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.

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:
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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.

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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