Content uploaded by T V Ramachandra
Author content
All content in this area was uploaded by T V Ramachandra on Feb 28, 2021
Content may be subject to copyright.
Content uploaded by T V Ramachandra
Author content
All content in this area was uploaded by T V Ramachandra on Jul 19, 2020
Content may be subject to copyright.
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
14 |https://giapjournals.com/gctl © Authors
EFFICACY OF REJUVENATION OF LAKES IN BENGALURU, INDIA
Ramachandra T.V a, b, c *, Sincy Va, Asulabha K.S a
a Energy & Wetlands Research Group, Centre for Ecological Sciences, b Centre for Sustainable Technologies (Astra),
c Centre for infrastructure, Sustainable Transportation and Urban Planning, Indian Institute of Science, Bengaluru,
Karnataka, India.
*tvr@iisc.ac.in, envis.ces@iisc.ac.in
Article History: Received on 20th May, Revised on 10th July, Published on 18th July 2020
Abstract
Purpose of the study: The main objective of the present work is to assess the efficacy of the restoration endeavour in
Bengaluru lakes, Karnataka, India. Rapid urbanisation coupled with industrialisation in urban areas has greatly stressed the
available water resources qualitatively and quantitatively. This has also resulted in the generation of enormous sewage and
wastewater after independence.
Method: Environmental monitoring of 40 restored lakes was carried out to identify the key issues and assessed water quality
(physical, chemical and biological). Weighted arithmetic water quality index (WQI) and Pearson’s correlation coefficient (r)
was determined using data of physicochemical parameters of lakes. Principal Component Analysis (PCA) performed using
PAST3 software to identify the factors responsible for variations in water quality.
Main Findings: The monitored forty lakes distributed across the three major watersheds namely Koramangala and
Challaghatta valley, Vrishabhavathi valley and Hebbal valley were grouped under three different WQI status like good water
quality (10%); poor water quality (37%) and very poor water quality (53%). Majority of these restored lakes has become
polluted which indicates improper decontamination and poor maintenance of restored lakes.
Application of this study: This study provides vital information for policymakers to understand the gaps which helps in the
course correction while implementing further rejuvenation of lakes.
Novelty/Originality of this study: The efficacy of rejuvenation was assessed through integrated cost-effective scientific
approaches for the lake monitoring. Monitoring during the pre and post rejuvenation period has aided in assessing the
efficacy of rejuvenation, which is done for the first time in India.
Keywords: Lake rejuvenation, Water quality, Pollution, WQI, Multivariate analysis
INTRODUCTION
Lakes and water bodies also referred to as wetlands are one of the most productive ecosystems contributing to ecological
sustainability thereby providing necessary linkages between land and water resources. The quality and hydrologic regime of
these lakes and wetlands are directly dependent on the integrity of its watershed. Urban lakes have been aiding in recharging
groundwater resources, microclimate moderation, floods mitigation, supported local livelihood (fish, fodder, etc.), local
water (irrigation and domestic) demand apart from recreation facilities. Washing, household activities, vegetable cultivation
and fishing are the regular activities in the lake for livelihood. In the last couple of decades, rapid urbanization coupled with
unplanned anthropogenic activities has altered the wetland ecosystem severely across the globe. Changes in land use and
land cover (LULC) in the wetland catchments influence the water yield and water quality of the lakes.
Reduction of wetlands in Bengaluru and the pollution load has increased over years due to population growth, urbanization,
industrialization, land use changes, encroachments, etc. (Ramachandra & Aithal, 2016). This has escalated greenhouse gas
(GHG) footprint of about 19796.5 Gg of CO2 equivalents from various sectors in Bengaluru (Ramachandra & Shwetmala,
2012; Ramachandra et al., 2015a), with significant share from waste sector, domestic wastewater sector emits 759.29 Gg
(15.42 and municipal solid waste emits 374.73Gg of CO2 equivalents (Ramachandra et al., 2015a). The sustained inflow of
untreated wastewater has increased the pollution levels which is evident from the nutrient enrichment and consequent profuse
growth of macrophytes, impairing the functional abilities of the wetlands. Reduced treatment capabilities of wetlands have
led to the decline of native biodiversity. Apart from this, prevailing unhygienic conditions with mosquito menace and
contamination of groundwater levels has been affecting the livelihood of wetland dependent population, which necessitated
rejuvenation of lakes in Bengaluru.
Lake restoration or rejuvenation endeavour is toward the recovery of lakes that has been degraded or damaged. Lake
restoration is very important as the pollutants in lake can cause serious problem for human health and the environment. In
Bengaluru, there are many para state agencies connected with the governance like BBMP (Bruhat Bengaluru Mahanagara
Palike), BDA (Bengaluru Development Authority), BWSSB (Bengaluru Water Supply and Sewerage Board), PCB (Pollution
Control Board) at Central and State Government and various departments including Revenue, Fisheries, Minor Irrigation,
Forest, Ecology and Environment Department, Citizens, NGOs etc. Figure 1 illustrates the steps involved in lake rejuvenation
and conservation.
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
15 |https://giapjournals.com/gctl © Authors
Figure 1: The major steps involved in lake rejuvenation and lake conservation
Different activities involved in lake rejuvenation process are:
a. Fencing around the lake helps to prevent land encroachment (due to construction of roads, infrastructure and
residential layouts, and other land uses) and dumping of garbage, loss of wetland area and shrinkage in water spread
area.
b. De-weeding which involves regular harvesting/removal of macrophytes in lakes through manual
operations/machines that will improve the quality of lakes.
c. Accumulation of silt in lakes and loss of interconnectivity among lakes have been contributing to frequent floods
(Ramachandra & Mujumdar, 2009). Thus, dredging (dry/wet dredging) helps in enhancing the water storage
capacity of a lake. The removal of contaminated silt and sediments deposited at the lake bottom help in de-
contamination. Before initiating dredging in lakes, one need to consider the following points: amount of sediment
to be removed, a destined place to dump sediment after removal, feasibility and the associated transportation costs
and release of contaminants into lake water during dredging operation.
d. Creating islands for birds for their resting, roosting and nesting activities.
e. Creating walkway/jogging path for visitors, which provides opportunities for recreation and tourism.
f. Afforestation activities, which include planting trees of native species in lake area, provide nectar and fruits, attract
butterflies, bees, birds and other biotas. The trees will also provide shade and cool environment to visitors.
g. Construction of idol immersion tank (Kalyani) in lakes for the people to offer pooja and immerse idols during
festivals. The chemical paints used for idols generally contain heavy metals like lead, copper, cadmium, iron,
calcium, manganese, chromium, zinc, mercury, arsenic etc. that can leach into lake water and alter the water quality.
