Pickering Beck

Question 1

Location and background

Answer 1

• a smallish river in its upper course from the North York moors
• population of 7000
• catchment area of 68km squared
• steep topography
• river long and thin -> causes discharge to go up very fast, higher drainage density -> speeds up water flows to the river
• the river has previously flooded: 1999, 2000, 2007
• 2007 flood:
  > 85 properties + main A170 route unwrought town restricting access to several parts including the market place

Question 2

Natural (physical) causes of flooding

Answer 2

• relief: steep topography -> above settlement means that the rivers have a very ‘flashy’ response i.e water runs off rapidly, producing a pronounced peak on the hydrograph
• geology: gritstone and limestone are both permeable
• peat: soft sand substrate leads to sediment being washed into water course (Peat = organic layer of soil consisting of partially decomposed organic matter, derived from plant material -> from conditions like water logging and oxygen deficiency)
• moorland: large, flat moorland receives a lot of precipitation; steep valley sides deliver this quickly to river and flat valley floor -> broadens at Pickering allowing water to spread out

Question 3

Human causes of flooding

Answer 3

• inappropriate cultivation (the growing of crops) of arable soils, overgrazing and overstocking of grassland
• excessive moorland and forestry drainage
• poor river management
• previous management strategies rejected due to cost benefit grounds
• all of these are thought to have increased the risk of downstream flooding as a result of reducing the river catchments natural water storage capacity

Question 4

Human impact on water quality

Answer 4

• Pickering failing to meet ‘good water status’ as defined by the water framework directive
• has been designated a ‘priority catchment’ for improving land management under the England catchment sensitive farming delivery initiative, with additional funding provided for agri-environment schemes

Question 5

Flood management strategies

Answer 5

• construction of low level bunds
• creation of riparian woodland
• restoration of large woody debris dams
• targeted woodland creation and form-scale measures
• targeted blocking of moorland drains
• establish no-burn zones along moorland streams
• restore stream side buffer zones al0ng forest streams
• educating farmers, landowners and homeowners

Question 6

My top 4 flood management

Answer 6

• creation of riparian woodland
• restoration of large woody debris dams
• establish no-burn zones along moorland streams
• educating farmers landowners and homeowners

Question 7

Land management: creation of riparian and floodplain woodland

Answer 7

• riparian woodland: plant communities along river margins are called ‘riparian vegetation’ and are characterised by hydrophilic plants such as alder and willow trees
  -> plan is to plant around 50 hectares of native woodland in strips 30m wide, either side of the watercourse
  -> riparian woodland can form barrier to slow the passage o the flood flows, helping to slow he passage of the flood peak and potentially increase upstream flood storage
• TO DATE: 19 hectares of riparian woodland have been planted within the Pickering Beck catchment

Question 8

Land management: restoration of large woody debris dams

Answer 8

• woody debris dams: man-made and natural gullies help water drain off the moorland plateau and from the forests of the North York Moors.
  -> ‘slow the flow’ construction of these small permeable dams allow normal flow to pass unhindered however slowdown water in the channel -> forcing it out onto the floodplain during high flows
  -> helps delay runoff from moorlands and forests
• SUMMER 2010: construction of approximately 100 debris dams planted around Pickering Beck catchment
• crouton forest forest = ideal location for this types of intervention due to the high density of artificial drainage gullies installed in the 1960’s to rain and improve soil for tree growth

Question 9

Land management: establish no-burn zones along moorland streams

Answer 9

• no-burn zones: heather burning is an integral part of traditional moorland management. However, burning moorland removes vegetation cover and spends up overland flow.
• heather burning has the potential to speed-up runoff by temporarily removing the vegetation cover and promoting hydrophobic soil conditions
• 10m wide no-burn buffer zones have been established along all main water courses in the upper catchment of Pickering Beck as part of a 10 year environment stewardship scheme

Question 10

Land management: educating farmers, landowners and homeowners

Answer 10

• an important aspect of the project is informing farmers and landowners about how to manage their land in order to paid rapid overland flow.
• simple actions like moving cattle feeders so that land does not become churned up or diverting water into small hollows to stores it temporarily on their land, may all help
• it remains to be seen whether slowing the flow at Pickering will achieve a significant reduction in flooding. However, if it does it may demonstrate alternative, cheaper and more environmentally compatible methods of reducing flood risk