Lesson 15- The water and carbon cycle-River Catchment Flashcards
Where is the River Don and its catchment?
- Upper course-Penistone
- Middle course- Rotherham and Sheffield
- Lower course- Doncaster- Humber estuary
-It flows 70 miles east
-This means water in theory takes a long time to reach the river which should lead to a less flashy hydrograph and less flooding.
- However it is a bit more complicated as the river Don has large tributaries including the Rother and Dearne and Trentwhich are also likely to flood.
Where is the River Don and its catchment- Upper course
Penistone
- Steep sided V shaped valleys – high rates of surface run off
- Peat bogs – area of storage of water and carbon
- Agriculture – intensive farming impacting water
Where is the River Don and its catchment- Middle course
Rotherham and Sheffield
- Artificially controlled river in lots of areas with human defences
- Urban land use – high surface run off
- (water abstraction EG Blakburn Meadows processing 438,000m3/day)
Where is the river don and its catchment- Lower course
Doncaster - Hull
- Flood plain areas towards Hull and the Humber estuary
- Large discharge - flooding
- Doncaster, farmland, water abstraction. Channelization work means the Don joins the Ouse instead of the Trent
What are the key features of the water cycle in the upper course?
- Resevoirs
- Peat bogs
- Agriculture
- Steep slopes
What are the key features of the water cycle in the upper course- Reseviours
- Winscaris the first reservoir(100m from source) which later flows into Langsett – this controls the discharge of the river
- 23 reservoirs increase lag time and reduce the impact of heavy rain, but if full in winter don’t do this
What are the key features of the water cycle in the upper course-Peat bogs
- Peat makes up the catchment near the source near Winscar and Langsett reservoirs.
- This is a big carbon store and also holds water in the upper course reducing discharge and flood risk lower down.
What are the key features of the water cycle in the upper course- Agriculture
- Sheep farming is the main agriculture, some cows.
- This has lead to the compaction of the soil, reducing infiltration rates and increasing surface run off.
- 25 Major farms near Penistone.
What are the key features of the water cycle in the upper course- Steep slopes
- Narrow river channels with steep slopes mean not that much options for creating storage for water.
- Steep slopes increase surface run off and reduce lag time
(2 hours for water to reach peak discharge at Sheffield)
What are the key features of the water cycle in the middle course?
- Historical industry and mining
- Urbanisation
- Historic hard engineering
- Recent soft engineering
What are the key features of the water cycle in the middle course- Historical industry and mining
- Deforestation occurred in the Dearne Valley to make way for mining.
- Mining caused pollution and sedimentation of the river channel decreasing channel capacity
What are the key features of the water cycle in the middle course- Urbanisation
- 26% Catchment is urban, this has decreased infiltration rates and increased surface run off.
What are the key features of the water cycle in the middle course- Historic hard engineering
- The River Don is not very natural, it is extensively channelised throughout Sheffield near Meadowhall and Forgemasters
What are the key features of the water cycle in the middle course- Recent soft engineering
- Five Weirs Walk
- SUDS – Manor Fields
- RSPB Old moor, wetland restoration in the Dearne valley to increase the storage of both water and carbon.
What are the key features of the water cycle in the lower course?
- Urbanisation
- Historic hard engineering
- Floodplain
- Confluence of many rivers
What are the key features of the water cycle in the lower course-Urbanisation
- Large urban areas built on floodplain.
- Fishlake and Doncaster both flooded 2007 and 2019 both built on floodplain.
What are the key features of the water cycle in the lower course- Historic hard engineering
- River regulators including weirs controlling flow were built from 1958-1988
What are the key features of the water cycle in the lower course- Flood Plain
- Low lying former marshland that was drained in the 1800s
- At Fishlake, Wetland restoration is occurring to store water on the land (60 hectare area) to reduce flood risk.
What are the key features of the water cycle in the lower course- Confluence of many rivers
- This increases discharge so important to have max channel capacity.
- Current plans include maintaining over 211 kilometres of river channels including removal of blockages likely to increase flood risk
What is the drainage basin water cycle like for the River Don?
-Inputs
- Precipitation: Varies spatially due to rain shadow with most in upper course (NW) (861mm/year) - high which leads to increased risk of flooding. Varies seasonally with most in winter.
- Other rivers: Tributaries EG Dearne The river Don meets the Trent and the Oose adding to the total discharge.
What is the drainage basin water cycle like for the River Don?
-Outputs
- River Discharge: Outputs into the North sea via the Humber estuary
- Evaporation: Seasonal variation, on average 40mm
- Transpiration: varies spatially, upper catchment has more vegetation so higher transpiration than lower
What is the drainage basin water cycle like for the River Don?
-Stores
- Artificial Reservoirs:
-16 major reservoirs human storage of water including Winscar and Langsett storing water and increasing lag time. Seasonal variation. - Natural Peatland storage:
-Upper course in the soil and peatland, estimated 6% of catchment area. - Natural Wetland storage:
-Middle course, Dearne – RSPB old moor
What is the drainage basin water cycle like for the River Don?
