Rivers Flashcards
(27 cards)
What are the two ways the graph can be used for?
To predict the magnitude over a certain time period
To estimate the frequency of a certain magnitude
What is magnitude and what can it be used for?
It refers to the severity of floods. And can be used to predict the return period of a flood event of a particular scale in conjunction with frequency.
How do you calculate the recurrence interval?
RI= (n+1) divided by R
What is the lag time and peak like for a FLASHY hydrograph?
Short lag time
High peak
What is the lag time and peak like for a FLAT hydrograph?
Long lag time
Low and flat peak
Does a Flashy hydrograph have a small or large basin?
Small
Does a Flat hydrograph have a small or large basin?
Large
What is the drainage density like for a Flashy hydrograph?
High
What is the drainage density like for a flat hydrograph?
Low
What type of rocks does a flashy hydrograph have?
Impermeable
What type of rocks does a flat hydrograph have?
Permeable
What does the storm hydrograph show?
The variation in a Rivers discharge over a short period of time
How do you calculate lag time
Peak discharge - peak rainfall
how does a reduced infiltration affect the surface run off?
Increases it
How does a reduced infiltration, and increased surface run off affect the lag time and peak discharge?
Reduces lag time
Increases peak discharge
Name the 4 erosion processes?
Abrasion
Attrition
Solution
Hydraulic Action
Name the 4 transportation processes?
Traction
Saltation
Solution
Suspension
Give a waterfall example?
Thornton Force in North Yorkshire
Name 3 delta shapes?
Cuspate
Arcuate
Birds Foot
How do you calculate drainage density?
Length of streams divided by area of basin
What is Water surplus in relation to the Water Balance Graph? - and what effect does this have on the soul and excess water
When precipitation is higher than evapotranspiration, so soil becomes saturated and excuses water has difficulty infiltrating
What is soil moisture recharge in relation to the water balance graph? - when does it happen and why
The replenishment of water into the dry pores of soil, which occurs when the autumn rainfall exceeds the amount which can be evaporated
What is soil moisture utilisation in relation to the water balance graph?
When evapotranspiration is higher than precipitation
In soil moisture utilisation how are water demands then met?
By water being drawn to the surface by capillary action - chains of droplets - reducing water amount in the soil or river
