GCSE geography 10 - river tees case study

length of the river tees

length of the river tees

137km

altitude at source

893m above sea level

location of source

Cross Fell, Cumbria Moorlands

annual rainfall at source

2000mm

geology at source

• peat soils

• sands

• shales

geology in upper course

limestone

geology in middle course

limestone

geology in lower course

• sandstone

• alluvium deposits

describe how cold climate at source affects erosion

• cold temperatures = lots of freeze-thaw weathering

• lots of freeze-thaw weathering = sharp bits of rock breaking off into river

• more sharp sediment in river = more abrasion and attrition

describe how high rainfall at source affects the river downstream

• more rainfall = higher carrying capacity of river

• higher carrying capacity = more flooding and erosion in lower course

explain how the geology of the river tees influences geomorphic processes

• more resistant rock in upper course = steep sided valleys and vertical erosion

• limestone is soluble = chemical weathering in water

• different rock resistance at high force = differential erosion

drop size of high force

21m

geology of high force

• resistant rock = whin sill caprock

• less resistant rock = limestone

number of reservoirs along the river tees

9

name of reservoir in upper course of river tees

cow green reservoir

size of cow green reservoir

41 million m³

explain the impact of cow green reservoir on geomorphic processes

• stops flow of river and transport downstream

• creates sediment build up in river

• prevents downstream flooding and deposition

location of meander cut off

stockton

what happened in the meander cut off

the mandale loop was cut off and shortened by 4km

explain the impact of the meander cut off on geomorphic processes

• increases water flow

• increases energy of water = increased carrying capacity

• prevents flooding on the wider loop

what year was the tees barrage opened

1995

what was the cost of the tees barrage

£50 million

what is the size of the tees barrage

70m wide

what is the impact of the tees barrage on geomorphic processes

• prevents flooding of lower course by preventing tidal flows upstream

what is the cost of the yarm flood defences

£2 million

what does the yarm flood defences deal with

1 in 100 year flood events

explain the impacts the yarm flood defences have on geomorphic processes

• earth embankments allow higher discharge in river before flooding = decrease in deposition on flood plains

• gabions reduce erosion of river banks

• concrete gates alter the flow of water

explain why dredging is a different management strategy to others

it is soft management and not hard management of the river

explain the impacts dredging has on geomorphic processes

• increases capacity of river = less flooding

• less flooding = less deposition on floodplains

describe what has been done to manage deforestation along the river tees (afforestation)

• coniferous plants have been planted along the upper course

explain the impacts of afforestation on geomorphic processes

• causes more water to be taken up by vegetation = less surface runoff

• less surface runoff = less chemical weathering

• more water being absorbed = more biological weathering

• more water being absorbed = less eroded material being moved into river

• less water in river = less erosion