Flood Discharge In FPS Unit By Fuller's Formula Calculator

Fuller's Formula:

\[ Q_{FLF} = C_{FLF} \times A^{0.8} \times (1 + 0.8 \times \ln(T_m)) \times (1 + 2 \times A^{-0.2}) \]

Flood Discharge by Fuller's Formula in FPS:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Fuller's Formula for Flood Discharge?

Fuller's Formula is an empirical equation used to estimate peak flood discharge in FPS (Foot-Pound-Second) units. It considers the catchment area, time period, and regional characteristics through Fuller's constant to provide flood discharge estimates.

2. How Does the Calculator Work?

The calculator uses Fuller's Formula:

\[ Q_{FLF} = C_{FLF} \times A^{0.8} \times (1 + 0.8 \times \ln(T_m)) \times (1 + 2 \times A^{-0.2}) \]

Where:

\( Q_{FLF} \) — Flood discharge (ft³/s)
\( C_{FLF} \) — Fuller's constant (empirical coefficient)
\( A \) — Area of basin (sq mi)
\( T_m \) — Time period for flood discharge (years)
\( \ln \) — Natural logarithm (base e)

Explanation: The formula accounts for the relationship between catchment area, return period, and regional hydrological characteristics to estimate peak flood discharge.

3. Importance of Flood Discharge Calculation

Details: Accurate flood discharge estimation is crucial for hydraulic structure design, floodplain management, disaster preparedness, and water resource planning. It helps in designing appropriate drainage systems and flood control measures.

4. Using the Calculator

Tips: Enter Fuller's constant (region-specific empirical value), basin area in square miles, and time period in years. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is Fuller's constant and how is it determined?
A: Fuller's constant is an empirical coefficient that varies by region and is determined through historical flood data analysis and regional hydrological studies.

Q2: What are typical values for Fuller's constant?
A: Fuller's constant typically ranges from 25 to 30 for most regions, but can vary significantly based on local hydrological conditions and catchment characteristics.

Q3: What time period should be used in the calculation?
A: The time period refers to the return period or recurrence interval for which the flood discharge is being estimated (e.g., 10-year flood, 100-year flood).

Q4: Are there limitations to Fuller's formula?
A: Yes, the formula is empirical and may not be accurate for very large or very small catchments, or for regions with significantly different hydrological characteristics than those used to derive the original constants.

Q5: How does this formula compare to other flood estimation methods?
A: Fuller's formula is one of several empirical methods. Other approaches include rational method, unit hydrograph method, and statistical frequency analysis, each with their own advantages and limitations.