Question: What Are Hydrographs Used For?

What factors affect Hydrographs?

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.Rising limb – shows the increase in discharge on a hydrograph.More items….

What will affect lag time?

Slope – steep slopes lead to rapid water transfer and shorter lag times. Gentle slopes slow down water transfer making the lag time longer. Drainage basin shape – a high density basin has more streams and rivers which speed up water transfer and shorten lag time.

What is the purpose of a hydrograph?

A hydrograph may be used to show how the water flow in a drainage basin (particularly river runoff) responds to a period of rain. This type of hydrograph is known as a storm or flood hydrograph and it is generally drawn with two vertical axes.

How can Hydrographs be used to manage floods?

Flood hydrographs can be used to predict flooding by showing how different levels of precipitation affect a river during a storm. Hydrographs can be different shapes. The characteristics of the river and how likely it is to flood affects its shape. A gentle hydrograph shows the river is at low risk of flooding.

What is a storm hydrograph and what factors can impact it?

There are a range of physical factors that affect the shape of a storm hydrograph. These include: 1. Large drainage basins catch more precipitation so have a higher peak discharge compared to smaller basins. … Basins that have many streams (high drainage density) drain more quickly so have a shorter lag time.

Why do natural levees build up after floods?

The natural movement of a body of water pushes sediment to the side, creating a natural levee. The banks of a river are often slightly elevated from the river bed. The banks form levees made of sediment, silt, and other materials pushed aside by the flowing water.

What information can be determined from a hydrograph?

Hydrographs are a representation of the physical geography of and the meteorological conditions in a watershed, and they include the combined effects of climate, hydrologic losses (e.g., evaporation, infiltration, and so on), surface runoff, subsurface stormwater flow, and groundwater flow.

What does hydrograph mean?

A hydrograph is a graph or plot that shows the rate of water flow in relation to time, given a specific point or cross section. These graphs are often used to evaluate stormwater runoff on a particular site considering a. development project.

What is the difference between hydrograph and Hyetograph?

A hydrograph is graphically plot of discharge of a natural system for river versus time. … A hyetograph is a plot of intensity of rainfall against the time interval it is usually represented buy a bar chart. 2.