Equation for Gross Recharge due to Rainfall and other Sources Calculator

Gross Recharge Equation:

\[ R_G = (h \times S_Y \times A) + D_G + B - I_s - I \]

Water Level Fluctuation (h):

Specific Yield (S_Y):

Watershed Area (A):

m²

Gross Water Draft (D_G):

m³/s

Base Flow into the Stream (B):

m³/s

Recharge of Ground Water Body (I_s):

m³/s

Net Ground Water Flowing Outside Catchment (I):

m³/s

Gross Recharge due to Rainfall (R_G):

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1. What is the Gross Recharge Equation?

The Gross Recharge due to Rainfall equation calculates the total amount of water that infiltrates the ground from precipitation and other sources, accounting for various hydrological components in a watershed area.

2. How Does the Calculator Work?

The calculator uses the Gross Recharge equation:

\[ R_G = (h \times S_Y \times A) + D_G + B - I_s - I \]

Where:

\( R_G \) — Gross Recharge due to Rainfall (m³/s)
\( h \) — Water Level Fluctuation (m)
\( S_Y \) — Specific Yield
\( A \) — Watershed Area (m²)
\( D_G \) — Gross Water Draft (m³/s)
\( B \) — Base Flow into the Stream from the Area (m³/s)
\( I_s \) — Recharge of Ground Water Body (m³/s)
\( I \) — Net Ground Water Flowing Outside Catchment (m³/s)

Explanation: The equation accounts for multiple hydrological components including water level changes, specific yield characteristics, watershed area, water extraction, base flow, groundwater recharge, and outflow from the catchment area.

3. Importance of Gross Recharge Calculation

Details: Accurate gross recharge estimation is crucial for water resource management, groundwater modeling, sustainable water extraction planning, and understanding the hydrological balance of watershed areas.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Water level fluctuation, specific yield, and watershed area must be positive values. Other parameters should be non-negative values for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is Specific Yield and how is it determined?
A: Specific Yield refers to the volume of water that a saturated rock or soil will yield due to gravity drainage. It is typically determined through laboratory tests or field measurements and varies by soil type.

Q2: How is Water Level Fluctuation measured?
A: Water Level Fluctuation is typically measured using monitoring wells or piezometers during monsoon seasons to track the irregular rising and falling of water levels.

Q3: What is the difference between Gross Water Draft and Base Flow?
A: Gross Water Draft refers to the total volume of water extracted from the catchment, while Base Flow refers to the natural groundwater flow into streams that occurs over extended periods.

Q4: Why subtract Recharge of Ground Water Body and Net Ground Water Flow?
A: These components represent water that is either recharging other groundwater bodies or flowing out of the catchment area, thus reducing the net recharge available within the specific watershed.

Q5: What are typical values for Gross Recharge in different regions?
A: Gross Recharge values vary significantly based on climate, soil type, and geological conditions. Arid regions may have values below 0.1 m³/s, while humid regions with large watersheds can have values exceeding 10 m³/s.