What is a storm hydrograph BBC Bitesize?
A hydrograph shows two graphs – a bar chart showing rainfall, usually from a storm and a line graph showing discharge from before, during and after the rain storm shown in the bar graph. Basically, a hydrograph shows you the ways in which a river is affected by a storm.
What does a hydrograph show GCSE?
A hydrograph shows how a river is affected by a storm. This helps to understand discharge patterns of a particular drainage basin and helps to predict flooding and plan flood prevention measures. As you can see in the graph below, the peak rainfall is the time of highest rainfall.
How would you describe a storm hydrograph?
A storm hydrograph is a way of displaying how the discharge of a river can change over time in response to a rainfall event. The discharge of a river is just the amount of water passing a certain point every second, and is calculated by multiplying the cross sectional area of the river by its velocity.
What is a hydrograph GCSE geography?
A hydrograph shows how a river responds to a period of rainfall. Peakdischarge – maximum amount of water held in the channel. Peak rainfall – maximum amount of rainfall (millimetres). Lag time – the time taken between peak rainfall and peak discharge.
What factors affect a storm hydrograph?
Factors Affecting a Storm Hydrograph
- The Drainage Basin. The shape of a hydrograph is altered by a few different things.
- Soil & Rock Type.
- Weather & Climate.
- Vegetation Cover.
- Human Activity.
How does temperature affect a storm hydrograph?
Hot, dry conditions and cold, freezing conditions result in hard ground, reducing infiltration and increasing surface runoff, this leads to a reduced lag time and peak discharge. High temperatures can also increase evapotranspiration, reducing the amount of water reaching the river channel and peak discharge.
How do soils affect the shape of a storm hydrograph?
Porous soils such as sands or rocks such as limestone are permeable, therefore runoff is reduced and leading to long lag times and gentler hydrographs.
What do hydrographs plot?
1. A hydrograph is a graph showing stage discharge Volume of runoff, or other properties of water flow with respect to time. When the stage is plotted against time, the graph is a stage hydrograph. When the discharge is shown against time, the graph is a discharge hydrograph.
What influences the shape of a storm hydrograph?
A number of factors (known as drainage basin controls) influence the way in which a river responds to precipitation and have an effect on the shape of the hydrograph. The size, shape and relief of the basin are important controls.
What factors influence storm hydrographs?
What factors affect hydrographs?
Let’s take a look at these different flood hydrograph dynamics.
- Shape. A circular shaped drainage basin leads to rapid drainage whereas a long drainage basin will take time for the water to reach the river.
- Topography & relief.
- Heavy Storms.
- Lengthy rainfall.
- Snowfall.
- Vegetation.
- Rock type.
What is a storm hydrograph and what factors can impact it?
Storm hydrographs allow us to investigate the relationship between a rainfall event and discharge. The starting and finishing level show the base flow of a river. The base flow is the water that reaches the channel through slow throughflow and permeable rock below the water table.
What are hydrographs used for?
1. A hydrograph is a graph showing stage discharge Volume of runoff, or other properties of water flow with respect to time.
What affects the shape of a storm hydrograph?
There are a range of physical factors that affect the shape of a storm hydrograph. These include: Large drainage basins catch more precipitation so have a higher peak discharge compared to smaller basins. Smaller basins generally have shorter lag times because precipitation does not have as far to travel.