Constant Used in FPS Unit given Flood Discharge by Fuller's Formula Calculator

Fuller's Formula:

\[ C_{FLF} = \frac{Q_{FLF}}{(A_1^{0.8}) \times (1 + 0.8 \times \ln(T_m)) \times (1 + 2 \times A_1^{-0.2})} \]

Flood Discharge by Fuller's Formula (Q_FLF):

ft³/s

Area of Basin (A₁):

mi²

Time Period for a Flood Discharge (T_m):

years

Fuller's Constant (C_FLF):

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1. What is Fuller's Constant?

Fuller's Constant for FPS refers to an empirical coefficient used in Fuller's formula to estimate peak flood discharge, adjusted for regional hydrological conditions. It's a crucial parameter in flood frequency analysis and hydrological modeling.

2. How Does the Calculator Work?

The calculator uses Fuller's formula:

\[ C_{FLF} = \frac{Q_{FLF}}{(A_1^{0.8}) \times (1 + 0.8 \times \ln(T_m)) \times (1 + 2 \times A_1^{-0.2})} \]

Where:

\( C_{FLF} \) — Fuller's Constant for FPS
\( Q_{FLF} \) — Flood Discharge by Fuller's Formula (ft³/s)
\( A_1 \) — Area of Basin (mi²)
\( T_m \) — Time Period for a Flood Discharge (years)
\( \ln \) — Natural logarithm (base e)

Explanation: The formula calculates the empirical constant by relating flood discharge to basin area and time period, accounting for regional hydrological characteristics.

3. Importance of Fuller's Constant

Details: Fuller's Constant is essential for accurate flood prediction and hydrological modeling. It helps in estimating peak flood discharges for different return periods, which is crucial for infrastructure design, flood risk assessment, and water resource management.

4. Using the Calculator

Tips: Enter flood discharge in cubic feet per second, basin area in square miles, and time period in years. All values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of Fuller's Constant values?
A: Fuller's Constant typically ranges from 20 to 40 for most regions, but can vary significantly based on local hydrological conditions and basin characteristics.

Q2: How does basin area affect Fuller's Constant?
A: Larger basin areas generally result in higher flood discharges, but the relationship is non-linear as accounted for by the exponents in the formula.

Q3: What time periods are typically used in this calculation?
A: Common time periods range from 2 to 100 years, with 10, 25, 50, and 100-year return periods being most frequently used in flood analysis.

Q4: Are there limitations to Fuller's formula?
A: While widely used, Fuller's formula may need regional calibration and may not be suitable for all hydrological conditions, particularly in extreme climate regions.

Q5: How is this constant used in practical applications?
A: Fuller's Constant is used to estimate flood discharges for various return periods, which helps in designing hydraulic structures, floodplain mapping, and developing flood mitigation strategies.