1. Case Study: Christchurch Bay
An extended stretch of coast.

2. Overview to Christchurch Bay
Christchurch bay is located on the South Coast of England. It is formed between the headland- Hegistbury Head near Christchurch, Dorset and a spit at Hurst, Keyhaven close to the town of Lymington in Hampshire.
Christchurch bay is located within cell 5 of the England and wales sediment cells however this stretch of coast acts as a sub cell on its own with little sediment leaving this area and coming into the area.
Christchurch Bay comprises a 16km section of open coastline exposed to dominant waves from the south-west.
This area of coast erodes at between 1-3m/ year

3. Geology
The rocks and clays forming the Christchurch Bay and Solent coasts include
materials laid down when the Solent was an estuarine river that drained the
Hampshire Basin. These were never subjected to the great pressures that formed
the harder rocks to the west. With rising sea levels after the last Ice Age, the
chalk ridge that formerly linked the Purbecks with the Isle of Wight was
breached, and the former river valley became the new coast, and started to
erode. This led to the formation of Poole Bay. The land to the east was protected
initially by the ironstone outcrop at Hengistbury Head, but in due course this too
eroded and, as sea levels continued to rise, Christchurch Bay began to develop.
The dominant south-westerly wind and waves created a littoral drift of shingle
and sand along the coast in an easterly direction, initially forming the Shingles
Bank which lies between the mainland and the Isle of Wight, and subsequently
forming Hurst Spit.

4. Fetch
Wind action generates waves that impinge on the shore from various directions.
The longer its ‘fetch’ (the distance the wind travels without interruption),
The more powerful are the waves that it generates. Around the District’s coast, winds are strongest in Christchurch Bay, where the fetch varies from 10 km for winds from the north to many thousands of kilometres for those from the south-west, extending across the Atlantic Ocean to the coast of South America.

5. Sediment Cell 5
LSD
wind
INPUT

6. WEST TO EAST Hegistbury Head Mudeford Quay Mudeford/Avon Beach Site 1
Highcliffe Cliffs site 2
Barton on sea site 3
Milford on sea Site 4
Hurst spit site 5

7. Hegistbury Head
Hegistbury Head is a sandstone headland located in Dorset on the south coast close to Christchurch between Southampton and Bournemouth.
HH is a SSSI
The headland on the west side of the bay. The groyne that sticks out into the sea makes sure that sediment from Bournemouth bay doesn’t spread into that of Christchurch bay.

8. Mudeford Quay
Mudeford is where the Avon and Stour flow out of Christchurch harbour into the sea this flow stops Hegistbury head connecting with Mudeford spit.
Hegistbury Head
Christchurch Harbour
Mudeford Spit
Mudeford

9. Mudeford/ Avon Beach Site 1
groyne
Mudeford quay
Mudeford spit
Avon beach is located to the east of the quay. This is one of the sandiest beaches in the bay . This is due to the coastal defences in the area but also due to artificial dredging.
embankment
Sea wall

10. Highcliffe site 2
LSD takes away material from these beaches. And takes it to Hurst
The HH long groyne stops these beaches looking like those at Bournemouth. As less sediment is transferred to this bay.
Friars cliff
Highcliffe castle beach
Site 2

11. Highcliffe site 2A
In this picture you can make out the coastal slump due to the recent bad weather. Naish holiday village sits on top of this cliff. The cliff is retreating at roughly 1m per year.
To Barton
TO HH

12. Barton-on-sea Site 3
Barton beach  -Coastal management: Groynes, Rock armour,  Each stone costs roughly £5000
- Erosion toward the middle of this picture you can see mass movement at Barton- rotational slip - this is due to cliff collapse due to a permeable rock sitting on an impermeable rock

13. Milford On Sea Site 4 Milford - sea wall rock armour
Cliff is very close to sea
this is eroding very quickly
up to 3m per year
rocks have been moved by current storms
The fetch here comes all the way from Brazil, this coast gets battered by storms.

14. Hurst Spit site 5
Currently there is Less material than usual at the spit is due to the recent storms.
Therefore emergency work is in place to rebuild the spit
without this spit Lymington and surrounding area would be under water!
Hurst spit it the headland at the most eastern part of the bay. Hurst spit is formed due to a change in direction on the coast and a river mouth, this creates the spit with Hurst castle on the end of it and Keyhaven salt marshes.

15. Case study – Erosion and Destruction JAN/FEB storm 2014
Highcliffe
Barton
Mudeford
Avon Beach
Milford Beach huts
Milford – marine restaurant
Hurst Spit
Hegistbury Head

17. Sources Ian West - Southampton University New Milton Advertiser
Google Maps