River severn Flashcards
(23 cards)
where is the source
plynlimon hills
where is the mouth
bristol channel
what is the starting altitude
610m
what is the altitude of the mouth
19m
Where are the urbanised areas
shrewsbury
worchester
glouchester
where are flood walls and embankments located
worchester
gloucester
shrewsbury
what is the geology of the upper basin
shale and slate
limits infiltration
what is the geology of the lower course
sandstone and limestone
more permeable
how much rain did storm Dennis bring
100mm+ in 48hrs
what is river regime
The river regime refers to the changes in a river’s discharge over the course of a year in response to a number of factors
What type of hydrograph is the upper course
flashy due to fast surface runoff
Where is the highest flood risk
upper basin due to limited infiltration
what type of flooding is the lower basin susceptible to
groundwater-fed flooding during prolonged wet periods
How much rain does the west uplands receive
2,500mm annually due to relief rainfall
how much rainfall does the eastern lowlands receive
650mm making them more reliant on river and groundwater sources for water supply
what agricultural practices impact the river system
plough
compaction reducing soil permeability, increasing surface run off
what happens in the winter that affects river discharge
melting snow form the plynlimon can rapidly increase river discharge
what happened during the flooding in shrewsbury 2020
100mm of rain in 24hr
river level peaked at 5.2m
£10 million+ in damages
What reservoirs are there
the elan valley reservoirs constructed in 1990s provide water to birmingham and midlands
What soft engineering strategies are used
floodplain restoration allows natural flood absorption
sustainable urban drainage systems reduce runoff in urban areas
what sustainable farming pracitices are there
contour ploughing
cover crops: planted during winter to reduce erosion and improve infiltration
riparian buffer zones: planting trees and hedgerows along rivers to reduce sediment and nutrient runoff
how much water passes through everyday
9 billion litres
what famous waterfall is there
water breaks its neck
