Advisory on Urban Waterbody Rejuvenation

Atal Mission for Rejuvenation

and Urban Transformation 2.0
Australia India Water Security Initiative (AIWASI)

Waterbody Rejuvenation
Advisory

Issued | 15 Nov 2023

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been produced for the sole purpose
of supporting MoHUA in the
AMRUT 2.0 Mission by Arup Pty
Ltd. This document is not intended
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Document Verification

Project title Atal Mission for Rejuvenation and Urban Transformation 2.0
Australia India Water Security Initiative (AIWASI)
Document title Waterbody Rejuvenation Advisory
Job number 283059-53
Document ref DOCUMENT REF
File reference FILE REF

Revision Date Filename

Issued 15 November Description Table of Content for the Waterbody
2023 Rejuvenation Advisory

Prepared by Checked by Approved by

Name Gaurav Bhatt Sian Harrick Barry Chisholm
Signature

Issue Document Verification with Document 

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Executive Summary
As one of the fastest growing economies of the world, India will continue to witness sprawling
urban centres as well as rapid urbanisation, leading to changes in land use and potential increase
in the hard cover. Coupled with the changing climate, wherein occurrences of high intensity
rainfall events are projected to become increasingly common, many urban centres will face the
challenges emanating from frequent instances of urban flooding leading to economic and social
losses.
Waterbodies have been an integral part of rural and urban India. They provide water for domestic
use, irrigation, and livestock while serving as an important source of food. They offer social,
environmental, and ecological value through supporting local flora and fauna while providing
sustenance and aesthetic value to the local communities.
From flood management perspective, the waterbody play an important role in peak flow
attenuation and thereby reducing flood risk and moderating the downstream stormwater flow. In
urban settings, healthy urban waterbodies have the potential to provide a broad range of socio-
economic benefits such as water supply, flood protection, recreation and amenity, as well as
supporting cultural and religious values, and ecological values.
The role of waterbodies in Urban Water Cycle is acknowledged under AMRUT 2.0 Mission. The
Mission’s guidelines underscores the importance of a waterbody wherein they provide unique
advantage in terms of urban environmental and social sustainability while fostering a resilient
and thriving urban ecosystems.
The Mission prioritises waterbody management through development of comprehensive
Waterbody Rejuvenation and Management Plan to accomplish a transformative, resilient, and
sustainable water reform, while enhancing the amenity value of waterbodies
The Objective of this advisory is to help the practitioners in development of a holistic, robust,
and implementable Waterbody Rejuvenation Plan and provides a framework for preparation of a
Waterbody Rejuvenation Detailed Project Report (DPR).
This advisory acknowledges that while each waterbody is unique in terms of its geographical
location, characteristics of its contributing catchment, meteorological features, flora, fauna,
existing users and uses, it’s purpose is to provide key steps for a comprehensive assessment of
the waterbody’s condition and developing a corresponding rejuvenation plan that is suitable for
the local context.

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Report Content

Executive Summary ..................................................................................................................... v

Tables .......................................................................................................................................... x
Figures .......................................................................................................................................... x
Part A – Background to Waterbody Rejuvenation .................................................................. 1

1. Introduction .................................................................................................................... 1

1.1 Importance and role of healthy waterbodies ............................................................... 1

1.2 Need for waterbody rejuvenation ................................................................................. 3
1.3 Objective and purpose of advisory ............................................................................... 4
2. Understanding waterbody rejuvenation ...................................................................... 5

2.1 Pressures on waterbodies .............................................................................................. 5

2.1.1 Urbanisation ..................................................................................................................... 7
2.1.2 Groundwater use .............................................................................................................. 9
2.1.3 Climate change ............................................................................................................... 10
2.2 Features and processes influencing a waterbody ...................................................... 10
Part B – Plan to Practice ........................................................................................................... 13

3. Development of a waterbody rejuvenation plan ....................................................... 13

3.1 Understanding waterbody rejuvenation framework ................................................ 13

3.2 Situation assessment .................................................................................................... 14
3.2.1 Establishing watershed characteristics ........................................................................... 14
3.2.2 Establishing waterbody characteristics .......................................................................... 15
3.2.3 Meteorological characteristics ....................................................................................... 17
3.3 Waterbody rejuvenation plan interventions ............................................................. 17
3.4 Waterbody monitoring requirements ........................................................................ 27
3.5 Stakeholder engagement.............................................................................................. 28
3.5.1 Strategy for stakeholder engagement ............................................................................. 29

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3.6 Development of institutional framework ................................................................... 31
3.7 Framework for preparation of Waterbody Rejuvenation Detailed Project
Report (DPR) ................................................................................................................ 33
3.7.1 Stage 1 –Situation Assessment ...................................................................................... 33
3.7.2 Stage 2 – Development of Waterbody Rejuvenation Plan............................................. 40
3.7.3 Description of interventions ........................................................................................... 42
Part C –Interventions for waterbody rejuvenation ................................................................ 45

Appendix A – Recommended quality parameters .................................................................. 45

A.1 – Water and sediment quality testing of waterbody ............................................................. 45

A.2 – Groundwater quality .......................................................................................................... 49
Appendix B – Potential measures for waterbody rejuvenation ............................................ 51

Section A. Flow management measures .................................................................................. 51

A1 – Flow interception and diversion around waterbody ........................................................... 51
A2 – Flow diversion into waterbody ........................................................................................... 53
A3 – Flow mixing and aeration ................................................................................................... 55
A4 – Flow redirection .................................................................................................................. 57
A5 – Flow recirculation ............................................................................................................... 59
A6 – Flow (stormwater) retention in the catchment .................................................................... 61
Section B. Physical form measures........................................................................................... 64
B1 – Bathymetry and bank reshaping.......................................................................................... 64
B2 – Desilting .............................................................................................................................. 66
Section C. Aquatic and riparian vegetation management ..................................................... 68
C1 – Aquatic planting .................................................................................................................. 68
C2 – Riparian planting ................................................................................................................. 71
C3 – Aquatic weed removal and management ............................................................................ 74
Section D. Treatment measures ................................................................................................ 76
D1 – Primary treatment ............................................................................................................... 78
D2 – Secondary treatment ........................................................................................................... 83
Appendix C – Data sources ....................................................................................................... 98

C1 – Establishing watershed characteristics ................................................................................ 98

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C2 – Establishing waterbody and meteorological characteristics ............................................. 100
Credits ....................................................................................................................................... 101

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Tables
Table 1: Classification of identified measures for waterbody rejuvenation 18
Table 2: List of measures that may be implemented to address common problems in waterbodies 19
Table 3: Flow monitoring sampling 28
Table 4: Sample type and sampling locations for water quality assessment in a waterbody 28
Table 5: Compilation of key waterbody details 34
Table 6: Collation of meteorology and watershed features 35
Table 7: Establishing waterbody characteristics 37
Table 8: Development of waterbody rejuvenation plan 40
Table 9: Sampling points for water quality monitoring 45
Table 10: Recommended list of parameters and sampling frequency for water quality monitoring 46
Table 11: Recommended list of parameters and sampling frequency for sediment quality monitoring 48
Table 12: Establishment of groundwater chemistry 49

