Blue Water Gone Black

Urban water bodies are crucial to the ecological and economic health of cities, serving as sources of water and sites for recreation. This article explores the alarming state of urban water bodies in India, underscoring the urgent need for conservation efforts to restore and protect these vital resources.

We learned as kids that water is the source of all life on Earth. As adults, we seem to have forgotten that. That is why our cities lack clean and usable water bodies. We drained the lakes, ponds, wetlands, and other water bodies to reclaim the land or dispose of our sewage into the water bodies. The water crisis in Bengaluru ought to be a cautionary tale for all cities. The city once hailed as the “land of a thousand lakes” by the Governor General of India, Lord Cornwallis, is now left with less than 200 lakes (199 to be exact).

The stories of Delhi, Chennai, and Hyderabad are not that different. A survey conducted by the Delhi Parks and Gardens Society in 2015 revealed that out of 611 water bodies in Delhi, 274 have dried up and 190 are in critical condition. In Chennai, out of 650 lakes, only 30 are left, while the area of 19 major lakes has shrunk to 645 hectares from 1,130 hectares. Hyderabad has also lost 3,245 hectares of its lake area in the last 15 years. The lakes that have managed to evade the scythe of the encroachers have been given a slow and steady death, thanks to the sewage and other trash we dump in them. The lakes that have managed to evade the scythe of the encroachers have been given a slow and steady death, thanks to the sewage and other trash we dump in them.

Receding Water Lines

The first water body census in India, which took place in 2018, found 69,485 water bodies in urban areas, with Delhi and Karnataka topping the list. However, almost all of them have been damaged beyond repair, says NIUA.

Coming to lakes in India, there were 22,361 (0.9 per cent of total water bodies), of which only 9,558 are still in use. A major portion of our urban lakes (57.6 per cent) are out of use, as they either have dried up (3134), are under construction (2337), are plugged with silt (2167), or have been destroyed beyond repair (750). Only a little over 40 per cent of the urban lakes are being used, yet they perform a very essential role. Over 1591 of them are helping recharge the groundwater table, 663 are being used for domestic or drinking purposes; and 227 are for industrial purposes.

The water body census also revealed that three per cent of the total urban water bodies are under various stages of encroachment. Lakes constitute 4.2 per cent of all encroached water bodies. Tamil Nadu topped the list with 500 water bodies, of which more than 50 per cent have been encroached on.

Water bodies that have managed to evade encroachers are not in the best shape either. They are heading towards a stage where water bodies will have no water. Only 35.6 per cent (23,785) of water bodies have water up to three-fourths of their total capacity. While 46.7 per cent (31,242) have water quantities ranging from 25 to 50 per cent of their total capacity, the remaining 17.7 per cent (11901) have completely dried up or have negligible water.

Concentrated poison

Rampant encroachment and lack of water are not the only problems that urban water bodies are reeling with. Increasing pollution levels is another major problem. Based on water quality, water bodies are classified into Class A, B, C, D, and E, with A representing the purest water with a minimum dissolved oxygen (DO) level of 6 milligrammes per litre (mg/l); a maximum biological oxygen demand (BOD) of 2 mg/L; and a maximum total coliform threshold of 50 most probable number (MPN) per 100 ml. After disinfection, water from Class A water bodies is safe for drinking. On the other hand, water containing total coliforms greater than 5000 MPN per 100 ml is not fit for human use.

When the National Water Quality Management Report 2022 assessed the water quality in Bhalswa Lake, near IIT Flyover, and Sanjay Lake in Delhi, the report found that Bhalswa Lake has a coliform level of 9,40,000 MPN per 100 ml and a BOD of 10 mg/L. The lake near IIT Flyover has a total coliform level of 8,40,000 per 100 ml, with a BOD of 3.3 mg/L. Lastly, Sanjay Lake has a coliform level of 7,00,000 per 100 ml, with a BOD soaring at 26 mg/L. The dissolved oxygen level in all three lakes is 0.3 mg/L.

Similarly, in Bengaluru, Ulsoor Lake has a minimum total coliform level of 5000 MPN per 100 ml and Chikkabanavara Lake has 3500 MPN per 100 ml. Dissolved oxygen in both lakes stands at 0.5 and 0.3 mg/L, respectively. Similarly, BOD in these lakes stands at 4mg/L. This clearly depicts how we have turned the blue spaces in our city into stinking gutters. As these water bodies lack sufficient oxygen levels, all life forms in them, including plants, die, and when they start decaying, the water disseminates a foul odor, almost that of a gutter.

Eventually, this contaminated water seeps through the surface and mixes with groundwater. Already, 716 districts in India, out of a total of 766, are finding traces of excess nitrates, fluoride, iron, arsenic, lead, chromium, and cadmium in the groundwater. Excessive consumption of these minerals and heavy metals leads to various types of cancer, blue baby syndrome, black foot disease, etc.

Therefore, to revive our critically ill urban water bodies and preserve the healthy ones, especially lakes, we must protect them from untreated sewage discharge, waste dumping, and encroachment, as they play a critical role in preserving the water table.

Experts say that when Bengaluru had its lakes intact, the groundwater table in the city was at 100 feet, but now the water table has gone below 1800 feet. That is true for most Indian cities. The essentiality of recharging the groundwater could be better understood by the fact that over 48 per cent of India’s urban water demand is met through groundwater alone.

The water body census revealed that three per cent of the total urban water bodies are under various stages of encroachment. Lakes constitute 4.2 per cent of all encroached water bodies.