Hydrological Cycle
Hydrological Cycle The hydrological cycle is a constant movement of water above, on, and below the earth's surface. It is a cycle that replenishes ground water supplies. It begins as water vaporizes into the atmosphere from vegetation, soil, lakes, rivers, snowfields and oceans-a process called evapotranspiration. As the water vapour rises it condenses to form clouds that return water to the land through precipitation: rain, snow, or hail. Precipitation falls on the earth and either percolates into the soil or flows across the ground. Usually it does both. When precipitation percolates into the soil it is called infiltration when it flows across the ground it is called surface run off. The amount of precipitation that infiltrates, versus the amount that flows across the surface, varies depending on factors such as the amount of water already in the soil, soil composition, vegetation cover and degree of slope. Surface runoff eventually reaches a stream or other surface water body where it is again evaporated into the atmosphere. Infiltration, however, moves under the force of gravity through the soil. If soils are dry, water is absorbed by the soil until it is thoroughly wetted. Then excess infiltration begins to move slowly downward to the water table. Once it reaches the water table, it is called ground water. Ground water continues to move downward and laterally through
Explain how human activity can modify the hydrological cycle.
Geography Essay Question 7 A) Explain how human activity can modify the hydrological cycle. B) With references to examples, outline the results of such modification. Explain how human activity can modify the hydrological cycle. Human activity can modify the hydrological cycle in many ways. The cycle is made up of two components, stores and flows. Stores consist of the atmosphere, for example clouds, oceans, lakes, glaciers and ice caps, ground water and vegetation. The ground water phase of the hydrological cycle represents only 0.6 per cent of the world's water; 2.1 per cent of it is in glaciers and ice sheets, and 97.3 per cent is held in the oceans. Flows include evaporation (contains 453 million m2 per year) and evapotranspiration (contains 72 million m2 per year), condensation (contains 41 million m2 per year), precipitation (contains 525 million m2 per year), runoff (contains 41 million m2 per year) and infiltration. In general humans affect the stores more than they affect the flows, especially when the water is on land. The hydrological cycle is a closed system in which there are no external inputs or outputs into, so these do not have to be taken into consideration. Humans affect the cycle both intentionally and unintentionally in many ways. The stores are affected by the removal of vegetation, the melting of ice caps due possibly to global warming, the usage
How may knowledge of the hydrological cycle and its components assist in devising flood prevention measures?
How may knowledge of the hydrological cycle and its components assist in devising flood prevention measures? The hydrological cycle is responsible for the circulation of water around the Earth, between the different systems in the planet. The knowledge of the entire cycle and its components, including precipitation, the different flows and stores involved in the cycle, one is able to gain insights into the movement of water and thus devise means to prevent floods. The key aspect of the hydrological cycle is that of the water input on land, which is precipitation. Understanding the seasonal variations in the inputs would allow us to gain insights into the seasonality of flooding and possibly even the frequency of flooding in a given area. As such, water at dams can be released at appropriate times so that the lakes can subsequently be used to hold back floodwaters when the high intense precipitation sets in. This way, flooding can be prevented. Precipitation in the form of snow would spend longer time on the land as it flows into channels only when they melt. Knowledge of the volume of water contained in the snow and the time taken for the melting would help assess if the area has the capacity to hold the water formed from snow melt. Flood can be prevented by attempting to melt some of the snow 1 during the winter time and allowing greater
In what way can the hydrological cycle be regarded as a system and what impact may human activity have on flows and stores?
In what way can the hydrological cycle be regarded as a system and what impact may human activity have on flows and stores? The hydrological cycle is a system, in the sense that it shows the global circulation of water/moisture between the atmosphere, land, and the seas and oceans. A system is a series of inputs outputs and outputs, and can be used at any scale. For example it could be either a global hydrological cycle or an individual drainage basin. In the global cycle there are a series of stores, such as the seas and the ice caps. It also contains flows or transfers that link the stores together. For example, evaporation. Water is moved between the stores, and the amount varies depending on the area or the given time. The system is a closed one, which means that no more water is added or lost, as there is a fixed amount. The flows in the hydrological cycle are evapotranspiration, interception, infiltration, and runoff. In a drainage basin hydrological cycle the stores are on the surface, in rivers, lakes, streams, and in puddles. It is also in the soil, deep below the ground surface as groundwater, and on vegetation after precipitation. Human activity plays an important role in the hydrological cycle because large amounts of water are needed in every day life. Large reservoirs are constructed so that water can be collected and then pumped to the areas surrounding
Explain the causes of hydrological hazards.
Explain the causes of hydrological hazards By, Satvinder Singh Sandhu Hydrological hazards are hazards associated with water which has the potential to cause loss of life and possessions whether the threat is direct e.g., death, or indirect threats such as loss of crops leading to famine, but it can be considered that the event is not a hazard if there are no influences on humans. The main hydrological hazards that seem to occur more often are those that provide the most severe effect upon people and because 60% of the world's population live within 60km of the coast, hydrological hazards provide a greater threat than any other hazards. The main hydrological hazards are river and coastal flooding and tsunamis, but other hazards such as tropical cyclones, monsoon s and jökulhlaups are all inter-related. Flooding of river valleys and coastal areas is the most frequent of natural hazards and is one of the most significant for human activity in terms of deaths, injuries and long term social and economic impacts. The numbers affected can be huge and the geographical area relatively large. Flooding regularly claims over 20,000 lives a year and affects 75 million people globally. This is because the attractiveness of river valley and coastal locations for human activity and settlement places large numbers at risk. Impacts can be severe at all levels of economic development.
