1. What is Potential Maximum Retention?

Potential Maximum Retention (S) is a parameter used in the Soil Conservation Service (SCS) Curve Number method for estimating runoff. It represents the maximum amount of water that can be retained in the soil after runoff begins.

2. How Does the Calculator Work?

The calculator uses the Potential Maximum Retention formula:

Where:

• \( S \) — Potential Maximum Retention (mm)
• \( CN \) — Curve Number (unitless, range 1-100)

Explanation: The formula calculates the maximum water retention capacity based on the curve number, which represents the runoff potential of a land area.

3. Importance of S Calculation

Details: Accurate calculation of Potential Maximum Retention is crucial for hydrologic modeling, flood prediction, watershed management, and designing drainage systems.

4. Using the Calculator

Tips: Enter the Curve Number value between 1 and 100. Higher curve numbers indicate lower infiltration capacity and higher runoff potential.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of Curve Number values?
A: Curve Number values range from 1 to 100, where lower values indicate higher infiltration capacity and higher values indicate higher runoff potential.

Q2: How is Curve Number determined?
A: Curve Number is based on soil type, land use, land treatment, and hydrologic condition of the area.

Q3: What are typical Curve Number values?
A: Typical values range from 30-40 for forested areas to 90-98 for impervious surfaces like paved areas.

Q4: What does a higher S value indicate?
A: Higher S values indicate greater water retention capacity in the soil, meaning less runoff will occur.

Q5: Are there limitations to this formula?
A: The formula assumes certain conditions and may need adjustment for different soil moisture conditions and regional variations.