Thus, immersing idols at the designated locations like Kalyani will prevent the water pollution with heavy metals.
h. The construction of Sewage Treatment Plant (STP) in lakes will help in wastewater treatment and optimal reuse.
Raw sewage or industrial effluents should not enter the water bodies. In Bengaluru, sewage is treated to secondary
treatment standards and then the treated water may be allowed to flow into the lakes through constructed wetlands
to ensure nutrient removal. Construction of artificial wetlands in lakes to enhance their self-purification capacity.
i. Instalment of fountains/aerators in lakes to increase the dissolved oxygen level in water, which helps aquatic
organisms to survive.
Water quality refers to various physical, chemical and biological characteristics. Water pollution reduces the availability of
freshwater resources and hence, leads to an increase in water demand resulting in water crisis. Water pollution due to
anthropogenic and natural factors would result in (a) decrease in water transparency due to the presence of high
concentrations of organic matter, nutrients, micro-organisms and suspended matter; (b) change in water quality
characteristics; (c) depletion of oxygen due to accumulated organic matter, nutrients and high microbial activities; (d)
bacterial contamination that affects public health; (e) destruction to habitats, (f) loss of biodiversity and invasion of exotic
as well as pollution tolerant species; (g) obstructs recreational activities and (h) economic consequences ending in negative
externalities (Ramachandra et al., 2014; Vincon-Leite & Casenave, 2019; Ho & Michalak, 2017; Carmichael & Boyer,
2016; Watson et al., 2016). Consumption of polluted water causes cholera, typhoid fever, diarrhoea, vomiting, headache,
stomach ache, dizziness etc. Industrial waste contains toxins that can cause immune suppression, reproductive failure and
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
16 |https://giapjournals.com/gctl © Authors
acute poisoning (Juneja & Chaudhary, 2013). The heavy metals release from industries pose serious threat to aquatic life
due to their toxicity, long persistence, bioaccumulation and biomagnification in the food chain (Ramachandra et al., 2018a).
This necessitates the water quality assessments to evaluate trends in water quality, identify the pollutants and their various
sources and augmenting certain mitigating measures/solutions.
RESEARCH PROBLEM: Most of the wastewater generated in the city is discharged directly into storm water drains that
ultimately link to water bodies. The pollution load on lakes in Bengaluru had increased over years due to population increase
with the rapid urbanization and industrialization, which resulted in land use changes, encroachments, loss of interconnectivity
among lakes, pollution from point and non-point sources etc. These in turn affected the aquatic biodiversity and contaminates
the surface and ground waters posing critical health problems to the citizens. Thus, it is necessary to monitor lakes in order
to assess the extent of pollution.
AIM OF THE STUDY: Main objective of the present work is to assess the water quality status and efficiency of restoration
endeavor of Bengaluru lakes. This study will help the different stakeholders to implement appropriate remedial measures to
enhance the ecosystem services to the society.
LITERATURE REVIEW
Prevalent restoration strategies adopted for lake management
Restoration methods for lakes need to focus on curtailing exogenous and endogenous pollution sources. Multiple restoration
approaches will enable to achieve better water quality and habitat conditions. Reduction in flow of nutrients to the lake can
reduce deterioration of lake water quality. The restoration methods proposed for Bielsko lake were phosphorus inactivation,
reconstruction of the food web, biomanipulation, filtration of treated municipal sewage through a 3-m layer of sand to
groundwater and treatment of stormwater in a two-part system consisting of a pond and constructed wetland, which will
function as a biofiltration and sedimentation system (Dondajewska et al., 2018a).
The concept of constructed wetlands in nutrient removal is widely accepted. Construction of surface and subsurface flow
artificial wetlands is essential to enhance the self-purification capacity of aquatic ecosystems (Wang et al., 2016).
Macrophytes have the capability to reduce nutrients in shallow eutrophic lakes (Srivastava et al., 2008; Quilliam et al., 2015).
Integration of constructed wetlands and algal ponds as in Jakkur lake, Bengaluru has helped in the removal of nutrients
(Ramachandra et al., 2018b). The concept of “wetlaculture” (integration of wetlands and agriculture) has been tried to protect
Lake Erie to achieve nutrient removal through restored wetlands and then recycling nutrients to agriculture to minimize the
use of additional fertilizers (Mitsch, 2017). Different restoration technologies tried in lakes across the world had successfully
achieved pollution abatement and re-established the pristine ecosystem (table 1).
