Sunday, 13 December 2015

The Floods in Cumbria 2015 - Extra Reading

The author, Rudyard Kipling, wrote of his six honest men, these were:

 I KEEP six honest serving-men
(They taught me all I knew);
Their names are What and Why and When 
 And How and Where and Who.
(Source)

and furnished with the details from the floods:

What: Storm Desmond was an extratropical cyclone that directed an atmospheric river (or plume of moisture), which brought record amounts of relief rainfall that led to floods.  
Why: Not such an easy answer, see causes
When: Friday the 4th of December to Sunday the 6th of December 2015
How: Not such an easy answer
Where: the Irish Midlands, the Shannon Basin in Ireland, the Scotish Borders, parts of Lancashire and Cumbria as well as Iceland, Isle of Man, Norway and Sweden
Who:  46,300 lost power

(Source)

Quick Statistics (Source):

  • Highest Wind - 81 mph (130 km/h)
  • Highest Gust - 112 mph (180 km/h) Aonach Mor, Scottish Highlands
  • Damage - Between £400-500 million (Euro 550 - 700 million)
  • Power Outages - 46,300 outages

Timeline (Source):

  • Friday
    • Weather warnings issued across the North West.
    • 7 pm: West Coast Trains between Workington and Carlisle are cancelled due to a landslip
    • 9 pm: A590 at Lindal closed due to flooding
  • Saturday
    • 6:26 am Environment Agency issued 23 flood warnings and 21 flood alerts across Cumbria
    • 2:34 pm Cumbria Police evacuate people in Keswick
    • 3:40 pm Cumbria Police declare a major incident
    • 8:30 pm All services between Carlisle, Preston and Barrow are cancelled
  • Sunday
    • 03:00 am Electricity North West 4,000 properties are without power across Cumbria
    • 11:30 am David Cameron calls a COBRA meeting to address an emergency response to the floods
    • 2 pm North Cumbria Univeristy Hospitals NHS Trust declares an internal major incident as, due to substation being down in Carlisle, the Cumberland Infirmary is forced to use a back-up generator.
    • 3 pm Pooley Bridge at Ullswater collapses.
    • 3:30 pm Network Rail warns that the West Coast mainline north of Carlisle will remain closed for several days after eight feet of water flooded the railway. 

(Source)

"The fold stays empty in the drowned field
And the crows are fatted with the murrain flock"
(Shakespeare - A Midsummer's Night Dream)

How much rain in a field is needed to create a litre of water?

An inch of rain on an acre of land is about 28,000 gallons per acre for an inch of "rain." (Source) 
But in metric?

In terms of volume with a rainfall of 10mm on a square metre of a field receives 0.01cubic metres or 10 litres.
Therefore, a rainfall of 1 mm on a metre square is 0.001 cubic metres or 1 litre per square metre. 
Some places in Cumbria, Honister Pass, experienced 341.4 millimetres of rain (in 24 hours), how many litres is that?

0.3414 cubic metres or 341.4 litres on one square metre.

What is the total amount of water received by a field of five hectares under a rainfall of 15 mm?

Each hectare is 10,000 square metres 
Each hectare is 10,000 square metres x 0.015m 
Each hectare is 150 cubic metres of water
Therefore, 5 x 150 cubic metres of water is 750 cubic metres of water. (Source)

Causes:


