#### Manning equation

## How is Manning calculated?

The Manning Equation was developed for uniform steady state flow (see Discussion and References for Open Channel Flow). S is the slope of the energy grade line and S=h_{f}/L where h_{f} is energy (head) loss and L is the length of the channel or reach.

## What is Manning’s n value?

The Manning formula is an empirical formula estimating the average velocity of a liquid flowing in a conduit that does not completely enclose the liquid, i.e., open channel flow. n is the Gauckler–Manning coefficient.

## What stream characteristics does Manning’s equation take into account when determining discharge?

Manning’s equation examines the relationship between the depth, slope, hydraulic radius, and channel roughness to the velocity and discharge within a channel.

## What is the hydraulic radius?

: the ratio of the cross-sectional area of a channel or pipe in which a fluid is flowing to the wetted perimeter of the conduit.

## What is friction slope?

The rate at which energy is lost along a given length of channel is called the friction slope, and is usually presented as a unitless value or in units of length per length (ft/ft, m/m, etc.). Energy is generally added to a system with a device such as a pump.

## What is the Manning?

The Manning’s n is a coefficient which represents the roughness or friction applied to the flow by the channel.

## What is Rugosity coefficient?

A value used in Manning’s formula to determine energy losses of flowing water due to pipe or channel wall roughness. Also see friction loss, Manning’s formula, and n Factor.

## What are the factors that will effect on the Manning coefficient of an open channel?

The degree of roughness depends on several factors, the most important of which in open-channel flow aresurface roughness of the bed material, cross- section geometry, channel variations, obstruction to flow, typeand density of vegetation, and degree of channel meandering.

## How do you calculate discharge?

Discharge = V x D x W If length is measured in feet and time in seconds, Discharge has units of feet^{3}/sec or cubic feet per second (cfs). Depth times Width gives the cross-sectional area.

## What is energy slope?

The energy gradient is at a distance equal to the velocity head above the hydraulic gradient. In both open and pipe flow the fall of the energy gradient for a given length of channel or pipe represents the loss of energy by friction.

## What is critical depth?

In biological oceanography, ‘Critical Depth’ is defined as a hypothesized surface mixing depth at which phytoplankton growth is precisely matched by losses of phytoplankton biomass within this depth interval. This concept is useful for understanding the initiation of phytoplankton blooms.

## How do you calculate hydraulic radius?

The hydraulic radius is a measure of the efficiency of a river channel. It is calculated.by comparing the wetted perimeter with the cross-sectional area of the channel. The.formula is as follows:Hydraulic Radius = Cross-sectional area ÷ Wetted.perimeter.The larger the hydraulic radius the more efficient the stream.

## How is hydraulic radius measured?

Hydraulic radius is defined as the cross sectional area of flow divided by the wetted perimeter, so the calculation of rectangle and trapezoid area and triangle area will be included along with the perimeter for each.