16-05-2025
Daily subject-wise quiz : Environment and Geography MCQs on presence of sediments in reservoir, Western Disturbances and more (Week 110)
UPSC Essentials brings to you its initiative of subject-wise quizzes. These quizzes are designed to help you revise some of the most important topics from the static part of the syllabus. Attempt today's subject quiz on Environment and Geography to check your progress.
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With reference to the Western Disturbances, consider the following statements:
1. These are east-moving rain-bearing wind systems that originate beyond Afghanistan and Iran.
2. These winds pick up moisture only from the Mediterranean Sea.
3. They are embedded within the subtropical westerly jet stream — a high-altitude, fast-moving air current that flows from west to east in the Earth's atmosphere — that lies over the Himalayan and Tibetan highlands.
4. They are most common during the summer months (April to June).
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) Only three
(d) All four
Explanation
— Western Disturbances are rain-bearing wind systems that begin east of Afghanistan and Iran and pick up moisture from the Mediterranean, Black, Caspian, and Arabian Seas. Hence, statement 1 is correct and statement 2 is not correct.
— These are examples of extratropical cyclones caused by low-pressure zones created by the interplay of polar and tropical winds. Western Disturbances are embedded in the subtropical westerly jet stream, which is a high-altitude, fast-moving air movement that runs from west to east in the Earth's atmosphere and passes over the Himalayan and Tibetan highlands. Hence, statement 3 is correct.
— They are most abundant during the boreal winter months (December to March) and have an impact on the weather in India, notably the northwest, Pakistan, Afghanistan, and Tajikistan. Hence, statement 4 is not correct.
— Experts believe that rising global temperatures are influencing the customary behaviour of Western Disturbances. For example, a 2024 study published in the journal Weather and Climate Dynamics found that Western Disturbances that occur in winter have increased dramatically over the western and central Himalayas and the Hindu Kush in the last 70 years.
Therefore, option (b) is the correct answer.
Etna, Dukono, Mauna Loa, and Merapi were recently in the news. These are
(a) Region in Sahara Desert
(b) Forest region in Amazon Rainforests
(c) Volcanoes
(d) Artificial Islands
Explanation
— There may be as many as 50 to 80 new volcanic eruptions worldwide at any given time, but only the most significant ones—Etna, Kilauea, Mauna Loa, Merapi, Eyjafjallajökull, or Fagradalsfjall—make headlines when they happen.
— Mount Etna is Europe's most active volcano and one of the largest in the world. Its recorded volcanic activity dates back to 1500 B.C. Since then, it has erupted more than 200 times.
— One of the most famous long-term eruptions was Kilauea volcano in Hawaii.
— Dukono in Indonesia started erupting in August 1933 and is still continuing. Santa Maria in Guatemala began erupting in June 1922 and continues to this day.
Therefore, option (c) is the correct answer.
Recently, the Pushkar Kumbh has begun at Keshav Prayag, which is located in:
(a) Uttar Pradesh
(b) Maharashtra
(c) Rajasthan
(d) Uttarakhand
Explanation
— After a 12-year, the Pushkar Kumbh has returned to Keshav Prayag, located in the border village of Mana in Chamoli district of Uttarakhand. According to authorities, the number of pilgrims visiting Badrinath Dham and Mana village has significantly increased.
— District Magistrate Sandeep Tiwari stated that the pedestrian route to Keshav Prayag in Mana village has been repaired in anticipation of the Pushkar Kumbh. Signboards in several languages have been put up for the comfort of devotees travelling along the route. He stated that the tehsil administration has been directed to perform regular monitoring to ensure the event runs well.
— After a 12-year hiatus, the Pushkar Kumbh is returning to Mana, a border village in Chamoli district. According to religious tradition, the Pushkar Kumbh takes place at Keshav Prayag, the confluence of the Alaknanda and Saraswati rivers near Mana village, once every 12 years when Jupiter enters the Gemini sign.
Therefore, option (d) is the correct answer.
With reference to the presence of sediments in the reservoir, consider the following statements:
1. Sediment reduces reservoir capacity and hampers hydropower output.
2. Flushing of reservoirs releases stored water to remove sediment build-up — sand, silt and clay — that settles in reservoirs over time.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Explanation
— With the Indus Waters Treaty (IWT) in limbo and the government having already completed the first flushing exercise at Baglihar and Salal, its two run-of-the-river hydroelectric projects on the Chenab River in Jammu and Kashmir, the Central Water Commission (CWC) has now recommended that such flushing become a monthly occurrence.
— Flushing is releasing stored water to eliminate sediment buildup—sand, silt, and clay—that accumulates in reservoirs over time. Sediment diminishes reservoir capacity and lowers hydropower output. By flushing these particles out on a regular basis, operators restore storage capacity and increase turbine performance, assuring consistent power generation and extending the life of hydroelectric plants. Hence, statements 1 and 2 are correct.
— However, Pakistan has consistently opposed this effort, citing the fact that flushing, or the discharge of stored water to remove debris, can temporarily increase downstream flow. Recharging, or replenishing the reservoir by closing gates, can lower the volume available for later release.
— Making flushing a monthly process is part of the government's short-term strategy to use Indus waters after the treaty was suspended following the Pahalgam terror assault.
Therefore, option (c) is the correct answer.
Recently, the Ministry of Environment, Forest and Climate Change has granted preliminary permissions to carry out an environmental impact assessment (EIA) study for a proposed 1,000 MW Upper Bhavani pumped hydropower project in the Nilgiri Hills. This hydropower project is near to:
(a) Mukurthi National Park
(b) Kudremukh National Park
(c) Bhimgad Wildlife Sanctuary
(d) Chandoli National Park
Explanation
— An expert panel of the Ministry of Environment, Forest, and Climate Change has granted preliminary permission to conduct an environmental impact assessment (EIA) study for a proposed 1,000 MW Upper Bhavani pumped hydropower project in the Nilgiri Hills, which are located in the ecologically fragile Western Ghats.
— NTPC Tamil Nadu Energy Company Limited, a joint venture of National Thermal Power Corporation Limited and Tamil Nadu Generation and Distribution Corporation Limited (TANGEDCO), is developing the pumped hydropower or pumped storage project, which aims to generate 1,000 MW of power from the Upper Bhavani Dam and Avalanche-Emerald reservoirs in the Nilgiris.
— The project will require 167.85 hectares of land, 56.35 hectares of which are forest land and 111.50 hectares of which are non-forest land, and will be placed within 1 kilometre of Mukurthi National Park. The Nilgiri Tahr, an endangered species found only in this section of the Western Ghats, is the national park's star attraction.
Therefore, option (a) is the correct answer.
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