Dhanauri Wetland
Why in news?
The Principal Bench of the National Green Tribunal (NGT) has asked the Uttar Pradesh government to provide an update on the progress of notifying the Dhanauri waterbody as a wetland.
About Dhanauri Wetland:

- Dhanauri Wetland is located in Greater Noida, Uttar Pradesh, near the Surajpur Wetland, forming part of the rich Yamuna River basin ecosystem.
- It plays a significant role in maintaining regional ecological balance by acting as a natural reservoir and supporting groundwater recharge, flood control, and water purification.
- The wetland is home to over 200 bird species, including the Sarus Crane, the tallest flying bird and a vulnerable species as per the IUCN Red List. Its thriving population of Sarus Cranes makes it a critical habitat for this endangered species.
- It supports a diverse range of flora and fauna, including amphibians, reptiles, and fish, making it a biodiversity hotspot in an urbanised area.
- Dhanauri’s wetland ecosystem is vital for local agriculture, serving as a natural water source and regulating soil quality through sediment deposition.
- The wetland is an important migratory bird site, attracting species during the winter season, which contributes to its global ecological importance.
- Designating it as a Ramsar Wetland would enhance its conservation, ensuring sustainable management and protection under international frameworks.
- Despite its importance, urban expansion and anthropogenic pressures threaten its integrity, underscoring the need for immediate government action to protect it.
- The wetland fulfils multiple Ramsar criteria, including supporting rare species, biodiversity, and maintaining ecological processes, making it a strong candidate for Ramsar recognition.
Other Ramsar Sites in Uttar Pradesh:
- Nawabganj Bird Sanctuary
- Parvati Arga Bird Sanctuary
- Saman Bird Sanctuary
- Samaspur Bird Sanctuary
- Sandi Bird Sanctuary
- Sur Sarovar
- Surajpur Wetland
- Haiderpur Wetland
- Bakhira Wildlife Sanctuary
- Sarsai Nawar Wetland
Theri Kaadu
Why in news?
Tourism Minister R. Rajendran announced plans to promote tourism at the red sand deserts in Tamil Nadu’s Thoothukudi district, locally known as Theri Kaadu.
About Theri Kaadu:

- Location and Geological activity:
- Theri Kaadu, located in the Thoothukudi district of Tamil Nadu, is a unique desert-like landscape characterised by extensive red sand dunes. It lies near the coastal regions of the Gulf of Mannar, blending coastal and semi-arid ecosystems.
- The red sand dunes of Theri Kaadu are formed through a unique geological process involving the weathering and erosion of sedimentary rocks.
- The sand contains high iron content, which gives it the distinctive reddish hue. Wind and coastal currents have shaped these dunes over thousands of years, making them an example of aeolian landforms.
- These dunes are surrounded by sparse xerophytic vegetation, consisting of plants adapted to thrive in arid conditions. The region also supports small patches of scrub forests, contributing to local biodiversity.
- Ecological and Cultural significance:
- The ecosystem of Theri Kaadu holds ecological significance as it acts as a natural barrier against wind erosion, preventing the degradation of surrounding fertile lands. Additionally, the dunes help regulate the microclimate of the region by absorbing and radiating heat.
- The soil composition, enriched with minerals, influences the growth of unique plant species. Despite its arid appearance, the region supports various small mammals, reptiles, and birds, making it an important ecological niche in an otherwise harsh environment.
- Theri Kaadu also plays a cultural and geological role, serving as a site for scientific study and a potential hotspot for ecotourism. Promoting tourism here could increase awareness of its geological heritage while providing sustainable livelihood opportunities for local communities.
- However, the fragile ecosystem of Theri Kaadu faces threats from human activities, including sand mining, deforestation, and agricultural expansion. Ensuring its conservation requires sustainable development measures and stricter environmental policies to protect its unique landscape and biodiversity.
- With its striking red dunes, rare flora and fauna, and geological history, Theri Kaadu stands as a natural wonder that exemplifies the interaction between landforms and ecosystems, making it a critical area for environmental and cultural preservation.
Kodaikanal Lake
Why in news?
- Authorities recently removed six tonnes of discarded liquor bottles from Kodaikanal Lake in Tamil Nadu during a cleanup drive.
- The waste, left by tourists and locals, posed serious environmental threats to the lake’s fragile ecosystem, emphasising the need for stricter waste management and conservation efforts in this popular hill station.
About Kodaikanal Lake:

