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Manning Equation Open Channel Flow Rate & Normal Depth Calculator

Easily calculate and compute manning equation open channel flow rate & normal depth calculator with accurate equations, live formulas, and expert guidance.

Bed width of rectangular or trapezoidal channel.

Flow depth.

Channel bed slope.

Roughness (0.013 smooth concrete, 0.025 clean natural river, 0.035 gravel).

Side slope z (0 for rectangular channel).

Calculated Result
14.49 m³/s

Discharge Flow Rate (Q)

Discharge Flow Rate (Q)

14.49 m³/s

Flow Rate Q_ M3 Per S

14.49

Mean Flow Velocity M Per S

1.55

Hydraulic Radius Rh M

0.996

Flow Cross Section Area M2

9.38

14.49 — m³/s

Calculation Breakdown

  1. Applied FormulaSolves the classic Manning equation for open-channel uniform flow rate Q, average velocity, hydraulic radius, and Froude flow regime classification.A = (b + zy)y, \quad P = b + 2y\sqrt{1 + z^2}, \quad R_h = \frac{A}{P}

Manning Open Channel Flow Metric Output

Interactive visualization based on your current inputs

Calculated Value
0.03.67.21114Discharge Flow Rate (Q)

What Is the Manning Equation Open Channel Flow Rate & Normal Depth Calculator?

This tool computes manning equation open channel flow rate & normal depth calculator with high precision arithmetic.

How Does the Manning Equation Open Channel Flow Rate & Normal Depth Calculator Work?

Solves the classic Manning equation for open-channel uniform flow rate Q, average velocity, hydraulic radius, and Froude flow regime classification.

Manning Equation Open Channel Flow Rate & Normal Depth Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

A=(b+zy)y,P=b+2y1+z2,Rh=APA = (b + zy)y, \quad P = b + 2y\sqrt{1 + z^2}, \quad R_h = \frac{A}{P}

Solves the classic Manning equation for open-channel uniform flow rate Q, average velocity, hydraulic radius, and Froude flow regime classification.

How to Use the Manning Equation Open Channel Flow Rate & Normal Depth Calculator

  1. Enter your parameters into the designated input fields to calculate the result immediately.

Step-by-Step Example Calculation

Manning Equation Open Channel Flow Rate & Normal Depth Calculator Example

Input Values:

channelBottomWidthMeters:4.0
waterDepthYMeters:1.5
channelBedSlopeS0:0.0015
manningsRoughnessN:0.025
sideSlopeZ:1.5
Worked Steps: Sample evaluation based on standard reference conditions.

Understanding Your Result

The calculated primary figure indicates the optimal or required m³/s.

Factors That Affect the Result

  • Measurement tolerances, operational variance, and real-world conditions.

When Should You Use This Calculator?

  • Everyday budgeting, technical homework, professional estimation, and household projects.

Assumptions & Limitations

  • Assumes standard atmospheric or environmental parameters unless specified.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Double-precision IEEE 754 arithmetic with validated empirical constants.

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