Skip to main content
Calcimator

Stream Flow Calculator

Calculate stream discharge from average velocity, channel width, and depth. Includes Froude number, hydraulic radius, and flow regime classification.

Inputs

m/s
m
m

Results

Discharge

18 m³/s

Discharge

18,000 L/s

Flow Regime

Subcritical

Discharge (Imperial)635.66 cfs
Daily Volume1.56 ML/day
Cross-Section Area12 m²
Hydraulic Radius0.968 m
Froude Number0.437
Reynolds Number5,783,318
Specific Energy1.315 m
How to Use This Calculator
  1. Enter Average Velocity, Channel Width, and Average Depth.
  2. Review Discharge (m³/s), Discharge (L/s), and Flow Regime.
  3. Use Discharge (Imperial) (cfs) and Daily Volume (ML/day) to inform your decision.
  4. Use the chart to visualize the results and explore different scenarios by adjusting inputs.

How the result changes with Average Velocity

Average VelocityDischargeDischargeFlow Regime
2.0124.12 m³/s24,120 L/sSubcritical
7.0184.12 m³/s84,120 L/sSupercritical
13156 m³/s156,000 L/sSupercritical
18216 m³/s216,000 L/sSupercritical

What each input means

Average Velocity
Mean cross-sectional flow velocity measured by current meter or float method
Channel Width
Width of the water surface at the measurement cross-section
Average Depth
Mean depth across the channel cross-section

How this is calculated

Formula

Q = V × W × D; Fr = V / √(gD)

Worked example, using the default values

  1. Identify Input Parameters
    Average Velocity = 1.5, Channel Width = 10, Average Depth = 1.2 = 3 input(s) provided
  2. Calculate Discharge
    Discharge = v
    18 = 18
  3. Calculate Discharge
    Discharge
    18000 = 18000
  4. Calculate Flow Regime
    Flow Regime
    Subcritical = Subcritical
  5. Calculate Discharge
    Discharge
    635.66 = 635.66
  6. Calculate Daily Volume
    Daily Volume
    1.56 = 1.56

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Hydrology

Rational Method Runoff

Calculate peak stormwater discharge using the Rational Method (Q = CIA/360). Estimate runoff from rainfall intensity, runoff coefficient, and catchment area.

Hydrology

Watershed Area Calculator

Calculate drainage area and morphometric parameters of a watershed from perimeter, shape factor, and longest flow path.

Paddlesports

Whitewater Flow Calculator

Evaluate river flow conditions for paddling suitability using flow rate, width, and depth to calculate velocity, Froude number, and feature suitability.

Ocean Engineering

Port Sedimentation Calculator

Calculate tidal current velocities and volumetric flow through channels and inlets. Determine peak and mean velocities, Froude number, and tidal power density.

Naval Architecture

Hull Speed Calculator

Calculate theoretical hull speed from waterline length using the speed-length ratio formula.

More in Environment, Weather & Climate.