How do you calculate overland flow?

Table of Contents

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 do you calculate overland sheet flow path length?

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

Is overland flow the same as sheet flow?

(also called overland flow) means shallow, unconcentrated and irregular flow down a slope. The length of strip for overland flow usually does not exceed 200 feet under natural conditions. Sheet flow means runoff which flows over the ground surface as a thin, even layer, not concentrated in a channel.

What is overland sheet flow?

Overland flow is defined as water that flows over the land surface as either diffuse sheet flow (laminar or mixed laminar flow) or concentrated flow (turbulent flow) in rills and gullies (Ward and Robinson, 2000).

What is overland flow in the water cycle?

Overland flow transfers water through the basin either as sheetwash, across the surface, or in tiny channels called rills. Beneath the surface, water is transferred via throughflow, which is the movement of water through the lower soil towards rivers, and groundwater flow.

What is the difference between overland flow and stream flow?

OVERLAND FLOW AND STREAMFLOW. Runoff that flows down the land slopes in broadly distributed sheets is called overland flow. This is different from streamflow, in which the water runs along a narrow channel between banks.

What’s the difference between overland flow and surface runoff?

Overland flow is surface runoff that occurs in the form of sheet flow on the land surface without concentrating in clearly defined channels. This type of flow is the first manifestation of surface runoff, since the latter occurs first as overland flow before it has a chance to flow into channels and become streamflow.

What is overland flow length?

The maximum overland flow length is the length of the flow path from the furthest drainage point of the subcatchment before the flow becomes channelized. Maximum lengths from several different possible flow paths should be averaged.

What is the difference between surface runoff and overland flow?

Surface runoff is water, from rain, snowmelt, or other sources, that flows over the land surface, and is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called overland flow. A land area which produces runoff draining to a common point is called a watershed.

What is saturated overland flow?

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 is overland flow?

How do hillslopes control overland-flow dynamics?

Because natural hillslopes are permeable, subsurface-surface interactions also control overland-flow dynamics. The infiltration-excess overland flow mechanism is most common where interactions with the subsurface are limited ( Smith et al., 2002 ).

What is infiltration-excess overland flow?

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.

What is the channel width of an overland cell?

The cells that have a channel receive a part of the overland flow, depending on the velocity. Thus the velocity is considered the average velocity existing in the cell. The channel is considered to be in the center of the cell so that the distance from the edge to the channel is 0.5* (DX-channelwidth).