disaster is what happens when that event meets exposed, vulnerable people. Bangladesh sits at the bottom of a basin that is 93% somebody else’s territory, so it cannot manage its own causes — only its own exposure. The depth study for the 2027 syllabus.
Module 9
River Pollution — the Yangtze, China
Almost all river pollution is human-made, and the biggest source is the one with no pipe to find. The Yangtze was written off and has genuinely come back — at the cost of 231,000 livelihoods and two species that are not returning. The depth study for the 2027 syllabus, and the last module of the unit.