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Dams and Hydroprojects

Dams and Hydroprojects

Meghalaya’s Umngot River turns Muddy

Why in the News?

The Umngot River, celebrated for its crystal-clear waters and tourist appeal at Dawki and Shnongpdeng, has turned murky and opaque.

Meghalaya’s Umngot River turns Muddy

About Umngot River:

  • Location: Flows through West Jaintia Hills district, Meghalaya, close to the India–Bangladesh border.
  • Origin: Arises from the Jaintia Hills, traversing limestone-rich terrain that naturally filters impurities and maintains clarity.
  • Distinct Appearance: Known for its crystal-clear waters that create the illusion of boats floating on air, earning it global recognition.
  • Length & Course: Flows southward to Dawki town, where it merges with Bangladesh’s Piyain River.
  • Ecological Features: Possesses high dissolved oxygen levels, preventing algal growth and supporting diverse aquatic biodiversity.
  • Tourism Hub: Popular at Dawki and Shnongpdeng for boating, fishing, camping, and eco-tourism, drawing thousands of visitors annually.
  • Infrastructure Landmark: The Dawki Suspension Bridge (1932) is a heritage structure spanning the river and serving as a trade route link.
  • Economic Role: Sustains cross-border trade, local fishing, and tourism-driven livelihoods vital to Meghalaya’s rural economy.
  • Cultural Boundary: Serves as a natural divider between Ri Pnar (Jaintia Hills) and Hima Khyrim (Khasi Hills).

Cause of Discoloration:

  • Primary Cause: Linked to Shillong–Dawki road-widening project upgrading it to a two-lane highway with a 400 m bridge at Dawki.
  • Pollution Source: Hill-cutting, excavation, and soil dumping along sites near Umtyngar and Dawki caused heavy sediment runoff.
  • Inspection Findings: The Meghalaya State Pollution Control Board (MSPCB) detected uncontained debris and sliding soil entering the river, reducing water transparency.
[UPSC 2021] Consider the following rivers:

1. Brahmani 2. Nagavali 3. Subarnarekha 4. Vamsadhara

Which of the above rise from the Eastern Ghats?

Options: (a) 1 and 2 (b) 2 and 4* (c) 3 and 4 (d) 1 and 3

 

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Dams and Hydroprojects

Naying Hydroelectric Project

Why in the News?

The Naying Hydroelectric Project (1000 MW), proposed on the Siyom (Yomgo) River in Shi-Yomi district, Arunachal Pradesh, represents a major addition to India’s clean energy expansion under the Decade of Hydro Power (2025–35).

About Siyom (Yomgo) River:

  • Geography: A right-bank tributary of the Brahmaputra, flowing entirely within Arunachal Pradesh.
  • Origin & Course: Arises in West Siang, travels ~170 km, and joins the Brahmaputra near Assam.
  • Ecology: Basin supports rich biodiversity, agro-pastoral livelihoods, and lies within the Eastern Himalaya Biodiversity Hotspot.
  • Protected Areas: Mouling National Park lies on its eastern bank, part of the Dibang–Siang biosphere landscape.
  • Hydrological Role: Ensures irrigation, microclimate regulation, and provides run-of-the-river potential for clean energy, though demanding careful ecosystem balance.

About Naying Hydroelectric Project:

  • Overview: A proposed 1,000 MW (4Ă—250 MW) run-of-the-river project located in Shi-Yomi district, Arunachal Pradesh.
  • Developers: Jointly undertaken by North Eastern Electric Power Corporation (NEEPCO) and Arunachal Pradesh Hydropower Corporation Ltd (APHCL).
  • Design & Output: Features a concrete dam, underground powerhouse, and diversion tunnels, expected to generate 4,966.77 GWh annually.
  • Regulatory Approval: Received Central Electricity Authority (CEA) concurrence in 2013; progress slowed by environmental and social concerns.
  • Public Consultation: Environmental hearing scheduled for 12 November 2025 at Yapik Community Hall to assess ecological and community impacts.
  • Timeline: Construction targeted to start by 2028, with commissioning by 2032.
  • Policy Context: Forms part of the state’s Decade of Hydro Power (2025–2035), aiming for 19 GW capacity addition to support India’s net-zero goals.
  • Regional Linkages: Among five key hydel projects in the region – Heo (240 MW), Hirong (500 MW), Tato-I (186 MW), and Tato-II (700 MW).
[UPSC 2022] Consider the following pairs:

Reservoirs – States

1. Ghataprabha — Telangana

2. Gandhi Sagar — Madhya Pradesh

3. Indira Sagar — Andhra Pradesh

4. Maithon —Chhattisgarh

Options:

(a) Only one pair (b) Only two pairs (c) Only three pairs (d) All four pairs”

 

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Dams and Hydroprojects

Sawalkote Hydro Project

Why in the News?

After suspending the Indus Waters Treaty, India is asserting water control in J&K by reviving the Sawalkote Hydroelectric Project — the UT’s largest planned hydro project.

Sawalkote Hydro Project

About Sawalkote Hydro Project:

  • Location: Ramban and Udhampur districts, Jammu and Kashmir.
  • River: Built on the Chenab River (a western river under the Indus Waters Treaty).
  • Agency: Implemented by National Hydroelectric Power Corporation.
  • History: Proposed in the 1960s; delayed due to Pakistan’s objections, environmental issues, and red tape. Revived after India suspended the Indus Waters Treaty post the April 2025 Pahalgam terror attack.
  • Status (2025): Forest clearance granted; tenders floated on 29 July 2025; declared a project of national importance.
  • Timeline: 96 months post-clearance; expected commissioning by or after 2032.

Key Features:

  • Type: Run-of-the-river (utilizes the natural flow and elevation drop of a river) hydroelectric project.
  • Capacity: 1,856 Megawatts (8 Ă— 225 MW + 1 Ă— 56 MW).
  • Dam: 192.5 m high, roller-compacted concrete gravity dam; reservoir holds 550 million cubic meters.
  • Powerhouse: Underground, with Francis turbines.
  • Cost: ₹22,704.8 crore (~2.6 billion United States Dollars).
[UPSC 2009] Gandhi Sagar Dam is a part of which one of the following?

Options: (a) Chambal Project * (b) Kosi Project (c) Damodar Valley Project (d) Bhakra Nangal Project

 

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