A STUDY ON THE IMPACT OF POLLUTION IN BELLANDUR LAKE DUE TO URBANIZATION

1
A STUDY ON THE IMPACT OF
POLLUTION IN BELLANDUR
LAKE DUE TO URBANIZATION
Done by-AMARTYA SHANKAR JHA

2
INDEX
1. Research and planning 1
2. Hypothesis 9
3. Methodology 10
4. Data collection and presentation 11
5. Observation 15
6. Socio-Economic survey 24
7. Conclusion 25
8. Evaluation 29

3
RESEARCH AND PLANNING
LAKES
Lakes are a dynamic inland aquatic ecosystem that support and maintain a parity in
the food web of organisms of that area. They are surrounded by land on all sides
and have no direct access to the sea. Lakes are mainly fed and drained by rivers
and streams.
CLASSIFICATION OF LAKES:
The first level of classification of lakes is based on origin. However, in the context
of lake use and assessments such a classification is of little value. Lakes can be
classified into two other systems, which provide basis for assessment strategies and
interpretations. These are the physical or thermal lake classification and the
classification by trophic levels.
 Physical/thermal lake types
This is defined by the uptake of heat from the solar radiation by lake waters,
and the cooling by the convection loss of heat, resulting in major physical or
structural changes in the water column.
Figure 1: Typical temperature profile from a stratified lake in the temperate zone, showing
the division of the water into three layers of different density

4
 Trophic status
The ability of a lake to support plant and animal life defines its level of
productivity or trophic state. The process of eutrophication underlying this
scheme is one of the most significant processes affecting lake management.
Figure 2:
Classifying lakes
according to the
degree of
eutrophication.

5
Lake Pollution:
Pollution is the introduction of contaminants into the natural environment that
causes adverse change. India is associated to having major problems with water
pollution, predominantly due to untreated sewage, high levels of biological oxygen
demand. Majority of lakes are eutrophic due to extensive urbanization.
Eutrophication is the excessive richness of nutrients in a water body, due to
runoff from the land, which causes dense growth of algae, leading to algal blooms.
An abundance of algae provides excessive decaying material, and hence a greater
reduction in oxygen as the material decomposes. With lack of sunlight and oxygen
the entire food web collapses.
ECOLOGICAL ROLE OF LAKE:
ROLE OF A LAKE
Regulating the flow of the river Storage of water during dry seasons
Maintaining the ecosystem Generation of Hydro-electric power
Biodiversity conservation areas Buffer for shore lines against erosion
Domestic use Fishing Water source
Tourist and recreational locations Natural balance preserving reservoirs

6
Lakes in Bangalore
Bangalore was once called “The city of a 1000 lakes”. The cities tanks were its
lifeline- they irrigated fields supplied fresh drinking water, recharged ground water
and supported teeming wildlife. As the city exploded with growth, we lost our
lakes to unplanned urbanization, encroachment, numerous high rises, sewage
dumping and even a malaria eradication program. In 1960 Bangalore had 282
lakes. Today, barely 34 remain.
Figure 1 shows the map of Lakes in Bangalore.

7
Bellandur Lake
Balladur Lake lies to the southeast of the city of Bangalore and is the largest lake
in the city. The lake is a receptor from three chains of lakes upstream, and has a
catchment area of about 148 square kilometers. Water from Bellandur flows to
Varthur Lake, ultimately joining the Pennar River.
Bellandur Lake is also the most polluted lake in Bangalore. Most of Bangalore
treated and untreated sewage is let into this lake, thus immensely polluting the
lake, and thus destroying its ecosystem.
Urbanization of the lake region has also played a major role in the degradation of
the lake and the depletion of the flora and fauna. The conversion of watershed area
of the lake to residential and commercial layouts has altered the hydrological
regime while enhancing the silt movement – lowering water yield in the catchment,
affecting the groundwater recharge. There has been a drastic increase in pollutants
and the waste dumped into the lake. The untreated sewage dumped into lake
hampers the ecological balance of the system. This has led to an enrichment of
nutrients, and has resulted in the eutrophication of the lake.
Figure 2 shows the map of Bellandur Lake.

8
FLORA AND FAUNA
Bellandur Lake once had diverse species of flora and fauna. At present, the number
of species has reduced drastically and is almost negligible.
Plate 1: Species that no longer inhabit the Bellandur lake area.

