Unit 3.1 - W&C - Temporal Variations in River Dishcharge Flashcards
Define River Regime and their two versions.
Month-by-month variations in river discharge over a year-long period.
Simple
Complex
Describe a simple river regime
Typically, there is just one high and low discharge period corresponding with seasonal temperature and precipitation changes (e.g. ‘wet season’ and ‘dry season’).
Describe a complex river regime
Several extremes of discharge in a year. This is more typical of large continental-scale rivers, such as the Colorado in North America, whose tributaries extend into different climatic zones and mountain ranges with very different annual temperatures and precipitation patterns.
State the physical factors that affect river regimes
The annual pattern of precipitation (and any snow melt); annual temperatures and evaporation rates and relief, vegetation, soils and geology.
State the human factors that affect river regimes
Human factors include domestic and industrial water demands; dams and reservoirs; irrigation for agriculture and transfer schemes which remove river water and transport it to other places.
What is a river hydrograph?
A river hydrograph shows the response of a river to one or more rainfall events. It shows the changing level of discharge (or rate of flow) of the river measured in cubic metres per second.
What is peak discharge?
The maximum rate of river flow.
What is peak rainfall?
The maximum rainfall value recorded during a storm event.
What is lag time?
The time period between peak rainfall and peak discharge
What is the baseflow of a river?
The normal minimum discharge of the river
Name the climactic factors that affect a storm hydrograph.
Precipitation type, amount, duration and intensity, temperature, evaporation, transpiration and antecedent conditions.
Name the Non-climatic catchment factors that affect a storm hydrograph.
These include catchment size, shape and drainage density; the porosity and permeability of soils and rock types; and slope angles, vegetation and land use.