Figures
Figure 1: Example waterbodies: Amenity at Man Sagar Lake (top figure, Source: https://siliconeer.com),
waterbody for religious rituals (bottom left figure, Source: Hindustan Times), and provision of
aquatic food (bottom right figure): 2
Figure 2: Decline in health of waterbodies 4
Figure 3: Key elements for development of a waterbody rejuvenation plan 5
Figure 4: Example of an urban waterbody and its catchment 6
Figure 5: Example of processes in the catchment and within the waterbody (Source: Waterbody Management
Guideline (2013), Water by Design 7
Figure 6: Used water pipelines laid within the stormwater drain and prevalent solid waste dumping in drains8
Figure 7: Impact of change in land cover on urban hydrology 9
Figure 8: Modes of interaction between waterbodies and groundwater 10
Figure 9: Waterbody Rejuvenation Framework cycle. 13
Figure 10: Common measures used to improve health of a waterbody and their locations of application 19
Figure 11: Rejuvenation opportunities and choices 25
Figure 12. Interception and diversion schematic 51
Figure 13. Interception & Diversion structure at Mahadevapura Lake, Bangalore (Source: CDD India) 52
Figure 14. Schematic of flow diversion into waterbody 53
Figure 15. Mixing and aeration 55
Figure 16. Schematic of flow redirection in a waterbody using flow bunds or bafflers 57
Figure 17. Schematic of flow recirculation in a waterbody 59
Figure 18: Rainwater and stormwater harvesting 61
Figure 19: Porous pavement 62
Figure 20: Infiltration system 62
Figure 21. Example of bathymetry and bank reshaping 65
Figure 22. Desilting of Sembakkam Lake, Chennai (Source: The Nature Conservancy) 66

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Figure 23. Different categories of aquatic planting (Source: ksuweb.kennesaw.edu/) 69
Figure 24. Establishment of aquatic emergent vegetation around the perimeter of waterbody (Source:
Coimbatore Lake restoration) 69
Figure 25: Role of riparian vegetation (Source: Adapted by Jean Miller, DNR) 71
Figure 26. Zoning to guide riparian planting based on soil moisture and inundation pattern. 73
Figure 27. Mechanical removal of aquatic weeds in Rankala lake (Source: GHONE, A. S., & SINGAL, S. K.
Performance Evaluation of Deweeding Operations Implemented for Conservation of Rankala
Lake, India.) 75
Figure 28. Constructed wetland installed at Rajokri lake, Delhi (Source: Srivastava and Prathna, 2021) 76
Figure 29. Schematic of a treatment train (Source: Srivastava and Prathna, 2021) 77
Figure 30. Illustration of a settling tank (Tilley et al., 2014) 78
Figure 31. Illustration of a sedimentation pond (Tilley et al., 2014) 80
Figure 32. Illustration of an Anaerobic baffled reactor (Tilley et al., 2014) 82
Figure 33. Treatment processes in a constructed wetland (Payne et al, 2015) 84
Figure 34. Illustration of a surface flow constructed wetland (Tilley et al., 2014). 85
Figure 35. Illustration of a sub-surface horizontal flow constructed wetland (Tilley et al., 2014) 86
Figure 36. Schematic of a decentralised used water treatment system installed at Arvind Eye Hospital,
Pondicherry (Source: CDD Society) 86
Figure 37. Schematic of a floating treatment wetland (Source: Department of Environment and Science,
Queensland Government, Australia). 89
Figure 38. Application of floating macrophyte bed at Neknampur Lake, Hyderabad (Source: The Hindu). 89
Figure 39. Schematic of a horizontal flow filter installed in a drain (Source: Satyendra et al., 2023). 92
Figure 40. Application of horizontal flow filter in canal leading to Udai Sagar Lake in Udaipur (Source:
Vikalpsangam) 92
Figure 41. Installation of floating wetlands cells in a drain (Source: NEERI) 93
Figure 42. Schematic of a vertical flow filter (Source: NEERI Satyendra et al., 2023) 93
Figure 43. Application and schematic of a biofiltration system 94
Figure 44. Application of biofiltration technology – Street scale raingarden (left), street scale linear swale
(middle) and end-of-pipe biofiltration basin (Source:Spiire) 95
Figure 45. Pre-treatment measures for biofiltration system and other stormwater treatment assets – Sediment
ponds (left) and swales (right) 96

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Part A – Background to Waterbody Rejuvenation

1. Introduction
As India continues to be one of the fastest growing economies of the world, we are witnessing
sprawling urban centres as well as expansion of our cities going through rapid urbanisation,
creating more hard cover through changes in the land use and land cover. Coupled with the
changing climate, wherein occurrences of high intensity rainfall events are becoming increasingly
common, many urban centres are now grappling with the frequent instances of urban flooding
leading to high economic and social losses.
Waterbodies play an important role in supporting and sustaining the local water cycle. They
provide societal and environmental sustenance to unique flora and fauna as well as livelihood and
aesthetic value to the local communities. One of their critical functions is to provide attenuation
within the catchment, allowing for a reduction in flood risk and improving flood response, by
storing the runoff, and moderating the downstream stormwater flow.
The AMRUT 2.0 operational guidelines acknowledge the importance of functioning waterbodies
and their contribution towards urban water cycle management. As cities strive to balance their
developmental needs with environmental and social sustainability, waterbody management
emerges as a key component of AMRUT 2.0’s endeavour to foster resilient and thriving urban
ecosystems and creating Water Sensitive Cities. Hence the mission prioritises waterbody
management through development of comprehensive waterbody rejuvenation and management
plan to accomplish a transformative, resilient, and sustainable water reform.

1.1 Importance and role of healthy waterbodies

Waterbodies are an integral part of the urban landscape and provide important environmental,
economic, and social benefits that are valued and used by the communities surrounding them.
Some example waterbodies are shown in Figure 1.

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 Figure 1: Example waterbodies: Amenity at Man Sagar Lake (top figure, Source:
https://siliconeer.com), waterbody for religious rituals (bottom left figure, Source: Hindustan
Times), and provision of aquatic food (bottom right figure):

Waterbodies have always held important environmental, social, livelihood, economic and
cultural significance in India. They provide a source of water for domestic use, irrigation, and
livestock as well as important sources of food. In the urban context, healthy urban waterbodies
have the potential to provide a broad range of socio-economic benefits such as water supply,
flood protection, recreation and amenity, as well as supporting cultural and religious values, and
ecological values.
Healthy urban waterbodies have the potential to provide a range of “values and uses” including:

• Water supply • Recreation and amenity

• Groundwater recharge • Culture

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 • Flood protection • Tourism
• Aquatic food • Ecological values (birds, fish, vegetation)
• Livelihood • Religious values

1.2 Need for waterbody rejuvenation

However, this potential is severely compromised when the health of waterbodies is poor, some
examples are shown in Figure 2.

