DL: The River Wye Flashcards
1
Q
Describe the course of the River Wye
A
- (Source) Plynlimon, Rhayader, Builth Wells, Hay-on-Wye, Hereford, Ross-on-Wye, Symonds Yat, Monmouth, Tintern, Chepstow (mouth)
2
Q
Where is the source of the River Wye?
A
- Plynlimon - Plynlimon Hills in Cambrian Mountains
- 690m above sea level
3
Q
Describe the geology at the source (Plynlimon)
A
- Gritstone, mudstone and shales - sedimentary rock which is easy for the river to erode vertically
- Thin soils
- Impermeable surfaces leads to more surface runoff
4
Q
Describe the climate at the source (Plynlimon)
A
- 2650mm rainfall a year
- Heavy rainfall due to relief rainfall = surface runoff
- Cold temps due to altitude = freeze thaw weathering
5
Q
How does the climate and geology work together at the source?
A
- More rain means more erosion creating V-shaped valleys
- Mass movement on the valley sides contributes material to the river
- More sediment in the river means more abrasion
6
Q
Describe what happens at Rhayader
A
- 219m above sea level
- Rapids form here due to alternation bands of less and more resistant rock
7
Q
Describe what happens at Bulith Wells
A
- 130m above sea level
- Valley begins to widen as the Wye begin to migrate across the floodplain and form meanders
- Lateral erosion is more important
8
Q
Describe what happens at Hay-on-Wye
A
- 97m above sea level
- River enters its middle course, meanders move across a wider floodplain and creates an ox-bow lake as they migrate
9
Q
Describe the geology at the middle course (Hay-on-Wye)
A
- Sandstone, more easily eroded allowing the river to erode laterally (side by side)
- Horse-shoe bend is an oxbow lake
10
Q
Describe what happens at Hereford
A
- Biggest settlement on the River Wye
- Downstream of Hereford the floodplain starts getting wider as the valley floor is flatter
- The river Lugg joins the Wye as a tributary, bringing more discharge
11
Q
Describe what happens at Ross-on-Wye
A
- As the floodplain as developed at Ross-on-Wye, levees have formed. Over time the levees become vegetated
12
Q
Describe what happens at Symonds Yat
A
- The meanders of the Wye are deeply incised forming a gorge as the river is unable to erode more resistant outcrops of limestone
- Important tourist feature
13
Q
A
At Chepstow the Wye and Severn have their confluence. At this point both the Severn and Wye are tidal and suspended sediment can be seen in the rivers.
14
Q
A
- In the past, humans have altered the Wye’s course and drainage basin in ways that have exaggerated flooding
- Deforestation, poor soil management and building on the floodplain have changed the landscape through which the Wye flows
- People have responded in the past using hard defences to prevent floodwater from reaching properties
15
Q
Natural flood management
A
- Increasing infiltration Into the soils - better soil management techniques
- Slowing the flow of water - creating features which obstruct flow across the river channel or floodplain
- Storing water upstream - water can be stored within the upstream catchment and released slowly
