Hydrosphere Lesson starter: What do we mean by Hydrosphere?

Title: Hydrosphere 05/06/2016 Aims: To find out the relationship water has with the planet Earth. To look at the Hydrological cycle and understand how it works. To find out how river drainage basins effect flooding and river flow. To look at the different features of rivers from their source to their mouth.

Water on planet Earth Why do you think that the study of the Hydrosphere is important to us?

Water on planet Earth Water is extremely important to us! It is a vital resource that we take for granted in countries such as the UK. It is estimated that there will be vast water shortages around the world before 2050 and that it will lead to tension between countries. Many people believe that this could lead to future wars, much like the oil wars of the late 1990’s. We are also at constant risk of flooding and water levels rising over the planet. This all means that studying the Hydrosphere is more important now that it ever has been.

So where is all of our water Take the sub heading: Location of the Earth’s water. Underneath try and write a list of where you think all of the Earth’s water can be found. 4 minutes.

The Hydrological Cycle

Task: The Hydrological cycle You have been given a piece of poster paper in front of you. In your group I want you to explain the Hydrological cycle. Try your best – I don’t expect you to be an expert yet. You may use diagrams.

Part 2 You have now been given a diagram that has no labels on it. You must now try and annotate on the labels that you think should go onto the diagram.

Hydrological Cycle (Closed System) Percolation

Hydrological Cycle (Closed System) Percolation

Hydrological Cycle (Closed System) In your groups write a detailed description of the hydrological cycle and how it works. You should structure it like an exam style question worth 5 marks.

The global hydrological cycle is a closed system. What does this mean? A closed system means that nothing is ever added or taken away. The amount of water in the system stays the same but it is just transferred and stored in different ways at different times. Copy

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The Hydrological cycle Heat from the sun results in evaporation of water from the oceans Moist air is blown inland; advection Condenses further as it rises over mountains Precipitation falls Rainwater returns to the sea/oceans via rivers and streams ; or overland flow

The Hydrological cycle Some precipitation falls as snow. Snow and ice stored in glaciers, so slow down the rate of return of moisture Water can infiltrate the soil and moves slowly down the slope; as throughflow Or percolating into the rock stored as groundwater store Vegetation take up water and through photosynthesis release water for evaporation as transpiration. Also known as evapotranspiration. Process starts again when water returns back to the ocean Closed system; no water is lost or gained through the process

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Hydrological cycle lesson 2 Drainage Basins 05/06/2016 Aims: To find out what we mean by drainage basins. To look at the hydrological cycle of a drainage basin.

Lesson starter: Answer the following questions: 1)What are labels 1-9? 2)Is the hydrological cycle a closed or open cycle? Answer the following questions: 3) Describe the global hydrological cycle.

What is a drainage basin? A drainage basin is an area of land drained by a river and its tributaries (river system).

Drainage Basins: A drainage basin is the catchment area of a river and its tributaries. The boundary of the catchment area is called the watershed. Drainage basins involve water being returned to the oceans as part of the global hydrological cycle. What is important in drainage basins is not the size of the basin but how much water flows through it.

Watersheds /meec/module01/whatis watershed.htm /meec/module01/whatis watershed.htm

Diagram of drainage basin.

The hydrological cycle of a drainage basin. An OPEN system means that it has INPUTS and OUTPUTS.

Out of the boxes here which ones are inputs, outputs and processes (storage or movement)? Soil Infiltration Rivers flowing into the sea Interception Surface Storage Precipitation Groundwater Percolation Evaporation Soil Moisture Storage Overland Flow Throughflow

INPUTSTRANSFERSOUTPUTS PrecipitationInterceptionEvaporation Surface StorageRivers flowing into the sea Soil Infiltration Soil Moisture Storage Percolation Groundwater Overland Flow Throughflow

The Drainage Basin is an OPEN system An OPEN system means that it has INPUTS and OUTPUTS.