-Transfers
- Surface run off: mainly in urban areas with lower infiltration (Sheffield)
- Ground water flow:
-Majority sandstone geology which is permeable so ground water recharge easy. - Through flow:
-Again, due to permeable geology through flow, reduced due to urbanisation and agriculture. - Discharge: High usually.
How are the imputs changing?
- Precipitation:
Increasing due to climate change in Western Catchment
How are the outputs changing?
- River Discharge:
-Increasing due to lowering rates of infiltration due to urbanisation. - Evaporation:
-Increasing due to warming climate. - Transpiration:
-Increasing due to tree planting projects in upper catchment.
How are the stores changing?
- Artificial Reservoirs:
-Change seasonally as water release downstream is controlled artificially, in winter though not controlled. - Natural Peatland storage:
-Increasing due to ‘Moors for the Future’ and peat bog restoration. - Natural Wetland storage:
-Increasing due to restoration in Dearne Valley
How are the transfers changing?
- Surface run off:
-Increasing due to urbanisation in middle and lower course. - Ground water flow:
-Decreasing due to abstraction of water and slower recharge. - Through flow:
-Increasing due to catchment management in upper course. - Discharge:
-Increasing due to precipitation
What is the climate like at the River Don catchment?
- There is high precipitation all year round, this is due to the catchment containing Pennine hills. This gives orographic rainfall
- Prevailing southwesterly winds bring moisture from the Atlantic, causing the air to rise over the Pennine hills in the Peak District. As the air rises, it cools and adiabatically contracts, holding less water until it reaches 100% humidity (dew point).
- This process leads to rainfall. Once the air moves past the peak and descends on the eastern side toward Doncaster, it warms up, increasing its capacity to hold more water, which in turn creates a rain shadow effect.
Seasonal variations in climate at River Don
- Rainfall total = 861mm/year
- Peak = Nov/Dec = 85mm
- Lowest = May
- Highest temp = 22 degrees July
- Lowest temp = 6.5 degrees Jan
- Average rainfall is 800mm/year
-In the west it is 2000mm/year and in the east 600mm/year
What is the water balance like?
- Surplus: Jan/Feb- low temps = low Evapotranspiration rates (10mm) + High precipitation (65mm)
- Utilisation: May/June – Low precipitation (55mm), May rising temps = high Photosynthesis + evaporation (70mm)
-
Defecit: Jul/Aug
High evaporation (80mm) and low precipitation (60mm) - Recharge: Nov, Dec Increasing precipitation totals (60+mm) and low evaporation (20mm)
What are the physical characteristics that impact the River Don?
- Geology
- Releif
- Size of Drainage Basin
What are the physical characteristics that impact the River Don- Geology
- The Don Catchment has varied permeability
- This means in areas of permeable rock we get more throughflow whereas in areas of impermeable rock we get more surface run off
- Soils here don’t drain easily in the NW and absorb large amounts of water when dry but in winter they get saturated increasing run off.
What are the physical characteristics that impact the River Don- Geology
-Examples of different rocks
- Millstone grit dominates the upper course which has permeable sandstone and impermeable mudstone – this means infiltration and run off vary spatially across the catchment.
- Dolostone is impermeable and this is found past Doncaster towards Goole and increases flood risk here.
What are the physical characteristics that affect the River Don- Relief
- The Don catchment responds very quickly to rainfall with rapid run off
-Time to peak discharge = less than 2 hours - Upper course:
-Steep slopes 346m elevation average relief average 3.8% - Middle course:
-This is where elevation rapidly decreases from 350m to only 29m above sea level in Rotherham – this causes rapid surface run off - Lower course:
-Flat topography, higher infiltration rates but increased risk of flooding and tidal floods. Lowest only 10m above sea level.
What are the physical characteristics that affect the river don- Size of drainage basin
- The river Don has a small catchment which decreases lag time it flows 70 miles East
- This means water in theory takes a long time to reach the river which should lead to aless flashy hydrograph and less flooding however a higher total discharge due to more area of land draining water to the river.
- Howeverit is a bit more complicated as the river Don has large tributaries including theRother and Dearne, Oose and Trentwhich are also likely to flood.
- Average discharge at Doncaster is 200m3/s which is high
What are the human characteristics that affect the river don?
- Agriculture
- Urbanisation
- River management (hard and soft engineering)
- Water abstraction
- Deforestation
- Peatlands and Wetlands
What are the human characteristics that affect the river don- Agriculture
- 24% of all land use is Agricultural here
- The compaction of soils from animals and farm machinery has decreased infiltration rates and agriculture has caused river bank erosion increasing sedimentation.
- This was an issue in Ingbirchworth where river banks had collapsed and high levels of nitrogen had polluted the water, this has now reduced by 50% due to better management
What are the human characteristics that affect the river don- Urbanisation
- It has major urban areas that include Barnsley, Chesterfield, Doncaster, Rotherham and Sheffield
- The increase in impermeable surfaces combined with the over development of land on the flood plain means increased overland flow and increased flood risk.
