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 flow length?
Flow Length is the horizontal projection length of the greatest surface distance from a point on the surface to the beginning(or end) of the stream along the flow direction.
Is sheet flow same as overland flow?
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 flow length?
Quote: The average length of overland flow was determined by dividing the watershed area by twice the total length of all waterways.
How is overland flow measured?
Measuring overland flow Overland flow can be assessed using a length of plastic guttering. Choose a 50cm or 1m long length, with both ends closed. Bury the guttering just in the soil so that the upper edge is parallel with the soil surface. Cover the open top of the gutter with a plastic cover to keep out the rain.
How do you determine the length of a stream?
Stream length is a dimensional property revealing the characteristic size of components of a drainage network and its contributing watershed surfaces (Strahler, 1964). It is obtained by dividing the total length of stream of an order by total number of segments in the order, Table 2.
What is longest flow path?
Longest Flowpath (L) The longest flowpath extends from the subbasin outlet to the most hydraulically-remote point upstream. Longest flowpath is significant in that it is typically used to determine the time of concentration for a watershed.
What is overland flow in hydrology?
Definition. Overland flow is the movement of water over the land, downslope toward a surface water body. Overland flow is a very important aspect of the water cycle and can be generated under two different physical mechanisms.
How do you calculate the length of a watershed?
Watershed length is measured along the course of the principal stream from the basin outlet to the divide (Figure 1). Gray (1961) (Table 1) demonstrated that for small basins watershed length correlates with basin area.
How do you calculate the length of a basin?
For basin length calculation you need longest flow path and basin area. By dividing basin area per longest flow path, basin length can be obtained.
How do you calculate hydraulic length?
The hydraulic length is the distance between the most distant point in the watershed and the watershed outlet….
| Q = | Peak rate of runoff in cubic feet per second |
|---|---|
| C = | Runoff coefficient, an empirical coefficient representing a relationship between rainfall and runoff |
What is overland flow in the water cycle?
Overland flow is the movement of water over the land, downslope toward a surface water body. Overland flow is a very important aspect of the water cycle and can be generated under two different physical mechanisms.
What is watershed hydraulic length?
Hydraulic length is the length of the flow path from the most remote point in the watershed to the point of discharge.
How do you calculate stream length?
Mean stream length (Lsm) reveals the characteristic size of components of a drainage network and its contributing surfaces (Strahler 1964). It has been computed by dividing the total stream length of order ‘u’ by the number of stream segments in the order (Table 3).
How is overland flow created?
when the intensity of precipitation that reaches the surface exceeds the infiltration capacity of the soil. This process is known as Hortonian overland flow. 2. 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.
What is time of overland flow?
Overland flow travel time is divided into sheet flow travel time and shallow concentrated flow travel time. The overland flow is occurring after completion of infiltration or saturation process, it is generally assumed to be turbulent even though it mostly representing laminar characteristics (Grismer, 2016).