Limnology

Study on Upper Lake

— by Pranjal Kulkarni, June 14 2021 —

UPPER LAKE, BHOPAL Source : http://www.swachhindia.ndtv.com

INTRODUCTION 

The capital city of Madhya Pradesh, Bhopal, is endowed with multiple man-made lakes and is thus referred to as a ‘City of Lakes.’ The Upper Lake (or the Bada Talaab or Bhojtal), located in the west ofl city, has a rich historical significance and serves as a major source of drinking water for the citizens. Along with the Lower Lake, it is identified as Bhoj Wetland of Bhopal as an internationally known Ramsar site declared in 2002 [1]. 

The Upper Lake is considered the oldest among the man-made lakes of Central India. It was created by Raja Bhoj, a local Paramara king, in the 11th century by creating an earthen dam across the tributary of Betwa river [2]. It is situated at 532 m above sea level,  between  77º 30’–77º 35’ E and 23’ 25”–23’ 26’N. It has a maximum depth and mean depth of 11.7 m and 6m respectively, with a submergence area of 36.5 sqkm . The main inflow of water for the lake is through the Kolans river along with several other drains in its catchment area [3]. 

SATELLITE IMAGE OF THE UPPER LAKE, BHOPAL Source: googleearth.com

The Upper Lake is significant for the identity of the city of Bhopal and allows multiple functions like recreation, commercial fishing etc. It is inseparable with the social-economical and cultural part of Bhopal and is considered the lifeline of the city. It has played a critical role in the existence and evolution of Bhopal. Before 1947, the water quality of the lake was considered so good that it did not require water treatment [6]. Due to increasing urbanization over the last few decades, the lake has been severely threatened and hence it is constantly within the focus of conservation plans. 

From 1995-2004, the Government of Madhya Pradesh implemented the Bhoj Wetland Conservation Project which was directly controlled by the Housing and Environment Department. The financial assistance for this project was given by JBIC (Japan Bank of International Cooperation). With the basic objective of improving the water quality of the lake, the project activities included both preventive and curative measures like increasing the capacity of storage through desilting, de-weeding, construction of sewage treatment plants, catchment area protection etc. Water quality monitoring post-project completion confirmed an improved status of water quality with a 4% increase in water holding capacity of the Upper Lake [6]. 

After more than a decade, the lake faces new challenges due to increasing demand for real estate development projects, agricultural pressure, anthropogenic stresses etc. It is of paramount importance to constantly keep a check on the condition of the Upper Lake for best possible conservation efforts. The report looks into the properties of the lake, its present state, and the possible scientific solutions for its restoration. 

PHYSICO-CHEMICAL PROPERTIES

BHOJ WETLAND BASIN Source: Lake Bhopal Conservation and Management Project report field survey, International Lake Environment Committee (ILEC) Foundation, 2007

PROPERTY / PARTICULAR VALUE NOTES
PERIOD OF CONSTRUCTION 11TH CENTURY 
TYPE OF CONSTRUCTION EARTHEN DAM 
CLIMATE HUMID/ SUBTROPICAL
GEOLOGICAL PROPERTY OF BASINROCKY BASALT, BURIED PEDIPLAINS, SHALLOW, STRATIFIED, OLIGRAPHICSOURCE [4][5]
SOURCE OF WATER RAINWATER, STREAMS
ANNUAL RAINFALL 1050-1261 mm / YEARSOURCE [4]
STORAGE CAPACITY 117.05 MILLION CUBIC M SOURCE [5]
CATCHMENT AREA 361 SQM SOURCE [5]
WETLAND AREA 3201 HArsis.ramsar.org
SUBMERGENCE AREA AT FLOOD LEVEL 36.54 SQKM SOURCE [5]
FULL TANK LEVEL (ABOVE MSL LEVEL)508.65 M SOURCE [5]
DEAD STORAGE LEVEL(ABOVE MSL LEVEL)503.53 M SOURCE [5]
INFLOW POINTS 31SOURCE [5]
SEWAGE INFLOW 50.47 MLD SOURCE [5]
SILTING RATE 1 – 2.58 CM/YEARSOURCE [1]
SEDIMENTATION RATE 3.67 HA.M/100SQM/YEARSAPROF REPORT,1994
pH5.5 – 8.3 SOURCE [6]
DISSOLVED OXYGEN 6.33 – 7.56 MG/LSOURCE [6]
TDS128 – 153.33 MG/LSOURCE [6]
TOTAL HARDNESS 50.33 – 66.67 MG/LSOURCE [6]
TOTAL ALKALINITY 103 – 123.33 MG/LSOURCE [6]
NITRATE0.3 – 1.7 MG/LSOURCE [8]
TOTAL COLIFORM (MPN)400 – 1800/ 100ML SOURCE [8]

