Skip to main content

Nutrient Loss Calculator

Updated February 24, 2021
John McMaine

John McMaine

Assistant Professor, SDSU Extension Water Management Engineer

Water flowing from a drain tile pipe.
Figure 1. Tile outlet with raised rodent guard. Courtesy: SDSU Extension

Trying to figure out the nutrient loss in your tile drainage system? The Nutrient Loss Calculator can help. This useful tool helps landowners collect a snapshot of nutrient loss in their drainage systems.

Use the calculator tool below to get started, or view the following quick guide and instructional video to learn more about using the calculator.

Important Notes

  • If your tile outlet has a rodent guard, be sure to lift the guard when taking flow measurements, since the rodent guard will change the depth of water for your measurement (Figure 1).
  • Nutrient loss varies throughout the year as flow and concentration change.
  • A measurement taken at one point in time does not paint a full picture. We highly recommend collecting data multiple times throughout a year at tile outlets of interest to understand how nutrient loss changes throughout the year.

 

Flow Rate Inputs


Indicate the type of pipe at the outlet. This is used to estimate pipe roughness for flow calculations


Indicate the pipe diameter at the outlet. This is used to determine the cross-sectional area for flow calculations




Indicate the depth of flow at the outlet. This is used to determine the cross-sectional area for flow calculations

Nutrient Inputs



Input the concentration of nutrient in mg/L or parts per million (ppm). ppm and mg/L are equivalent measurements



Results

Flow Rate Value (gpm):

Nutrient Loss (lbs/day):

Value of nutrient loss ($/day):

 

Quick Guide

Landowner measuring the slope of an outlet with a measuring tape and level.
Figure 2. Proper technique for measuring the slope of an outlet. Courtesy: SDSU Extension

Step #1. Determine Flow Rate Inputs

 

Photo demonstrating correct and incorrect measuring techniques for depth of water.
Figure 3. A) Correct technique for measuring depth of water (thin edge forward). B) Incorrect measuring technique (wide edge forward). Courtesy: SDSU Extension

Step #2. Determine Nutrient Concentration Inputs

Related Topics

Soil Health