Table 1: Different approaches of lake restoration and their efficiency
Name and location of
the Lake
Restoration method adopted
Results achieved due to
restoration
Reference
Jakkur Lake, Bengaluru,
Karnataka, India
Treated water from STP send
through integrated system of
constructed wetlands and algal
pond
Nutrient removal, increased algal
diversity
Ramachandra et
al., 2018b
Uzarzewskie Lake,
Western Poland
P precipitation from lake
water/sediments and nitrate
treatment for permanent P binding
in sediments
Suppressed internal P loading;
concentrations of P, chlorophyll-a
content and cyanobacterial biomass
reduced
Dondajewska et
al., 2018b
Swarzędzkie Lake, West
Poland
Aeration of lake water; phosphorus
inactivation using small doses of
iron sulphate and magnesium
chloride; biomanipulation with
removal of cyprinids and stocking
of pike fry
Increased secchi depth;
oxygenation improved; reduction in
nutrients; decreased phytoplankton
population; eliminated
cyanobacteria with increase in
number of chlorophytes,
chrysophytes, cryptophytes
Rosinska et al.,
2018
Varsity Lake, University
of Malaya, Kuala
Lumpur
Stoppage of wastewater flow to the
lake; soil dredging; harvesting of
algae and Najas sp. and installation
of soil retainer
Reduced pollutant concentration;
reduction in NO3- (95.6%); PO43-
(96.8%); BOD (99.8%) and TSS
(95.6%)
Mood et al.,
2017
Sankey Lake, Bengaluru,
Karnataka, India
Aeration of lake water using
fountain
Reduced cyanobacterial blooms
Ramachandra et
al., 2015b
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
17 |https://giapjournals.com/gctl © Authors
Uzarzewskie Lake,
Poland
Supply of nitrates rich water from
small tributaries to the
hypolimnion of lake
Hydrogen sulfide disappeared;
redox potential in the hypolimnion
increased; phosphorus in the
hypolimnion and internal P loading
decreased
Goldyn et al.,
2014
Durowskie Lake, Poland
Oxygenation of hypolimnetic
waters using wind aerators; iron
treatment with small doses of
coagulant and biomanipulation
Water quality improved; water
transparency and oxygen content
increased; chlorophyll-a decreased;
dominant cyanobacteria was
replaced by diatoms,
dinoflagellates and chrysophytes;
benthic macroinvertebrate taxa and
submerged macrophytes increased
Goldyn et al.,
2014
Experiment with water
from Xiangjiang River
Basin, China.
A restoration-promoting integrated
floating bed (RPIFB) was designed
to combine the processes of water
purification and macrophyte
restoration
Best purification capacity; removal
efficiencies of RPIFB for TN, TP,
NH4+-N, NO3--N, CODCr,
Chlorophyll-a and turbidity were
74.45%, 98.31%, 74.71%, 88.81%,
71.42%, 90.17% and 85%,
respectively
Guo et al., 2014
Lake Yuehu, central
Wuhan, China
Sediment dredging
Reduction in phosphorus, organic
matter, total suspended solids,
chlorophyll-a and secchi depth;
reduced internal nutrient load and a
shift in zooplankton dominance by
less eutrophic species
Zhang et al.,
2010
Lake Taihu, China
Enclosure experiment included fish
removal, stocking of piscivorous
fish, aquatic macrophyte planting,
shoreline reconstruction, benthic
macro-animal stocking and silver
carp cultivation in pens
Enhance water transparency in
spring and reduce algal bloom in
summer
Chen et al., 2009
Finjasjon Lake, Southern
Sweden
Food web manipulations through
cyprinid reduction; control of
external nutrient loading and
construction of 30 ha wetland
Nitrogen and phosphorus
reduction; increase in transparency
allowed the development of
submerged macrophytes; reduction
in phosphorus and phytoplankton
biomass.
Annadotter et al.,
1999
Restoration efforts in some lakes had only resulted in short term improvement in the water quality. For instance, water quality
of Lake Geerplas improved initially for four years after restoration. But later, increased internal loading was evident due to
an increase in bicarbonate concentration and high P:Fe ratio of the sediment (Van Duin, 1998). This emphasises the need to
decontaminate the lake completely by arresting external sources of pollution and the removal of endogenous elements, which
entails desilting, which helps in the removal of accumulated contaminants in sediments. Chemical treatment to reduce the
productivity of Lake Wolsztynskie water did not bring about permanent improvement of the water quality (Dunalska et al.,
2018). Rate and magnitude of recovery of Lake Okeechobee seems to depend on the residence time of lake and the available
P in sediments to drive internal loading (James & Pollman, 2011). Dredging can reduce internal P loading but the quantity
to be dredged out of the lake and the quality of dredged material influences lake restoration measures. Dredging the top 55
cm sediments would remove 123 g P/m2 approximately, when compared to 80 and 108 g P/m2 for 30 and 45 cm dredging,
respectively (Reddy et al., 2007). This underlines the fact that we need to choose multiple scientific restoration strategies to
achieve better wetland efficiency.
LEGAL FRAMEWORK TO PROTECT WETLANDS IN INDIA
In India, lakes/wetlands are protected by various acts and rules which includes: The Indian Fisheries Act - 1897; The Indian
Forest Act - 1927; Wildlife (Protection) Act - 1972; Water (Prevention and Control of Pollution) Act - 1974; Water
(Prevention and Control of Pollution) Cess Act - 1977; Forest (Conservation) Act - 1980; The Environment (Protection) Act
- 1986; Wildlife (Protection) Amendment Act - 1991; National Conservation Strategy and Policy Statement on Environment
and Development - 1992; The Biological Diversity Act - 2002; National Water Policy - 2002; National Environment Policy
- 2006; Environment Impact Assessment Notification - 2006; Wetlands (Conservation and Management) Rules - 2010,
Government of India; National Water Policy - 2012; Wetlands (Conservation and Management) Rules - 2017, Government
of India; Karnataka Lake / Tank Conservation and Development Authority Act, 2014.
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
18 |https://giapjournals.com/gctl © Authors
Lakes in Bengaluru are protected by Karnataka Tank Conservation and Development Authority Act - 2014. The main
functions are to protect, conserve and restore lakes to facilitate recharge of depleting ground water; to prevent and remove
encroachment of lakes; to conduct environmental impact assessment studies for lakes; environmental planning and mapping
of lakes with the help of geographical information system (GIS) and prepare database and atlas of lakes along with their
catchments; to prepare a plan for integrated development of lakes; to improve habitat quality by reducing point and non-
point sewage impacts; to promote research pertaining to lakes and conduct public awareness programs for lake conservation,
preservation and protection.
The Ministry of Environment, Forest and Climate Change (MoEFCC), India has categorized industrial sectors into Red,
Orange, Green and White based on the Pollution Index considering the levels of emissions (air pollutants), discharge of
effluents (water pollutants), generation of hazardous wastes and resource consumptions. It should be noted that none of the
industries in Red category shall be permitted in an ecologically fragile area or protected area. These rules/acts need to be
followed for the protection and conservation of lakes or wetlands.
