River Management - Melton Mowbray, Leicestershire

Where is Melton Mowbray?

Melton Mowbray is a market town world renowned for it's food, most famously perhaps are its pork pies and stilton cheese. It is the 'Rural Capital of Food'.

It is located in Leicestershire, 19 miles NE of Leicester.

Map Showing Leicestershire in England

                     

In 1998 Melton experienced the worst floods for some time. They were 1 in 50 year floods and inundated much of the town.

Melton 1998

In response a Flood Management Scheme was proposed and implemented. Management schemes were put onto the River Eye, which becomes the River Wreake west of Melton, and the Scaffold Brook.

COST : Over £7 million

Completed :  2003

What did they do?

Both Hard and Soft Engineering methods were employed in the scheme.

Some examples are below-

Hard Engineering

1. Scalford Brook - Water storage. 

An earthen dam holds back the water and controls the river discharge into the town centre.

2. Brook Crescent, Asfordby Valley 

Brick flood wall to protect 20 homes

3. Brentingby Dam 

Concrete dam and steel pilings inserted to stabilise river bank and railway above. On the River Eye.

The dam cost £6.7 million it protects 650 homes by restricting the flow of the river.

Soft Engineering and Sustainable Management

The area upstream from the Brentingby dam is a SSSI (Site of Special Scientific Interest) as the river meanders freely and is home to crayfish as well as other species of birds, mammals, invertebrates and so on. However, it is also heavily cultivated. 

1. Flooding of fields

The surrounding fields can be flooded to a height of 4.5m above the current flood plain

2. Green Engineering - Green sediment filters 

- densely planted willow and hazel will trap sediment upstream from the SSSI.

3. Sediment Traps 

Upstream from Ham Bridge - sediment traps have been dug into the river bed.

4. Green Barriers of Willow

Willow trees filter wash-off from the fields. Filtering chemicals such as Phosphates.

Willow Trees have been planted in the riparian zone (side of the river before the farmland begins)

The Environment Agency were aware that these defences required maintenance and monitoring.

Maintenance

• Debris Removal
• Sediment Removal
• Coppicing of hazel and willow

Monitoring

• Phosphate levels (if too high can lead to eutrophication of water)
• Condition of gravel spawning grounds
• Success of new planting areas
• Presence and type of crayfish
• Success of artificial bat roosts ( Daubenton's and Pipistrelle bats show health of river as they feed on insects over water).

Stakeholders

• Residents
• Melton Borough Council
• Leicestershire County Council
• Business Owners
• English Nature (in area of SSSI)
• English Heritage (in area of ancient monuments)
• Environment Agency

Possible GCSE Questions

• Examine the sustainability of a flood management scheme you have studied.
• How sustainable are flood management schemes?

Here is a Prezi of this information

River Processes

Geomorphic processes (those processes operating at or near the earth's surface) that operate in the river system.

1. Weathering

        - Biological

        - Chemical

        - Physical / Mechanical

Biological - animals, plants and humans burrow or trample the soil and so cause the break up of the surface.

Chemical - slightly acidic water (rain or river) reacts with the rocks and dissolves them eg limestone or chalk as these rocks are Calcium carbonate (CaCo3).

Physical / Mechanical - eg Freeze thaw. Diurnal temperature change above and below freezing causes water to freeze and then thaw in cracks in the rock. Freezing widens the cracks as the water expands, on melting more water can enter the crack and then freeze again, as this is repeated. 

2. Processes of Erosion

• Hydraulic Action - the shear power of the water erodes the river bed and banks as water and air is forced into weaknesses in the rock.

• Abrasion / Corrasion - the river uses the load of the river to abrade or scrape away at the bed and the banks

• Attrition - pebbles and rocks knock into each other and break into smaller pieces (tools for abrasion)

• Corrosion / Solution - minerals such as Calcium in the rock are dissolved by the slightly acidic river water.

3. Processes of Transport

• Traction - the largest material, such as boulders in the river is rolled along the bed

• Saltation - smaller material, such as gravel (too large for suspension) bounces along the bed

• Suspension - silt is carried in the water. If there is a lot of suspended sediment then the river will look 'muddy'.

Tsavo River, Tsavo West

• Solution - dissolved material is carried by the river. Particularly in limestone or chalk areas. 

