What is the relationship between infiltration and overland flow?

What is the relationship between infiltration and overland flow?

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 saturated overland flow?

when the intensity of precipitation that reaches the surface exceeds the infiltration capacity of the soil. when the combination of precipitation intensity and duration (and run-on from higher areas) saturates the soil and raises the water table to the surface. This process is known as saturation overland flow.

What causes overland flow?

Saturation Excess Overland Flow occurs when the soil becomes saturated, and any additional precipitation or irrigation causes runoff. Increased interflow levels due to precipitation inputs. Elevated water table due to increased water inputs. Exceeded water holding capacity in shallow soil.

How can overland flow be reduced?

A suite of best management practices for reducing overland flow may include actions to increase surface roughness and canopy interception, maintain soil porosity, and otherwise disperse concentrated or fast-moving flows of water.

How do you control infiltration?

The simplest way to control the building infiltration is to offset the ventilation or outdoor air intentionally brought into the building from the exhaust or relief air expelled from the building.

What affects infiltration?

Soil texture, or the percentage of sand, silt, and clay in a soil, is the major inherent factor affecting infiltration. Water moves more quickly through the large pores in sandy soil than it does through the small pores in clayey soil, especially if the clay is compacted and has little or no structure or aggregation.

Which kind of flow is overland flow?

Overland flow is the term used to describe surface flow that is outside the confines of a stream channel. The generation of overland flow is traditionally divided into two primary mechanisms, infiltration excess (Horton; after Horton (1945)) and saturation excess (Dunne; after Dunne and Black (1970a, 1970b)).

What does overland flow mean?

What is Local Overland Flow? Local Overland Flow is the inundation by local runoff rather than overbank discharge from a stream, river, estuary, lake or dam.

How do you calculate overland flow?

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.

What is the difference between infiltration capacity and infiltration rate?

Infiltration rate is the rate at which the water actually infiltrates through the soil during a storm and it must be equal the infiltration capacities or the rainfall rate, which ever is lesser. Infiltration capacity the maximum rate at which a soil in any given condition is capable of absorbing water.

What are the six factors that affect infiltration?

Factors that affect infiltration

• Precipitation.
• Soil characteristics.
• Soil moisture content.
• Organic materials in soils.
• Land cover.
• Slope.
• General hydrologic budget.
• Richards’ equation (1931)

How can we control infiltration?

Decreasing temperature, which increases water viscosity, reducing infiltration. Entrapped air in the unsaturated zone, which tends to reduce infiltration. Surface gradient. Infiltration capacity is usually greater at the start of a rain that follows a dry period, but it decreases rapidly (Fig.

When does infiltration excess overland flow occur?

Infiltration Excess Overland Flow. 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.

When does overland flow occur in arid regions?

Infiltration-excess overland flow develops when the rate of water input on the land surface is higher than the infiltration rate. It is common in arid regions with limited vegetation, particularly where soils are thin, and rainfall intensities are high.

How does overland flow routing affect the sewer system?

Overland flow routing tranforms the net rainfall into a runoff hydrograph which subsequently enters the sewer system. This process has to take account of the frictional resistance and storage in the channels created by the catchment topography and in the drainage conduits upstream of the sewer system.

Which is less erosive surface flow or overland flow?

Except in extreme circumstances such as pipe flow, subsurface flow is less erosive than surface flow because surface flow is more likely to attain high-enough velocities for erosion and sediment transport. Overland flow is the term used to describe surface flow that is outside the confines of a stream channel.