Outline the factors influencing a rivers flood hydrograph.
Outline the factors influencing a rivers flood hydrograph. A flood hydrograph shows river discharge over a period of time. It shows the response of a river to a specific rainfall event. There is usually a time-lag between the peak rainfall intensity and peak flood flow. There are a number of factors that influence a flood hydrograph. A flood hydrograph is split in two, with the baseflow (which is mostly groundwater flow through rock) and the stormflow (overland flow, throughflow and direct channel precipitation) stormflow accounts for most of the hydrograph. The graphs different shapes depend on a number of things, the flatter hydrographs tend to occur if the storm is light whilst the steep ones when there has been a lot of overland flow. One factor that impacts the graph is the type of bedrock. Bedrock can be permeable or impermeable. Impermeable bedrock, like shale, does not allow water to pass though it whilst permeable rocks such as chalk does. There are two types of permeable rock; porous, which contains pours that fill with and store water as well as pervious. Pervious bedrock is cracked and so allows water to run in its joints. An example of this is carboniferous limestone. A basin with impermeable bedrock is likely to produce a much more dramatic hydrograph than one with permeable bedrock. The basins drainage density is another factor. Drainage density is defines
What caused the Soufrire Hills Volcano to erupt?
What caused the Soufrière Hills Volcano to erupt? The Caribbean island of Montserrat is situated on a destructive plate boundary. A plate boundary occurs when two of the plates that make up the surface of the earth meet. Underneath Montserrat the Atlantic plate is slowly being forced under the Caribbean plate. This happens because the oceanic plate is denser than continental plate. Convection currents pull the dense Atlantic plate into the mantle where intense heat and friction cause the rock to melt. This molten rock is lighter than the surrounding rock, forcing it to rise through cracks in the in the rock towards the earth's surface. Molten rock or magma gathers under the volcano until the pressure is so great that it is forced up through a vent towards the surface of the earth. The Soufrière Hills Volcano produces a thick sticky lava called andesite. The lava is so thick that it builds up at the top of the volcano in a dome until it becomes too heavy and the dome collapses. When the dome collapses hot rocks, gases and ash are released from the volcano causing the following hazards. Pyroclastic flows are extremely fast-moving flows of lava, hot rocks and gas that flow down the side of the volcano. Pyroclastic Surges are fast-moving clouds of hot ash that travel with the pyroclastic flow. Tiny pieces of volcanic ash are blasted into the air forming a plume of ash. As it
Decision Making how will we manage the Essex coastline?
Decision Making - how will we manage the Essex coastline? In February 1953 disaster struck Essex. The North Sea flood, a combination of high spring tide and a severe wind storm caused a storm surge. With the tidal surge of the North Sea the water level locally exceeded 5.6 meters. The flood and waves overwhelmed sea defences and caused extensive flooding. Essex, an area hit by subsidence and sea level rise relies highly upon sea defences. Most of the casualties occurred in the province of Jaywick, in Essex 307 people were killed and 22,000 made homeless. This flood also hit the Netherlands, which suffered 1,800 deaths. As subsidence and sea level rise grow worse due to global warming, there is a large chance that Essex if hit by a storm surge again will be very vulnerable. Essex is made especially defenceless as it has also been hit had by isostasy. And this is why I eager you to make a decision upon who we will defend our Essex coastline. There are several areas in Essex becoming increasingly susceptible to flooding. In order to protect these areas action must be taken. This plan provides a long term strategic view on how the balance between losses and gains to Essex can be maintained in the light of rising sea levels, and the flood defence response to it. The plan concludes that Essex cannot be maintained in its present form. Maintaining the present levels of flood
Development is hazardous to natural and build environments
Developing country areas will decrease the amount of poverty throughout all of Asia, including the assistance to the countries economic growth. The development of road built infrastructure, water availability and aid will assist in the reduction of poverty. "Infrastructure development is a driving factor that can affect poverty negatively and positively. Infrastructure is important for poverty reduction. This can be the case where development aid, road construction or water and sanitary investments have been made with poverty reduction in mind." - (Environmental Knowledge of Change) The increased development and aid from more developed countries would help reduce the amount of poverty in many developing countries, also helping the population's health while helping to deteriorate the amount of poverty driven families. Economic growth can be helped by increasing the amount of contact within inland areas around Asia. "Rapid economic growth in recent years has put enormous pressure on Asia's transport, energy, and communications infrastructure. Unless these can be improved, they will continue to be a bottleneck to growth...Better connectivity with inland areas, for instance, would boost trade and economic growth in both coastal areas and inland...Following the 1997-1998 Asian financial crisis, countries with significant investments in infrastructure recovered faster than
A super volcano is a mega colossal volcano that erupts at least 1,000km3 of material. Super volcanoes do not look like a volcano with a characteristic cone. Instead, they have a large depression called a caldera, often marked by a rim of higher land around the edges. Beneath the caldera is a huge magma chamber, where all the magma is stored before the volcano erupts. Yellowstone is a super volcano in Montana, North America. There is evidence that the magma beneath Yellowstone is shifting. The caldera is bulging up at one end beneath Lake Yellowstone. There are signs of increasing activity at Norris, and the ground has risen as much as 70cm in some places. The magma chamber beneath Yellowstone is believed to be 80km long, 40km wide and 8km deep. It is not known whether the magma is on top of other materials, which would be necessary for an eruption. If Yellowstone, or any other super volcano did erupt, there would be many major effects globally. An eruption is likely to destroy 10,000km2 of land, kill 87, 000 people, and 1 in 3 people affected would die. Ash would be deposited all over the United States, which would affect transport, electricity, water and farming. Harvests would disappear instantly, leaving many people hungry, and the water supplies would get contaminated, leaving hundreds of thousands of people without clean water. Global climates would change, which may
Describe and explain the economic and social costs and benefits of ageing and youthful populations
Describe and explain the economic and social costs and benefits of ageing and youthful populations Ageing populations usually shows that a country is an MEDC, which of course is a good thing. It shows that medical care is very good, diseases are low, diets are nutritional and that there is a good standard of living. The benefits of having lots of elderly people is that the death rate is lower, some provide a service for the country if they are still working and often they are involved in politics using their wisdom to help the country, so in an MEDC an ageing population can be a good thing. However if they are too many elderly then problems start to develop. After all the elderly are part of the dependant population and most, although some do, don't have jobs and contribute to the country and its economy. They do not pay taxes because they are not earning and so just take money from the country in the form of state pensions and other social security benefits. The young and active population therefore has to work hard to support the dependant population so that they can obtain their pensions. However if there are too many elderly people then the country, for example the United Kingdom, which has an ageing population will become very strained. They are too many elderly dependant people to support, this occurs when the active population cannot equal by working the amount of
Why do similar kinds of hazards have different impacts in different places?
