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Tees River Basin (Modified for floods (upper course (cow green reservoir…
Tees River Basin
Modified for floods
upper course
- cow green reservoir is a large store that holds 40 million m3 of water. It controls peak flows and reduces flooding by storing excess water and releasing it in times of low flow
- discouraged development on low lying areas
- tunnel connecting Kielder water via R.Tyne to R.Tees that adds water during low flow
lower course
- Improved flood warning system
- river, sea and tidal defences
- tees barrage (1995) minimises risk of river and tidal flooding
- improved navigation through dredging
- meanders cut
- new sewerage systems and laws on dumping
- floodplane zoning to allow rivers to flood naturally
changes over time
- URBANISATION- particularly in the lower course will have increased to 70% by 2050 which creates more surface run off
- DEFORESTATION- the lower course now has less vegetation so less interception and more infiltration which creates a more flashy hydrograph
- AGRICULTURE- farmers now use more machinery which leads to soil compaction and less infiltration
- RESERVOIR- built in 1970 and holds 40 million m3 of water. It is a large store and will create a gentle, less flashy hydrograph as there will be more infiltration due to an increase in groundwater stores
water supply needs
- LARGE URBAN AREAS- Darlington has a population of 100,000 and Teesside has a population of 375,000
- INDUSTRY- iron and steel making, ICI chemical works
- DOMESTIC
- AGRICULTURAL
flood events
- the summer of 2012 was the wettest ever recorded leading to saturated ground and high river levels
- 25th to 26th September has 24 hours of persistent heavy rain
- 112 properties were flooded but 150 were affected
- expected to get 50mm of rain in some areas
- 1,200 areas lost electricity
- highest was in Ravensworth which had 89mm of rain in 24 hours
- caused by an area of low pressure which moved north across the country from the Bay of Biscay to the north east coast
LOCATION-
- located in North East England
- source is the Cow Green Reservoir in the Pennines
- flows east
- flows through the urban areas of Darlington and Teesside
- the estuary is just north of Middlesbrough
- flows into the North Sea
TOPOGRAPHY-
- much higher near the source then becomes lower as the river moves
- Cow Green (over 500m)
- Barnard Castle (150m)
- Darlington (30m)
- Middlesbrough (6m)
LAND USE-
- upper course is more rural and has less settlements
- has more vegetation and peat soil which stores water
- large number of dams and reservoirs
- lower course is drier and has more alluvial soils (high infiltration)
- more urban environments and heavy industry
REGIME- the tees barrage at broken scar is from the lower course and has more water than the upper course at Middleton in Teesdale as it has more tributaries than the upper course
- due to it's relief, the upper course will have higher rainfall and in turn higher discharge
- the lower course will also have high discharge in the areas of urbanisation e.g Darlington
- The dam and the reservoir act as a store
- Middleton has a steep relief so has more run off as well as thin soil and bare rock
RESERVOIR/DAM
- Cow Green Reservoir
- stores water so there is less water further through the course
- it lowers the discharge and creates a less flashy hydrograph
- more water may infiltrate to increase groundwater
SOIL STORES
- upper course has peat soils and lower course has alluvial soils
- peat soils will store more water
- In winter, there will be large surface water when it cannot retain more
- alluvial soils have high infiltration rates
- the upper course will be more flashy when saturated
OVERLAND FLOW/ SURFACE RUN-OFF
- more run-off in upper course
- the upper course will have more run-off due to it's steep relief
- it will be a more flashy hydrograph
INFILTRATION
- more infiltration in lower course
- infiltration will be faster in the lower course due to alluvial soil
- more vegetation in upper course will decrease infiltration as it will increase interception
- lower course has deforestation so has less interception