MATERIALS AND METHODS
Study area
Bengaluru landscape with undulating terrain forms three major watersheds namely Koramangala and Challaghatta Valley,
Vrishabhavathi Valley and Hebbal Valley. Bengaluru (Greater Bangalore or Bangalore) lies between the latitude 12°39’00”
to 13°13’00” N and longitude 77°22’00” to 77°52’00” E, covering an area of 741 square kilometres and located at an altitude
of 920 meters above mean sea level. The study involves monitoring of 40 lakes of Bengaluru spread over the 3 valleys (figure
2). The exploratory field survey was done for determining the location coordinates (longitudes and latitudes) and identifying
the key issues in and around the lakes.
Sample collection and water quality analysis
Water samples for determining the physicochemical characteristics were collected from the forty lakes in the clean and sterile
polypropylene bottles during the years 2016 - 2019. Various physicochemical analysis like water temperature (WT),
dissolved oxygen (DO), pH, total dissolved solids (TDS), electrical conductivity (EC), total alkalinity (TA), chloride (Cl),
total hardness (TH), calcium (Ca), magnesium (Mg), nitrate (Nit), ortho-phosphate (OP), chemical oxygen demand (COD)
and biochemical oxygen demand (BOD) of lake water samples were analyzed using standard methods (APHA, 2005). Some
parameters like water temperature, pH, total dissolved solids (TDS), electrical conductivity (EC), dissolved oxygen (DO)
and turbidity (TB) were measured onsite while other chemical and nutrient parameters were estimated in laboratory. Each
experiment was carried out in triplicates to determine the overall water quality.
WQI estimation
Weighted arithmetic water quality index (WQI) was computed for the monitored forty lakes using ten key water quality
parameters like total dissolved solids, electrical conductivity, dissolved oxygen, pH, calcium, magnesium, total hardness,
chloride, total alkalinity and nitrate (Chaurasia et al., 2015; Sincy et al., 2016). Created distribution maps with water quality
data using QGIS software.
Data analysis
Pearson’s correlation coefficient (r) was determined using data of physicochemical parameters of lakes. In order to identify
the main factors responsible for variations in water quality, multivariate analysis like Principal Component Analysis (PCA)
was done using PAST3 software.
RESULTS AND DISCUSSION
Physicochemical characteristics of restored lakes
The variations in physicochemical characteristics of lakes during the study period are presented in figure 3. Water
temperature ranged from 23.6 to 34.2°C, which showed diurnal and seasonal variations. Water temperature affects the
physicochemical characteristics of lake water and accelerates the metabolic/biological activities of aquatic organisms. In the
present study, total dissolved solids and electrical conductivity ranged from 150.5 - 1230 mg/L and 311 - 2814 µS/cm
respectively. Less TDS in water indicates of lower pollutants and can be used for domestic purposes (Bhatia et al., 2018;
Ravikumar et al., 2013). pH is an important parameter which influences the availability and release of nutrients like ammonia,
phosphate, iron and trace metals into lake water. pH ranged from 7.08 - 9.43 in the monitored lakes. Total alkalinity ranged
from 102.6 - 595 mg/L and gives the measure of bicarbonates, carbonates, phosphates and hydroxides etc. in water samples.
Dissolved oxygen (DO) which represents the amount of oxygen present in water that supports aquatic life, varied from 0 -
16.53 mg/L. Oxygen enters water from the air and through photosynthesis by algae and aquatic plants. The increase or
decrease in DO depends on photosynthesis and decomposition activities in lakes.
Organic pollution in lakes represented by chemical oxygen demand (COD) and biochemical oxygen demand (BOD), which
ranged from 8 - 164 mg/L and 4.07 - 99.59 mg/L respectively. Total hardness, calcium and magnesium in monitored lakes
ranged from 79 - 738 mg/L, 21.11 - 224.45 mg/L and 5.03 - 49.07 mg/L respectively. Chloride ions exist in natural waters
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
19 |https://giapjournals.com/gctl © Authors
as the salts of sodium, potassium and calcium. In the monitored lakes, chloride ranged from 46.86 - 1586.14 mg/L. Polluted
lakes receiving sewage water, industrial effluents and agricultural run-off have higher amount of chloride. Basapura lake - 2
had higher values of water temperature, total dissolved solids, electrical conductivity and BOD, which indicated ionic and
organic pollution. Ambalipura Kelagina kere had higher ionic contents with chloride, total hardness and calcium. Lesser
ionic pollution was evident in Yediyur lake with lower values of chloride, total hardness, magnesium, electrical conductivity
and total dissolved solids. Handrahalli lake had lowest organic pollution compared to others evident from minimum values
of BOD and COD. Dorekere lake had high nutrient loadings of ortho-phosphate and nitrate. Domestic wastewater mainly
containing detergents, organic wastes, industrial effluents and agricultural run-off contribute to higher levels of phosphates
in surface waters (Iscen et al., 2008).
Pearson’s correlation coefficient (r) helped to identify the correlation among water quality parameters. In the current study,
strong positive correlation was found between EC - TDS (r = 0.95); COD - BOD (r = 0.98); total hardness - chloride (r =
0.81); calcium - chloride (r = 0.80); magnesium - total hardness (r = 0.90) and nitrate - orthophosphate (r = 0.73).