Dry Sowl kere during the Summer, Bengaluru Landfill site at Deepor Beel, Assam, Guwahati
(Source: www.bengaluru.citizenmatters.in) (Source:
www.lakesofindia.com/author/lucygibson98/)

Fire due to illegal dumping of waste mixed with Houses encroaching the dried up Mudichur lake,
untreated sewage at Bellandur lake, Bengaluru Chennai (Source: The Indian Express, 2017)
(Source: www.thelogicalindian.com/)

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 Nagapattinam lake filled with silt, Tamil Nadu Hussainsagar lake with poor water quality,
(Source: www.thelogicalindian.com) Hyderabad (Source: IANS)
Figure 2: Decline in health of waterbodies
External pressures, such as those from land uses in the catchment of waterbodies, and direct
pressures, such as encroachment and development within the waterbodies, have impacted the
health of waterbodies and their values and uses that the community have come to rely on.
Waterbody rejuvenation seeks not only to reduce negative impacts on waterbodies, but to
protect and nurture them so that their social, environmental and amenity value enhances into the
future.

1.3 Objective and purpose of advisory

The objective of this advisory is to provide users with guidance for developing a holistic, robust,
and implementable Waterbody Rejuvenation Plan. While each waterbody is unique in terms of
its geographical location, characteristics of its contributing catchment, meteorological features,
flora, fauna, existing users and uses, the purpose of this advisory is to provide key steps for a
comprehensive assessment of the waterbody’s condition and developing a corresponding
rejuvenation plan that is suitable for the local context.
This advisory focuses on inland surface standing water systems (i.e., low flow or no flow) that
are either ephemeral or permanent in nature, including lakes, ponds, cut-off meanders,
wetlands, waterlogged areas, reservoirs or barrages, and ponded sections of rivers or channels.
The advisory covers the key elements for development of a waterbody rejuvenation plan, as
shown in Figure 3.

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 Role and importance Factors impacting Principles of
of a healthy the health of waterbody
waterbody waterbody rejuvenation

Stakeholder
Key steps in
Development of engagement & public
development
O&M plan outreach
rejuvenation plan
requirements

Regulatory and
Development of
Institutional
Detailed Project
arrangement
Report
requirements

Figure 3: Key elements for development of a waterbody rejuvenation plan

2. Understanding waterbody rejuvenation

Waterbody rejuvenation is a set of actions to improve the health of a waterbody by managing
pressures on the waterbody and improving its damaged or compromised elements so that it can
better support its values and uses.
The following section presents key processes and factors that impact the health of waterbodies
and understanding their interaction in developing a waterbody rejuvenation plan.

2.1 Pressures on waterbodies

Pressures on the waterbodies can include natural factors as well as human activities occurring
within the waterbody or its catchment, impacting the waterbody’s health. As such, a waterbody
ecosystem extends beyond the waterbody’s footprint into its catchment, which is the land
contributing runoff to the waterbody (Figure 4).

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Figure 4: Example of an urban waterbody and its catchment
Pressures affecting waterbodies may be located a long way from the waterbody itself (e.g.,
polluting activities occurring upstream of the waterbody in its catchment), and therefore it is
critical to adopt a whole-of-catchment perspective when rejuvenating waterbodies to ensure
pressures are appropriately managed. Figure 5 shows illustratively some of the pressures that
may existing within the waterbody catchment that could impact waterbodies.

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Figure 5: Example of processes in the catchment and within the waterbody (Source: Waterbody
Management Guideline (2013), Water by Design
It is necessary to understand the full range of pressures impacting the waterbody and how they
should be managed. Key phenomena contributing to the pressure on waterbody, are described in
the following subsections.

2.1.1 Urbanisation
Urbanisation is one of the critical growth engines for the economy. Offering ample job
opportunities, education, and medical facilities, urban centres and cities continue to act as a
magnet to which people migrate from different parts of the country and the world.
However, with increased demand for land to accommodate additional businesses and
population, often urbanisation entails modification of land use and land cover to create new
infrastructure, thereby altering the physical and hydrological characteristics of catchment of
urban waterbodies. Often, the growth of the urban population exceeds the pace of water utilities
and drainage infrastructure development in the region. Waterbodies and their contributing
drainage network often bear the brunt of such development.
Catchment flooding, inadvertent discharges of untreated used water from areas that are not
connected to sewerage, illegal dumping of waste in or around the waterbodies and drains, and
change in quantity and quality of diffuse stormwater runoff generated in the waterbody
catchment causes severe deterioration of the health of the waterbody. In many cities, the used
water treatment plants are located in the vicinity of a waterbody, discharging treated water into
them. If such treatment plants are not performing well or are under maintenance, untreated or
undertreated water may be discharged into the downstream waterbodies, further deteriorating
the water quality.

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In some cities, there have been instances of laying used water pipelines within stormwater
drains to take advantage of the drain’s gradient, increasing the risk of leakage of sewage into
waterbody catchments. Often, the stormwater drains in cities are exploited as an illegal site for
dumping garbage and solid waste. Some examples are shown below in Figure 6.

Figure 6: Used water pipelines laid within the stormwater drain and prevalent solid waste
dumping in drains

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Figure 7 below, shows the contrast between a forested and an urbanised catchment, and the
impacts on water hydrology and runoff.

Figure 7: Impact of change in land cover on urban hydrology

When the degree of disturbance becomes significant within a waterbody’s catchment, this can
impact on the health of the waterbody through:
• higher pollutant load into the waterbody (litter, sediment, nutrients, heavy metals, oils, etc)
• higher frequency and larger flows into the waterbody, leading to erosion and scouring of
banks and bed and changes in the hydrologic regime of the waterbody
• reduced baseflow into the waterbody.
Therefore, while conventional approaches to stormwater management may focus primarily on
drainage and flood protection, to achieve waterbody rejuvenation, diffuse pollution and
hydrologic disturbances in waterbodies must also be considered.

2.1.2 Groundwater use

Urbanisation and the associated increase in impervious surfaces also impact local groundwater
recharge. The interaction between waterbodies and groundwater plays an important part in lake
sustainability and waterbody rejuvenation, both from the perspective of water quality and
quantity. The three main modes of interaction between waterbodies and groundwater are shown
below in Figure 8

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Figure 8: Modes of interaction between waterbodies and groundwater
With an increase in contaminants entering the waterbody, shallower water tables are typically
more susceptible to pollution, due to the reduced time and capacity for attenuation of
contaminants between the surface and the groundwater table.
Therefore, when formulating a waterbody rejuvenation strategy, it is important to understand
the status of groundwater and its extraction as well as the hydrogeology in the catchment area,
as these can have a large influence on the hydrologic regime and water quality in the
waterbody.

2.1.3 Climate change

The changing climate is having an impact on the intensity, location, duration and frequency of
extreme rainfall events and drought. In an urbanised system, the impacts of these hydrological
extremes are evident, with flooding having severe repercussions for urban infrastructure
(stormwater drains, used water systems), life and properties (particularly buildings in low lying
areas, basements, and urban slum settlements).
For waterbody rejuvenation, it is important that the long-term historic variation in
meteorological characteristics, particularly rainfall and evaporation, are well understood. This
data can be used to determine the seasonal trends of rainfall and evaporation, especially during
monsoon and summertime, including recorded extreme rainfall events, and recorded flood
extent impacting the waterbody/catchment area. Online resources are available for download to
support assessments of projected rainfall data in the face of climate change, including gridded
data from https://climateknowledgeportal.worldbank.org/download-data.
Based on comprehensive analyses of long-term meteorological data along with the catchment
physical characteristics such as land use and land cover, hydrology, contributing drainage
infrastructure to the waterbody, variation of groundwater in the catchment area, an informed
waterbody rejuvenation plan should be developed.

