What is specific stream power and how is it calculated?

Specific stream power ω = ρgQS/w = ρgVdS, where ρ = 1000 kg/m³, g = 9.81 m/s², Q is discharge (m³/s), S is energy slope (m/m), w is channel width (m), V is mean velocity (m/s), and d is mean flow depth (m). Units: W/m². Stream Power Index (SPI) = ln(A_s × tan β), where A_s is specific catchment area and β is slope angle.

What stream power levels cause erosion?

Erosion thresholds (specific stream power): 1000 W/m² — severe erosion, typical of flash floods and steep mountain channels. Stable alluvial channels typically plot on the Shields diagram below the threshold of motion (τ_c* ≈ 0.047).

Stream Power Index Calculator

Calculate specific stream power and stream power index for assessing erosion potential, sediment transport capacity, and channel stability.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Calculate specific stream power and stream power index for assessing erosion potential, sediment transport capacity, and channel stability. Use the stream power index result to inform your clinical assessment.

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Frequently Asked Questions

What is specific stream power and how is it calculated?

What stream power levels cause erosion?