- Location:
- Kodaikanal Lake is a star-shaped, man-made freshwater lake situated in the Kodaikanal hill station of Tamil Nadu, at an elevation of approximately 2,133 meters in the Palani Hills of the Western Ghats. The lake lies at the heart of Kodaikanal and is a prominent tourist attraction.
- The lake was constructed in 1863 by Sir Vere Henry Levinge, the then Collector of Madurai, who transformed a marshy area by damming streams flowing through the valley. Over time, the lake became a centrepiece of the hill station, fed by natural springs and rainfall.
- Ecological and Economic importance:
- Ecologically, Kodaikanal Lake plays a crucial role in supporting a variety of flora and fauna. It is surrounded by lush shola forests, which provide habitat for several species of birds, amphibians, and aquatic life. The lake also serves as a freshwater reservoir, contributing to the groundwater recharge of the area.
- Economically, the lake is vital to the local tourism industry. Boating, cycling, and horse riding along its periphery are major attractions for visitors. The lake’s scenic beauty supports businesses such as hotels, restaurants, and local handicraft vendors, driving significant revenue to the local economy.
- Multidimensional challenges:
- The lake faces numerous environmental challenges. The influx of tourists has led to increased littering, with plastic waste and liquor bottles polluting the water.
- Eutrophication caused by untreated sewage and agricultural runoff has degraded water quality, threatening aquatic ecosystems.
- Encroachment around the lake has also disrupted natural drainage patterns, reducing its ability to sustain biodiversity.
- The lake is further impacted by deforestation in its surrounding areas, causing soil erosion and sedimentation, which gradually reduce its depth and water-holding capacity.
- Moreover, unregulated tourism activities, including excessive boating, disturb aquatic life and contribute to water contamination.
- Efforts to restore and conserve Kodaikanal Lake include regular clean-up drives, awareness campaigns, and the implementation of stricter waste management policies. However, addressing these issues requires sustainable tourism practices, better enforcement of environmental laws, and community participation in lake conservation.
- As a lifeline for both the local ecosystem and economy, Kodaikanal Lake demands urgent and consistent efforts to protect its natural beauty and ecological balance for future generations.
Lake Victoria
Why in news?
An international research team from North America and Kenya conducted a genetic survey of cyanobacteria in the Winam Gulf of Lake Victoria, Kenya. It is conducted to understand their ecological impact and genetic diversity in the region.
About Lake Victoria:

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- Location:
- Lake Victoria, Africa’s largest freshwater lake, is located in East Africa, bordered by Tanzania, Uganda, and Kenya.
- It spans an area of about 68,800 square kilometres, making it the second-largest freshwater lake in the world by surface area after Lake Superior.
- The lake lies at an elevation of approximately 1,135 meters above sea level and serves as the primary reservoir for the White Nile.
- Formation:
- Lake Victoria was formed around 400,000 years ago due to tectonic and geological activity in the East African Rift system.
- The lake’s basin was created by the uplifting of surrounding plateaus and the subsidence of the central basin, allowing water from rivers and rainfall to accumulate.
- Today, it is fed by numerous rivers, including the Kagera River, and has a single outlet at Jinja, Uganda, where the Nile River begins its journey.
- Economic Significance:
- The lake is vital for the livelihoods of millions, primarily through fishing of species like Nile perch and tilapia, which are major export commodities.
- It facilitates transportation and trade between bordering countries and contributes to regional hydropower generation, providing electricity to Uganda and parts of Kenya and Tanzania.
- Ecological Importance:
- Lake Victoria is a biodiversity hotspot, home to hundreds of fish species, including many endemic cichlids.
- It supports various bird species, aquatic plants, and mammals. The lake helps regulate the local climate and provides freshwater for domestic, agricultural, and industrial use.
- Environmental Concerns:
- The rapid growth of cyanobacteria or harmful algal blooms is a major environmental challenge for Lake Victoria. This is caused by eutrophication, driven by excessive nutrient loading from agricultural runoff, untreated sewage, and industrial waste.
- Phosphates and nitrates promote algal blooms, which deplete oxygen levels, causing hypoxic conditions and fish die-offs. The destruction of wetlands, which act as natural filters, has worsened the problem.
- Other factors include rising water temperatures due to climate change, deforestation, and urbanisation. The dominance of invasive species, like water hyacinth, has further altered the lake’s ecosystem, enabling the growth of harmful algal blooms.
- Conservation Measures:
- Tackling the issue of cyanobacteria requires reducing nutrient pollution through sustainable agricultural practices, minimising fertiliser runoff, improving wastewater treatment infrastructure, and restoring wetlands around the lake.
- Controlling invasive species like water hyacinth can help restore the lake’s ecological balance.
- Preserving Lake Victoria’s ecological health is vital for the millions who rely on it for their livelihoods and for maintaining the balance of East Africa’s freshwater ecosystems.
Mandovi and Zuari River
Why in news?
The Goa State Environment Impact Assessment Authority (SEIAA) has decided to review the updated District Survey Report (DSR) for issuing Environmental Clearances (EC) for 12 sand mining zones, which include five zones in the Zuari River and seven in the Mandovi River.
About Mandovi and Zuari River:

- Mandovi River:
- Originating from the Bhimgad Hills in the Belagavi district of Karnataka, the Mandovi River flows through Goa, covering approximately 77 kilometres before emptying into the Arabian Sea at Panaji.
- Historically, it is believed that around 20,000 years ago, the Mandovi and Zuari rivers flowed together as a single water body.
- Zuari River:
- The Zuari River originates from the Dighi Ghat in the Sahyadri Hills of Karnataka.
- It traverses Goa in a zigzag path, covering about 145 kilometres before merging with the Arabian Sea near Mormugao.
- Economic Significance:
- Both rivers are vital to Goa’s economy. The Mandovi River supports the Goa State Pollution Control Board and is crucial for ferry services, connecting various parts of the state.
- The Zuari River is commercially important for barge transport, facilitating the movement of goods like iron ore and coal.
- Ecological Significance:
- The Mandovi River is often referred to as the ‘lifeline’ of Goa, supplying fish, drinking water, and water for irrigation.
- The Zuari basin, extending from Netravali to Panjim, covers an area of about 975 km² and constitutes about 27% of Goa's total area.
- The basin has a forest area of 31.4% and hosts the Netravali Wildlife Sanctuary.
- Environmental Challenges:
- Both rivers face environmental challenges due to pollution from industrial discharge, agricultural runoff, and untreated sewage.
- These issues have led to water quality degradation, affecting aquatic life and the livelihoods of communities dependent