2.2 Features and processes influencing a waterbody

The health of a waterbody is based on the condition of the following factors.
• Catchment and waterbody processes which explain the major inputs into the waterbody
(in terms of water, nutrients, sediments, carbon, and other chemicals as a result of

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 interaction between the hydrological cycle, geology, vegetation, and land use practices in the
catchment) and key processes within the waterbody itself.
• Hydrologic regime and hydraulics. The hydrologic regime refers to the magnitude, timing,
frequency and duration of inundation in the waterbody. It is the product of catchment runoff,
groundwater connection and other water sources. Hydraulics refers to water movement into,
within, and out of the waterbody.
• Water quality which is primarily determined by inputs from the catchment (natural factors
and human activities), as well as processes within the waterbody, such as mixing,
circulation, and interaction with sediments.
• Physical form which refers to the shape of the waterbody, profile of its banks and profile of
its base (bathymetry). Physical form is influenced by natural factors (e.g., geology and
topography) and human activities within the waterbody and its catchment.
• Aquatic and riparian ecosystems which refers to the flora and fauna conditions within the
waterbody and its buffer zone (plants, animals and microbial life), and usually depend on
and develop in response to the hydrologic regime, water quality and physical form of the
waterbody.
• Stakeholder and community engagement. Communities are often the guardians of
waterbodies. An educated, aware and active community can positively impact the health of
a waterbody through care, advocacy and monitoring.
Waterbody health responds to pressures that act on the waterbody either directly or within the
catchment of the waterbody. Therefore, it is important to have a thorough understanding of
these features and processes and their interaction.
The following section Part B – Plan to Practise presents the key tasks and activities to be
undertaken as part of developing Waterbody Rejuvenation Plan.

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Part B – Plan to Practice

3. Development of a waterbody rejuvenation plan

The following section presents key steps involved in the development of a waterbody
rejuvenation plan. While the below general principles apply, it is important to note that
waterbody characterisation and rejuvenation requirements are dependent upon various region-
specific features such as climatic zone, meteorology, land use and land cover, hydrology,
hydrogeology, etc., and would require contextualisation of approach based on the local
conditions.

3.1 Understanding waterbody rejuvenation framework

There are two fundamental steps involved in formulating a waterbody rejuvenation project: a
situation assessment of the waterbody (Stage 1); followed by development of a waterbody
rejuvenation plan (Stage 2) as shown in Figure 9. A Detailed Project Report (DPR) for
waterbody rejuvenation should cover these two stages.

Figure 9: Waterbody Rejuvenation Framework cycle.

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Situation assessment and Strategy development are the two fundamental steps for formulating a
waterbody rejuvenation project. This section of the advisory outlines what needs to be
considered in both Stage I and 2 including a list of fundamental aspects to consider. An
indicative framework is also provided to ensure critical elements in Stage 1 and 2 are
considered by proponents who are developing a waterbody rejuvenation DPR.
Implementation refers to the execution of the proposed actions, while monitoring & evaluation
is about determining the extent to which the waterbody rejuvenation goals and objectives have
been met over time. These two aspects are not covered in this advisory.

3.2 Situation assessment

One of the critical requirements in developing a Waterbody Rejuvenation Plan is to undertake a
comprehensive situation assessment of the waterbody and its contributing catchment.
This includes undertaking the following key activities:
• Identification of the key drivers and objectives for the Waterbody Rejuvenation Plan based
on the values and uses in Section 1.2 of this document.
• Collecting the waterbody and catchment’s physical feature information through
reconnaissance survey and available secondary data to identify any major technical, social,
and environmental issues related to the waterbody’s current condition.
• Identification of any ongoing waterbody restoration works, and infrastructure works (e.g.,
for water, used water or drainage) that have a bearing on the waterbody.
• Identification of data gaps and developing strategy for primary data collection required
(explained in subsequent section) for a holistic analysis.
• Identification of key stakeholders including residents and collecting their inputs regarding
waterbody restoration.

3.2.1 Establishing watershed characteristics

To establish the waterbody’s contributing watershed characteristics, the following data should
be collected for analysis.
Land use and land cover (LU & LC): LU and LC have a significant bearing on the quality
and quantity of runoff generated within the catchment. Increase in imperviousness leads to
reduced time of concentration 1, quantity of flow as well as the quality of runoff. Typical urban
land uses comprise commercial, industrial, residential (high, medium low density), institutional,
agricultural, forest, open urban land etc. The land use will also provide guidance on the kind of
point and non-point pollution sources that are likely to be present in the runoff. Based on LU

1
Time of concentration (Tc) is the time required for runoff to travel from the hydraulically most distant point in the
watershed to the outlet.

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LC Maps, the % imperviousness can be calculated to determine the quantity of runoff that will
be generated in the catchment. Online resources available for assessment of Land Use and Land
Cover are provided in Appendix C C1 – Establishing watershed characteristics.
Hydrogeology: The interaction between waterbody and groundwater is controlled by soil type,
degree of rock weathering and fracture pattern, and rainfall. Soil type in the catchment area of
the waterbody determines the opportunity for infiltration to the groundwater as well as
interconnection between the waterbody and shallow groundwater. Based on hydrogeology of
waterbody’s catchment, opportunities for artificial recharge can be developed. In an urban
catchment, available open land such as parks, open fields, etc., provide an opportunity for
groundwater recharge. and should therefore be designed with appropriate levels and edge
treatments to allow for surface runoff from the surrounding areas to reach and be collected.
While developing the opportunities for artificial recharge at the catchment level, the most
favourable formation for artificial recharge would be terrace gravels or sandy alluvium
associated with river valleys and/or palaeo-channels. Based on existing soil characteristics and
its infiltration potential, strategic interventions such as infiltration basins and galleries, bio
swales, infiltration trenches, porous pavements, etc., can be placed to enhance groundwater
recharge within the waterbody’s catchment. Online resources available for assessment of soil
type, land use and land cover are provided in Appendix C C1 – Establishing watershed
characteristics.
Catchment topography and drainage information: Information on the catchment topography
provides forms and features of a waterbody’s catchment area. This can be used to develop a
bare earth surface model, indicating relevant features such as general land elevation and
catchment slope, as well as hydrological characteristics, such as sub-catchment features and
connectivity among waterbodies within the catchment, identification of flood prone areas, and
pattern of surface runoff.
Topographical data should be supplemented by drainage information: this can be obtained
through a stormwater drainage survey providing cross-sectional and longitudinal section, as
well as water control structures, particularly for any primary stormwater drains that lead directly
to the waterbody, and any that connect different waterbodies within the catchment. These data
are critical for developing the waterbody rejuvenation plan as they will influence the
conveyance of flow, point source pollution, possible flood risk and development of remedial
measures. Sources of topographical and drainage information are provided in Appendix C C1 –
Establishing watershed characteristics.

3.2.2 Establishing waterbody characteristics

For developing the Waterbody Rejuvenation Plan, it is important to understand its physical
features as well as its physico-chemical characteristics of the waterbody, and the following data
are recommended for collection and analysis.

