This TSI Calculator allows users to evaluate the trophic state of a water body by inputting concentrations of Chlorophyll-a and Total Phosphorus, along with Secchi Depth, and generates corresponding TSI values and a classification of the water’s trophic state.
Tsi Calculator
Use Our Tsi Calculator
Using the TSI (Trophic State Index) Calculator
This guide provides a step-by-step walkthrough on how to use the TSI (Trophic State Index) Calculator to determine the trophic state of a water body using chlorophyll-a concentration, total phosphorus concentration, and Secchi depth measurements.
Step 1: Input Values
- Chlorophyll-a (μg/L): Enter the concentration of chlorophyll-a found in the water body. Ensure this value is between 0.01 and 1000 as per the calculator’s requirements.
- Total Phosphorus (μg/L): Input the total phosphorus concentration. This value must also fall within the range of 0.01 to 1000.
- Secchi Depth (meters): Provide the Secchi depth measurement, with acceptable values ranging from 0.01 to 100.
It is important that all fields are filled in as they are marked as required, and leaving any input field empty will result in an incomplete analysis.
Step 2: Understanding the Calculations
- TSI (Chlorophyll-a): This value is calculated using the formula 9.81 * ln(chlorophyllA) + 30.6.
- TSI (Total Phosphorus): Calculated through 14.42 * ln(totalPhosphorus) + 4.15.
- TSI (Secchi Depth): This is determined by 60 – 14.41 * ln(secchiDepth).
Step 3: View the Results
- Average TSI: The average of the three TSI scores is calculated with the formula (tsiChlorophyll + tsiPhosphorus + tsiSecchi) / 3, giving you a single TSI value.
- Trophic State: Based on the average TSI, the water body’s trophic state will be categorized as:
- Oligotrophic, if TSI is ≤ 40
- Mesotrophic, if TSI is ≤ 50
- Eutrophic, if TSI is ≤ 70
- Hypereutrophic, if TSI is above 70
Once your inputs are provided and you initiate the calculation, the calculator will display each of these results for your interpretation and further action.