Factors affecting hydrograph. What are the factors affecting hydrograph? 2022-11-15

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A hydrograph is a graphical representation of the flow rate of a river or stream over time. There are several factors that can affect the shape and characteristics of a hydrograph, including precipitation, infiltration, evapotranspiration, channel geometry, and land use.

Precipitation is a major factor that can affect the flow rate of a river or stream. When it rains, the water from the precipitation can either infiltrate into the ground or run off into nearby waterways. If the ground is saturated with water, or if the soil has a low infiltration rate, then more of the precipitation will run off into the river or stream, causing the flow rate to increase. Conversely, if the soil has a high infiltration rate, then more of the precipitation will be absorbed into the ground, causing the flow rate to decrease.

Infiltration is the process by which water seeps into the ground. The rate of infiltration is influenced by factors such as the type and structure of the soil, the slope of the land, and the presence of vegetation. Soils with a high clay content or that are compacted tend to have a low infiltration rate, while looser, more porous soils have a higher infiltration rate. Similarly, slopes that are steep or have a hard, impermeable surface will have a lower infiltration rate than gentler slopes or those with a porous surface. Vegetation, particularly grass and other shallow-rooted plants, can help to increase the infiltration rate by intercepting and slowing down runoff, allowing it to soak into the ground.

Evapotranspiration is the process by which water is returned to the atmosphere through the transpiration of plants and the evaporation of water from the surface of the ground and bodies of water. The rate of evapotranspiration is influenced by factors such as temperature, humidity, and wind speed. In general, evapotranspiration rates are higher in warmer, dryer conditions, and lower in cooler, more humid conditions.

Channel geometry refers to the physical characteristics of the river or stream channel, such as its shape, size, and slope. These factors can affect the flow rate of the water by influencing how quickly it moves through the channel. For example, a wide, shallow channel will have a lower flow rate than a narrow, deep channel of the same length, because the water has more space to spread out and slows down as it moves through the channel. Similarly, a channel with a steep slope will have a higher flow rate than one with a gentle slope, because the water will be moving more quickly as it flows downhill.

Land use can also affect the flow rate of a river or stream. For example, if an area is heavily developed with roads, buildings, and other impermeable surfaces, more of the precipitation will run off into the river or stream, increasing the flow rate. On the other hand, if the land is covered in vegetation or has permeable surfaces, more of the precipitation will be absorbed into the ground, decreasing the flow rate. Land use can also affect the rate of evapotranspiration, as vegetation tends to have a higher rate of evapotranspiration than other land covers.

In summary, there are several factors that can affect the shape and characteristics of a hydrograph, including precipitation, infiltration, evapotranspiration, channel geometry, and land use. Understanding these factors can help us to better predict and manage the flow of rivers and streams, and to make informed decisions about land use and development in the surrounding areas.

River Regime

factors affecting hydrograph

Wet winters create increase in discharge. This result in short lag times and high peak discharge. In the elongated basins, the time taken to reach output from remote parts is different. KW equations have been solved through Preissmann implicit method. How are flood hydrographs used in the real world? Therefore, the temperature is also an indirect influence. ADVERTISEMENTS: The factors affecting the runoff are as follows: 1. River properties The main property of the river that affects the river discharge and, by extension, the river regime is the cross-sectional area.

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Factors Affecting Runoff

factors affecting hydrograph

Rising Limb Water entering the river, steeper rising limbs indicate fast entering of water into the river Peak Discharge Flow of water is at its highest. Findings — Different watershed models were developed for different rainfall events. It is also helpful in predicting the expected flood flow from a catchment if rainfall intensity in the catchment is known. Geographical Conditions : The nature of the soil, its permeability, has an effect on the infiltration rate and has indirect effect on the runoff. What are the examples of hydrological hazards? Factors Affecting River Regime A drainage basin is an area drained by a river.

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Hydrograph Analysis

factors affecting hydrograph

The time base of the hydrographs from larger basins will be larger than those of corresponding hydrographs from smaller basins. Hydrographs illustrate river discharge and rainfall over time. When a storm begins rain does not readily enter into the river and fills it, instead, most contributions comes from overland flow runoff or throughflow. What are some examples of a hydrological hazard? Long lag times indicate that rain water runoff is slowly reaching the river. This type of hydrograph is known as a storm or flood hydrograph and it is generally drawn with two vertical axes.

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HYDROGRAPH

factors affecting hydrograph

The results are high peak discharges and short lag times. Because the timing, magnitude, and duration of groundwater return flow differ so greatly from that of direct runoff, separating and understanding the influence of these distinct processes is key to analyzing and simulating the likely hydrologic effects of various land use, water use, weather, and climate conditions and changes. In the UK, typical patterns include higher levels of precipitation in the winter months and higher levels of evapotranspiration in the summer months. When the stage is plotted against time, the graph is a stage hydrograph. In very small catchments, the shape of the hydrograph can also be affected by the intensity. Human factors While the land surrounding a river can change naturally, anthropogenic influence can severely disrupt the natural environment and the reaction of a river to a storm event. As such, it is perhaps of lesser influence in the case of many rivers.

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Physical factors affecting flood hydrograph dynamics

factors affecting hydrograph

If there is more evapotranspiration, the amount of water and therefore the river discharge is lower. Although these concepts, at least in their simplest form, have been largely superseded, a study of Horton's archived scientific papers reveals that his perceptual model of infiltration processes and appreciation of scale problems in modelling were far more sophisticated and complete than normally presented in hydrological texts. Short lag times indicate that rain is heavy and entering the river fast. Seasonally, in the UK the vegetation will reduce discharge in the summer whereas in the winter it will have less of an impact due to less foliage being present on trees. If the discharge of a river is particularly high, it can mean that the water has passed over the banks resulting in a flood. The hydrograph shows changes in discharge over time.


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Storm Hydrographs: Definition, Factors & Analysis

factors affecting hydrograph

What physical factors affect the shape and timing of the unit hydrograph? Method 2 In this method, the tangent line is drawn at beginning of runoff i. This paper presents a study to develop a flood inundation model for partially gauged upper Ganga catchment. An important model parameter to be calibrated is roughness. Shape of Basin In the fan-shaped basin, the time taken for water to reach the outlet from remote parts is almost similar. This is often used after a storm when the flow is much higher than normal. Types of Hydrographs A hydrograph is a graph showing stage, discharge, velocity, or other properties of water flow with respect to time.

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Geography: Storm Hydrograph and Factors Affecting It

factors affecting hydrograph

Let's have a look at a few examples: Physical factors There are many drainage basin characteristics that can alter the shape of a storm hydrograph: If a drainage basin is large in area, then it typically takes the rainfall it receives longer to reach the river because it has a further distance to travel. Slope of Catchment The slope of the catchment is more, infiltration less, runoff more, and discharge will be high. The average value of: i. Heavy Storms Runoff will increase after soil field capacity is met which means water will reach the channel quicker. Changes in the river regime can alter the water balance because factors affecting it e. His understanding of surface controls on infiltration remain relevant today. How do you explain a hydrograph? If the sides of a drainage basin are steeper, then rainfall will move down them more quickly, resulting in a flashy hydrograph.

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Factors affecting the shape of a hydrograph

factors affecting hydrograph

Most changes in land use tend to increase the amount of runoff for a given storm e. In this special issue, ten papers are collected that cover the hydrological hazards in a changing environment. How is a contour contour map or equipotential map or equipotential map constructed? Rising Limb It is the ascending portion of the hydrograph. Snowfall Until the snow melts, the water is held in storage but when the snow melts this can lead to flooding. Clay would create a Soil Type Clay, sand etc.

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