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Waterbody bathymetry: Bathymetric survey is used to assess the current water carrying
capacity of the waterbody, and assessment of the volume for desilting required to bring
waterbody to its natural condition, including need for further deepening to augment storage.
Bathymetry data is critical for developing the Waterbody Rejuvenation Plan, and the grid size
for survey points can be selected based on the size of waterbody. the grid size for survey points
can be selected based on the size of waterbody. A minimum grid size of 10 m × 10 m is
recommended for waterbody bathymetry surveys. Sources of topographical and drainage
information are provided in Appendix C C2 – Establishing waterbody and meteorological
characteristics.
Waterbody inlet, outlet, and bypass structure: The total volume of water that can be held in
each waterbody is a function of its storage curve (water stored versus waterbody depth), its inlet
and outlet structure elevation, and the capacity of the downstream drainage system’s
conveyance capacity. Therefore, while developing the waterbody rejuvenation plan, waterbody
inlet and outlet surveys should be done to capture the type of structures, their invert elevation,
existing flow control measures, and the waterbody boundary survey to ascertain the High Flood
Level.
The bypass structures ensure that, where the waterbody receives any dry weather flow in the
form of untreated used water discharges or excess flow during high rainfall events, the
waterbody can be safely bypassed such that these flows do not enter it. If the waterbody
receives treated used water discharges as dry weather flow, it is critical that the long-term
quality of such water is determined, and in the event of any maintenance work in the treatment
plant, there are arrangements to ensure that any untreated water does not enter the waterbody.
Water and sediment quality of waterbody: The water quality data, i.e., physico-chemical and
biological parameters, are indicative of natural or anthropogenic activities in the waterbody’s
catchment area. Any long-term pollution adversely impacts sediment quality, aquatic flora, and
fauna along with associated food webs. Sediment is an integral and inseparable component of
aquatic environment and plays an key role in the dynamics and balance of ecosystems.
Therefore, collection of water and sediment quality data is critical for developing a Waterbody
Rejuvenation Plan. The recommended parameters for water and sediment quality are provided
in Appendix A – Recommended quality parameters.
Current users/uses and existing Operations & Maintenance (O&M) practices: As part of
any rejuvenation plan, it is important to identify the current and post-restoration users and uses
of the waterbody, existing operation and maintenance practice for waterbody management.
Following any waterbody rejuvenation project, it is recommended that the following be
developed and implemented:
• Stakeholder and public outreach program
• O&M plan
• waterbody monitoring plan (presented in the subsequent section)

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3.2.3 Meteorological characteristics
Meteorological characteristics assessment and analysis, including consideration of climatic
conditions, rainfall, and evaporation data, are critical for developing the waterbody rejuvenation
plan. Assessment of these parameters will provide the temporal and spatial trend of rainfall and
evaporation patterns over the long term. Identification of occurrences of extreme climatic
events, such as high-intensity rainfall or drought events, as well as potential future impacts of
climate change on these, will also help inform the remedial measures necessary to sustainably
maintain the health of the waterbody and the ecosystem that is dependent on it. Moreover, these
parameters to develop waterbody’s water balance. To account for spatial variability, it is
recommended that rainfall data be collected from multiple rain gauges. The meteorological data
time frame should ideally be collected for longest available time to account for variability trend
analyses as well as calculation of potential runoff generation. Recommended time interval
resolutions for rainfall and evaporation data are, respectively, hourly, and daily.

3.3 Waterbody rejuvenation plan interventions

This section presents the key interventions that can be used in developing a Waterbody
Rejuvenation Plan. Sections A-D below provide details of each intervention in terms of its
application (purpose and functionality), design and planning considerations, and operations and
maintenance considerations. The interventions have been grouped into these four sections based
on their main function:
• Section A – Flow management measures which are measures that influence the volume and
frequency of water moving into and out of a waterbody, including how long water resides in
the waterbody (duration), and how water moves within the waterbody (hydraulics)
• Section B – Physical form measures which refer to measures to restore or modify the profile
of the waterbody’s base and banks to improve flow movement in the waterbody (hydraulics)
and to achieve the desired water depths to support aquatic and riparian vegetation and other
“values and uses” (such as water storage to meet water supply requirements).
• Section C – Aquatic and riparian vegetation management which includes measures to
improve coverage and diversity of desirable aquatic and riparian vegetation within and
around the waterbody, to ensure healthy flora and fauna (an essential element of a healthy
waterbody).
• Section D – Treatment measures which refer to measures that manage inputs (pollutants)
generated in the catchment to improve water quality entering the waterbody. Water quality
in a waterbody is influenced both by processes within the waterbody and inputs from the
catchment. Hence, in addition to treatment measures, actions that address issues with water
regime, hydraulics, aquatic and riparian vegetation, and physical form of the waterbody
should also be considered to improve water quality in the waterbody.
The following presents the classification of identified measures within each of the above four
types of intervention that may be used as part of a waterbody rejuvenation plan.

17
Table 1: Classification of identified measures for waterbody rejuvenation

Flow management Physical form Aquatic and Treatment

measures measures riparian vegetation measures
management

A1 – Flow B1 – Bathymetry and C1 – Aquatic D1 – Primary

intersection and bank reshaping planting Treatment
diversion around B2 – Desilting C2 – Riparian D1.1 – Settling tank
waterbody planting D1.2 – Sedimentation
A2 – Flow diversion C3 – Aquatic weed pond
into waterbody removal and D1.3 – Anaerobic
A3 – Flow mixing management baffled reactor
and aeration
D2.1 – Constructed
A4 – Flow wetland
redirection
D2.2 – Floating
A5 – Flow wetlands
recirculation
D2.3 – In-situ drain
A6 – Flow treatment
(stormwater)
retention in the D2.4 – Biofiltration
catchment system

18
Figure 10: Common measures used to improve health of a waterbody and their locations of
application
The below presents the measures that may be implemented to address typical problems in
waterbodies (Refer to sections A-D below for details on each measure).
Table 2: List of measures that may be implemented to address common problems in
waterbodies

Typical problems in waterbodies Potential measures

Poor water regime and hydraulics

Uncontrolled inflow; Frequent • A1 – Flow interception and diversion
flooding
• A6 – Flow (stormwater) retention in catchment
Reduction in stored volume; • A2 – Flow diversion into waterbody and outlet
Reduced inflow to waterbody management

Poor flushing of waterbody and • A2 – Flow diversion into waterbody and outlet
formation of eutrophic zones management
• A4 – Flow redirection
• A5 – Flow recirculation

19
Typical problems in waterbodies Potential measures

• B1 – Bathymetry and bank reshaping

Other potential measures:
• Redesign stagnant zones as wetlands
• Retrofit inlet and outlets to maximise flushing
Low dispersion of incoming flow • A4 – Flow redirection
in the waterbody (Short-circuiting)
• B1 – Bathymetry and bank reshaping
Other potential measures:
• Move inlets/outlets or remove clump vegetation
to promote longer flow paths
Physical alteration
Accumulation of coarse sediments, • B2 – Desilting
organic matter and litter in
• D1 – Primary treatment
waterbody bed

Erosion of banks • B1 – Bathymetry and bank reshaping

• C1 – Aquatic planting
• C2 – Riparian planting
Other potential measures:
• Reinforce areas prone to erosion with rock
protection
• Rock lining channels that direct high
uncontrolled flows down the banks of the
waterbody
Growth of invasive flora and fauna/loss of ecological values

