FOR A large number of Chandigarh residents, the morning is incomplete without a walk in the serene environs of Sukhna Lake. The lake is an inseparable part of life in the City Beautiful. A steady stream of visitors continues to pour in during the day to spend time at the man-made water body at the foothills of the Shivaliks. It is one of Chandigarh’s principal tourist attractions and its defining feature. Winter brings its own visitors to the lake — a large number of migratory birds flock to the water body, making it their home for a few months before flying away again.
But all this could soon be history. The rainfed lake is facing a crisis. The water level has been declining due to heavy silting. Deficient monsoons have added to the problem. Sewage flows into it from nearby villages. Weeds choke the lake at one corner.
The problem is not new. Seven years ago, the problem was serious enough for the Punjab and Haryana High Court to take suo motu notice of it in November 2009. There have been over 50 hearings in the case by different benches of the High Court. Over the years, the urgency to do something has grown as both climate change and the rapid growth of Chandigarh, with settlements now touching the lake’s borders, have added to Sukhna’s problems.
On the last date of hearing on August 22, the High Court ordered the Chandigarh Administration to make the lake weed removal a continuous process. It also asked the administration to issue a public notice seeking suggestions from Tricity residents for saving Sukhna.
The Punjab government was asked to inform the court if the lake could be connected with water supply pipes or by boring of wells to maintain water level.
CREATED IN 1958 by Le Corbusier and then chief engineer P L Verma at a cost of Rs 1 crore, the lake was constructed across Sukhna Choe by damming it along with Kansal and Nepali Choe. The dam was a 12.8 metre high rock-filled earthen structure. Such was Corbusier’s attachment to the lake that the ashes of the first Chief Architect of Chandigarh and his cousin Pierre Jeanneret were immersed here in 1970 as per their wishes.
But ever since its creation, silting has plagued the lake. From the erosion-prone Shivalik hills, the water that flowed into the Sukhna Choe arrived with silt and sediments.
At the time of construction, the storage capacity of the lake was 10.47 million cubic metre (mcm) and water spread area varying between 1.52 sq km and 2.28 sq km. Between 1958 and 1962, the lake lost more than 20 per cent of its capacity on account of heavy silting.
In 1971, the Irrigation Department of the Punjab government took up the issue. The Kansal Choe was diverted into Suketri Choe which joined the lake at its eastern end.
But this very measure to increase the water in the lake contributed to more silting, with more of it flowing in down the steep slopes of the new channel.
The Indian Agricultural Research Institute (IARI), New Delhi, conducted a detailed survey of catchment area in 1972 and stated that soil erosion, steep sloping hills and steep bare hills were the main reasons for siltation.
Following this, the Chandigarh Administration launched intensive water and soil conservation measures in 2,540 hectare forest catchment of the lake which included effective closure, plantation, and the construction of more than 190 silt-detention earthen dams.
By the year 1988 around 2,600 hectares of Sukhna Lake were converted into Sukhna Wildlife Sanctuary and another 880 hectares classified as Reserve Forest. The lake has a catchment area of 42.7 square kilometre of which 29.8 square kilometre falls in Chandigarh while the remaining 10.22 square kilometre and 2.77 square kilometre falls in jurisdiction of Haryana and Punjab, respectively.
During the 6th Plan (1977-1978 to 1982-1983), the UT Forest Department implemented the Central government- sponsored scheme of soil conservation at a cost of Rs 73.41 lakh.
These measures taken over a period of almost three decades reduced the siltation rate of the lake from more than 140 tonnes per year to 5 tonnes per year.
Heavy siltation has also led to a fall in the number of fish in the lake. As per a study carried out by Prof M S Johal and Dr Y K Rawal in 2005, there were a total of 33 different species in the lake. However, due to the lake drying up in 2012, the number of species fell drastically. As per current data available with Dr Y K Rawal, there are only 19 species of fish left in the lake.
In 1987, the lake bed almost dried up due to a deficient monsoon combined with silting. The administration then started de-silting of the lake bed through mechanised and manual means. City residents flocked to participate in “Shramdan” to save the city’s landmark. This became an annual ritual till it was stopped in 2004.
By 2002 the lake had lost almost 63 per cent of its original water-holding capacity. The water flow too decreased. In 2002, an average flow of 225 acre-feet water was entering the lake compared to an average flow of 7,370 acre-ft water from 1958 to 1978.
Santosh Kumar, chief conservator of forests, said that with sustained measures made over the years, the administration has managed to bring down the rate of siltation. “We have taken all the possible steps for saving the lake from silt and weeds. The rate of siltation was brought down with sustained measures which included extensive plantation in the catchment area. As far as water is concerned, it totally depends upon rain,” said Kumar.
THE CITY has been witnessing below normal rainfall for the last six years. This year, Chandigarh received about 42 per cent less than normal rain – only 286.2mm rain against the normal rainfall of 686.6mm. In 2015, 572.8mm rainfall was received which was 30.9 per cent less while in 2014, 389.2mm rain was recorded that was 53.1 per cent deficit.
Low rainfall in the city plays havoc with the lake bed. Islands of silt emerge regularly, showing up the precariously low water levels. A study by the Society for Promotion and Conservation of Environment (SPACE) in 2009 on “Impacts of Conservation Measures in the Catchment of Sukhna Lake on Ground Water, Soil and Geology” pointed out that the Sukhna Lake catchment area was practically floating in water.
As per the report, around 48 water bodies in the wildlife sanctuary linked to the silt retention dams are filled with water throughout the year. The report further states that in case of normal rainfall, around 60 hectare metre (hams) water could be released into the Sukhna Lake from these water bodies. During years of low rainfall, the quantity would be around 40 hams.
