Work on reservoir project has affected key habitat for migratory waterbirds: trust

1. At a Glance

• The Water Resources Department (WRD) of Tamil Nadu is building the proposed Mamallan reservoir in the Kovalam–Nemmeli backwaters near Chennai. Dredging and bund work for it has reportedly damaged a key habitat for migratory waterbirds [1].
• The site is a stopover on the Central Asian Flyway (CAF). India provides critical stopover sites to over 90% of the bird species known to use this route [1][3].
• The case is a textbook example of the clash between water security infrastructure and wetland or mudflat biodiversity. It also shows a problem with coastal zone management plans that do not record ecologically active mudflats [1].
• It links GS-III (environment, EIA, conservation) with India's commitments under the Convention on Migratory Species (CMS) and its leadership role in the CAF [1][4][5].

2. Why in the News

• The Palluyir Trust for Nature Education and Research sent a representation to the WRD. It said ongoing dredging and bunding for the Mamallan reservoir had affected a crucial waterbird habitat (The Hindu, Chennai edition, 4 October 2026, p. 6) [1].
• A survey on 29 September 2026 by four naturalists and zoologists recorded about 3,500 waterbirds of 51 species. Of these, 25 migratory species are protected under the UN Convention on Migratory Species [1].

3. Background & Evolution

• January 2008: The CAF Action Plan was formally adopted. It covers 175 waterbird species across 30 Range States [2].
• 2018: MoEFCC prepared India's National Action Plan for Conservation of Migratory Birds and their Habitats along the CAF (2018–2023) [3].
• CMS COP13 was held in India and ended with major new actions for migratory species [6]. The venue (Gandhinagar) and date (February 2020) are (unverified).
• 2021: A two-day meeting of the 30 CAF range countries began, convened by India [4].
• 2023: A meeting of range countries was held to strengthen conservation of migratory birds and their habitats in the CAF [5].
• A CMS decision approved a CAF Programme of Work and set up a Coordinating Unit in India, funded by the Government of India. Under Resolution 14.13, its official launch was due by COP15 [2].
• 2026: Work began on the Mamallan reservoir in the Kovalam–Nemmeli backwaters. The Palluyir Trust objected [1].

4. Core Static Facts

Item	Fact
Project	Proposed Mamallan reservoir, Kovalam–Nemmeli backwaters, Chennai region [1]
Executing agency	Water Resources Department (WRD), Tamil Nadu [1]
Disputed works	Dredging and bund construction [1]
Petitioner	Palluyir Trust for Nature Education and Research [1]
Survey date	29 September 2026 [1]
Birds counted	~3,500 waterbirds; 51 species; 25 CMS-protected migratory species [1]
Key species	Garganey (>1,500; breeds in temperate regions incl. Russia, Mongolia); Greater flamingo (>700) [1]
Migration window at site	August–September (CAF arrivals) [1]
Habitat type	Biologically active intertidal mudflats, not recognised in the coastal zone management plan [1]
CAF Action Plan	Adopted Jan 2008; 175 species; 30 Range States [2]
India NAP on CAF	2018–2023; MoEFCC [3]
NAP components (6)	Species conservation; habitat conservation and sustainable management; capacity development; communication and outreach; research and knowledge base; international cooperation [3]
CAF Coordinating Unit	Hosted by India [2]

5. Multi-Dimensional Analysis

Environmental

• Garganey need mudflat foraging grounds as refuelling stops. Dredging and bunding turn tidal mudflats into deep, stable water bodies, which takes away their food supply [1].
• Large counts (>1,500 garganey, >700 flamingos) suggest the site matters for the whole flyway, not just locally [1].
• Because India supports >90% of CAF species at stopovers, losing habitat here cuts into flyway connectivity [3].

Legal / Governance

• The site's mudflats are not shown in the coastal zone management plan [1]. Unmapped ecosystems escape CRZ protection by default (unverified).
• India has CMS obligations for the 25 CMS-listed species recorded at the site [1]. Applying those obligations to state-level projects is a federal implementation gap.

Economic / Administrative

• Reservoirs on the urban fringe are meant to improve drinking water security for a fast-growing coastal metro. The project's exact purpose and capacity are not in the retrieved text.
• The trust approached the WRD directly [1]. This shows the need for biodiversity screening before work starts, not after.

