16 terms

Factors affecting the hydrograph

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Bankfull
The maximum discharge that a river channel is capable of carrying without flooding
Base flow
This represents the normal day to day discharge of the river and is the consequence of slow moving soil throughflow and groundwater seeping into the river channel
Discharge
The amount of water in a river flowing past a particular point expressed as m^3s^-1 (cumecs)
Lag time
The time between the peak rainfall and peak discharge
Peak discharge
The point on a flood hydrograph when river discharge is at its greatest
Storm flow
Discharge resulting from storm precipitation involving both overland flow, throughflow and groundwater flow
Storm hydrograph
A graph of discharge of a river over the time period when the normal flow of the river is affected by a storm event
River flow is studied by measuring
Discharge of a river
The UK has a dense gauging station network of around ___ measuring stations supported by secondary and temporary monitoring sites
1500
Discharge calculation
Multiply cross-sectional area of river by its velocity at the measuring point
Discharge is measured in
Cumecs
River regime
The variability in its discharge throughout the course of a year in response to rainfall events
CUMEC
Cubic metres per second
Physical factors affecting discharge
Steepness of sides, amount of precipitation, soil type, rock type, vegetation cover, vegetation type, type of precipitation
Human factors affecting discharge
Deforestation, afforestation, agriculture, farming, urbanisation, flood management schemes, water abstraction
Features of hydrograph
Base flow, rising limb, receding limb, lag time, peak discharge