Figure 2: Restored lakes of Bengaluru, Karnataka, India
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
21 |https://giapjournals.com/gctl © Authors
Figure 3: Spatial variation in water quality parameters
ENVIRONMENTAL VARIABLES AFFECTING WATER QUALITY OF LAKES
Principal Component Analysis (PCA) aided in identifying the most important environmental variables that significantly
influence the water quality of lakes. PCA performed on normalized water quality data of forty lake samples described by
fourteen physical and chemical parameters (14 variables), yielded 4 PCs with eigenvalues >1. The eigenvalues were 5.75,
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
22 |https://giapjournals.com/gctl © Authors
3.08, 1.60 and 1.49 and the % variance were 41.07, 22.02, 11.41 and 10.67% for PC1, PC2, PC3 and PC4 respectively and
these components explained the variability in water quality variables (table 2). PC1 has strong positive loading on pH,
dissolved oxygen, orthophosphate and nitrate whereas negative loading on total hardness. PC1 indicates non-point sources
of pollution due to the presence of nutrient and organic pollution. PC2 influenced by chloride which indicates pollution in
lakes through domestic sources. PC3 influenced by BOD and COD, which indicate domestic as well as industrial pollution
of lakes. PC4 influenced by water temperature and TDS, showed the influence of climatic factors. Thus, PCA revealed that
the physicochemical parameters like pH, dissolved oxygen, orthophosphate, nitrate, chloride, calcium, BOD, COD, water
temperature and TDS played an important role in the present study.
Table 2: Loadings and eigenvalues of water quality parameters on significant principal components
Parameters
Abbre.
PC 1
PC 2
PC 3
PC 4
Water Temperature
WT
0.36
-0.27
0.03
0.76
TDS
TDS
0.17
-0.29
-0.47
-0.73
EC
EC
0.57
-0.59
-0.36
0.18
pH
pH
0.92
0.21
-0.06
0.30
DO
DO
0.91
0.30
-0.10
0.04
BOD
BOD
0.55
-0.50
0.59
-0.21
COD
COD
0.37
-0.63
0.63
-0.09
Alkalinity
TA
-0.61
-0.51
-0.25
0.28
Chloride
Cl
-0.08
0.76
0.50
-0.17
Total Hardness
TH
-0.74
0.48
-0.15
0.18
Calcium
Ca
-0.45
0.56
0.23
0.18
Magnesium
Mg
0.61
0.44
-0.31
-0.15
Ortho-Phosphate
OP
0.91
0.34
-0.04
0.02
Nitrate
Nit
0.91
0.34
-0.04
0.03
Eigenvalue
5.75
3.08
1.60
1.49
% variance
41.07
22.02
11.41
10.67
WQI STATUS OF RESTORED LAKES
Monitored lakes were grouped under three different WQI status like good water quality (10%); poor water quality (37%)
and very poor water quality (53%). WQI results revealed that only 4 lakes such as Jakkur, Devasandra 1, Ullal and
Handrahalli had good water quality. About 15 lakes fell under poor water quality i.e., Dasarahalli (Chokkasandra),
Kattigenahalli, Narsipura - 20, Kodigehalli, Kattigenahalli kere - 136 (Palanahalli), Narsipura - 26, Sowl kere, Dorekere,
Sankey, Yediyur, Rachenahalli, Ulsoor, Vijnanapura, Mangammanapalya kere and Yelahanka. Rest of the lakes such as
Ambalipura Melina kere, Kasavanahalli, Haraluru, Chinnappanahalli, Herohalli, Munnekolalu, Parappana Agrahara,
Garudacharpalya, J.P. Park, Sheelavanthakere, Kaikondrahalli, Seegehalli, Basapura - 2, Uttarahalli, Allalasandra, Malagala
(Ballehannu), Devarabisanahalli, Kowdenhalli (Gangadharkere), Ambalipura Kelagina kere, Deepanjali Nagara kere and
Puttenahalli lake had very poor water quality (figure 4).
Most of the restored lakes were polluted as they continue to receive pollutants in the form of untreated or partially treated
sewage from the catchment and dumping of industrial effluents. Inflow of sewage and industrial effluents resulted in
chemical pollution and microbial contamination of groundwater in Bengaluru city, causing health risks (Sheeba et al., 2017).
Rejuvenation is expected to improve the overall quality of lakes. Comparison of the status of Devarabisanahalli lake before
and after restoration activities, it was found that the water quality of Devarabisanahalli lake has not improved, evident from
the WQI of very poor water quality during the two scenarios. This shows a lacuna in the current restoration measures. This
also underlines an urgent need to maintain these restored lakes before further deterioration. Awareness programs and
implementation of environmental norms is required to arrest further deterioration (Ladu et al., 2018).
CONCLUSION
Bengaluru lakes are under stress due to the mismanagement with the uncoordinated and fragmented governance, which is
evident from the sustained inflow of untreated or partially treated sewage, untreated industrial effluents, dumping of
municipal solid waste including construction and demolition waste, encroachment of storm water drains and lake bed.
Despite the attempts to restore degraded lake to the original status has proved to be futile due to the lack of ecological
approaches in the restoration. Multivariate analyses showed that the physicochemical parameters like pH, dissolved oxygen,
orthophosphate, nitrate, chloride, calcium, BOD, COD, water temperature and TDS played an important role in determining
the water quality of these restored lakes. WQI results revealed only 4 lakes such as Jakkur, Devasandra 1, Ullal and
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
23 |https://giapjournals.com/gctl © Authors
Handrahalli has good water quality. It was noted that Devarabisanahalli lake has very poor water quality before and after
restoration activities which shows a lacuna in the current restoration measures. Proper restoration measures should be
practiced to control and prevent pollution due to indiscriminate disposal of liquid and solid wastes from domestic and
industrial sources into water bodies for improving and maintaining their quality and there is an urgent need to maintain these
restored lakes before further deterioration.
Gaps in the current rejuvenation path are (i) lack of understanding of functional aspects of a lake – ecological, hydrological
and remediation aspects in addition to recreation services; (ii) the focus of lake rejuvenation is only to utilize the allocated
funds (activities matching the allocated funds have been proposed and implemented) without any scientific evaluation of the
lake and the need assessment; (iii) not decontaminating the lake – partial removal of contaminated silt (accumulated over a
period); (iv) reuse of contaminated silt – shoreline stabilization, creation of ‘islands’. Contaminants in the silt leaches to the
lake and maintain the contaminated status of the lake; (v) not arresting fresh pollutants – sustained inflow of partially treated
or untreated sewage and industrial effluents; (vi) removal of riparian vegetation and wetlands (which would have removed
the nutrients). Riparian vegetation also aids as breeding ground for dependent biota – birds, butterflies, etc.; (vii) emphasis
of rejuvenation based on civil works than on ecological restoration; (viii) converting the lake to a ‘cement bowl’ than
restoring the ecology of the lake system; and (ix) the focus of rejuvenation is on creating jogging path and beautification of
the lake than ecological restoration.