Earthquake and Volcanic Eruption April 2015

Chile has seen the eruption of the volcano, Calbuco; whilst Kathmandu, Nepal has just been struck by a devastating Earthquake.

Calbuco has erupted without warning for the first time in over 4 decades. The volcano sits in the southern Andes - a destructive (subductive) plate boundary. The Nazca oceanic plate is subducted below the continental South American plate.

Location of Calbuco, Chile

Flights have been cancelled and or diverted due to the ash cloud that has drifted 20 km up into the atmosphere. 5000 people have been evacuated from the surrounding areas.

Ash has rained down. Remember volcanic ash is not like dust, but is powdered rock. Once mixed with water it becomes like a cement, so can be deadly if inhaled. It can lead to lahars if mixed with snow melt or flood waters.

Excellent footage of eruption

Meanwhile in Kathmandu, Nepal an earthquake of 7.8 has shaken the region. It has caused mass destruction in the towns in the central Nepal region as well as avalanches in the Himalayas. This is the worst earthquake to hit Nepal for 80 years. 

The region lies on a Collision Plate Boundary where the Indian sub-continent (Indo-Australian plate - Continental) is colliding with Eurasia; a Continental plate also. As the Indo-Australian plate continues to plough into Eurasia the Himalayas continue to rise and earthquakes are a common occurrence. 

The location and magnitude of this earthquake, as well as it's shallow focus are the reasons why this particular earthquake has been so destructive.

Over 1000 people have died in Nepal and this is number will probably grow with many wounded and many trapped under rubble. There were also victims in Bangladesh, Tibet and on Mount Everest. 

Immediate responses have included

USA - £0.7 million and a disaster response team have been employed USAID

Other aid has been pledged by the UK, France, India and Pakistan.

Nepal Earthquake BBC Report 25 April 2015

Nepal Earthquake BBC 26 April 2015

Supervolcanoes

What is a Supervolcano?

• The term "supervolcano" implies a volcanic center that has had an eruption of magnitude 8 on the Volcano Explosivity Index (VEI), meaning the measured deposits for that eruption is greater than 1,000 cubic kilometers (240 cubic miles). 

• The VEI scale was created as a general measurement of the explosivity of an eruption. 

• All VEI 8 eruptions occurred tens of thousands to millions of years ago making the volume of ejecta or deposits the best method for classification. 

• An eruption is classified as a VEI 8 if the measured volume of deposits is greater than 1,000 cubic kilometers (240 cubic miles). 

• Therefore a supervolcano is a volcano that at one point in time erupted more than 1,000 cubic kilometers of deposits. Yellowstone, like many other supervolcanoes, has also had much smaller eruptions.

The Formation of a Supervolcano

Cool Geography

Where are Supervolcanoes Located?

Locate the supervolcanoes game

Yellowstone Supervolcano

Where is Yellowstone Supervolcano?

Yellowstone is located in the Yellowstone National Park, NW Wyoming, USA

Diagram of the Caldera

Map Showing the Migration of the Hot Spot below Yellowstone

Yellowstone interactive NGM

Natural Attractions of Yellowstone National Park

Video

Find out some more about the attractions of Yellowstone National Park

Yellowstone Attractions Panoramas

Fact File:

• The Yellowstone Plateau volcanic field developed through three volcanic cycles spanning over two million years and including two of the world's largest known eruptions. 

• Yellowstone is presently the site of one of the world's largest hydrothermal systems including Earth's largest concentration of geysers.

• The magma chamber stretches for more than 90km (55 miles) and contains 200-600 cubic km of molten rock.

• The last major eruption, which occurred 640,000 years ago, sent ash across the whole of North America, affecting the planet’s climate.

• Some believe a massive eruption is overdue, estimating that Yellowstone’s volcano goes off every 700,000 years or so.

• 3 eruptions so far 2.1 million years ago, 1.3 million years ago and 640,000 years ago.

What would happen if Yellowstone Erupted?

What would be the effects short term and long term?

• • • on a local, national, international/global scale

• Social : human life, agriculture (farming/food supply), amenities (electricity, water etc), health, transport / infrastructure
• Economic
• Environmental

Possible effects of an eruption

Eruption of Yellowstone

Links

BBC Supervolcanoes

The World's Biggest Bang

GCSE Bitesize Supervolcanoes

Supervolcanoes Radio Programme

USGS - Yellowstone

National Geographic Magazine Article