Lakes – Long Answer Questions
Medium Level (Application & Explanation)
Q1. Distinguish between permanent and seasonal lakes in India. Give reasons and examples.
Answer:
- Permanent lakes have water through the year.
- Seasonal lakes hold water mainly in the rainy season.
- Seasonal lakes are common in low rainfall and semi-arid areas.
- Sambhar Lake in Rajasthan is a seasonal, saltwater lake.
- Permanent lakes include Dal, Bhimtal, Nainital, Loktak, and Barapani.
- These lakes exist due to steady water sources like glaciers, rivers, or springs.
- Thus, climate and water availability decide whether a lake is permanent or seasonal.
Q2. Explain how lakes are formed in India. Use suitable examples.
Answer:
- Lakes form in many ways.
- Glacial lakes form when glaciers and ice sheets melt and leave depressions.
- River action can create lakes when rivers meander and form ox-bow lakes.
- Wind can shape basins in dry areas, which later hold water.
- Human activity creates lakes by building dams and reservoirs.
- Coastal lakes form by spits and bars. Examples: Chilika, Pulicat, Kolleru.
- Dams create lakes like Guru Gobind Sagar in the Bhakra Nangal Project.
Q3. Why are most freshwater lakes found in the Himalayan region? Explain with examples.
Answer:
- The Himalayas have many glaciers that melt and fill basins.
- These basins become freshwater lakes.
- The cold climate and high altitude help lakes store water longer.
- Some lakes also form due to tectonic activity, like Wular Lake.
- Wular Lake is India’s largest freshwater lake.
- Other lakes in or linked to upland regions include Bhimtal, Nainital, and Dal.
- Thus, glaciers and tectonic forces support freshwater lake formation.
Q4. Describe the importance of lakes for humans and the environment.
Answer:
- Lakes help in flood control by storing excess water.
- They provide water supply during the dry season.
- They support hydropower generation where reservoirs exist.
- Lakes moderate climate around them and keep it pleasant.
- They support aquatic ecosystems and biodiversity.
- They promote tourism and recreation like boating and sightseeing.
- They add natural beauty and help the local economy.
Q5. How are coastal lakes like Chilika, Pulicat, and Kolleru formed? Why are they significant?
Answer:
- Coastal lakes form when spits and bars block sea water from the coast.
- This creates lagoons or coastal lakes along the shoreline.
- Examples include Chilika Lake, Pulicat Lake, and Kolleru Lake.
- These lakes support fishing and local livelihoods.
- They attract tourists and support birdlife and other species.
- They also act as buffers against storms and coastal changes.
- Thus, they are important for both people and nature.
High Complexity (Analysis & Scenario-Based)
Q6. A hill town like Nainital is losing its lake due to silt and poor care. Analyze the impacts and suggest remedies.
Answer:
- Loss of the lake will hurt tourism and reduce income.
- The town may lose its main water source in the dry season.
- The local climate may become harsher and less pleasant.
- Jobs in hotels, boating, and shops will suffer.
- Plants and animals in the lake will decline.
- Remedies: desilt the lake, protect the catchment, and control waste.
- Promote responsible tourism and steady monitoring of water levels.
Q7. A new dam creates a reservoir like Guru Gobind Sagar. Evaluate benefits and challenges for locals.
Answer:
- Benefits include hydropower, irrigation, and flood control.
- The reservoir can boost fisheries and local income.
- It can improve water supply to nearby towns and farms.
- Challenges include possible displacement of people.
- There can be changes to local ecosystems and land use.
- Management needs fair rehabilitation, careful water release, and catchment care.
- Balanced planning helps share benefits and reduce losses.
Q8. A river forms many ox-bow lakes on its floodplain. As a planner, how will you use them safely and well?
Answer:
- Use ox-bow lakes as flood storage to reduce river flooding.
- Develop them for recreation and tourism with strict rules.
- Support fisheries for local livelihoods.
- Keep water clean by stopping dumping and runoff.
- Plant trees along banks to stop silt entering the lakes.
- Educate communities on wise use and lake care.
- Monitor water levels and health during monsoon and summer.
Q9. Compare coastal lakes (Chilika, Pulicat, Kolleru) with Himalayan freshwater lakes (Dal, Nainital, Wular).
Answer:
- Coastal lakes form by spits and bars along the coast.
- Himalayan lakes form by glaciers and sometimes tectonics.
- Coastal lakes often have brackish water; Himalayan lakes are freshwater.
- Coastal lakes support fishing and birdlife; Himalayan lakes boost tourism and water supply.
- Coastal lakes face coastal changes; Himalayan lakes face siltation and seasonal stress.
- Examples: Chilika, Pulicat, Kolleru vs Dal, Nainital, Wular.
- Both types are vital for people, nature, and the economy.
Q10. During a drought, a city depends on a nearby lake. Propose a plan for sustainable lake management.
Answer:
- First, protect catchment areas to improve inflows.
- Reduce demand by saving water at home and in industry.
- Stop pollution and keep the water clean.
- Desilt the lake to increase storage capacity.
- Promote rainwater harvesting to support the lake.
- Share water fairly between homes, farms, and industry.
- Build a long-term plan for monitoring and maintenance.