1. The Drainage Basin The Hydrological (Water) Cycle: Drainage Basin –
The continuous circling of water between the
land, sea and atmosphere
Drainage Basin –
An area of land drained by a river and its tributaries
Drainage Basin Features
Watershed –
Tributary –
Confluence –
Source –
Mouth –
How does the Water Cycle Work?
Solar Radiation: is the driving force behind the cycle as it enables e____________ to take place from the land & sea
Condensation of the water vapour leads to P_____________. Most of the water that falls on the land is then returned to the sea through River Run-Off and Groundwater Flow
Key Terms:
Evaporation –
Transpiration –
Condensation –
Precipitation –
The Drainage Basin
Drainage Basin As A System
Key Terms
Inputs ~
Stores
Transfers
Outputs

2. River Processes Discharge: With increased distance downstream:
VELOCITY × VOLUME = DISCHARGE
With increased distance downstream:
Discharge increases
Depth increase
Width increases
Bedload increases
Particle size decrease
A: V- Shaped Valley
B: U-Shaped Valley
C: Floodplain
Middle Course
In the middle course the angle that the river flows down is less steep
The river begins to meander and the valley sides are also less steep.
What factors affect drainage?
Discharge varies downstream with changes in:
Urban Area
Rural / Forested Areas
Upper Course
The upper course is the highest section which is found in the mountains
Here the river erodes a v-shaped valley, the path is fairly straight and it flows downhill steeply.
Lower Course
The lower course has the gentlest slopes.
This almost flat land is
known as the flood plain.
The river may have very large meanders and ox-bow lakes before it enters the sea.
River Processes
Transportation
Rivers pick up and carry material as they flow downstream. A river may transport material in four different ways:
Solution
Suspension
Saltation
Traction
Deposition
When a river loses energy, it will
drop or deposit some of the material
it is carrying.
Erosion
Erosion involves the wearing away of rock and soil found along the river bed and
banks.
There are 4 main forms of river erosion:
Hydraulic action
Abrasion
Attrition
Solution

3. River Features Floods River Meander Waterfall Causes of flooding
In the middle course the river has more energy and a high volume of water. The gradient here is gentle and lateral (sideways) erosion has widened the river channel. The river channel has also deepened. A larger river channel means there is less friction, so the water flows faster:
The formation of meanders is due to both deposition and erosion and meanders gradually migrate downstream.
The force of the water erodes and undercuts the river bank on the outside of the bend where water flow has most energy due to decreased friction.
On the inside of the bend, where the river flow is slower, material is deposited, as there is more friction.
Waterfall
When a river runs over alternating layers of hard and soft rock, rapids and waterfalls may form. When the river courses over resistant rock, erosion happens slowly, while downstream the erosion occurs more rapidly Often over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, and it will carve deeper into the ridge above it. The rate of retreat for a waterfall can be as high as one and half metres per year.
Causes of flooding
A flood occurs when a river bursts its banks and the water spills onto the floodplain.
River Features
Floods
Floodplain
Case Study- Flood River Derwent- March 1999
Impacts of Flooding
Physical Causes
Human Causes
Heavy rainfall over North York Moors, 250mm in 12 days, as much as usually falls in 3-4mths
Ground in Derwent drainage basin was already saturated by previous rain so it could hold no more
The peat of the North York Moors used to store water like a sponge for days before releasing it to rivers, but people had cut and removed lots of peat
Houses had been built on the fooldplain at Malton making the ground impermeable
A floodplain is the area around a river that is covered in times of flood. A floodplain is a very fertile area due to the rich alluvium deposited by floodwaters. This makes floodplains a good place for agriculture. A build up of alluvium on the banks of a river can create levees
Levees
are natural embankments of silt along the banks of a river, which are often several metres higher than the flood plain.

4. River Management Case Study- River Management River Nene
Location
The River Nene is the tenth longest river in the United Kingdom.
It has a catchment area of 631 square miles (1,630 km2) and a mean flow of 328 cubic feet (9.3 m3) per second.
Flood Risk
The River Nene used to flood frequently at Northampton
Heavy rains on 9th April 1998 caused the River Nene and Grand Union Canal to overflow, flooding parts of the town and leading to two people’s deaths
Flood Management Strategies in Northampton
By 2002 The Environment Agency had completed a £6.8 million project to protect areas of Northampton hardest hit by past flooding.
In 2003 the warning system was upgraded
The areas at risk of flooding are covered by the Environment Agency Flood Warning Service where they aim to give two hours’ notice of the possible onset of flooding
At foot meadow close to the railway station 4m high floodwalls have been installed to protect housing, industry and the Castle inn. This has created an open area of land which the river can flood onto giving protection to the railway station.
Flood Management In Upton
A new housing estate called Upton Square has been built just above the level of the floodplain.
The river channel capacity at Upton was increased by building earth embankments set back 10m from the river which have footpaths along the tops. The area has been visually improved by planting trees.
cost £8 million. Washland created where water can be diverted from the River Nene in a controlled way.
Sustainable River Management
River Management:
Maximising the potential benefits of a river-
Transport, Power, Recreation
Whilst minimising the potential threat to
human life & property
Soft Engineering Strategies
Waslands
Land-use zoning
Afforestation
Hard Engineering Strategies
Dams
Levees, Embankments & Floodwalls
Dredging
Straightening
Storage Areas
River Management