There is also a large low-lying area that receives spills, leakages, seepage from the water bodies located on higher elevations in drainage lines. However, due to an “impervious layer”, this water is not able to flow into the Sukhna.
President of SPACE Dr S S Grewal said that a mechanism to release the water into the lake needs to be found. “The wildlife sanctuary has enough water to save the lake from drying up,” he said.
The SPACE team also visited more than 150 silt retention dams, measuring the water available in each, concluding that even as they caught silt, they also prevented enough water from flowing into the lake. The study says that when the lake becomes alarmingly shallow, the water stored in dams can be drained to augment the capacity of the lake.
FORMER CHIEF engineer of the Punjab Irrigation Department Dr G S Dhillon says that there is a need for a permanent solution to the problem. “Due to the construction of the silt retention dams, there is a reduction in the amount of water that enters the lake. At places like Sukhomajri and Kansal, people have put up obstructions and do not let the water flow to the lake. The right over water is not notified. There is a need for the Centre to intervene and issue a notification that the water should be used only for Sukhna Lake and not be used by people on the way,” said Dr Dhillon.
He added that there was no water management. There should be an engineer who is given this task. Shallow tubewells should be allowed in the catchment area and a channel be constructed to take the water to the lake. Dr Dhillon added that there was a need for rainwater harvesting in the northern sectors and the water could be diverted to the lake.
Save Sukhna Forum was set up around a decade ago with the aim of maintaining water levels and activity in the lake. President of the forum, former UT chief engineer S S Virdi said that a detailed report was made and submitted to the UT Administration around two years ago. The forum recommended forming an independent body, Sukhna Lake Development Authority.
“Just depending on rains is not good enough. The dams at the wildlife sanctuary have reduced intake into the lake. Excess water from there can be drawn into the lake. There is enough sub-soil water available. Tubewells can be installed to pump water. Tertiary water can be pumped in,” said Virdi.
ANOTHER PROBLEM encountered at the lake is that of weeding. There are eight types of weeds that are spread over more than half of the lake. Typha, Hydrocharitaceae and Ceratophyllaceae are the most common type of weeds found in different seasons.
According to assistant professor Dr Y K Rawal, from the Department of Zoology, Panjab University, who along with Professor Emeritus Prof M S Johal, conducted a study on the lake said that presence of a large number of weeds in the lake is one of the reasons for depleting water level.
On Dr Rawal’s recommendation, the administration has put a species of fish called Ctenopharyngodon Idella commonly known as Grass Crap for weed control. Ctenopharyngodon Idella consumes a large quantity of weeds. Dr Rawal said that other measures include manual removal of weeds, which is a continuous process.
Experts are of the view that rapid siltation and inflow of sewage into the lake from nearby areas are the main reasons for weeds. As per a report prepared by the UT Forest and Wildlife Department, the sewage flowing from Kansal and Saketri village is causing damage to flora and fauna of Sukhna Lake reserve forest and polluting the lake as well.
To stop sewage water from flowing into the Sukhna Lake, the forest department has started bio-treatment of the sewage water by way of oxidation. The sewage water of Kansal is being collected in a large-sized water body and is being treated through natural bio-mechanism in which the sewage water is passed through long channel having plants like Saccharum munja and rice straw and iron ores which lead to oxidation of the sewer water.
The Punjab and Haryana High Court has directed the Panchkula administration for taking steps to ensure that sewage from Saketri does not enter the lake.
The problem of weeding and siltation was also highlighted in a study by the National Institute of Hydrology, Roorkee, conducted in 2013. The experts suggested that the primary objective of desilting should not be to increase the capacity or surface area of the lake. This could cause evaporation which is already high for the lake. The average decline in water level during October 1, 2011, to June 28, 2012, is 5.99 mm/day. Approximately 300 ham of water is lost due to evaporation.
Mukesh Anand, UT chief engineer, told Chandigarh Newsline that the engineering wing removes weeds manually throughout the year. “Steps have been take to ensure that sewage from Kishangarh and Kansal does not enter the lake,” said Anand.
DUE TO the intervention of the court, the Chandigarh, Punjab and Haryana authorities were in 2012 pressed into action to deploy their labourers and JCB (excavation machine vehicles) so that Kansal nadi (rivulet) was cleaned to ensure natural flow of water into the lake. The court had also ordered the authorities to make every effort to ensure unhindered flow of surface run-off towards the lake guided by natural gradient from Punjab area.
The High Court had on May 14, 2012, also put stay on the construction activities in the catchment areas of Sukhna Lake which is still in operation but the construction activities in the catchment area are continuing unabated under the nose of the authorities, especially at Kansal village falling in Mohali district.
The court had also asked the Chandigarh Administration to consider the option of pumping in surplus water from UT into Sukhna between December 15 and January 15 when the demand is lower than in the summer. Also, the court had suggested that instead of wasting the storm water, it should also be channelised to flow into the lake. If these ideas have been considered at all, there is no evidence to suggest that the administration acted on them.
GURDEEP SINGH Dhillon (70), who retired from the Punjab State Warehousing Corporation, said he had been regularly going for morning walks for the past 20 years. “If I do not visit the lake every morning, something seems to be amiss. The residents of have an emotional connect with the lake. When the lake filled up with silt, hordes of people participated in Shramdan to manually remove it every year till the drive was discontinued by the administration,” said Dhillon.
Manjot Singh, who has been regularly going for morning walk to the lake for the past 15 years, said that he like a large number of residents have developed a emotional connect with the lake. “Lake has become an integral part of our lives. It is imperative to save the lake, no matter what it takes. The residents should come forward to help the administration in saving the lake,” said Manjot Singh.
(with inputs from Sanjeev Verma)