Loss of desired aquatic and • C1 – Aquatic planting

riparian vegetation
• C2 – Riparian planting
Aquatic weed/flora infestation • C3 – Aquatic weed removal

Invasive fauna • Trapping and removal of pest species

• Regular dewatering of waterbodies to manage
exotic fish

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Typical problems in waterbodies Potential measures

• Improve habitat and water quality for native

species
• Implement a native fish stocking program
• Improving fish passage among waterbodies
Loss of water quality

High concentration of nutrients • A3 – Mixing and aeration (particularly if

(nitrogen and phosphorus) phosphorus is released from bed sediments due
to low dissolved oxygen)
• A5 – Flow recirculation (through wetlands)
• B2 – Desilting
• C1 – Aquatic planting
• C2 – Riparian planting
• D1 – Primary treatment
• D2.1 – Constructed wetland
• D2.2 – Floating wetland
• D2.3 – In-situ drain treatment
• D2.4 – Biofiltration system
Other potential measures:
• Diversion of dry weather flow, particularly
untreated used water
High turbidity levels • B2 – Sediment removal
• C1 – Aquatic planting
• C2 – Riparian planting
• D1 – Primary treatment
Depending on levels of suspended solids and
dissolved solids in incoming flows, other potential
measures:
• D1-D2
• Repair bank erosion

21
Typical problems in waterbodies Potential measures

• Remove exotic fish that promote sediment

resuspension
Pathogens Measures that can reduce pathogens to some
extent:
• D2.1 – Constructed wetland
• D2.3 – Floating wetland
• D2.3 – In-situ drain treatment
• D2.4 – Biofiltration system
Other potential measures:
• Diversion of dry weather flow, particularly
untreated used water
• Remove or cull waterfowl
Algal bloom • Refer to actions for addressing high nutrients
and high turbidity.
• A2 – Flow diversion into waterbody (to flush
algae) and outlet management
Stratification and low dissolved • A3 – Flow mixing and aeration
oxygen
• A4 – Flow redirection
• A5 – Flow recirculation
• B1 – Bathymetry and bank reshaping (fill zones
with poor water movement)
• C1 – Aquatic planting
• C2 – Riparian planting (provision of shade to
reduce surface water temperature and risk of
stratification)
• D2.2 – Floating wetlands (reduce surface water
temperature and risk of stratification)
Contamination by toxic chemicals • Monitoring of water quality in the drains
contributing to waterbody to thwart illegal
dumping
• Bypass arrangements

22
 Typical problems in waterbodies Potential measures

• Clean-up activities from spills

The details of measures identified in the Table 2 above are provide under Appendix B.
Potential measures for waterbody rejuvenation.
For easy referencing and understanding of the reader, the Rejuvenation opportunities and
choices are presented in Figure 11.

23
THIS PAGE IS INTENTIONALLY BLANK

24
Figure 11: Rejuvenation opportunities and choices

25
THIS PAGE IS INTENTIONALLY BLANK

26
3.4 Waterbody monitoring requirements
The effectiveness of waterbody rejuvenation interventions is predicated on the improvement in
the availability of hydrometric and water quality data.
Waterbody monitoring is important as it underpins efficient O&M and long-term sustainability.
Some of the key advantages of waterbody monitoring plan are:
• Better quantification of the relationship between rainfall and runoff, which will help to
minimise the risk of damage and disruption due to issues pertaining to flooding
• Effective real time operation of treatment and storage elements by allowing gates to be
opened and closed according to prevailing levels and flow conditions
• Effective and reliable determination of quality of influent to better manage loadings and
treatment to avoid significant contamination.
Flow monitoring: Flow meters installed within stormwater drains help to estimate the amount
of runoff generated in the catchment. This is used to design the drain capacity. Data collected
from flow monitors installed at the entrance or exit of the waterbody can be used to predict
trends in the amount of runoff reaching and exiting the waterbody.
Flow monitoring methods available are:
• Control structure
• Acoustic Doppler measurement (side-looking or vertical)
• Time of travel ultrasonics
• Spot flow measurement using channel survey and handheld velocity measurements with a
velocimeter
• The preferred and recommended location of monitoring stations could be:
Flow monitoring sites of individual waterbody: These would help to determine the flow rates
into the waterbody. As such, the location of these sites would be best near to (but not next to, so
as not to be influenced hydraulically) the inlet.
Flow monitoring sites on drains: These would ideally be located in a free flowing stretch of a
drain that is clean, straight, with no bends, blockages, constrictions or changes in shape within
100m.. This would determine the true rainfall-runoff relationship for similar catchments.
Flow monitoring sites at Used Water Treatment Plant (UWTP): This approach is used if the
waterbody is downstream of UWTP and receives treated effluent from the plant. This would
help to warn site operators of potential floods and mitigate flood risk through bypassing the
waterbody.
Flow measurement and corresponding frequency as presented in Table 3 below, is
recommended to be included as part of waterbody monitoring plan:

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Table 3: Flow monitoring sampling

Data Frequency Methods of

communication

Flow • High data resolution: hourly • Automatic-digital, data

stored on site for
• Moderate data resolution: twice
manual collection; and
daily. Facility should be available to
measure hourly flow in case of • Automatic digital, data
rainfall event. transmitted by phone
network to offsite
database.
• Manual reading

Water quality: Water quality monitoring is critical to assess the efficacy and proper
functioning of any waterbody rejuvenation plan. Apart from understanding the pollution from
the watershed, water quality monitoring helps determine the level of treatment achieved at each
level of depth of the waterbody (in cases where natural treatment systems, such as floating
wetland, are installed in the waterbody). The below Table 4 presents sample type and sampling
locations for assessment of water quality in the waterbody.
Table 4: Sample type and sampling locations for water quality assessment in a waterbody

Sample type Sampling point Relevance

Shallow zone
Lake water Representative of quality of water in the waterbody
Deeper zone

Representative of state of eutrophication of the waterbody

Lake sediment Sediment surface
and its overall health.

Inlet water At inlet Representative of quality of water entering the waterbody.

Representative of quality of water, particularly demonstrating

Outlet water Outlet
the efficacy of any deployed natural treatment system.

The recommended frequency of sampling for all sample types is at the minimum bi-monthly.
The quality parameters recommended for water and sediment quality assessment are provided
in Appendix A – recommended quality parameters.

