Surpluses in the hydrological cycle - PowerPoint Presentation

Surpluses in the hydrological cycle

Today we are learning this content: 5.5 (a and b and c)

Prepare for learning Complete the key terms Flooding the occurs when intense rainfall has insufficient time to infiltrate the soil, so flows overland Flooding that occurs after the ground has become saturated from prolonged heavy rainfall A flood with an exceptionally short lag time - often minutes or hours A type of glacial outburst flood that occurs when the dam containing a glacial lake fails. Groundwater flooding Flash flooding Jokulhlaup Surface water flooding

A number of environments are more at risk Low-lying parts of flood plains and river estuariesUrbanised areasSmall basins For each of these environments explain why they may be more at risk of flooding – use Hodder p30

What causes flooding? Present new information What meteorological factors cause flooding ? Physical factors! Page 31 and top of p32 Hodder. Use the fig 2.12 too

E xaminers key points Its crucial to have case studies for each one

Flooding - examples Present new information Monsoon rain – Pakistan http:// www.bbc.co.uk/news/world-asia-india-29171823 Prolonged rainfall - The UK Snow melt- Bangladesh For each of these examples, you need to read through the geo factsheet and highlight the key points. You need to formulate notes in your book which helps you to explain why the floods occurred in these places. Be sure where applicable that you make sense of the synoptic chart that is shown. Recap on how monsoons happen: http ://climate.ncsu.edu/edu/k12/. monsoons The Effects: https:// www.britannica.com/science/West-African-monsoon Flash Floods: http://www.bbc.co.uk/news/av/world-europe-29529414 / french -flash-floods-wreak-havoc-in-southern-city-of- montpellier Snow Melt: https :// water.usgs.gov/edu/watercyclesnowmelt.html

Today we are learning this content: 5.5 (a and b and c)

Human causes of flooding Human causes of flooding Climate change River management Change of land use Urbanisation Deforestation

Flood risk in Ashford, Kent Highlight the sheet in your LL booklet with physical and human causes of flooding.

The impact of flooding in UK Winter 2015-2016Read the Geo Factsheet 353Highlight and annotate the following Causes – Hydrological and human – specific named examples Impacts – Social, economic and environmental – long and short term (again a range of named examples are needed

How can we understand flood risk? Flood frequencyThe size of the largest flood event for each year for a particular location is placed in rank order, with Rank 1 being the largest for all available records for any given location. The following calculation is applied to calculate the time interval between floods of a similar size.   T = n+1 M Where T = recurrence interval N = number of years of observation M = rank order  The calculated recurrence level indicates the number of years within which a flood of this size might be expected.Limitations: based on historic data which means similar floods may occur more/less frequently. Climate change would lead us to think events will be more frequent.The floods of highest magnitude will have much longer return periods – While they have the highest impact they may be less likely to occur. Flood return Also known as the flood recurrence interval Estimate of the likelihood of a flood of a certain size recurring. A flood likely to happen once in ten years has a 10% chance of happening in any one year However…. This cannot be used as a forecast as a flood may happen more than once in the same time interval or may not occur at all.

Complete all the LL sheets for 5.5

Extra Exam Question Construct new meaning Using examples , discuss the impact of flooding on people and the environment (12 marks) Level 1: 1-4 marks Level 2: 5-8 marksLevel 3: 9-12 marks