Why do similar kinds of hazards have different impacts in different places? Similar kinds of hazards can cause a different scale of impact in different places due to many factors, the main influence being the countries economy. A hazard is an unexpected event or process which affects people, causing loss of life or injury, economic damage, disruption to people's lives or environmental degradation. A natural hazard could become a disaster when is has serious effects such as a large loss of life or property. The disaster risk has many factors which could increase or decrease the risk. This can be shown in an equation; Disaster Risk = Hazard X Vulnerability Capacity Hazard relates to the frequency of the hazard or the scale of the hazard, for example the magnitude of an earthquake, or the height of a wave. Vulnerability is the conditions determined by physical, social, economic and environmental factors which increase the susceptibility of a community to the impact of hazards. Capacity is the combination of strengths and resources available that reduce risk. Hurricane Katrina, 2005, New Orleans. Hazard: Hurricane Katrina passed east of New Orleans and winds downtown were in the Category 4 range with a minimum central pressure of 902 millibars and frequent intense gusts and tidal surge. 80 percent of New Orleans was flooded, with some parts under 15 feet of water.
Why is Antarctica so important?
The last great wilderness is very important to us and to everyone else. This unique, wonderfully, and beautiful place is a place almost entirely covered with snow and ice, it maybe doesn't look like the most important thing in the world but it is one of those things that is made important. The continent of Antarctica is important to us because it has become an international science laboratory where scientists study its weather and climate, oceanology, meteorology, astronomy, ozone layer, marine life and geology. We are only now beginning to realize the profound effects that Antarctica has on our environment and way of life. Antarctica may hold the key to understanding food chains, and the role of plankton in those chains. It is possible that these small organisms form the base of the ecosystems that support all living things. The continent of Antarctica is also important because it is thought to have large deposits of valuable mineral resources including platinum, gold and silver. Coal in commercially attractive deposits has been found, but no other minerals are known to exist in potentially useful amounts. Large deposits of oil and natural gas are believed to exist in Antarctica's continental shelf. In understanding global change the Antarctic has a crucial role to play. Locked up in its 4 km thick ice sheet is a record of past climate for the last 500,000 years.
Marine Pollution I am writing to convince the UK Government that it is time to take action to protect the seas around us. The harm being done to our oceans is damaging in many ways - not least because with increasing speed, we are severely depleting the world's stock of fish. For four centuries the seas have been considered on inexhaustible resource from which people could take as much as they wanted. Now we have to face up to the fact that our oceans are not limitless - more and more people competing for less and less fish are which is making the existing crisis worse. Many marine ecosystems are at the point of collapse and will be destroyed unless we act quickly to protect them from the most serious threats. Pollution from ships Ships can pollute waterways and oceans in many ways. Oil spills can have devastating effects. While being toxic to marine life, polycyclic aromatic hydrocarbons (PAHs), the components in crude oil, are very difficult to clean up, and last for years in the sediment and marine environment. Discharge of cargo residues from bulk carriers can pollute ports, waterways and oceans. In many instances vessels intentionally discharge illegal wastes despite foreign and domestic regulation prohibiting such actions. Ships create noise pollution that disturbs natural wildlife, and water from ballast tanks can spread harmful algae and other invasive
Why did so many people die in the Kobe Earthquake?
Why did so many people die in the Kobe Earthquake? Kobe is a major city in central Japan, its population is 1,528,948. It is situated on a minor fault, the Najima fault line. It lies above a destructive plate margin, hence why Japan has so many volcanoes. At 5.46pm, 17th January 1995 an earthquake measuring 7.2 on the Richter scale and lasting for 30 seconds, struck Kobe. This colossus earthquake was caused by "The Philippines plate" and the "Pacific plate", (Oceanic Crust) getting forced downwards when pressure was applied to it by the Eurasian plate (continental crust). The seismic waves caused by the plates rippled through the earth's surface. As well as causing earthquakes these events can cause Volcanoes. The magma rises out of the earth and out of the cracks which have been formed. Although this earthquake may seem big, it is still relatively small compared to the ones that the American people have to endure in San Francisco and California. These one's reach 8-9 on the Richter scale! They are located on the "Ring of fire", which also lies above a destructive plate margin. As you may or may not know, Japan is basically an island made up of volcanoes sticking out of the ground. This means there is very little flat land other than at the base of the volcanoes. Due to this, it is very crowded and congested. Believe it or not the population Of Japan is 124