Geopolitical / Strategic

• India hosts the CAF Coordinating Unit and has convened range-country meetings [2][4][5]. Damage to its own stopover sites hurts that leadership's credibility.

Ethical

• Today's water needs are being weighed against intergenerational and transboundary duties to shared migratory species.

6. Recent Developments (last 12–18 months)

• 2025: CMS COP15 documents on flyways (Doc. 26.3.1, dated 24 September 2025) were prepared, covering CAF arrangements [2].
• 29 September 2026: The Palluyir Trust surveyed the Mamallan project site [1].
• 4 October 2026: The Hindu reported the trust's representation to the WRD [1].

7. Prelims Hooks

• The Mamallan reservoir is proposed in the Kovalam–Nemmeli backwaters, Chennai [1].
• Implementing agency: Tamil Nadu Water Resources Department [1].
• Garganey is a migratory duck that breeds in temperate regions including Russia and Mongolia and winters or stops over in India [1].
• Greater flamingos (>700) were recorded at the Kovalam–Nemmeli wetland [1].
• Kovalam–Nemmeli is a Central Asian Flyway stopover during the August–September migration [1].
• The CAF Action Plan was adopted in January 2008 [2].
• The CAF Action Plan covers 175 waterbird species and 30 Range States [2].
• India provides critical stopover sites to >90% of CAF bird species [3].
• India's National Action Plan on CAF ran from 2018 to 2023 and had six components [3].
• The CAF Coordinating Unit is hosted and funded by India (CMS Resolution 14.13) [2].
• CMS COP13 was hosted by India [6].
• The CMS is a UN treaty under UNEP, also called the Bonn Convention (1979) (unverified).

8. Why the Law Did Not See This Wetland

• India's own bird plan expects coastal rules to protect coastal wetlands
• The MoEFCC's National Action Plan on the CAF says coastal wetlands are protected under the CRZ Notification 2011. CRZ means Coastal Regulation Zone: the rules that limit building near the sea and in tidal areas [3].

• So the bird plan does not set up its own protection for coastal sites. It depends on the coastal rules to do that job.

• But the coastal rules only protect what is on the map

• A coastal zone management plan (CZMP) is the official map that shows which coastal land falls in which CRZ category.
• The Kovalam–Nemmeli mudflats are biologically active, but they are not shown in that plan [1].

• If a habitat is not on the map, no officer is forced to check it before dredging. The CAF plan and the coastal rules both fail together here.

• The objection came only after the work started

• The damage was first raised by a private trust, after dredging and bund work had already begun [1].
• The survey that showed the site's value was done by four naturalists. It was not part of any official approval [1].
• What this shows: right now, checking a site for birds depends on volunteers. It is not a required step before work begins.

9. Mudflats Keep Disappearing, Even Under 'Green' Projects

• India lost a large area of mudflats in just 12 years
• Intertidal mudflats (land that is flooded at high tide and exposed at low tide) shrank by 116,897 hectares between 2006 and 2018. Salt marshes shrank by 5,647 hectares [7].

• One major reason was mangrove planting on mudflats. This is a project counted as conservation [7].

• So the problem is how we see mudflats, not only this one reservoir

• Planners treat open mud as 'empty' or 'waste' land that should be turned into something: a forest, a reservoir, a port.
• For birds like the garganey and flamingo, that open, shallow, tidal mud is the habitat [1].

• Mamallan is one more example of the same pattern. The mudflat is turned into something else, and the birds lose a feeding ground that rarely comes back.

• Why one site matters to the whole route

• India gives stopover sites to more than 90% of CAF species [3]. As other mudflats shrink [7], the birds crowd into fewer sites. That makes each remaining site, like Kovalam–Nemmeli, more important.

10. The Case for the Reservoir, and Where It Falls Short

• The strongest argument for the project
• Chennai is a fast-growing coastal city with a real need for drinking water. A state cannot stop every water project because birds use the site.

• The WRD is a water agency. It is doing its legal job, and the mudflats had no official protection on the map [1].

• What this argument gets right

• Wetland protection that ignores a city's water needs will not last politically.

• The fault lies mostly with the mapping gap, not with the WRD alone [1].

• Where it falls short

• The fight is not really 'reservoir or birds'. It is about where and when the work happens.
• The birds arrive in August–September [1]. The survey on 29 September found about 3,500 birds, so dredging during that window does the most damage [1].
• The retrieved reports do not give the project's purpose or storage capacity, so the water benefit cannot yet be weighed against the habitat lost. Public debate on the project lacks that basic number.

