Storm hydrographs and drainage basins Flashcards
(16 cards)
What does the shape of a storm hydrograph depend on?
The physical features of a drainage basin such as size, shape, rock type, soil, relief and vegetation
What are the key shapes of a storm hydrograph?
Steepness of rising limb
Nature of the peak discharge
Characteristics of the falling limb
Size
Smaller basins will mean that overland flow will more quickly reach the river and create a steeper limb and shorter regime
Density
High density = overland flow more quickly
Rock type
Permeable or impermeable
Soil type
High or low infiltration rates
Topography
Steep or shallow slope
Vegetation
Sparse or dense
Levels of antecedent soil moisture
Saturated or not
What is the water budget formula?
P = Q+E +/- changes in storage
Precipitation = runoff + evapotranspiration +/- changes in storage
What is a water budget for?
Shows the balance between water inputs and outputs in an open physical system such as a drainage basin
What is the boundary of a drainage basin called?
The watershed
Is a drainage basin an open or closed system?
As a subsystem of the hydrological cycle, drainage basins are open systems this means that they have inputs and outputs
Inputs = the addition of water to a drainage basin through precipitation
What are the 5 features of a drainage basin?
Watershed = boundary
Source = where the river starts
Confluence = the place where two or more rivers/streams meet
Tributary = a stream/river flowing into a bigger stream/river
Mouth = where the river enters the ocean or lake
Types of precipitation
Frontal = hot rise over cold, cools, condenses and falls
Orographic = hot air rises over mountains, forced to rise, cools and condenses
Convectional = sun heads the ground, moisture evaporates and rises, as it gets higher it cools and condenses - occurs in the tropics
Drought
Meteorological = less precipitation
Hydrological = less water in groundwater stores, streams and rivers
