Coasts Revision

Focus on Case Studies CASE STUDY: Two Geologically contrasting coastlines CASE STUDY: One Coastal Ecosystem CASE STUDY: Retreating Coastline, causes, impacts and management

GEOLOGICALLY means- Rock, therefore this could be as case study of an area of hard/soft rock or a discordant vs concordant coastline. You could use Pamunugama and contrast this with Holderness. OR- Swanage

Geologically contrasting coastline

Explain the difference between two geologically contrasting coastlines Explain the difference between two geologically contrasting coastlines. Swanage is located in South England and features both a discordant and concordant coastline (see diagram below) Due to this contrasting geology a number of differences can be outlined. The discordant coastline is an areas with alternating bands of more resistant and less resistant rock, in the case of Swanage the coastline consists of sands and clay (less resistant) Chalk (more resistant) and Limestone (more resistant). It is these alternating bands of different rock at a right angle to the sea that create several erosional features. Differential erosion is where the rock is eroded at different rates. Where differential erosion takes place along the Swanage coastline this causes the less resistant sands and clays to be eroded at a faster rate to the more resistant chalk and limestone. This creates bays such as Studland bay and Swanage bay ( located on the diagram) which are large semi circular erosions in the land. Sand is often deposited in these bays due to their sheltered positions to form beaches such as Swanage beach. Inbetween these bays are the areas of more resistant rock which have eroded at a slower rate to create headlands and the features associated with the erosion of a headland such as Old Harry a stack located at the foreland. This contrasts with the features found on the concordant area of coastline where the band of limestone runs parallel to the sea. Less differential erosion takes place in this area therefore the coastline is straighter and the formation of cliffs often takes place such as those at Portland stone cliff. However, features are still formed such as Lulworth cove further along the coast where a weakness in the limestone has been attacked by processes of erosion and weathering (explain these processes to extend your answer!) forming a cove, the cove has eroded into the band of clay that lies behind a narrow entrance in the limestone creating a wider area. The rate of erosion has been slowed by the more resistant chalk creating a horsehoe shaped inlet. Therefore the key differences between a discordant and concordant coastline are the rates of erosion and the features created as a result of this, thus affecting the shape of the coastline.

Coastal Ecosystems

Threats and Management Almost 20% of India’s population lives within 50km of the coastlines. CASE STUDY- INDIA 7.45 4639sqkm of India’s coastline 39 species of mangroves East coast of India lays the largest mangrove ecosystem sunderbans as UNESCO world heritage site and a Biosphere reserve. 8.55The Sunderban Delta is home to many species including the TIGER all adapted to the saline and harsh conditions of the mangrove forests. 9.30 Each year nutrients from the mangroves wash into the oceans which allow fish to thrive; size can increase almost 7 times 10.00 Bay of Bengal acts like a basin allowing nutrients to build up. Creates one of the world s largest brackish 2million tones of fish each year. If the mangroves disappear much of the productivity would too. 3.2 million People supported by the mangroves. Communities more than 11.11400 000 fishermen earn their livelihoods from the mangrove forests. 11.25Also provide natural resources such as food, firewood, timber alluvial rich fertile land and honey gathering. Numerous medicines are also derive from mangroves. PROBLEM 12.00 Coastal communities worried, fish catches are falling, coastal and marine resources are dwindling. Today under great pressure- still being destroyed and degraded. Over the last 3 decades global areas shrinking due to deforestation, degradation, freshwater diversion and conversion to land uses such a shrimp farming and agriculture and human populations have increased. Almost 60% lives in coastal cities and settlements- areas cleared to make way for roads etc. Agriculture run off, pollution and heavy siltation have killed many species of flora and fauna- many disappeared and others are rare. 13.50 During the past 50 years almost 40% of mangrove forest has been lost worldwide- 14.10 India too mangrove shave been threatened but post tsunami awareness has grown leading to better management. Gujarat- what has changed? 1982 lost huge mangrove covers camel grazing and firewood were the two causes which were controlled so the mangrove cover has now been restored- requires scientific intervention 16.10 MANAGEMENT the Indian govt and state forest department has initiated a mangrove plantation along the grove. The project aims to restore the fragmented areas and conserve the remaining raes with the help of volunteers- local, NGOs result can be seen in 15 years Periodic monitoring- rare species identified and protected and a nursery replaces old mangroves. Locals now more aware of the benefits- increasing fish and crabs- 3-5 kg of fish earn about 150 rupees per day 17.55- seminars workshops and visits especially local children and women. Also self help groups to build awareness and involve them in the activities. Objective is to restore the degraded. 3500 km have been forested to stabilize mudflats and embankments. Involves many agencies . 2rs per sapling

In your booklets! Next Lesson- 9 Mark exam questions for coasts Holderness In your booklets! Next Lesson- 9 Mark exam questions for coasts

Sunderbans Attrition Coral Reef Mappleton Kobe Manchester Segregation Bangladesh Cave Spit Holderness destructive mangroves Storm beach Conservative Stack Ecosystem