What determines the amount of runoff

Runoff volumes are affected by various factors: type of precipitation, duration, amount, and intensity of precipitation. … Watershed size, topography, shape, orientation, geology, interflow, soil, and land use are important factors in determining runoff volumes.

What two factors are most important in determining the amount of runoff?

The principal climatic factors that affect the amount of runoff for a given watershed are rainfall duration and intensity, the season of the year, and the meteorologic and frozen soil conditions before the storm. Total runoff for a storm is related to the rainfall duration and intensity.

What are the factors affecting surface runoff?

Temperature, wind speed, and humidity are the major meteorological factors, which affect runoff. Temperature, wind speed and humidity affect evaporation and transpiration rates, thus soil moisture regime and infiltration rate, and finally runoff volume.

What causes more runoff?

In addition to increasing imperviousness, removal of vegetation and soil, grading the land surface, and constructing drainage networks increase runoff volumes and shorten runoff time into streams from rainfall and snowmelt. As a result, the peak discharge, volume, and frequency of floods increase in nearby streams.

What factors contribute to runoff variability?

The principal climatic factors affecting runoff variation are precipitation and temperature. Precipitation change will directly disturb the discharge of the drainage basin, whereas temperature change influences the runoff by altering the capacity of evaporation.

What are the two factors that influence how much runoff and or infiltration occurs in an area?

Surface slopes and roughness greatly influence runoff. Seep slopes reduce time of concentration and detention volume. Roughness increases surface storage and promotes greater infiltration, both of which decrease runoff.

Which factor affects the amount of runoff that occurs in an area quizlet?

Runoff appears in uncontrolled surface streams, rivers, drains and sewers. Factors that affect runoff include the amount of rainfall, permeability, vegetation and the slope of the land.

How does overland flow occur?

Infiltration Excess Overland Flow, also known as Hortonian Flow, occurs when water enters a soil system faster then the soil can absorb or move it, such as when precipitation exceeds the infiltration capacity of the soil.

What causes urban runoff?

Urban runoff is either wet weather (rainwater) or dry weather (water waste) flows from urban landscapes into storm drain systems that lead to the beach. … Hosing sidewalks is illegal and generates urban runoff.

Which activity has caused the greatest increase in polluted runoff?

Runoff pollution is increasing because the amount of land covered by parking lots, roads, roofs, and driveways, continues to grow. Meanwhile, forests, meadows, and other natural filters are disappearing, and manmade filtration systems to control runoff have not compensated for the loss.

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What are the components of runoff?

• Direct rainfall over the stream:-
• Surface runoff or overland flow: –
• Subsurface flow or interflow:–
• Base flow, groundwater flow or Dry weather flow:-

What is runoff and write the factors affecting runoff?

 Runoff depends on the intensity of rainfall.  More the rainfall, more will be runoff.  If the rainfall intensity is very less and it rains as light showers then much of the water will be lost in infiltration & evaporation resulting less runoff.  If precipitation is in case of snow then less runoff.

What are the physical characteristics affecting runoff?

Physical characteristics affecting runoff: Drainage area. Basin shape. Elevation. Topography, especially the slope of the land.

What factors affect runoff and infiltration?

Factors Influencing Infiltration Rate. Soil characteristics, plants and animals, and slope angle are among the natural factors controlling the proportion of precipitation that is converted to runoff in a given landscape, and the time it takes for runoff to enter a stream.

Which catchment contributes more runoff?

Topography of Catchment If the surface slope is steep, water will flow quickly, and absorption and evaporation losses will be less, resulting in greater runoff. – If the catchment is mountainous, and is on the windward side of the mountains, the intensity of rainfall will be more, and hence runoff will be more.

What is a runoff ratio?

Runoff ratio is the runoff for each watershed divided by the precipitation for that watershed. It is the proportion of rainfall that does not infiltrate and is not taken up by evapotranspiration, and thus ends up as runoff. … These areas will have high runoff ratios.

Which features help reduce the amount of runoff?

Trees are increasingly recognized for their importance in managing runoff. Their leaf canopies help reduce erosion caused by falling rain. They also provide surface area where rain water lands and evaporates. Roots take up water and help create conditions in the soil that promote infiltration.

Which feature may form as result of erosion related to runoff?

Rill erosion describes erosion that takes place as runoff develops into discrete streams (rills).

What material is moved by runoff?

Runoff is the portion of precipitation on land that ultimately reaches waterways, often with dissolved or suspended material. Erosion is the process by which sand, silt, rocks and sediment are moved from one place to another. Water is the most powerful agent of erosion.

What factors affect how much infiltration can occur?

• Precipitation. Precipitation can impact infiltration in many ways. …
• Soil characteristics. The porosity of soils is critical in determining the infiltration capacity. …
• Soil moisture content. …
• Organic materials in soils. …
• Land cover. …
• Slope. …
• General hydrologic budget. …
• Richards’ equation (1931)

What are the factors influence the infiltration rate?

The main factors that influence the infiltration are: the soil type (texture, structure, hydrodynamic characteristics). The soil characteristics influence capillary forces and adsorption; the soil coverage.

How does slope affect surface runoff?

Slopes, Soils and Runoff In general, the steeper and longer a slope is, the faster water runs off of it, and the greater potential there is for erosion.

What is industrial runoff?

Industrial runoff typically contains high concentrations of pollutants such as heavy metals and petroleum hydrocarbons. These contaminants place a heavy burden on the Bay’s fish and other animals. … We’re using this analysis to propose precise limits for every harmful pollutant in industrial runoff.

How runoff affects water quality?

Runoff picks up fertilizer, oil, pesticides, dirt, bacteria and other pollutants as it makes its way through storm drains and ditches – untreated – to our streams, rivers, lakes and the ocean. … Reducing runoff can help prevent water pollution, reduce flooding, and protect our precious drinking water resources.

How does urbanization lead to flooding and water pollution?

The runoff from the increased pavement goes into storm sewers, which then goes into streams. … Changing a stream channel can cause flooding and erosion along the stream banks. More sewage is discharged into streams that weren’t “designed by nature” to handle that much water.

How is overland flow length determined?

The average length of overland flow was determined by dividing the watershed area by twice the total length of all waterways.

How can overland flow be prevented?

1. Strategically place downed wood to deflect.
2. slow and pool overland flow water as snow melts over saturated soils and frozen soils.
3. Use wattles and water bars to slow overland flow water velocity and increase retention and recharge into soils.

How is overland flow measured?

If the catchment area is symmetrically distributed around the drainage network, an approximate value for the overland flow length can be found by dividing the area by twice the length of the drainage channel.

How is runoff generated?

Runoff occurs when there is more water than land can absorb. The excess liquid flows across the surface of the land and into nearby creeks, streams, or ponds. … Mountains that cannot absorb water from heavy snowfalls produce runoff that turns into streams, rivers, and lakes.

How does increased runoff affect the environment?

Stormwater runoff can cause a number of environmental problems: Fast-moving stormwater runoff can erode stream banks, damaging hundreds of miles of aquatic habitat. … Stormwater runoff can push excess sediment into rivers and streams. Sediment can block sunlight from reaching underwater grasses and suffocate shellfish.

How does vegetation affect runoff?

Trees and other vegetation in urban areas considerably reduce urban-water runoff. As rain falls upon vegetation, it clings to the rough surfaces of leaves, branches, and trunks. … By intercepting and slowing precipitation hitting the ground, vegetation substantially reduces the volume and rate of stormwater runoff.