More States, One Lake Each

A further set of Indian lakes recur often enough in exams to deserve individual mention, even though each belongs to a state not otherwise covered with its own full section above. Treat each as a single self-contained peg rather than trying to force them into a competing ladder.

Kolleru Lake, in Andhra Pradesh between the Krishna and Godavari river deltas, is one of the largest freshwater lakes in India and a Ramsar-designated wetland, important as a wintering ground for migratory birds including pelicans and painted storks. It has faced serious and well-documented shrinkage from encroachment by aquaculture (fish and prawn farming) ponds built directly on the lake bed — a 2006 Andhra Pradesh government drive to demolish unauthorised aquaculture structures around Kolleru is a frequently cited example of enforcement action to reclaim an encroached wetland, paired usefully against Dal Lake's more contested, still-ongoing restoration story.

Sasthamkotta Lake, in Kerala's Kollam district, is the state's largest freshwater lake and serves as the primary drinking-water source for Kollam town — an unusual and exam-favoured detail, since most large Indian lakes are known chiefly for tourism, ecology, or salinity rather than for directly supplying a city's drinking water. It is a Ramsar-designated wetland and is fed largely by natural springs rather than a major river, keeping its water unusually clean relative to many of India's other large lakes.

Deepor Beel, near Guwahati in Assam, is a former channel of the Brahmaputra river, now a permanent freshwater lake and Ramsar wetland, and one of the largest stormwater storage basins for the Guwahati metropolitan area — meaning it does double duty as both a wildlife habitat (elephants, migratory waterfowl) and urban flood-control infrastructure, a functional pairing worth remembering distinctly from purely scenic or purely ecological lakes elsewhere in this book.

Harike Wetland, in Punjab, is technically a reservoir rather than a fully natural lake — it was created at the confluence of the Sutlej and Beas rivers by a barrage built in 1953 for irrigation and water-supply purposes, but it has since developed into one of North India's most significant Ramsar wetlands, hosting one of the largest populations of the endangered Indus river dolphin (gharial has also historically been recorded here) found in Indian waters outside the Indus system proper, along with major waterfowl congregations — a good example of an originally engineering-driven water body acquiring major independent ecological value over time.

Bhoj Wetland, in Madhya Pradesh, refers jointly to the Upper Lake and Lower Lake of Bhopal city — the Upper Lake, an artificial lake created in the 11th century by a dam across the Kolans river (making it one of India's oldest known artificial lakes, predating the modern reservoir era by many centuries), supplies a significant share of Bhopal's drinking water and is jointly Ramsar-designated with the smaller, more urban Lower Lake immediately downstream — together illustrating both the "very old artificial lake" and "twin urban lake pair" categories in one Ramsar site.

Memory hook: "Kolleru's ponds got demolished, Sasthamkotta supplies Kollam's taps, Deepor Beel floods for Guwahati, Harike's a dam that grew dolphins, Bhoj's twin lakes are eleventh-century old." Five states, five one-line identities.

Practice Recall: Before reading on, name the Kerala lake that is the primary drinking-water source for Kollam, and the Madhya Pradesh lake pair that together make up the Bhoj Wetland Ramsar site.

Answer: Sasthamkotta Lake; the Bhopal Upper Lake and Lower Lake.