Tubewell Command Area Calculation
The problem asks for the command area of a tubewell, given its discharge rate, daily operating hours, irrigation interval, and irrigation depth.
Key Information Provided:
- Tubewell Discharge ($Q$): $40$ m$^3$ h$^{-1}$
- Daily Operating Hours ($T_{op}$): $20$ h
- Irrigation Interval ($T_{int}$): $20$ days
- Depth of Irrigation ($d$): $8$ cm
Calculation Steps:
-
Calculate Total Operating Time:
Determine the total hours the tubewell operates during the irrigation season.
Total Hours = Daily Operating Hours $\times$ Number of Days
Total Hours = $20$ h/day $\times 20$ days = $400$ h
-
Calculate Total Water Discharged:
Find the total volume of water pumped during the operating time.
Total Volume ($V$) = Discharge ($Q$) $\times$ Total Hours
$V = 40$ m$^3$ h$^{-1} \times 400$ h = $16000$ m$^3$
-
Convert Irrigation Depth to Meters:
Ensure consistent units for calculation.
$d = 8$ cm = $0.08$ m
-
Calculate Irrigated Area in Square Meters:
The volume of water applied is equal to the area irrigated multiplied by the depth of irrigation ($V = A \times d$).
Area ($A$) = Total Volume ($V$) / Depth ($d$)
$A = 16000$ m$^3$ / $0.08$ m = $200000$ m$^2$
-
Convert Area to Hectares (ha):
Since $1$ ha = $10000$ m$^2$.
Area in ha = Area in m$^2$ / $10000$
Area in ha = $200000$ m$^2$ / $10000$ m$^2$/ha = $20$ ha
The command area of the tubewell is calculated to be 20 ha.
Important Questions from Water Requirement of Crops
- A tubewell operating $10\text{ hours}$ per day discharges water at a rate of $25\text{ m}^3\text{.h}^{-1}$. The average irrigation depth is $80\text{ mm}$, and irrigation interval is $20\text{ days}$. If intensity of irrigation is $80\%$, the culturable command area (in hectares) is ________. (Rounded off to two decimal places)
Irrigation water having SAR value of 20, is called
The ratio between the areas of a crop irrigated and the quantity of water required during its entire period of growth is known as
Alkaline soils are reclaimed by
For crops like potato and sugar-beets, the commonly adopted method of surface irrigation is