Figure 4: WQI status of restored lakes
RECOMMENDATIONS
Restoration efforts should reduce pollution, improve the lake water quality and provide habitat, which supports maximum
aquatic biodiversity. The following measures need to be adopted to save these restored lakes (table 3):
Table 3: Rejuvenation protocol
Rejuvenation Protocol: Restore to enhance ecological integrity and not to fool public
DECONTAMINATE
• Complete removal of accumulated contaminated silt in the lake. Desiltation not only enhances storage capacity but also aid
in removing contamination. Adopt latest state of the art technology - wet dredging to remove deposited sediments;
• Scientific approaches in desilting; Remove all accumulated silt considering the original topographic contours;
• Do not reuse the silt (removed from the lake) for shoreline stabilisation or for creating ‘islands’ as the contaminants get
leached to the water, impairing the chemical integrity of an ecosystem;
• Ensure the complete removal of silt and verification of the achieved depth through scientific survey (total station survey);
• Implementation of ‘polluter pays’ principle as per the water act 1974; Zero discharge from industries;
• Stop dumping of solid waste and Construction & Demolition (C & D) wastes in the lake bed, storm water drain; Treat C &
D Waste as per C & D waste management rule 2016, GoI;
• Stop Pollution – only treated sewage shall enter the lake. Sewage treatment through integrated constructed wetlands (similar
to Jakkur Model – Secondary Treatment Plant (STP) + Constructed Wetlands + Algae ponds, will remove nutrients, etc.);
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
24 |https://giapjournals.com/gctl © Authors
• No diversion of sewage from upstream to downstream regions and
• Adopt de-centralized sewage treatment option (similar to Jakkur lake – removal of chemical ions and nutrients) and reuse
of treated sewage in the locality.
EVICT ENCROACHERS
• Remove all blockades at outlets as well as inlets– to prevent stagnation of water and enhance aeration in the water body;
• Remove all encroachments without any considerations or political interventions (lake bed, storm water drains, buffer zone);
• Remove the nexus of consultants, contractors and engineers.
REGULAR MAINTENANCE
• Minimum 5 years maintenance of the lake by an agency (who implemented rejuvenation);
• Remove macrophytes (covered on the water surface) regularly to (i) maintain the water spread area of lakes, (ii) minimise the
instances of nutrient re-release to the lake by decay of macrophytes, and (iii) to allow the photosynthesis of algae and
improving the trophic level performance.
• Install fountains (with music and LED) to enhance surface aeration and recreation value of the ecosystem;
• No introduction of exotic species of fauna (fish, etc.);
• Identify Local NGO for regular maintenance and management;
• Public Participation: Decentralised management of lakes through local lake committees involving all stakeholders - Involve
local stakeholders in the regular maintenance and management.
MONITORING AND SURVEILLANCE
• Regular surveillance through vigilant resident groups and a network of local education institutions;
• Regular monitoring of treatment plant and lake water quality (physical, chemical and biological) and the dissemination of
information to the public through internet;
• Online portal for all urban lakes (with the regular updation of information of water quality, photographic evidences, etc.)
SENSIBLE POLICY & IMPLEMENTATION
• Shun the path of rejuvenation to siphon off the public funds;
• Ban on use of phosphates in the manufacture of detergents; will minimise frothing and eutrophication of water bodies;
• Digitation of land records (especially common lands – lakes, open spaces, parks, etc.) and availability of this geo-referenced
data with query based information system to public;
• Implementation of ‘polluter pays’ principle as per water act 1974;
• Planting native species of macrophytes in the buffer zone (riparian vegetation) as well as in select open spaces of lake
catchment area;
• Restrictions on the diversion of lake for any other purposes;
• NO construction activities in the valley zones.
GOOD GOVERNANCE
• Protect flood plains (buffer zones) to enhance the water retention capability of the lake. Enrich floodplains with riparian
vegetation so that water gets treated as it passes through riparian zones;
• Maintain a minimum of 75 m buffer zone in urban lake and for larger lakes the buffer zone depends on the topography and
shape of the catchment;
• Avoid comparisons with the neighbouring regions (who are in the clutches of land mafia) and reduce the buffer zone;
• Single agency with the statutory and financial autonomy to be the custodian of natural resources [ownership, regular
maintenance and action against polluters (encroachers as well as those who contaminate through untreated sewage and
effluents, dumping of solid wastes)]. Effective judicial system for speedy disposal of conflicts related to encroachments;
• Autonomous status to the agency to ensure minimal interference by the local politicians;
• Legislators to legislate and ensure effective implementation through the executive mechanism;
• Efficient decentralised administration through elimination of Land, Water and Waste Mafia.
• Make bureaucrats and engineers of the respective para-state agencies accountable for the poor status of urban lakes.
FUTURE SCOPE OF WORK
The present work underlines the gaps in the current restoration of lakes in Bengaluru, which will be helpful for different
stakeholders and other government agencies who are involved in lake development and watershed management.
Implementation of the recommendations would help in improving the local environment conditions. Development of
environment health card for all lakes at regular interval would help in mitigating pollution of vital ecosystems.
CONFLICT OF INTEREST AND ETHICAL STANDRADS: We have no competing interests either financial or
non-financial.
RESEARCH ETHICS: The publication is based on the original research and has not been submitted elsewhere for
publication or web hosting.
ANIMAL ETHICS: The research does not involve either humans, animals or tissues
ACKNOWLEDGEMENTS
We thank (i) UNSD and the Ministry of Statistics and Programme Implementation, Government of India, (ii) The ENVIS
Division, The Ministry of Environment, Forests and Climate Change, Government of India and Indian Institute of Science
for the sustained support to ecological research.