PRESENT CONDITION 

The Upper Lake is used for providing drinking water to more than 40% of the citizens of Bhopal through 8 pumping stations and five water treatment plants. Over nine Sewage Treatment Plants are also established  to minimize addition of raw sewage in the water bodies of Bhopal, but are incapable of running in full capacity. The pressure of urbanization is increasingly affecting the Lake and many specialists and concerned citizens fear for its health and longevity. There are multiple factors that are responsible for degradation of the lake in the last few decades. They are:

  1. Physical and Chemical pollutants 
  • Due to ageing of the earthen dam and displacement of the stone masonry, there is a need to monitor and control seepage of sewage through the earthen dam [11].
  • Since 2007, addition of biomedical waste has also become a critical concern, when a local hospital was found guilty of mismanagement in its waste disposal [11].
  1. Sewage and Pathogenic agents
  • The Bhoj wetland suffers from degradation due to solid waste pollutants, sewerage of 7500 cubic m/ day and 360 cubic m/ day of animal discharge [1].
  • There is increasing input load of nitrate and phosphorus from untreated sewage. According to the wetland conservation project report, various initiatives have been taken to reduce the amount of pollutants in the lake through desilting and dredging.
  • There is a need to improve the sewage system that can work in its full capacity as the current system is increasingly getting burdened. A high amount of water usage and its disposal goes unaccounted for since Bhopal has a large number of privately owned borewells and dugwells, indicating that more water is in circulation than what is monitored by the government [12].
  • The sewerage system can only cater to dry weather flow and during monsoons, polluted water from Pul Patrah is directly discharged into the Upper Lake. The population of Bhopal is exposed to contaminated drinking water. 
  • Apart from industrial waste, drains from urban areas stretching from Sehore to Bairagarh flows into the lake, according to a recent report by CEPT. 

Source:Singh, Sandhoor; Singh, Mohan; Bhat, Manzoor Ahmad, ‘Evaluation of water quality index of Upper Lake – A Ramsar site,’ Scholars Research Library, 2016

3. Agricultural Pollution

  • The catchment area of the Bhoj wetland basin is mainly agricultural land and rural settlements dependent on farming. Heavy use of fertilizer is practised by these farmers due to increasing market pressures and they are thus reluctant to cease its usage. These chemicals, through unmonitored run-offs, are added into the water of the Upper Lake [9].
  • Soil erosion and sedimentation also results in addition of agricultural fertilizers into the lake which increases the tendency for eutrophication. Agricultural nutrients enhance the rate of eutrophication which is reflected through the presence of floating algae like Microcystis Aeruginosa etc. These biological species through their decay and decomposition further increase load on organic pollution, euphotic zone reduction and decrease in hypolimnetic dissolved oxygen content [7].

4. Anthropogenic Activities

  • The Upper Lake is an active spot for tourism in the city. 
  • The motorboats used by the tourism department have increased the pollution level of the lake.
  • The report by CEPT also warned that increasing commercial activities in the boat club area can also be detrimental to the health of the lake.  [10]
  • The BMC has estimated that around 2000 people use the lake everyday for the purpose of bathing, washing clothes resulting in large scale pollution.

5. Urbanization and Governance

  • The wetland has reduced in area due to encroachment even though the government strictly checks illegal development. 
  • The Bhoj Wetland Conservation Project of 2004 was only partially successful due to lack of funds and expiry of the scheme. 
  • The latest development plan, BDP 2031 has received severe criticism for its lack of consideration for the conservation and preservation of the Upper Lake. Multiple proposals, according to environmentalists and planners, are against the Wetland rules of 2017 [14]. Lands that were previously entitled to conservation shall be used for development without any special clearances [15].

On an optimistic note, citizens and environmentalists are constantly vigilant, and the city has put in multiple efforts to conserve the Upper Lake. In 2009, through a public campaign – Apna sarovar apni dharohar, bada taal sanrakshan abhiyaan, the state government led a movement of manual desilting, by offering shramdaan. The movement received great public attention and was carried out in full force and enthusiasm. The government also removed illegal encroachments and plans public drives for further actions.

