# What Is Sheet Flow Runoff?

July 28, 2022

Stratified runoff means the movement of water, usually storm runoff, flowing across the soil surface in a thin layer; also called overland flow, which occurs when excess rainwater, meltwater, or other water sources flow over the surface of the ground.

## What is the sheet flow?

Leaf Flow . (also called overland flow) means flat, unconcentrated and irregular flow down a slope. The length of the strip for overland flow does not typically exceed 200 feet under natural conditions.

## Where does sheet flow occur?

As already mentioned, sheet currents occur above all at extremely high precipitation rates or in areas with impervious surfaces; Most of the water entering surface water comes from groundwater. Several regions below the soil surface that receive infiltration have been described (Fig. 4.3).

## What is the difference between sheet flow and shallow concentrated flow?

LEAF FLOW: It is the flow of water over the flat surface as a more or less uniformly thick film or sheet of water. SHALLOW CONCENTRATED FLOW: At the end of the sheet flow, water begins to accumulate in small gullies and grassy hollows.

## How do you calculate sheet flow?

Calculating the length of the overland (strata) river by Equation 1 requires that the sum of the river lengths and the area of ​​the watershed are in consistent units. For example, if Dd is 48,900 feet, the watershed area should also be in square feet, or 206 acres times 43,560 square feet per acre.

## What is sheet flow dispersion?

Stratification is the simplest method of flow control. This BMP can be used for any impervious or permeable surface that is graded to avoid concentrated currents.

## What is overland sheet flow?

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

## What is the cause of sheet erosion?

Plate erosion is caused by the force of raindrops hitting bare ground (Ellison 1944) and shedding soil particles. This force is a function of drop velocity (a function of drop length and wind speed) and weight (a function of drop diameter).

## How can you prevent sheet erosion?

Foliar erosion can be prevented by preserving plant cover (preventing splash erosion) and maximizing pond water infiltration by preserving soil structure and organic matter.

## What is sheet wash erosion?

Sheet erosion or sheetwash is the uniform erosion of the substrate over a wide area. It is found in a variety of environments such as coastal plains, hillsides, flood plains and beaches. Water moving fairly evenly across a surface with a similar thickness is called strata flow and is the cause of strata erosion.

## What is SCS method?

The SCS-CN method predicts runoff using an expression for a precipitation-runoff curve that varies according to a single parameter called the curve number (CN). The dimensionless CN parameter describes the preceding potential water retention of a watershed [Hawkins, 2014].

## What are concentrated flows?

Updated: November 16, 2021. A concentrated flow path (CFP) that began to flow away from an agricultural field after a large rain event. Most of these CFPs are driven by topography, but they can start flowing even in flatter landscapes as water always finds its way downhill. Water flows downhill.

## What is the difference between lag time and time of concentration?

In the hydrograph analysis, the lag is the time interval between the center of excess precipitation and the peak runoff rate (Fig. 15-3). The concentration time (Tc) is the time it takes for the outflow to travel from the hydraulically most distant point in the watershed to the outflow.

## How do you calculate peak flow runoff?

The rational formula is expressed as Q = CiA where: Q = peak discharge rate in cubic feet per second C = discharge coefficient, an empirical coefficient that represents a relationship between precipitation and discharge.

## How do you calculate rainfall flow?

• Q is stormwater runoff in gallons per minute (GPM)
• C is runoff coefficient,
• I is precipitation intensity in inches per hour.
• < li>A is the drainage area in square feet.

• 23 is a conversion factor if you want flow rate in GPM and your drainage area is in square feet.

### References:

1. https://www.lawinsider.com/dictionary/sheet-flow
2. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/sheet-flow
3. http://www.professorpatel.com/time-of-concentration.html
4. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/16/stelprdb1043054.doc
5. https://www.sanjuanco.com/DocumentCenter/View/1621/BMP-T512-Sheet-Flow-Dispersion-PDF
6. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/overland-flow
7. https://www.fao.org/3/t1765e/t1765e0d.htm
8. https://nre.tas.gov.au/agriculture/land-management-and-soils/soil-management/soil-erosion/soil-erosion-types/water-erosion/sheet-erosion
9. https://en.wikipedia.org/wiki/Sheet_erosion
10. https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2015WR018439
11. https://extension.psu.edu/concentrated-flow-paths-an-introduction
12. https://directives.sc.egov.usda.gov/27002.wba