3.5 Stakeholder engagement

28
The success of any waterbody rejuvenation intervention is dependent on cooperation among all
stakeholders, many of whom are likely to have different objectives for management of the
waterbody. It is therefore imperative that key stakeholders are engaged early to identify their
respective drivers. To determine appropriate engagement strategies, it is critical that all
stakeholders are classified. Classification can be undertaken using several characteristics,
including ownership, geographical proximity, influence, and the potential to contribute
financially to the project. Moreover, waterbody rejuvenation interventions should be considered
through a gender equality, disability, and social inclusion (GEDSI) lens. This is particularly key
during stakeholder engagement. As noted in the AMRUT 2.0 operational guidelines, while
formulating all projects, it “should be ensured that households of informal settlements and low-
income groups are duly considered”.
The stakeholders can be grouped into two categories:
• Primary Stakeholders – who have a direct interest or influence on the waterbody
management; these include:
- municipal organisations, land/building development authorities, regional
development authorities, water board/utility, water resources
conservation/management authorities, pollution control boards, central and state
governments, general public and communities including women or women’s groups
dependent on the waterbody for their water needs or those living in close proximity
• Secondary Stakeholders – who are not responsible for specific activities that relate to
waterbody management, but they do have an indirect interest in waterbody; these include:
- state agriculture/horticulture/aquaculture/energy departments, research institutes,
non-governmental organisations, suppliers and contractors,

3.5.1 Strategy for stakeholder engagement

Effective stakeholder engagement requires a comprehensive and inclusive strategy that seeks
out engagement and input from a broad range of stakeholders (government bodies, industries
and businesses, funding organisations, regulators, community groups and the public). The
strategy must also adapt and evolve at different stages in the lifecycle of the waterbody
rejuvenation plan, and of a given project, from planning, through design and implementation.
At each of these stages, the extent to which a specific stakeholder should be engaged may
change, as may their specific interests. All stakeholder engagement should promote principles
of honesty, trust and integrity and include transparency, respect, and partnership, ensuring that
stakeholders are not judged for their values and that common ground is established.
Healthy debates and disagreements are essential to the working of a stakeholder group and
should be viewed positively. The focus of a stakeholder engagement should be on finding
solutions and that all stakeholders remain receptive to each other.
Potential formats for stakeholder engagement are provided below.

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3.5.1.1 Water forums
Forums for selected attendees or open membership (public meetings) are effective for
communicating information or educating about new concepts. The less structured format may
however be less suited to collective planning of projects.
A diverse mix of forum attendees should be sought. Representatives across the Gender,
Equality and Social Inclusion spectrum, such as local women groups or non-profit groups
working with urban poor communities should be sought. Specific identification of how
vulnerable groups can be engaged may be initiated in these forums and later carried through
into focus groups.
Existing local research institutions and academia working in waterbody rejuvenation should be
part of these forums.
Forums can be organised as physical meetings or virtual platforms to increase outreach,
however, such events require careful management to ensure attendees remain engaged
throughout.
The Delhi Water Forum was launched in January 2023 under the AIWASI Community
Demonstration Project, and this can be leveraged further for waterbody rejuvenation in the
National Capital Territory of Delhi. Similarly, existing forums on water can be used to open
discussion on waterbody rejuvenation in other states.
3.5.1.2 Waterbody focus groups
The forums organised at a city level can help set up focus groups on waterbodies. Focus groups
require a clear agenda, attendance list and expected outcomes. They can be very effective in
brainstorming ideas for specific groups and needs.
Focus groups can focus on different geographies within a state/city and different social groups
especially women and children. For example, seeking engagement of specific groups such as
the federation of self-help groups to understand the needs of women, especially those dependent
on waterbodies for their water needs, can help design and manage waterbodies and their
rejuvenation more effectively.
These groups can also become neighbourhood watch groups that can help build awareness on
sustenance and maintenance of waterbodies. In addition, they can also be involved in water
testing.
These opportunities have also been clearly stated in the AMRUT 2.0 guidelines and the GESI
(Gender Equality and Social Inclusion) guidelines for AMRUT 2.0. Focus groups can help
explore possible collaborations with citizens’ groups and build awareness on the issue.
3.5.1.3 Working groups
Working groups are ongoing collaborative initiatives between multiple stakeholders that
provide a platform for sharing information and coordinating research. Singapore’s WaterHub is
an excellent example of this concept. The facility provides a venue for collaborative working
and an avenue for networking within the broader water industry, locally and internationally.

30
3.5.1.4 Questionnaires
Questionnaires can be a useful means of gaining an early understanding or appreciation of
stakeholder interest and/or concerns. They should be followed by direct engagement to
collectively develop ideas and solutions. Other qualitative methods using both online and
offline methods of engagement for greater outreach can help strengthen the data base especially
regarding vulnerable and underserved areas of the city/state.
These groups should be anchored by the municipal authorities in the city as they are able to
bring together multiple stakeholders including community/political and women representatives.
Based on the above format, a city-level stakeholder engagement of waterbody rejuvenation
strategy may include:

Water forums
City- and state-level forums using online and offline platforms to initiate discussion on
waterbody rejuvenation involving individuals and organisations, industries working in the water
sector and active in the state/city, and the public sector. Examples may include municipal and
development authorities, mayors/councillors, water departments, district/zonal offices, premier
engineering colleges with research on water, water research organisations, water companies,
nonprofits, community-based organisations and federations.

Focus groups on water body rejuvenation covering different geographies and social
groups

Federations and nonprofits working with

Resident welfare associations of planned areas
communities living in vulnerable parts,
with waterbodies that are mostly used for
disaster prone areas and communities using
recreational purposes.
waterbodies for water needs

Water departments and state and city

Academia, technology leaders and industrial
authorities managing waterbodies, flood
partners, contractors working on nature-based
control and irrigation departments, municipal
as well as mechanised solutions for waterbody
authorities responsible for operation and
rejuvenation and management.
maintenance of waterbodies

Waterbody working groups

Area-based working groups on geographical and topographical challenges.
Social groups and vulnerable groups based working groups based on challenges of population
densities, vulnerable communities, uses of waterbodies, etc.

3.6 Development of institutional framework

31
The objective of institutional frameworks is to create an effective ecosystem that supports
sustainable management of waterbodies. The National Plan for Conservation of Aquatic
System 2 (MoEF CC, April 2019) underscores the importance of institutional frameworks by
stating that “effective institutional structures need to be created within the States and UTs to
ensure cross sectoral decision making for wetlands”. Therefore, there is a requirement to
establish effective institutional arrangements for implementation of sustainable waterbody
rejuvenation programs.Such a framework is required to ensure smooth implementation of the
project, and O&M of assets that will be created under the project.
The institutional framework may include setting out the formation of a committee, which would
be responsible for project monitoring, review of progress and monitoring the quality of work
and schedule of project implementation, and subsequently management of waterbody post-
execution of the rejuvenation plan. Guidance and suggestions of the committee on technical and
management related issues of the project shall be helpful in resolving the intra- and inter-
departmental issues and challenges. Resolution of any public grievances and hindrances may
also be facilitated with the help of the committee.
In some instances, a government organisation may be responsible for managing multiple
services, however, the below list provides departments that may typically be considered for
selection of members of the committee, depending upon the services these departments provide
within the relevant local context. The structure of the committee can be decided based on the
key stakeholder departments that have a bearing on the functioning and management of the
waterbody. These departments may include:
• Municipal corporation/irrigation and flood control department/public works department –
drainage infrastructure
• Lake development authority (where these exist) – lake management
• Regional development authority/city planning authority – land use, land cover
• Water board/utility – water and used water services
• Forest department – plantation of flora species
• Fisheries department – management of fishes in the waterbody
• Department of industries – Industrial effluent management
• Public representation – Lake focus groups, non-government organisations, public
representative, research institutions
As noted in the previous section, it is critical to use a GEDSI lens in waterbody rejuvenation
interventions. In this regard, existing government outreach programs in health and education
can be leveraged for GEDSI-specific inputs. For example, in every city most of the slums/urban
villages or unplanned areas has a network of ANMs (Auxiliary nurses and midwives) now

2
http://moef.gov.in/wp-content/uploads/2019/09/NPCA-MOEFCC-guidelines-April-2019-Low-resolution.pdf

32
known as ASHA workers who can provide key insights on challenges faced by women in
vulnerable areas. Similarly, schoolteachers and principals of government schools can help
highlight issues of underserved areas. Federated self-help groups or representatives under
NULM can also be part of a formal mechanism of seeking GEDSI inputs.