SCIENTIFIC SOLUTIONS FOR RESTORATION

  • A study has indicated that the use of aeration in the lake using floating fountains increased the content of dissolved oxygen in the lake while reducing Biochemical Oxygen Demand and Chemical Oxygen Demand, effectively improving the water quality[13].
  • Internal ecological processes can be controlled through modern eco-technologies or measures for in-lake treatment for improving water quality [7].
  • Through large scale rainwater harvesting in the fringes, and channelizing of storm water drains with screening and silt trapping can increase the volume of water and reduce nutrient content [7].

POLICIES ON CONSERVATION 

  • The catchment area of the lake is divided between two districts which makes it difficult to regulate construction and development that can ecologically modify the wetland. There is a dire need for a national policy on conservation of water-bodies.
  • No Development Zones should be strictly established and monitored around the riparian buffers 
  • The lake must be preserved along with its catchment, and managed as a composite whole. This should include prohibition on any landscape activity that affects its green cover, or changes the course of its streams or their health due to pollution from human settlements, industries etc.
  • There needs to be generation of awareness in the agricultural sector on the consumption of fertilizers. Stakeholder involvement and participation, raising awareness and educating communities is a critical part of lake conservation and management program [6].
  • Non point source run-offs from drains should be trapped [6]

Source:  Manisha, Keerti; Pandey Rama U, ‘ Conserving Catchment Area of Lakes through Development Regulations: A Case of Upper Lake in the City of Bhopal, India

REFERENCES

[1] Singh, Apoorva; Naseer, Fiza, ‘Tragedy of the Commons – Bhoj Wetland,’ International Journal on Emerging Technologies 8, 2017 

[2] Purohit, Makarand ‘Twin Lakes of Bhoj’ www.indiawaterportal.org/articles/twin-lakes-bhoj

[3] Manisha, Keerti; Pandey Rama U, ‘ Conserving Catchment Area of Lakes through Development Regulations: A Case of Upper Lake in the City of Bhopal, India,’ GSTF Journal of Engineering Technology (JET) Vol.5 No.1, 2018

[6] Singh, Sandhoor; Singh, Mohan; Bhat, Manzoor Ahmad, ‘Evaluation of water quality index of Upper Lake – A Ramsar site,’ Scholars Research Library, 2016

[4] Manisha, Keerti; Pandey Rama U, ‘ Conserving Catchment Area of Lakes through Development Regulations: A Case of Upper Lake in the City of Bhopal, India,’ GSTF Journal of Engineering Technology (JET) Vol.5 No.1, 2018

[5] Kumar, Amit; Chaudhary, Om, ‘Conservation Plan of Upper Lake, Bhopal: Water-Quality Centric Case Study’ International Journal of Emerging Technology and Advanced Engineering, Vol 3 Issue 1, 2013

[7] Upadhyay Rahul , Pandey K. Arvind , Upadhyay S.K, ‘Assessment of Lake Water Quality by Using Palmer and Trophic State Index- a Case Study of Upper Lake, Bhopal, India,’ International Research Journal of Environment Sciences, 2013

[8] KalpanaKumari Thakur , Avinash Bajpai and Shailbala Singh Baghel, ‘Water Quality Assessment of Upper Lake Bhopal (M.P.) with special references to Aeration System, International Journal of Science, Environment and Technology, Vol. 4 No 4, 2015

[9] Pandey Pratap, Banerjee Souparno, Narain Sunita, ‘Excreta Matters, Central Highlands Bhopal’ 2012  

[10] https://timesofindia.indiatimes.com/city/bhopal/sewage-seeps-into-upper-lake/articleshow/70865978.cms?utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst

[11] https://swachhindia.ndtv.com/bhopals-twin-lakes-one-of-which-is-a-water-supplier-to-the-city-is-struggling-with-encroachments-and-disposal-of-untreated-sewage-12227/  

[12] Lake Bhopal Conservation and Management Project report field survey, International Lake Environment Committee (ILEC) Foundation, 2007

[13]Dixit, Savita ; Verma, Neelam; Tiwari, Suchi, ‘The Effects of Aeration Units on Water Quality in Upper Lake, Bhopal, India,’ UCLA Electronic Green Journal, 2005

[14] Why Bhopal’s development plan could kill its upper lake – India Today Insight News

[15]Some cities have lost up to 70% of wetlands. Will Bhopal face the same fate? (citizenmatters.in)

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