Indian Geography: UPSC Previous Year Questions (Geography)

Explanation

The first sunrise of the new millennium (1 January 2000) in India was observed at the 92°30’ E meridian in Arunachal Pradesh, the country’s easternmost region. Located near the Myanmar border, this was the first point in India to receive sun-light as the millennium began. While countries like New Zealand saw it earlier due to their proximity to the International Date Line, within India, 92°30’ E, the nation’s easternmost meridian amongst the given options, marked the dawn of the new era, highlighting its significance as the first place in the country to witness sunrise.

Explanation

Statement 1 is correct: Tides play a significant role in both navigation and fishing activities. Tides help ships navigate shallow waters by increasing water depth during high tide. They also influence fishing, as certain fish species move with tidal currents, making them easier to catch.

Statement 2 is correct: High tides increase the water level in harbors, which is essential for larger ships to enter or leave safely. Without the rise in water levels brought about by tides, large ships might find it difficult to dock or leave the harbor, as they need sufficient water depth to avoid grounding.

Statement 3 is correct: The ebb and flow of tidal waters help to flush out silt, sand, and other debris from the harbor area. This natural process reduces the risk of siltation, ensuring that ports and harbors remain navigable by preventing the accumulation of sediments that could otherwise block ships.

Statement 4 is correct: Both Kandla Port (in Gujarat) and Diamond Harbour (near Kolkata) are tidal ports, meaning they are influenced by tidal movements. The activities at these ports depend on the high and low tide cycles for ships to dock and undock, as well as to ensure proper water levels for smooth navigation.

Explanation

Assertion (A) is true: The frequency of floods in the north Indian plains has indeed risen in recent decades. This can be attributed to a combination of factors:

Climate Change: With global warming, the frequency and intensity of rainfall events have increased. In many parts of India, especially in the north, monsoon rains have become more unpredictable, leading to sudden heavy downpours that overwhelm the drainage systems and flood the plains. Urbanization and Poor Drainage Systems: As more urban areas are developed, the natural landscape changes. Cities with poor drainage systems cannot handle heavy rainfall, leading to waterlogging and flooding. Deforestation: Deforestation, particularly in the catchment areas of rivers, reduces the land’s ability to absorb rainfall. The lack of tree cover and vegetation increases surface runoff, which can rapidly flow into rivers and cause them to overflow. River Management Issues: Rivers like the Ganges and Brahmaputra are heavily managed with embankments, dams, and other infrastructure. However, many of these structures have not been properly maintained, or they have been poorly designed, leading to insufficient control of water flow. This poor management has exacerbated the flood situation. Reason (R) is true: Over time, rivers in flood-prone regions like the Ganges, Brahmaputra, and their tributaries have experienced significant sediment deposition, which raises the riverbed and reduces the river’s depth. Several factors contribute to this:

Sediment Transport: Rivers like the Ganges and Brahmaputra carry a large amount of sediment, the continuous accumulation of sand, silt, and clay sediment raises the riverbed, gradually reducing the depth of the river valleys. This process is particularly noticeable in the north Indian plains, where large rivers meander and deposit substantial amounts of sediment. Shallow Riverbeds: As the riverbed rises due to sedimentation, the rivers become shallower and have less capacity to hold and carry water. When heavy rainfall occurs, rivers with reduced capacity cannot contain the additional water, causing them to overflow and flood the surrounding areas. Floodplains and Siltation: Floodplains are areas adjacent to rivers that are prone to flooding during high-water events. These floodplains naturally receive silt deposits from the river during floods, but when silt deposition becomes excessive, the height of the floodplain increases, reducing the storage capacity of the river. The increased frequency of floods (Assertion A) is directly related to the siltation or sediment buildup in the river valleys (Reason R).