11. Who Should Act, and What Each Should Do

• Tamil Nadu WRD: pause work during the migration window and get a bird survey
• Plan dredging and bund work outside August–September, when CAF birds arrive [1].

• Order a proper survey of how birds use the site before going further. The CAF National Action Plan already lists 'habitat conservation and sustainable management' and 'research and knowledge base' as two of its six parts [3].

• State coastal authority and MoEFCC: add active mudflats to the CZMP map

• The National Action Plan relies on CRZ rules to protect coastal wetlands [3]. That works only if mudflats are mapped.

• The 116,897-hectare loss [7] shows this is a national gap, not just a Chennai one.

• MoEFCC: write a new CAF plan that covers state projects

• India's National Action Plan ran from 2018 to 2023 [3]. The sources retrieved here do not show any plan that replaced it.

• India hosts and funds the CAF Coordinating Unit under CMS Resolution 14.13 [2]. A new plan could require states to check flyway sites before approving water and coastal projects.

• Stop counting mudflats as 'empty land' to be planted or filled

• Mangrove planting on mudflats is one major reason they are being lost [7]. Forest and coastal departments should not plant mangroves on open mud that waterbirds feed on.

12. Anchors for Answers

• Data: India's intertidal mudflats shrank by 116,897 ha between 2006 and 2018; mangrove planting on mudflats was a major cause [7]
• Data: About 3,500 waterbirds of 51 species, 25 of them protected under CMS, were counted at the Mamallan site on 29 Sept 2026 [1]
• Data: India provides stopover sites to more than 90% of CAF bird species [3]
• Report/Committee: MoEFCC, National Action Plan for Conservation of Migratory Birds and their Habitats along the CAF (2018–2023), which relies on CRZ 2011 for coastal wetlands [3]
• Law/Case: CRZ Notification 2011, as cited in the CAF National Action Plan [3]; CMS Resolution 14.13, which set up the CAF Coordinating Unit hosted by India [2]
• Scheme: CAF Programme of Work and the India-hosted Coordinating Unit, a ready platform to monitor domestic stopover sites [2]

13. Mains Relevance

• GS-III: Conservation, environmental pollution and degradation, environmental impact assessment.
• GS-II: Important international institutions and agreements (CMS, CAF).
• GS-I: Distribution of key natural resources, water resources, and urbanisation and its problems.

Possible question stems:

1. Urban water infrastructure in India often comes at the cost of wetland ecosystems. Examine with reference to coastal backwaters and migratory bird habitats. (15 marks)
2. India's leadership of the Central Asian Flyway initiative demands domestic coherence in habitat protection. Discuss. (10 marks)
3. Unmapped mudflats are the blind spot of coastal regulation in India. Critically analyse. (10 marks)

14. Related Topics to Study Next

• Convention on Migratory Species and its Appendices. This is the legal basis for "protected migratory species."
• The nine global flyways and the CAF. India's place in the flyway system.
• Ramsar sites in Tamil Nadu (e.g., Pallikaranai, Kazhuveli). Nearby wetland protection precedents.
• CRZ Notification 2019 and coastal zone management plans. The mapping gap the trust pointed out.
• Wetlands (Conservation and Management) Rules, 2017. The regulatory tool for non-Ramsar wetlands.
• EIA Notification 2006 and its exemptions. Whether reservoir projects need biodiversity appraisal.
• Chennai water security (desalination, reservoirs, Day Zero 2019). The development pressure behind the project.
• Intertidal mudflats and shorebird decline. Ecological science for answer enrichment.

15. Common Errors / Trap Areas

• CAF vs. East Asian–Australasian Flyway: India falls mainly in the CAF. Do not mix up the range-state counts.
• CMS vs. CITES vs. Ramsar: CMS covers migratory species, CITES covers trade, and Ramsar covers wetland sites. Being "protected under CMS" does not make a site a Ramsar site.
• Garganey vs. Greater flamingo: The garganey is the long-distance Palearctic duck (Russia/Mongolia). Flamingos form the second-largest group in this news item [1].
• Agency confusion: The project is a state WRD project, not a Central Water Commission or MoEFCC project [1].
• NAP years: India's CAF National Action Plan covers 2018–2023, not 2008. 2008 is when the CMS CAF Action Plan was adopted [2][3].