9
Hypothesis
“To investigate the impacts of urbanization on Bellandur Lake, where the problem
of lake management is becoming a serious issue and to understand the present
scenario and shortcomings.”
OBJECTIVES
 To analyze the ecological peril posed on the water body.
 To investigate the gravity of the situation of the degradation of the lake.
 To provide sustainable solutions that will replenish the overall quality of the
lake and also resurrect the lake’s ecosystem.
Figure 3: Bellandur Lake at present.
Figure 4: Bellandur Lake in the past.

10
METHODOLOGY
The investigative study includes an extensive research through the survey of the
lake area, determination of water quality by water quality analysis and socio-
economic surveys.
1. Survey of the lake:
The lake was observed and surveyed. The points of water inflow and outflow were
examined. And the water samples were collected from three different areas of the
lake. Safety measures were followed while collecting the samples.
2. Water Quality Analysis:
Water samples were collected from three different sites of the lake. The following
parameters were taken in for the study for determining the water quality:
 Turbidity
 Conductance
 pH
 BOD (Biochemical Oxygen Demand)
 COD (Chemical Oxygen Demand)
 Coliform bacteria
 DO (Dissolved Oxygen)
 Measuring Water Quality Index
3. Secondary sources of data:
Journals, magazines and websites were used for reference to supplement my
research.

11
Data collection and presentation
Site A: Bellandur area
It is surrounded by small scale industries and shops. These industries have a direct
exposure to the lake. This part of the lake emits a pungent smell that can be
detected throughout the region. The lake has vast amount of foam floating on it.
Plate 2: Bellandur area

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Site B: Yemalur Area
Apartment complexes and residential areas surround this part of the lake. This
region appears less turbid than the Bellandur area, but still looks polluted.
Plate 3: Yemalur Area

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Site C: Kempapura area
This region is completely surrounded by agricultural belt. This part of the lake is
covered with water hyacinth showing intense eutrophication.
Plate 4: Kempapura area

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Collection of samples
To determine the overall water quality, water samples were collected from 10-
40cm below the water surface in the morning. Samples were collected in 1liter
plastic containers and taken to the lab within 2 hours of collection for chemical
analysis.
Water quality analysis
Onsite analysis includes temperature and transparency of the water samples. Lab
analysis included parameters like pH, DO, BOD, COD, electrical conductivity,
turbidity and coliform testing. Water analysis followed standard procedures using
water quality testing kits.
Procedure
(1.) Temperature: With the help of a digital thermometer, temperature was
recorded for 3 sites.
(2.) pH: The degree of acidity or alkalinity can be determined by the pH value of
the water source. A digital pH meter was used to test the samples.
(3.) Dissolved oxygen: Low DO values represent severe pollution, healthy lake
with high DO values supports a wide range of aquatic life. DO was tested by
titration method.
(4.) BOD: It is a measure of the quantity of oxygen used by the microorganisms in
the aerobic oxidation of organic matter. BOD was tested by incubation method.
(5.) COD: It is a measure of oxygen consumed during the oxidation of organic
matter by a strong oxidizing agent.
(6.) Turbidity: It is the amount of particulate matter suspended in water. Turbidity
was measured using a turbidometer.
(7.) Coliform bacteria test: Coliform bacteria are found in the feces of humans
and other warm blooded animals. It spreads water borne diseases.
The samples were given for testing to Aquadiagnostics Water Research and
Technology Centre Ltd.

15
Observations
Results for the analysis at the 3 sites are presented in table 1 along with the
standard value for unpolluted water.
Table 1
Parameters Results Standard Value
SITE A
(Bellandur
area)
SITE B
(Yemalur
area)
SITE C
(Kempapura
area)
Temperature ºC 27.0 27.0 27.0 -
Electrical conductivity
ms/Cm
0.815 0.817 0.801 300
pH value 7.02 7.0 7.03 6.5-8.5
Turbidity NTU 9.20 2.90 114.0 5
BOD mg/L 24.0 48.0 24.0 2.0
COD mg/L 80.0 120.0 1000.0 20.0
Dissolved oxygen mg/L 5.60 5.0 4.60 6
Total Phosphate mg/L
mg/L
1.03 1.13 0.97 0.005-0.020
Nitrate mg/L 06.60 06.60 14.14 45
Total dissolved solids
mg/L
531.0 486.0 473.0 500
Total coliforms
MNP/100ml
1600 1600 1600 Absent
Fecal Coliform
MNP/100ml
240 170 900 Absent

