🌧️Case Study - Pickering Beck Flashcards
What is Pickering Beck?
A river in North Yorkshire
How far does the beck run for?
29km (18 miles)
Which National Park is the beck located in?
The North York Moors
Why is the river prone to flooding?
Due to the steep sided valley that the water runs off into the beck
Which government scheme was piloted in the town?
‘Slowing the Flow’
When does the beck flood in particular?
In the summer, flash flooding
How many times was the town flooded between 1999 and 2007?
4
How much did the 2007 flood cost in damage?
£7 million
How can rainfall increase chance of flooding?
Rainfall in the area is heavy and hydrographs flashy. Peak discharges fluctuate
How does the geology affect flooding?
It consists on Gritstone and Limestone, permeable and porous allowing the water to flow through. Soil is also soft and sandy, so permeable, slow lag time
How does the local relief affect flooding?
The drainage basin has steep relief in the hills of the North York Moors, decreasing time taken to reach the river
How does the vegetation affect flooding?
Largely moorland shrubs and heather, growing in peat bogs which can soak up water, preventing run off and further flooding. If water is redirected for agriculture or forestry, peat dries out
What are the main land uses in the river catchment area?
Arable crops
Improved grassland
Heather Moorland
Forestry and woodland
How has the town impacted flooding?
Impermeable surface increase run off rates
How have farming practices impacted the river?
Farming has lead to diffuse pollution, lowering the water quality
What was adopted to manage flooding?
A land management technique instead of hard defences
What was constructed at Newtondale?
A large low level bund to hold up to 120,000m3 in flood events to store water
What was planted around the river catchment?
19ha of hydrophillic plant such as alder and willow trees to create a natural barrier to flood flows
What was constructed in the river catchment?
Large woody debris damns, and natural gullies to help water drain from moorlands into forests
How many Large Woody Debris Dams have been constructed in Pickering Beck catchment?
129
How much farm woodland has been planted?
15 ha
How many heather bale dams have been constructed?
187
Why were no-burn zones established?
As burning has the potential to speed up run off by lowering interception and promoting hydrophobic soil conditions
What has been created in terms of no burn zones?
A 10 metres wide buffer zone along the main watercourse
How big is the catchment area?
68km2
What does the catchment area contain?
Moorland, arable farming and coniferous forests
When was it flooded
Back in 1999, 2000 and 2007
What was flooded in 2007?
85 properties and the main A170
What does the large, flat moorland receive near the source?
Large amounts of water which flows quickly to the Beck when the moorland is saturated
What is there a risk of and why?
Summer flash floods due to the steep catchment
What is there a high variability of?
Discharge of the river from year to year
Geology and soil type
Gritstone and limestone, peat, soft sand substrate - mixed permeability
Human causing of flooding
. Inappropriate cultivation of arable soils
. Overstocking and overgrazing of grassland
. Excessive moorland
. Forestry drainage
Why have many management strategies been rejected?
Cost benefit grounds due to low value rural catchment areas and intervention in the wrong area
What has the beck failed to meet?
Good water standards
What is a major local issue?
Diffuse water pollution
What has the beck been designated as
A priority catchment for improving land management under England Catchment Sensitive Farming Initiative
What has worsened water quality?
Farming and poor treatment of land
What policy has been adopted and what does it aim to do?
‘Slowing the flow’ to reduce peak flow in Pickering through land management
How much of the land is under public ownership?
1/3
What is the current unsustainable management strategy?
Engineered flood defences, need to develop a catchment approach
Main principles of management
. Slow water at the top of the catchment
. Store water in the middle of the catchment
. Improve water flow passing through the middle of the catchment
Riparian woodland
Plant communities along river margins - hydrophilic plants
How many hectares of native woodland to they plan to plant?
50 ha of native woodland in strips 30m wide either side of the water course
To date how many ha of riparian woodland have be planted?
19ha within Pickering Beck and a further 10ha in River Severn catchment
Low level bunds
Water stored on the floodplain for short periods, once peak flow has passed this water will drain back naturally into the channel
Where is the low level bung being built?
In the floodplain at Newtondale
How many large woody debris dams have been built?
129 in Pickering Beck catchment, 38 in River Severn catchment
What do large woody debris dams allow?
Allow slower moving water through which had previously been removed
Targeted woodland creation and farm scale measures
Woodland can help to protect sensitive soils
How many hectare of farm woodland have been planted within the River Severn catchment?
15 ha
How many heather bale dams were constructed on smaller streams and why
187 - to hold more water back and improve water retention
How many eroding footpaths have been repaired?
800m
What zone was created?
10m wide no burn buffer zones established along main watercourse
Why was a new floodplain treated?
To allow 4,200,000 cubic feet of floodwater to be retained
Will these management strategies work?
Too early to tell but it would demonstrate it is a cheaper sustainable approach to flood management if they do work
