Questions:

1. Explain what drainage-related factors could cause this situation.
2. Suggest two land-management measures to reduce runoff and erosion.

Answers:

• Factors: Steep local slopes (high relief), sparse vegetation cover, impermeable or shallow soils and a high drainage density causing rapid surface runoff.
• Measures: (a) Contour bunding and terracing to reduce slope runoff. (b) Afforestation/planting grasses to increase infiltration; construct check dams or percolation pits to slow water speed and recharge groundwater.

Question: Identify the drainage pattern and explain what it indicates about the underlying rocks and slope.

Answer: This is a dendritic drainage pattern. It indicates relatively uniform, homogenous rock strata and a gentle, uniform slope — allowing tributaries to join the main stream in many directions like branches of a tree.

Questions:

1. Which is likely to be perennial and why?
2. Give an example of each type of river in India.

Answers:

• Perennial river: The glacier-fed river is likely perennial because melting snow and glaciers provide a continuous source of water even in dry months (example: Ganga).
• Monsoon-dependent (seasonal) river: Depends on rainfall and may have reduced flow in the dry season (example: many Peninsular rivers such as the Godavari upper reaches).

Question: Explain two potential benefits and two environmental concerns of inter-basin water transfer.

Answer:

• Benefits: (1) Improved water availability for irrigation and drinking in deficit areas. (2) Reduced regional water stress and potential boost to agriculture and livelihoods.
• Concerns: (1) Disruption of aquatic ecosystems and fish migration. (2) Social displacement, altered sediment regimes and increased risk of transferring pollutants or invasive species to new basins.

Questions:

1. Why do Himalayan rivers cause widespread floods during monsoon?
2. How can the deposition be beneficial for agriculture?

Answers:

• Flood causes: Intense monsoon rainfall in the catchment, high river discharge, steep gradients that carry large water volumes and sediment, and river channel capacity being exceeded.
• Benefits of deposition: Flood-deposited alluvium replenishes soil nutrients and creates highly fertile plains ideal for intensive agriculture (e.g., the Ganga plains).

Question: Explain what braided channels are and why Brahmaputra exhibits such behaviour.

Answer: Braided channels are multiple interweaving channels separated by sediment bars. The Brahmaputra shows braiding due to high sediment load from the Himalayas, variable discharge, and easily erodible banks — causing frequent deposition and channel shifts.

Question: Which river is more suitable for large-scale hydropower projects and why?

Answer: Himalayan rivers are generally more suitable for large-scale hydropower because they have higher gradients, perennial flow from snow and glaciers and larger discharges. However, geological instability and social impacts must be considered.

Question: Identify the river and list two unique features.

Answer: This describes the Narmada (or Tapti if smaller). Unique features: (1) Flows westwards in a rift valley between Vindhya and Satpura ranges. (2) Has a linear course with a relatively straight path and fewer tributaries compared to peninsular east-flowing rivers.

Question: Explain how dams/reservoirs on such rivers help agriculture and one environmental drawback.

Answer:

• Benefits: Provide regulated water supply for irrigation during dry seasons, enable multi-cropping and improve food security (e.g., Godavari and Krishna projects).
• Drawback: Submergence of land and displacement, disruption of sediment flow leading to downstream erosion and ecological changes.

Question: Suggest two adaptation strategies that local communities and planners can adopt.

Answer:

• Plant and restore mangroves and coastal vegetation to act as natural buffers against storm surges and reduce erosion.
• Develop salt-tolerant crop varieties, raised-field farming, and improved embankments and early warning systems for cyclones.

Question: Name an example of such a lake in India and explain why siltation is a concern.

Answer: Chilika Lake is an example. Siltation reduces water depth, affecting fish habitats, navigation and connectivity to the sea, and can change salinity balance — harming biodiversity and local fisheries livelihoods.

Question: Identify the lake type and propose two conservation measures.

Answer:

• Type: Tectonic lake (example: Wular).
• Conservation measures: (1) Strict regulation to prevent encroachment and restore lake buffer zones. (2) Sewage treatment and catchment management to reduce pollution and silt inflow.

Questions:

1. Mention three economic benefits rivers provide to such a city.
2. One major management challenge the city would face.

Answer:

• Benefits: Reliable water for domestic and industrial use; cheaper inland transport of goods; fishery resources and tourism potential.
• Challenge: Ensuring water quality by treating sewage and industrial effluents to prevent river pollution and health hazards.

Question: Explain "integrated river basin management" and one advantage of this approach.

Answer: IRBM coordinates land and water use, pollution control, and resource allocation across the entire river basin. Advantage: Reduces inter-state conflicts by equitable water sharing and allows holistic planning for flood control, irrigation and ecosystem protection.

Questions:

1. List immediate actions authorities should take.
2. Give two long-term preventive measures.

Answers:

• Immediate actions: (1) Contain the spill, stop illegal discharge, and test water quality. (2) Issue health advisories and provide alternate water supply for affected communities.
• Long-term measures: (1) Enforce stricter effluent treatment standards and regular monitoring of industries. (2) Establish emergency response plans, buffer zones and community monitoring systems.

Question: Explain eutrophication and one farming practice that can reduce nutrient runoff.

Answer: Eutrophication is nutrient enrichment (mainly nitrogen and phosphorus) that causes excessive algal growth, depleting oxygen and harming aquatic life. Practice to reduce runoff: Use of buffer strips, contour farming and precision fertilizer application (right dose, right time) to reduce runoff into water bodies.

Question: How do check dams help both stream flow and groundwater, and one limitation of this measure?

Answer: Check dams slow runoff, promote infiltration to recharge groundwater, reduce peak flows downstream (less flooding) and trap sediments. Limitation: They may need regular maintenance and may not be effective in highly permeable or very steep terrains.

Question: Suggest two infrastructural or policy measures to ensure year-round water supply.

Answer:

• Construct storage reservoirs and recharge structures to capture monsoon flows for use in dry months.
• Implement demand management policies such as metering, reducing leakage, promoting rainwater harvesting and recycling wastewater for non-potable uses.

Question: Provide two sustainable fishery practices that can be adopted.

Answer:

• Establishing regulated fishing seasons and catch limits to allow fish stocks to recover.
• Improving water quality through pollution control and restoring riparian vegetation to provide habitat and breeding grounds.

Answer (concise checklist):

• Stop open dumping; set up waste segregation and composting.
• Organise community clean-ups and awareness drives.
• Promote tree planting along riverbanks and protection of mangroves/wetlands.
• Monitor water quality and report pollution incidents.
• Adopt sustainable agriculture practices in the catchment to reduce runoff.