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
25 |https://giapjournals.com/gctl © Authors
AUTHORS CONTRIBUTION
i. Ramachandra T V: Conceptualization and design of experiments; data analysis and interpretation of data, article
revision and final editing.
ii. Sincy V: Field monitoring of lakes, carrying out experiments, data analysis and result interpretation and paper
writing.
iii. Asulabha KS: Lake monitoring, water quality analysis, data analysis and interpretation and paper writing.
REFERENCES
1. Annadotter, H., Cronberg, G., Aagren, R., Lundstedt, B., Nilsson, P.A., & Strobeck, S. (1999). Multiple techniques
for lake restoration. Hydrobiologia, 395/396, 77-85. https://doi.org/10.1023/A:1017011132649
2. APHA, AWWA, WEF (2005). Standard methods for the examination of water and wastewater. 21st Edition. D.C.,
Washington: American Public Health Association.
3. Bhatia, D., Sharma, N.R., Kanwar, R., & Singh, J. (2018). Physicochemical assessment of industrial textile effluents
of Punjab (India). Applied Water Science, 8, 1-12. https://doi.org/10.1007/s13201-018-0728-4
4. Carmichael, W.W., & Boyer, G.L. (2016). Health impacts from cyanobacteria harmful algae blooms: Implications
for the North American Great Lakes. Harmful Algae, 54, 194-212. https://doi.org/10.1016/j.hal.2016.02.002
5. Chaurasia, L. G., Singh, B. S., Singh, S., Gupta, K. M., Shukla, N., & Tandon, K. P. (2015). Water quality index
and correlation study for the assessment of ground water quality of Allahabad city. Green Chemistry & Technology
Letters, 1(1), 71-76. https://doi.org/10.18510/gctl.2015.1111
6. Chen, K.N., Bao, C.H., & Zhou, W.P. (2009). Ecological restoration in eutrophic Lake Wuli: A large enclosure
experiment. Ecological engineering, 35(11), 1646-1655. https://doi.org/10.1016/j.ecoleng.2008.10.009
7. Dondajewska, R., Kozak, A., Budzyńska, A., Kowalczewska-Madura, K., & Gołdyn, R. (2018a). Nature-based
solutions for protection and restoration of degraded Bielsko Lake. Ecohydrology & Hydrobiology, 18(4), 401-
411. https://doi.org/10.1016/j.ecohyd.2018.04.001
8. Dondajewska, R., Kozak, A., Kowalczewska-Madura, K., Budzyńska, A., Gołdyn, R., Podsiadłowski, S., &
Tomkowiak, A. (2018b). The response of a shallow hypertrophic lake to innovative restoration measures -
Uzarzewskie Lake case study. Ecological engineering, 121, 72-82. https://doi.org/10.1016/j.ecoleng.2017.07.010
9. Dunalska, J.A., Napiórkowska-Krzebietke, A., Ławniczak-Malińska, A., Bogacka-Kapusta, E., & Wiśniewski, G.
(2018). Restoration of flow-through lakes - theory and practice. Ecohydrology & Hydrobiology, 18(4), 379-390.
https://doi.org/10.1016/j.ecohyd.2018.06.009
10. Gołdyn, R., Podsiadłowski, S., Dondajewska, R., & Kozak, A. (2014). The sustainable restoration of lakes - towards
the challenges of the Water Framework Directive. Ecohydrology & Hydrobiology, 14(1), 68-74.
https://doi.org/10.1016/j.ecohyd.2013.12.001
11. Guo, Y., Liu, Y., Zeng, G., Hu, X., Li, X., Huang, D., Liu, Y., & Yin, Y. (2014). A restoration-promoting integrated
floating bed and its experimental performance in eutrophication remediation. Journal of Environmental Sciences,
26(5), 1090-1098. https://doi.org/10.1016/S1001-0742(13)60500-8
12. Ho, J.C., & Michalak, A.M. (2017). Phytoplankton blooms in Lake Erie impacted by both long-term and spring
time phosphorus loading. Journal of Great Lakes Research, 43(3), 221-228.
https://doi.org/10.1016/j.jglr.2017.04.001
13. Iscen, C.F., Emiroglu, O., Ilhan, S., Arslan, N., Yilmaz, V., & Ahiska, S. (2008). Application of multivariate
statistical techniques in the assessment of surface water quality in Uluabat Lake, Turkey. Environmental Monitoring
and Assessment, 144(1-3), 269-276. https://doi.org/10.1007/s10661-007-9989-3
14. James, R.T., & Pollman, C.D. (2011). Sediment and nutrient management solutions to improve the water quality of
Lake Okeechobee. Lake and Reservoir Management, 27(1), 28-40. https://doi.org/10.1080/07438141.2010.536618
15. Juneja, T., & Chaudhary, A. (2013). Assessment of water quality and its effects on the health of residents of
Jhunjhunu district, Rajasthan: A cross sectional study. Journal of Public Health & Epidemiology, 5(4), 186-191.
https://doi.org/10.5897/JPHE12.096
16. Ladu, J.L.C., Athiba, A.L., Lako, S.T.V., & Alfred, M.L. (2018). Investigation on the impact of water pollution on
human health in Juba County, Republic of South Sudan. Journal of Environment Pollution and Human Health,
6(3), 89-95. https://doi.org/10.12691/jephh-6-3-2
17. Mitsch, W.J. (2017). Solving Lake Erie’s harmful algal blooms by restoring the Great Black Swamp in Ohio.
Ecological engineering, 108, 406-413. https://doi.org/10.1016/j.ecoleng.2017.08.040
18. Mood, N.C., Othman, F., Amin, N.F.M., & Adham, M.I. (2017). Effectiveness of Lake remediation towards water
quality: Application in Varsity lake, University of Malaya, Kuala Lumpur. Sains Malaysiana, 46(8), 1221-1229.
http://dx.doi.org/10.17576/jsm-2017-4608-07
19. Quilliam, R. S., van Niekerk, M. A., Chadwick, D. R., Cross, P., Hanley, N., Jones, D.L., Vinten, A.J., Willby, N.
& Oliver, D.M. (2015). Can macrophyte harvesting from eutrophic water close the loop on nutrient loss from
agricultural land? Journal of Environmental Management, 152, 210-217.
https://doi.org/10.1016/j.jenvman.2015.01.046
20. Ramachandra, T.V., & Mujumdar, P.P. (2009). Urban floods: Case study of Bangalore. Journal of the National
Institute of Disaster Management, 3(2), 1-98.
