1. What is the Waterfall Pump Size Calculation?

The waterfall pump size calculation determines the required horsepower for a pump based on flow rate, head pressure, fluid properties, and pump efficiency. Proper sizing ensures adequate water flow for your waterfall while optimizing energy use.

2. How Does the Calculator Work?

The calculator uses the pump power equation:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total dynamic head in feet
• \( SG \) — Specific gravity of fluid (1.0 for water)
• \( \eta \) — Pump efficiency (typically 0.7-0.9)
• 3960 — Conversion factor (foot-pounds per minute to horsepower)

Explanation: The equation calculates the theoretical power required to move fluid against gravity and system resistance, then accounts for pump inefficiency.

3. Importance of Proper Pump Sizing

Details: Correct pump sizing prevents energy waste (oversizing) and inadequate flow (undersizing). It affects waterfall appearance, energy costs, and pump lifespan.

4. Using the Calculator

Tips: Measure flow rate and head accurately. For waterfalls, typical flow is 100-200 GPM per foot of weir width. Head includes vertical rise plus friction losses in pipes.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical efficiency for waterfall pumps?
A: Centrifugal pumps typically have 70-85% efficiency. Higher quality pumps may reach 90%.

Q2: How do I account for pipe friction losses?
A: Add 1-3 feet of head per 100 feet of pipe (depending on diameter) to your vertical head measurement.

Q3: Should I round up the calculated horsepower?
A: Yes, select the next available pump size (typically in 0.25 or 0.5 HP increments).

Q4: What if my water has additives (algaecides, etc.)?
A: Most water treatments don't significantly change specific gravity (SG). For saltwater, use SG = 1.025.

Q5: How does altitude affect pump performance?
A: At higher elevations, pumps produce slightly less head due to lower atmospheric pressure.