"The Hydrological Study Of the River Conwy"
GCSE Coursework "The Hydrological Study Of the River Conwy" This project will study the transition of the River Conwy as it flows downstream. It will concentrate on the following variables: * Water Width * Depth * Wetted Perimeter * Gradient * Flow Velocity * Float Velocity * Stone Roundness * Stone Size Another variable we could have measured is the pH value of the water in the river. This would have detected pollution levels as it goes downstream. These 8 variables will provide us with the sufficient information. Aims The aims of the project are: . To investigate changes in the channel form and river processes at different sites downstream on the River Conwy. 2. To identify landforms associated with river processes Hypothesis The following hypotheses were tested: . Downstream, the width will increase. 2. Downstream, the depth will increase 3. Downstream, the velocity will decrease 4. Downstream, the cross sectional area will increase 5. Downstream, the discharge will increase 6. Downstream, the gradient will decrease 7. Downstream, the wetted perimeter will increase 8. Downstream, the bed load size will decrease 9. Downstream, the bed load roundness will increase. Background Information Site 1- (Nant-y-Brwyn) Ref- 792 450 Nant-y-Brwyn was the site highest above sea level and therefore the nearest to the source, which we studied. This site
Nitrogen Cycle
Nitrogen Cycle Most nitrogen is found in the atmosphere. The nitrogen cycle is the process by which atmospheric nitrogen is converted to ammonia or nitrates. Nitrogen is essential to all living systems. To become a part of an organism, nitrogen must first be fixed or combined with oxygen or hydrogen. Nitrogen is removed from the atmosphere by lightening and nitrogen fixing bacteria. During electrical storms, large amounts of nitrogen are oxidized and united with water to produce an acid which is carried to the earth in rain producing nitrates. Nitrates are taken up by plants and are converted to proteins. Then the nitrogen passes through the food chain from plants to herbivores to carnivores. When plants and animals eventually die, the nitrogen compounds are broken down giving ammonia (ammonification). Some of the ammonia is taken up by the plants; some is dissolved in water or held in the soil where bacteria convert it to nitrates (nitrification). Nitrates may be stored in humus or leached from the soil and carried to lakes and streams. It may also be converted to free nitrogen (denitrification) and returned to the atmosphere. The nitrogen cycle is one of the most difficult of the cycles to learn, simply because there are so many important forms of nitrogen, and because organisms are responsible for each of the introversions. Remember that nitrogen is critically
Cardiac Cycle
Cardiac Cycle Organisms require a transport system for several reasons. As the organism gets larger, so the transport system becomes more complex in order to fulfil its requirements. The surface area to volume ratio becomes smaller to the point where a long-distance transport system is required in order to move substances more rapidly. These systems have two primary functions: to link the interior of the organism with the outside world and to link each cell and organ of the organism to each other. Humans are fairly large mammals and so they naturally have a more intricate transport system. The type of system in a human is known as a closed vascular circulatory system. It involves pumping blood around the body at sustained high pressure, which eventually flows back to the heart. The heart is the organ that pumps blood around the body. The transport in humans is also known as a double circulatory system. This means that the system is in two parts: deoxygenated blood is first pumped from the heart to the lungs and then returns back to the heart as oxygenated blood. The second part is when the blood is pumped again by the heart but to the rest of the body to carry out its functions. http://images.google.co.uk/images?hl=en&q=systole-diastole&btnG=Search&sa=N&tab=wi The cardiac cycle is the sequence of events that occur when the heart beats. There are two phases of this cycle:
Life cycle
Chapter 8 Objectives . Understand the concept of a life cycle as a repeating series of processes and phases from one generation to the next. 2. Describe binary fission in bacteria and distinguish the process from cell division in eukaryotes. 3. Outline the general progression and overall results of meiosis and contrast them with the process of mitosis. 4. Explain the ways that meiosis provides possibilities for genetic recombination i.e. independent orientation of chromosomes, random fertilization and crossing over. 5. Understand that crossing over during prophase I produces new combination of genes. Tetrads are formed during prophase I. 6. Name the factors controlling cells growth. 7. Explain the way meiosis provides possibilities for genetic recombination. I. Introduction. A life cycle is the sequence of life forms (and the processes forming them) from one generation to the next. . Sexual reproduction involves passing traits from two parents to the next generation. 2 . Asexual reproduction involves passing traits from only one parent to the next generation. 3 . Cell division is the basis of all of the processes (developmental or reproductive) that link the phases in a life cycle. II. Connections Between Cell Division and Reproduction. A. Like begets (forms) like. (a dog with reproduce forming an likeness of him/her self). . This is strictly true
Carbon cycle
The Carbon Cycle The Biochemical Cycle is the flow of an element through the living tissue and physical environment of an ecosystem; eg, the carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus cycles. The carbon cycle involves the movement of carbon from the air, into plants, animals, people, the Earth and back into the air. Carbon is cycled around the world by different physical, chemical and biological processes. Carbon is a key element on Earth because many organic molecules are made of carbon. On short time-scales carbon is transferred among living organisms, the atmosphere, the land, and the oceans by, for example, physiological processes such as photosynthesis and respiration. On longer, geological, time-scales weathering of rock releases carbon dioxide to the atmosphere. Carbon is the fourth most abundant element in the Universe and is the building block for all living things. The conversion of carbon dioxide into living matter and then back is the main pathway of the carbon cycle. Plants draw about one quarter of the carbon dioxide out of the atmosphere and photosynthesize it into carbohydrates. Some of the carbohydrate is consumed by plant respiration and the rest is used to build plant tissue and growth. Animals consume the carbohydrates and return carbon dioxide to the atmosphere during respiration. Carbohydrates are oxidized and returned to the