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Past paper question: “A drainage basin is an open system with four elements—inputs, storage, transfers and outputs.” Describe the movement of water within a drainage basin with reference to the four elements above. 7 marks

Inputs The main input to the system is precipitation. The type of precipitation (rain or snow, etc), the intensity, the duration and frequency all have an effect on the amount of water in the system. Each subsystem of the drainage basin system will also have inputs and ouputs, and the output from one stage of the diagram will form the input for another. Storage Water is stored in a drainage basin on the surface in lakes and channels or underground in the groundwater store. Water reaches the groundwater store via the processes of infiltration and percolation. During these processes, some water will be stored in the soil and rock. The amount of water stored will vary depending on the porosity of the soil and on the permeability of the rock. Water can also be temporarily stored via interception. This refers to the storage of water on leaf and plant stems. Dense foliage may result in little water reaching the ground, since it often evaporates from the leaves. Transfer The sum of all the water flowing over the drainage basin’s surface is called runoff. It is made up of streamflow, which is flow through permanent river channels and overland flow or surface runoff. Overland flow transfers water through the basin either as sheetwash, across the surface, or in tiny channels called rills. Beneath the surface, water is transferred via throughflow, which is the movement of water through the lower soil towards rivers, and groundwater flow. Groundwater flow is typically very slow. Water that has been intercepted by foliage may also be transferred, either directly as throughfall, or by running down branches and stems via stemflow. Outputs The final release of the water in a drainage basin is known as its output. Typically, rivers flowing into the sea will be the main output of a drainage basin. Some water will also be lost via evapotranspiration. This process refers to direct evaporation, and also to the extend that moisture lost from leaves will result in plants withdrawing water from the soil via their roots.

Factors affecting a drainage basin output What factors do you think affect the output/discharge of a river basin? (What factors make the water flow out faster or slower) Can anyone think of an answer? Take 2 minutes to discuss and come up with ideas.

Factors affecting a drainage basin output Interception Relief Soil Rock type Drainage density Other use of the river Land use Now that you know some of the factors discuss how you think each one could affect output.

Interception Water can be intercepted in many different ways and this can greatly affect the river basin discharge. More trees and vegetation means that discharge will be decreased as water is stopped and stored.

Relief How steep is the land? If it is very steep then water will run through the basin quickly and it will have a greater discharge. If it is flat then the opposite will happen as the water will flow gently, reducing discharge.

Soil If the soil is very thin in an area then there will be less infiltration (percolation) and therefore groundwater flow and through flow will happen more quickly leading to a greater discharge. If the soil is thick and takes up a lot of water then this will mean that the discharge is less as it is stored in the soil.

Rock type If the rock type is impermeable (water can’t get through it – granite for example), then you will get far more surface run off. This increase the speed of water discharge. If the rock is permeable – chalk for example then you will get more through flow and groundwater flow, reducing the speed of water discharge.

Drainage density The higher the drainage density the greater the discharge. The more streams that you have the greater the drainage density will be. (Drainage density is the total length of all the streams and rivers in a drainage basin divided by the total area of the drainage basin.) streamsriversdrainage basin

Drainage density (Drainage density is the total length of all the streams and rivers in a drainage basin divided by the total area of the drainage basin.) streamsriversdrainage basin

Other use of the river If the river is not used for other reasons (by humans) then output is generally increased. If the river is used for industry, HEP, reservoirs, irrigation or domestic use – all of these will decrease discharge.

Land use If it is urban then there will be an increase of tarmac (impermeable layer) and drains which increase runoff. Urban also means less trees and forestry– this will mean less trees for interception and exposed soil, increasing output speed.

Land use Rural areas mean less tarmac, drains and concrete. Trees and crops mean more interception decreasing output.

Lot of vegetation Urban area Rural area HEP station Thick soil Impermeable rock

Lesson plenary Think, pair, share: Working in 2’s you will answer the following questions and be ready to feed back. Q1) Is the hydrological cycle of a drainage basin a closed or open system? Q2) In what ways is water stored in a drainage basin. Q3) What factors affect the output of a drainage basis?

Extension work below:

Task 1: Using your New Higher Geography textbook, page 12. Answer question (a), (b), (c) and (d) in Activity 2. You have 30 minutes to do this

Task 2 With the aid of an diagram, describe the movement of water within the drainage basin system. You have 15 minutes to answer this question