16
WATER QUALITY INDEX (WQI)
In an attempt to devise a system to compare lakes in various parts of the country,
the National Sanitation Foundation (NSF) created and designed a standard index
called the Water Quality Index (WQI). The overall results of nine separate tests are
used to determine whether a particular stretch of the water body is healthy.
The WQI consists of nine tests:
Dissolved Oxygen
Fecal Coliform
pH
BOD (Biochemical Oxygen Demand)
Temperature
Total Phosphate
Nitrates
Turbidity
Total Solids
After completing the nine tests, the results are recorded and transferred to a
weighting curve chart where a numerical value is obtained. For each test, the
numerical value or Q-value is multiplied by a “weighting factor”. The resulting
values are then added to arrive at an overall water quality index.
Water Quality Factors and Weights
Factor Weight
Dissolved Oxygen 0.17
Fecal coliform 0.16
pH 0.11
Biochemical oxygen demand 0.11
Temperature change 0.10
Total phosphate 0.10
Nitrates 0.10
Turbidity 0.08
Total solids 0.07

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Table 2.1: Bellandur
Parameters Raw data Q value Weighting
factor
Total
pH 7.02 88 0.11 9.68
DO 5.60 5 0.17 0.85
BOD 24.0 8 0.11 0.88
Fecal
coliform
240 36 0.16 5.76
Total
phosphates
1.03 39 0.10 3.9
Nitrates 06.60 59 0.10 5.9
Turbidity 09.20 78 0.08 6.24
Total solids 531.0 20 0.07 1.4
Based on 8 factors the WQI is 38
Water Quality Index Legend
Range Quality
90-100 Excellent
70-90 Good
50-70 Medium
25-50 Bad
0-25 Very bad
The WQI of Bellandur area suggests that the quality of water is bad.

18
Table 2.2: Yemalur
factor
Total
pH 7.0 88 0.17 14.96
DO 5.0 5 0.11 0.55
BOD 48.0 5 0.16 0.8
Fecal
coliform
170 39 0.10 3.9
Total
phosphates
1.13 37 0.10 3.7
Nitrates 06.60 59 0.08 4.72
Turbidity 2.9 90 0.07 6.3
Total solids 486.0 34 0.11 3.74
Based on 8 factors entered, the WQI is 41
Range Quality
90-100 Excellent
70-90 Good
50-70 Medium
25-50 Bad
0-25 Very bad
The WQI of Yemalur area suggests that the quality of water is bad.

19
Table 2.3: Kempapura
factor
Total
pH 7.03 89 0.17 15.13
DO 4.60 4 0.11 4.4
BOD 24.0 8 0.16 1.28
Fecal
coliform
900 23 0.10 2.3
Total
phosphates
0.97 41 0.10 4.1
Nitrates 14.14 44 0.08 3.52
Turbidity 114 5 0.07 0.35
Total solids 473.0 36 0.11 3.96
Based on 8 factors, the WQI is 29
Range Quality
90-100 Excellent
70-90 Good
50-70 Medium
25-50 Bad
0-25 Very bad
The WQI of Kempapura area suggests that the quality of water is bad.

20
Weighted Curve Charts
In order to indicate the water quality of the three sites, weighted curve charts were
drawn and the coordinates of where the three sites lie on the curve charts are
mentioned next to these graphs.
Weighted curve chart for fecal coliform:
Coordinates of the three sites on the graph:
Bellandur (240, 36)
Yemalur (170, 39)
Kempapura (900, 23)
Weighted curve chart for BOD:
Bellandur (24, 8)
Yemalur (48, 5)
Kempapura (24, 8)

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Weighted curve chart for Total solids:
Bellandur (531, 20)
Yemalur (486, 34)
Kempapura (473, 36)
Weighted curve chart for DO:
Bellandur (5.60, 5)
Yemalur (5, 5)
Kempapura (4.60, 4)

22
Weighted curve chart for pH:
Bellandur (7.02, 88)
Yemalur (7.0, 88)
Kempapura (7.03, 89)
Weighted curve chart for turbidity:
Yemalur (2.9, 90)
Kempapura (114, 5)

23
Weighted curve chart for nitrates:
Coordinates for the three sites on the graph:
Bellandur(06.60,59)
Yemalur(06.60,59)
Kempapura (14.14,44)
Weighted curve chart for total phosphates:
Coordinates for the three sites on the
graph:
Yemalur (1.13, 37)
Kempapura (0.97, 41)

24
SOCIO-ECONOMIC SURVEY
A socio-economic survey was conducted to collect relevant data for planning and
formulating data. I understood the impact of lake pollution on the people residing
in Bellandur lake and also learnt about the transition of the lake from clean to a
contaminated one. Following is a summary of my interaction with the residents.
Residents were highly concerned about the severe water contamination. The lake
had been used for swimming, fishing, drinking purposes in the yester years. People
barely come out of their houses due to the stench and foam emitting from the lake.
Ground water has become contaminated, people are forced to buy water cans,
bore wells are drilled to depths of 1,200ft and beyond. Over the past seven years,
agricultural production had declined, 90% of farm land were sold to companies.
Doctors complain that they receive about 50 patients with complaints of wheezing,
respiratory illness, malaria, dengue and skin related problems every day.
Bellandur Lake, once was a biological hotspot is now a burden to the people living
in the vicinity.

