According to Indian standard, the number of rain gauge stations for an area of 5200 km2 in plains should be
10
Calculating Rain Gauge Stations for Area in Plains (Indian Standard)
Understanding the required density of rain gauge stations is crucial for accurate rainfall data collection, which is essential for hydrological studies, water resource management, and weather forecasting. According to Indian standards, specific guidelines are provided for the number of rain gauge stations needed based on the terrain and the area being considered.
Indian Standard Guidelines for Rain Gauge Density
The Indian Standard (IS: 4987 - 1968) provides recommendations for the minimum network of rain gauge stations. The required density varies depending on the type of terrain:
- In plains, the recommended density is 1 station per 520 km².
- In hilly areas, the recommended density is 1 station per 260-390 km².
- In mountainous areas, the recommended density is 1 station per 130 km² or even denser in specific cases.
The question specifically mentions an area in "plains". Therefore, we will use the density requirement for plains according to the Indian standard.
Applying the Standard to the Given Area
We are given:
- Total area = 5200 km²
- Terrain type = Plains
According to the Indian standard for plains, the required density is 1 rain gauge station for every 520 km².
To find the number of rain gauge stations required for a given area, we divide the total area by the area served by a single station according to the standard density.
The formula to calculate the number of stations is:
\(\text{Number of Stations} = \frac{\text{Total Area}}{\text{Area per Station according to Standard Density}}\)
Substituting the given values:
\(\text{Number of Stations} = \frac{5200 \text{ km}^2}{520 \text{ km}^2/\text{station}}\)
Calculating the result:
\(\text{Number of Stations} = 10\)
Therefore, based on Indian standards for an area of 5200 km² in plains, the required number of rain gauge stations is 10.
Summary of Calculation
| Parameter | Value |
|---|---|
| Given Area | 5200 km² |
| Terrain Type | Plains |
| Indian Standard Density (Plains) | 1 station per 520 km² |
| Calculated Number of Stations | 10 |
The calculated number of stations, 10, matches one of the provided options.
Revision Table: Indian Standard Rain Gauge Densities
| Terrain Type | Recommended Area per Station (approx.) |
|---|---|
| Plains | 520 km² |
| Hilly Areas | 260 - 390 km² |
| Mountainous Areas | 130 km² |
Additional Information on Rain Gauge Networks
A well-distributed network of rain gauge stations is vital for obtaining representative rainfall data over a region. The density of the network affects the accuracy of estimating average rainfall over an area (areal rainfall). Higher density networks generally provide more accurate estimates, especially in areas with high rainfall variability.
Apart from the terrain, other factors can influence the optimal density of a rain gauge network, such as:
- The purpose of the study (e.g., flood forecasting requires denser networks in critical areas).
- Accessibility and cost of installing and maintaining stations.
- Variability of rainfall within the region.
Different types of rain gauges are used, including non-recording gauges like the Symons rain gauge (which needs manual reading) and recording gauges like the tipping bucket or weighing type rain gauges (which provide continuous rainfall data). The choice of rain gauge type can also influence network design and data collection strategies.
Important Questions from Precipitation
- Penman's equation is based on:
Isohyet is a line joining points having
Which of the following is a non-recording rain gauge?
In Symons rain gauge, the rim of the collector is set in a horizontal plane at a height of ________ above the ground level.
The total rainfall in a catchment area 1200 km2 during a 6 hours storm is 16 cm. While the surface run-off due to storm is 1.2 × 108 m3. The φ index is
