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Waterfall Pump Calculator

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A waterfall pump calculator is a handy tool designed to simplify the process of selecting the right pump for a waterfall feature in a garden pond or landscape. This calculator takes into account various factors that influence the flow and height of the waterfall, ensuring that the chosen pump meets the specific needs of the waterfall design.

Purpose and Functionality

The primary purpose of a waterfall pump calculator is to help users determine two key factors: the Flow Rate Required (FR) and the Total Dynamic Head (TDH). The FR indicates how much water needs to flow through the waterfall per hour to achieve the desired visual effect, while the TDH calculates the total height the pump must push water, taking into account any resistance from pipe length, bends, and diameter.

Inputs Needed:

  • Height of the Waterfall (H): The vertical distance from the water’s surface to the waterfall’s highest point.
  • Width of the Waterfall (W): The overall width of the waterfall’s widest section.
  • Desired Water Flow Rate (Q): A subjective measure, typically ranging from 100 to 200 gallons per hour (GPH) per inch of width for varying flow intensities.
  • Length of Pipe from Pump to Waterfall (L): The total distance the water travels through the pipe from the pump to the waterfall.
  • Diameter of the Pipe (D): The internal width of the pipe used.
  • Number of Bends in Pipe: Each bend in the piping can add to the resistance or friction loss, affecting the pump’s efficiency.

Formulas Used:

  1. Flow Rate Required (FR) FR=W×Desired_GPH_per_inch
  2. Total Dynamic Head (TDH) TDH=H+(10L​)+(Number_of_Bends×1)+(Friction_Loss_per_100ft×100L​)

Step-by-Step Example

Let’s calculate the requirements for a waterfall with the following characteristics:

  • Height: 5 feet
  • Width: 24 inches
  • Desired flow rate: 150 GPH per inch
  • Pipe length: 20 feet
  • Pipe diameter: Not directly used in the basic formula but important for determining friction loss
  • Bends: 2


  1. Flow Rate Required: FR=24×150=3600GPH
  2. Total Dynamic Head: TDH=5+(20/10)+(2×1)+(2×(20/100))=9.4feet

Relevant Information Table

InputExample ValuesNotes
Height of the Waterfall (H)5 feetFrom pond surface to top of waterfall
Width of the Waterfall (W)24 inchesWidest point of the waterfall
Desired Water Flow Rate (Q)150 GPH/inchVaries based on desired visual effect
Length of Pipe (L)20 feetFrom pump to waterfall
Number of Bends in Pipe2Each bend adds resistance
Friction Loss per 100ft2 feetExample value; actual loss varies by pipe material


This not only ensures a beautiful waterfall but also efficient operation. Remember, the example values provided are for illustrative purposes, and actual friction loss can vary. For precise calculations, especially concerning friction loss, consulting detailed hydraulic tables or fluid dynamics software is recommended. With the right calculations in hand, selecting the perfect pump for your waterfall becomes a straightforward and hassle-free process.

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