Green Chemistry & Technology Letters
eISSN: 2455-3611, Vol 6, No 1, 2020, pp 14-26
https://doi.org/10.18510/gctl.2020.613
26 |https://giapjournals.com/gctl © Authors
21. Ramachandra, T.V., & Shwetmala, (2012). Decentralised carbon footprint analysis for opting climate change
mitigation strategies in India. Renewable and Sustainable Energy Reviews, 16(8), 5820–5833.
https://doi.org/10.1016/j.rser.2012.05.035
22. Ramachandra, T.V., Asulabha, K.S., & Lone, A.A. (2014). Nutrient enrichment and proliferation of invasive
macrophytes in urban lakes. Journal of Biodiversity, 5(1,2), 33-44.
https://doi.org/10.1080/09766901.2014.11884749
23. Ramachandra, T.V., Aithal, B.H., & Sreejith, K. (2015a). GHG footprint of major cities in India. Renewable and
Sustainable Energy Reviews, 44, 473-495. https://doi.org/10.1016/j.rser.2014.12.036
24. Ramachandra, T.V., Asulabha, K.S., Sincy, V., Vinay, S., Bhat, S.P., & Aithal, B.H. (2015b). Sankey Lake: Waiting
for an immediate sensible action, ENVIS Technical Report 74, CES, Indian Institute of Science, Bangalore.
25. Ramachandra, T.V., & Aithal, B.H. (2016). Bengaluru's reality: Towards unlivable status with unplanned urban
trajectory. Current Science, 110(12), 2207-2208
26. Ramachandra, T.V., Sudarshan, P.B., Mahesh, M.K., & Vinay, S. (2018a). Spatial patterns of heavy metal
accumulation in sediments and macrophytes of Bellandur wetland, Bangalore. Journal of Environmental
Management, 206, 1204-1210. https://doi.org/10.1016/j.jenvman.2017.10.014
27. Ramachandra, T.V., Sincy, V., Asulabha, K.S., Mahapatra, D.M., Bhat, S.P., & Aithal, B.H. (2018b). Optimal
treatment of domestic wastewater through constructed wetlands. Journal of Biodiversity, 9(1-2), 81-102.
https://doi.org/10.31901/24566543.2018/09.1-2.077
28. Ravikumar, P., Mehmood, M.A., & Somashekar, R.K. (2013). Water quality index to determine the surface water
quality of Sankey tank and Mallathahalli lake, Bangalore urban district, Karnataka, India. Applied Water Science,
3(1), 247-261. https://doi.org/10.1007/s13201-013-0077-2
29. Reddy, K.R., Fisher, M.M., Wang, Y., White, J.R., & James, R.T. (2007). Potential effects of sediment dredging on
internal phosphorus loading in a shallow, subtropical lake. Lake and Reservoir Management, 23(1), 27-38.
https://doi.org/10.1080/07438140709353907
30. Rosinska, J., Kozak, A., Dondajewska, R., Kowalczewska-Madura, K., & Gołdyn, R. (2018). Water quality
response to sustainable restoration measures – Case study of urban Swarzędzkie Lake. Ecological Indicators, 84,
437-449. http://dx.doi.org/10.1016/j.ecolind.2017.09.009
31. Sheeba, G., Jalagam, A., & Venkatasubramanian, P. (2017). Drinking water contamination from peri-urban
Bengaluru, India. Current Science, 113(9), 1702 - 1709.
32. Sincy, V., Asulabha, K.S., Vinay, S., Vishnu, D.M., Srikanth, N., Subashchandran, M.D., & Ramachandra, T.V.
(2016). Ecological status of lotic ecosystem in kans and non-kans of central Western Ghats. Proceedings Lake 2016:
Conservation and Sustainable Management of Ecologically Sensitive Regions in Western Ghats, 195-208.
33. Srivastava, J., Gupta, A. & Chandra, H. Managing water quality with aquatic macrophytes. (2008). Reviews in
Environmental Science and Bio/Technology, 7, 255–266. https://doi.org/10.1007/s11157-008-9135-x
34. Van Duin, E.H.S., Frinking, L.J., Van Schaik, F.H., & Boers, P.C.M. (1998). First results of the restoration of Lake
Geerplas. Water Science and Technology, 37(3), 185-192. https://doi.org/10.1016/S0273-1223(98)00069-9
35. Vinçon-Leite, B., & Casenave, C. (2019). Modelling eutrophication in lake ecosystems: A review. Science of the
Total Environment, 651, 2985-3001. https://doi.org/10.1016/j.scitotenv.2018.09.320
36. Wang, W., Liu, X., Wang, Y., Guo, X., & Lu, S. (2016). Analysis of point source pollution and water environmental
quality variation trends in the Nansi Lake basin from 2002 to 2012. Environmental Science and Pollution Research,
23(5), 4886-4897. https://doi.org/10.1007/s11356-015-5625-x
37. Watson, S.B., Miller, C., Arhonditsis, G., Boyer, G.L., Carmichael, W., Charlton, M.N., Confesor, R., Depew, D.C.,
Hook, T.O., Ludsin, S.A., Matisoff, G., Mc Elmurry, S.P., Murray, M.W., Richards, P.R., Rao, Y.R., Steffen, M.M.,
& Wilhelm, S.W. (2016). The re-eutrophication of Lake Erie: Harmful algal blooms and hypoxia. Harmful Algae,
56, 44-66. https://doi.org/10.1016/j.hal.2016.04.010
38. Zhang, S., Zhou, Q., Xu, D., Lin, J., Cheng, S., & Wu, Z. (2010). Effects of sediment dredging on water quality and
zooplankton community structure in a shallow eutrophic lake. Journal of Environmental Sciences, 22(2), 218-224.
https://doi.org/10.1016/S1001-0742(09)60096-6