  • Climate Change: The Met Office published a paper recently "that for the same weather pattern, an extended period of extreme UK winter rainfall is now seven times more likely to than in a world without human emissions of greenhouse gases". (Source)
  • El Niño - definition: "the El Niño-Southern Oscillation (ENSO) cycle. The ENSO cycle is a scientific term that describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific." (Source) El Nino is the warmer of the two, whilst La Niña is the cooler. This change in the ocean and atmosphere interface does affect global patterns of the oceans and atmosphere. 
  • El Niño: "The Met Office anticipated a wet, stormy start to winter in our three month outlooks, associated with the strong El Niño and other factors." (Source) "More heat means more energy in the system...more moisture in the atmosphere" (Source)  
  • Flood Defences: Helped to delay the flooding, "allowing vital time to prepare and evacuate those most at risk...but the extraordinary downpour overwhelmed them." (Source) They did a lot of river work on the Derwent at Keswick, ensuring water moves downstream more efficiently.Unfortunately, more water is moved downstream - to Cockermouth, where serious flooding now exists (Facebook source). Waterways should meander slowing the flow to an extent that bottlenecks have a high water mark for longer periods but not to flood levels. 
  • Flood Defences, cuts in: "The Government's Climate Change advisors...told ministers there was £500 million hole in their flood defence plans...the shortfall would leave £3 billion of damages...in May 2013...the staff (working on a national adaptation plan) has fallen from 38 to six...the National Audit Office said every £1 spent on flood defences prevented almost £10 in damage". (Source) "...almost all of the money devoted to freshwater flood relief is being spent at the bottom of river catchments. This means waiting until the wall of water arrives before seeking to contain it..."(Source)
  • Impermeable (Impervious) Surfaces: Water falling onto soil is normally absorbed into the ground unless it is saturated and then it flows over land to where it can reach sea level. If the surface is impermeable (for instance concrete or covered in tarmacadam) then it also flows off this and attempts to reach sea level. The greater the percentage of the impermeable surface the greater potential there is for flooding in high rainfall events. (Source)
  • Infiltration: "A study in Wales suggests that rainwater's infiltration rate into the soil is 67 times higher under the trees than under sheep pasture. Rain that percolates into the soil is released more slowly than rain that flashes over the surface...Cumbria's hills are almost entirely treeless." (Source)  
  • Lag Time: "The peak rainfall is the time of highest rainfall. The peak discharge (the time when the river reaches its highest flow) is later because it takes time for the water to find its way to the river (lag time)." (Source) 
  • Rain: "Heavy and persistent heavy rain is expected tonight rain (Friday) throughout Saturday and into Sunday morning". (Source) 
  • Rain, location: "The weekend's record rainfall was associated with a persistent, south-westerly flow bringing a 'river of moisture' from as far away as the Caribbean and the Gulf of Mexico. (Source)
  • Rain, quantity: At Honister Pass (the centre of the Lake District), 341.4 millimetres of rain recorded in the 24 hours upto 1800 GMT on the 5th of December 2015 (beating 316.mm set in November 2009 in Seathwaite, Cumbria). (Source) 
  • River Channels, cleared: "If beaver dams and woody debris slowed the flow of upland rivers, existing flood protection systems would be quite adequate...perhaps the reintroduction of European beavers should be accelerated as a form of urban flood defence." (Source)
  • Saturated soil: "The heaviest rain is expected to fall on saturated high ground in Cumbria and Northumberland...the potential risk of river and surface water flooding in these areas..." (Source)
  • Sea Temperatures: "The ocean temperatures in the West Atlantic are currently well above normal and may well have contributed to the very high levels of moisture in the air masses which unleashed rainfall on the Cumbrian fells." (Source) 

Impacts:


  • Disease
    • Potential waterborne diseases - cholera and typhoid
  • Disruption
    • Heavy Rainfall caused disruption in Appleby, Keswick and Kendal in Cumbria with blocked roads, collapsed bridges and homes evacuated.
    • Many houses in Carlisle flooded
    • Businesses disrupted
    • Farms flooded so disruption to food production. 
    • "Storm Desmond has caused an estimated £500 m of damage across Cumbria", nearly double the cost from six years ago and could rise further. (Source).
    • A major incident has been declared due to extensive flooding across Cumbria. Fire crews have been called to an extremely high number of calls with crews dealing with more than 162 incidents between 7am on December 5 and midnight yesterday (6 Dec) (Source).
    • The Royal National Lifeboat Institution's (RNLI) flood rescue team has been deployed to the area.Cumbria. (Source)
    • "British Red Cross teams set up rest centres in Keswick, Appleby and Kendal, while medical groups issued an urgent call to draft in extra doctors amid fears the storm could cause casualties." (Source) 
    • Clear up of contaminated houses - 
      • water may contain sewage effluent from flooded sewage works.
      • There is also the removal of silt, water damaged plaster board, the drying out of houses.
      • The removal of water damaged property and awaiting the insurance assessments.
    • Reduced safe accommodation to live in whilst house dries out.
    • Cost of this accommodation and the purchasing of new property lost in the floods.
  • Fractured Transport Links: 
    • "Just 30 cm of flowing water is enough to move your car..."  (Source)
    • "West Coast trains between Workington and Carlisle are cancelled due to a landslip (Source)
    • "A590 at Lindal suffered serious flooding" (Source)
    • Major disruption to rail services in England and Scotland on the 5th and 6th of December including Abellio ScotRail, First TransPennine Express, Northern Rail and Virgin Trains as well as the Caledonian Sleeper due to flooding and landslides. 
    • "One of the biggest casualties of Storm Desmond was the 251 year old Pooley Bridge, which partially collapsed when it was unable to cope with the sheer volume of water surging under it" It has now been replaced with the title (planned) on Google maps. (Source)
  • Loss of life: 
    • One "90-year-old man was blown into the side of a bus outside Finchley Central" (Source)
  • Loss of livestock:
    • 45 prize heifers (a cow that has only given birth to one or no calves) swept away, 42 returned with some on a golf course 20 miles away (Facebook source)


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