The Water Cycle And Water Insecurity Exam Style Questions And Answers

The Water Cycle And Water Insecurity Exam Style Questions And Answers Describe how deforestation is affecting the Amazon basin - The amount of water  returning to the atmosphere by evapotranspiration is greatly reduced — from  75% to 25% of intercepted water. More precipitation enters the river by runoff.  Overland flow increases the amount of soil erosion. Huge quantities of soil are  entering the rivers and causing extensive silting. Mudslides are increasing in  frequency and scale. The flood risk is raised by the faster runoff. Aquifers are  becoming depleted because less water infiltrates to recharge them Name three other ways in which people disrupt the drainage basin cycle - Urban  growth; constructing dams and reservoirs; abstracting water for irrigation Distinguish between a water budget and a river regime - Water budget is the  difference between precipitation and evapotranspiration, which varies from place  to place and seasonally. River regime is the seasonal variation in the discharge or  flow of a river and it too varies, but from drainage basin to drainage basin How does climate affect water budget? - It affects the amount of precipitation  received, while temperatures affect rates of evaporation and transpiration Identify three physical factors affecting a river's regime - Amount and intensity of  precipitation; geology and soils; vegetation cover How do you explain the seasonal variations in runoff when rainfall is evenly  distributed throughout the year? - The lower runoff during the summer and early  autumn is due to the higher temperatures and high water losses due to  evapotranspiration. Also the dry ground means that much of the rain infiltrates  and percolates below ground What is a storm hydrograph? - A storm hydrograph shows the response of a  river's discharge following a period of rainfall. A critical aspect of the hydrograph  is the lag time between the rainfall peak and the river's peak discharge How does geology affect the shape of a storm hydrograph? - If the geology is hard  and impervious, then the speed of runoff will be such as to result in a relatively  short lag time. If the geology is soft and porous, then runoff will be less and the  water will reach the river more slowly as it takes place below ground. The lag time  will be relatively long Why does urbanisation increase the risk of flooding? - The large areas of concrete  and tarmac mean that most falling rain becomes surface runoff which moves  quickly to the nearest stream or river. Underground drains and sewers also move  water quickly to drainage channels. Because of this swift transfer of water, rivers  quickly reach the bank-full stage and water begins to overspill their channels as  floods What is meant by a store and a flow? - A store is where water is held for varying  amounts of 'residence' time. A flow is the movement of water between stores Identify the three largest stores in size order - 1. The oceans 2. Icecaps and glaciers 3. Groundwater Which two water stores are non-renewable, and why? - 1. Fossil water: old, deep  groundwater from former wetter periods 2. Losses from the cryosphere: melting of ice as a result of global warming Distinguish between blue and green water - Blue water is stored in rivers, lakes  and groundwater in liquid form — a visible part of the hydrological cycle. Green  water is water stored in the soil and vegetation — an invisible part of the  hydrological cycle Why is the hydrological cycle a closed system? - There are no external inputs and  outputs. It is a self-contained entity. Some might argue solar energy, which drives  the cycle, is an input What is the water budget, and why does it vary from place to place? - The water  budget of a place is the difference between the amount of water gained from  precipitation and the amount lost as a result of evapotranspiration. The budget is  in surplus when precipitation exceeds evapotranspiration. It is in deficit when the situation is reversed. It varies from place to place because climate (precipitation  and temperature) does What are the main inputs of a drainage basin system? - Precipitation. Also  possibly water from a tributary basin What are the main outputs of a drainage basin system? - Evaporation,  transpiration and river discharge How does relief affect the inputs and outputs of a drainage basin? - Altitude will  affect the precipitation input (orographic rain or snow). The steepness of slopes  will affect the rate of runoff — the steeper the slope, the faster the rate Distinguish between interception and infiltration - Interception is the process by  which water is stored in the vegetation. Infiltration is the process by which water  soaks into, or is absorbed by the soil How does geology affect the flows in a drainage basin? - Geology affects the  balance of the flows by which precipitation reaches a river. Where the geology is  hard and impermeable (e.g. granite), there will be much surface runoff and  relatively little infiltration and percolation. Where rock is porous, then the balance  will be the reverse with little runoff and much percolation and water reaching the  river via through flow and groundwater flow Describe three different ways of conserving water - More efficient use of  irrigation water; greater use of grey water; filtration technology; water metering