Lesson 4 - River Hydrographs: Flashcards
What are Flood Hydrographs?
Flood hydrographs represent rainfall for the drainage basin of a river, and the discharge of the same river on a graph.
What is Discharge?
Made up of baseflow and stormflow, and is the volume of water passing through a cross-sectional point of the river at any one point in time, measured in Cumecs.
What is the Rising Limb on a Flood Hydrograph?
The line on the graph representing the discharge increasing.
What is the Falling Limb on a Flood Hydrograph?
The line on the graph representing the discharge decreasing.
What is Lag Time?
The time between the peak rainfall and peak discharge.
What is Baseflow?
The level of groundwater flow.
What is Stormflow?
Comprised of overland flow, and throughflow.
What is the River Regime?
The general discharge throughout the course of the year.
What is Bankfull Discharge?
The maximum capacity of the river.
What is a Flash Hydrograph?
Short lag time, and high peak discharge, most likely to occur during a storm event.
What is a Lag Hydrograph?
Long lag time, and low peak discharge.
What Factors create a Flash Hydrograph?
1) Elongated River Basin,
2) Large Relief,
3) Impermeable Surfaces.
What Natural Factors create a Flash Hydrograph?
1) High Rainfall Intensity,
2) Antecedent Rainfall,
3) Impermeable Underlying Geology,
4) High Drainage Density,
5) Small River Basin,
6) Circular River Basin,
7) Low Temperatures,
8) Precipitation Type,
9) Vegetation Cover.
What Human Factors create a Flash Hydrograph?
1) Urbanisation,
2) Pastoral Farming,
3) Deforestation.