25
CONCLUSION
Based on the water analysis and WQI of the three sites, the following conclusion
can be drawn.
The PH of the water samples were 7.02, 7.0 and 7.03 for sites A, B and C
respectively. Hence the water samples were found to be slightly alkaline.
Turbidity of an area determines the presence of toxic contaminants of the lake and
thus increases the chance of water borne diseases. Site one (9.2) and site three
(114) had a very highly turbid value.
DO is required for the survival of aquatic life. All the three sites had an extremely
low DO value. Low DO values create an anoxic condition that can be detrimental
to living organisms.
High BOD and COD values indicate the influx of sewage into the lake. It signifies
the decomposition of organic matter and is the main factor leading to low DO levels.
Aquatic plants consume much of the oxygen during nighttime respiration. High
BOD values denote that the samples comprises largely of degradable organic matter
and less amount of inorganic constituents that cannot be oxidized by bacteria.
Fecal coliform bacteria are positive for all three sites. This increases the risk of
hepatitis, dysentery, skin diseases etc.
Levels of nitrates are less than the standard values attributing to the process of
ammonification- conversion of organic nitrogen to ammonium during the
decomposition of organic matter. Due to low oxygen concentration, nitrate is
converted to nitrite and this process is responsible for the lower nitrates
concentration in the water. During periods of high plant growth, the levels of nitrates
may be significantly reduced.
The WQI for the three sites indicates that the lake is totally deteriorated, highly
eutrophic with foams emitting from the lake due to presence of chemicals.

26
Problems
Faced by
Bellandur
lake
Garbage
dumped in the
lake
Eutrophication
Salinization
Acidification
Saprobization
Urbanization
Nobody is held
accountable
for the
pollution of
the lake
No initiative
has been
taken to clean
up the lake so
far
Large scaale
encroachment
of the land
adjoining the
water body
Fire due to
methane
emission
Frothing of the
lake
Problems faced by Bellandur Lake

27
Impact on the environment:
 Micro-climatic changes.
 Reduction in flora and fauna diversity.
 Ground water contamination.
 Loss of fresh water.
Impact on the people
 Serious health concerns including cancer
 Unhealthy living environment
 Scarcity of water
In recent years, population pressures and anthropogenic activities had led to the
expansion of unplanned infrastructure. Lakes are either drained or converted in to
solid waste dumping sites. The 1000 year old Bellandur lake is losing its charm
due to sustained inflow of industrial effluents, untreated sewage, dumping of
building debris and solid waste. Heavy metals are causing severe groundwater
pollution in the neighbouring areas of the lake, high nitrate levels could take health
concerns.
Serious restoration efforts has to be taken up by the citizens of Bangalore and the
government of Karnataka.

28
Lake
Restoration
Fencing the
lake
boundaries
to prevent
trespassing
Desiltation
of the lake
Educating the
public and
Encouraging
ecotourism
activities as a part
of school
curriculum
reduction of
non-point
source, waste
minimization
Setting up of
more sewage
treatment
plants &
increasing their
capacity
Organising
rallies and
fundraisers for
the restoration
of the lake
Imposing fines
on those who
contribute to
the degradation
of the lake
Recommendations for lake restoration

29
EVALUATION
Through my study, I have understood the fragility of fresh water ecosystems and
the responsibility mankind should adopt to conserve water bodies. I was made
aware of the adversity faced by the residents of Bellandur. I am satisfied with my
work, as I have explored the major aspects of the impact caused by urbanization on
the lake body. The time provided for doing this coursework was sufficient and this
was helpful as the Bellandur lake pollution was an ongoing problem during the
time I was working on this study. Bellandur lake has been one of the most
prominent lakes in Karnataka and is worsening at a rapid rate. BWSSB Chairman
T M Vijay Bhaskar said that it will take at least five years to get rid of the toxic
foam that has been emanating from the Bellandur Lake in the City.
Restoration of the lake would require adequate funds, dedication and constant
support.

A STUDY ON THE IMPACT OF POLLUTION IN BELLANDUR LAKE DUE TO URBANIZATION

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