- 30mm/hour rain in Sheffield causes flash flooding
- 26% catchment is urban areas with lots of human intervention meaning impermeable surfaces and high rates of surface run off
What are the human characteristics that affect the River Don- River Management (hard engineering)
River re-routing
* Historically the Don has been massively engineered by humans
* The Don navigation was made to link Sheffield with the sea
Hard Engineering:
* Lower Don Valley Flood Defence Scheme (2008)
* Near Meadowhall
* 500 Businesses Protected
* Cost £21.4 million
* Created flood gates to shut during flood
* 300 flap valves and pipes to discharge river water
* Removal of willow trees which drop debris
What are the human characteristics that affect the River Don- River Management (soft engineering)
- Upper Don
- Urban River Corridors and Sustainable Living Agendas (URSULA)
- Sheffield Strategic Flood Risk Management Strategy
What are the human characteristics that affect the River Don- River Management (soft engineering)
-Upper Don
- £12 million including river Loxley and Rivelin
- £420,000 for natural flood management of A616 including leaky ponds and planting 6000 trees
What are the human characteristics that affect the River Don- River Management (soft engineering)
-Urban River Corridors and Sustainable Living Agendas (URSULA)
- 11.3Ha area
- Barnsley council to plant 10,000 trees
What are the human characteristics that affect the River Don- River Management (soft engineering)
-Sheffield Strategic Flood Risk Management Strategy
- Kelham Island
- Use of SuDs and wildflower meadows
-Grey to Green Scheme in Sheffield created 1.3km
-24,000 bathtubs worth of water prevented from entering rivers and drains in Sheffield - Enhanced river habitat to increase storage and interception
What are the human characteristics that affect the River Don- Abstraction
- Water abstraction reduces peak discharge and in general the total amount of water reaching the lower course of the river.
- 270 abstraction licences to prevent over 30 billion litres of water per year being removed from the environment where abstraction is unsustainable
- Yorkshire Water is investing £40m in its Blackburn Meadows wastewater treatment works to improve water quality and control river flow
What are the human characteristics of the River Don-Deforestation
- This occurred historically in the Don catchment however deforestation rates are now low.
- Deforestation reduced interception, increased soil erosion and therefore reduced channel capacity.
- Near Forgemasters in Sheffield, yearly dredging of the river is now taking place to increase channel capacity,.
- This also increased surface run off.
What are the human characteristics of the River Don- Peatlands and Wetlands
- This holds water in the upper course of the Don, reducing flood risk for Sheffield and other urban areas to the South East.
- Historically this peatland was destroyed for agriculture or burnt for grouse shooting –government funded to create rural jobs.
- Today it is being restored by Moors for the Future (£3.5 million)
- The Government is investing over £50 million in peat restoration, building on its pledge to restore approximately 35,000 hectares of peatland in England
How has flooding impacted the River Don?
- 2007 and 2019 floods
How has flooding impacted the River Don-2007 floods
- 80 million m3 of rainfall fell on 25/06/07
- 1200 houses flooded
- Hillsborough stadium 1.8m deep in water
- M1 motorway closed
- £50 million repair costs
How has flooding impacted the River Don- 2019 floods
- 84mm of rainfall in 24 hours
- 500 homes flooded in Doncaster
- 1000 properties evacuated
- Dozens of people forced to spend the night at Meadowhall
- River Don hit its highest recorded peak discharge with river levels at 6.3m higher than 2007 floods
- £3 million spent to repare and improve defences at Bentley, Doncaster
How are we reducing the flood risk for the River Don catchment?
- Taking a catchment approach
- NATIONAL HIGHWAYS LITTLE DON NFM FUND PILOT PROJECT
- Five Weirs Walk, SUDS
- Ingbirchworth Project
How are we reducing the flood risk for the River Don Catchment- Taking a catchment approach
- River Don has a management plan
- This has meant deciding whether to continue with existing hard engineering
- Take further action by building new defences
- Or taking action to store water and manage run off to have environmental benefits.
How are we reducing flood risk for the River Don catchment-NATIONAL HIGHWAYS LITTLE DON NFM FUND PILOT PROJECT
- 5.3km2 area
- Reducing soil compaction to increase infiltration rates
- Installing channel leaky barriers to slow down the flow
- Cross slope hedge planting to increase interception and reduce surface run off on steep slopes
- Peatland Restoration in the catchments of Langset to increase both water and carbon storage
How are we reducing flood risk management for the River Don catchment- Five Weirs Walk, SUDS
- Protects over 300 businesses, securing approximately 5,000 jobs
How are we reducing flood risk for the River Don catchment- The Ingbirchworth Project
- Too much nitrogen in water and increased surface run off due to compaction of soil by cows.
- Educational visit to farmers and nitrogen use reduced by 50% and surface run off by 20%.
How is flood risk changing at the River Don management?
- Climate change
-In total the properties at risk of flooding is 16,587 currently and is predicted to rise to to 18,399
Tidal risk rises from 10,041 to 10,079 properties during the 0.5 per cent flood