3.7 Framework for preparation of Waterbody Rejuvenation Detailed

Project Report (DPR)
The aim of the framework presented below is to identify and present important tasks and
activities that should be considered while developing a comprehensive waterbody rejuvenation
DPR. This framework may be adapted to cover a cluster of waterbodies that fall within the
same catchment, have similar characteristics, and have similar pressures and problems.

3.7.1 Stage 1 –Situation Assessment

Situation Assessment is the key step towards developing a comprehensive Waterbody
Rejuvenation DPR. It includes:
• Assessment of key features of the waterbody that influences its physical form, such as
location, water spread area, water carrying capacity, flow control infrastructure, etc.
• Physicochemical analyses of stored water and sediment within the waterbody to assess the
degree of eutrophication,
• Meteorological assessment for understanding the variation in rainfall patterns, and
occurrence of extreme flood or drought events,
• Assessment of peripheral and catchment level features such as stormwater drainage
infrastructure, expanse of water and used water infrastructure, land use and land cover, etc.,
that have a bearing on the quality and quantity of runoff generated,
• Understanding waterbody’s social, environmental, and economic impact on the community
it serves, as well as the key stakeholders who influence waterbody management.
Waterbodies serves multiple purposes, and therefore while developing the Waterbody
Rejuvenation Detailed Project Report (DPR), it is critical that a comprehensive waterbody
situation assessment is undertaken. It will help the planning/implementing agency to develop a
contextual and implementable plan which aligns with the rejuvenation needs of waterbody, as
well as the needs of the community that the waterbody serves.
The following section presents step wise description of tasks to be undertaken as part of
Situation Assessment
3.7.1.1 Compilation of key waterbody details
Objective of this task is to collect key details pertaining to distinctive physical, environmental,
and operational features of the waterbody. Some of the major activities undertaken in this task
includes assessment of:

33
• Physical characteristics such as water spread area, recorded water storage volume,
• Flow control measures,
• Distinctive environmental features
• Ownership and jurisdiction details, including major stakeholders who have a bearing on the
waterbody
The following Table 5 presents the description, objective, and source of data required for
compiling comprehensive details of the waterbody.
Table 5: Compilation of key waterbody details

Description Objective Source

Key waterbody details
Location • Waterbody’s physical • Municipal corporation, lake
Area (ha) features development authority

Average depth • Relative location and • Secondary reports

(m) connectivity in catchment
• Primary survey – drainage,
Volume (m3) waterbody bathymetry

Number of inlets
and outlets

Environmental Visible features indicating the • Secondary reports

features current environmental
• Reconnaissance survey
condition of waterbody, such
as presence of algal blooms,
any overgrowth of aquatic and
terrestrial plants, local
avifauna, any evidence of
used water inputs
Jurisdiction Towards development of • Municipal corporation, lake
waterbody rejuvenation development authority, revenue
Ownership
implementation, O&M Plan department
Stakeholders Major stakeholders, including Non-government organisations,
public representative groups, research institute, community
NGOs, that have a direct or groups engaged in management
indirect bearing on the of the waterbody
waterbody management

34
This information feeds into subsequent task, collation of meteorology and watershed features
that is required to undertake qualitative and quantitative analyses of runoff entering the
waterbody.
3.7.1.2 Collation of meteorology and watershed features
A waterbody can typically receive water from multiple water sources including dry weather
flow, wet weather flow, groundwater infiltration, direct rainfall, overflows from the upstream
etc. The outflows from the waterbody can be in the form of extraction for different uses,
seepage, downstream discharges, and evaporation. The wet weather flow contributed through
surface runoff during a rainfall event, and water loss due to evaporation, are primarily driven by
the meteorology.
The objective of this task is to undertake a comprehensive collection of meteorological data, as
well as watershed features that have an impact on overall water balance of the waterbody. This
task entails following key activities:
• Marking the primary catchment area contributing surface flow to the waterbody,
• Understanding the stormwater drainage infrastructure that carries the surface runoff to the
waterbody,
• Land use and land cover within the catchment area of waterbody; the land use type and the
land cover will have an impact on the quality and quantity of generated runoff,
• Hydrogeology around the waterbody to establish the waterbody and groundwater
interaction,
The following Table 9 presents the description, objective, and source of data required for
collating the meteorological and watershed features.
Table 6: Collation of meteorology and watershed features

Description Objective Source

Meteorology and watershed features

Catchment area • Flow contributing area • Municipal corporation, lake

(sq.km) development authority
• Soil & Land Use Survey of India
• DEM analysis (refer to Appendix
C Data sources)
Drainage • Contributing drainage • Municipal corporation, lake
information infrastructure (incoming, development authority
outgoing, peripheral,
• Secondary reports
diversion)
• Primary survey – drainage

35
 Description Objective Source
Land uses and • Runoff generation Refer to Appendix C Data sources
cover
Hydrogeology • Waterbody and
groundwater interaction,
infiltration
• Development of catchment
scale measures to enhance
absorption of runoff in
groundwater (such as bio
swales, infiltration basin)
Other sources • Flow from upstream used Refer to data availability listed in
contributing to the water treatment plants, Appendix C Data sources
waterbody untreated used water
discharged in the drains
leading to the waterbody
• Development of
waterbody’s water balance
Meteorology – • Rainfall in the catchment
rainfall and area to calculate runoff
evaporation
• Establish rainfall trend
over years, extreme flood
and drought events
• Evaporation data to assess
the evaporation losses
The outputs from this task will feed in to subsequent task, establishing waterbody
characteristics to understand the health of waterbody.
3.7.1.3 Establishing waterbody characteristics
Establishing waterbody characteristics entail understanding the features and processes that have
an impact on quality, as well as quantity of water stored within a waterbody. It includes
assessment of
• Quality of water and sediment in the waterbody,
• Flora and fauna in the vicinity of waterbody,
• Current users and uses of that are directly or indirectly dependent on the waterbody,

36
• The kind of external pressures, emanating from changes in the land use and land cover,
change in hydrologic characteristic in the catchment impacting the surface runoff, pollution
due to point and nonpoint sources,
• Waterbody’s water balance to capture the inflows (from the catchment, infiltration),
outflows (downstream discharges, groundwater losses, any other consumptive uses), and the
minimum environmental volume requirement for the water body,
• Physical form of waterbody that includes lakebed profile, water carrying capacity, lake
boundary, etc.,
The following Table 7 presents the description, objective, and source of data required for
establishing the waterbody characteristics.
Table 7: Establishing waterbody characteristics

Description Objective Source

Waterbody characteristics

Water and • Assessment of waterbody • Refer to Appendix A –

sediment quality health Recommended quality
parameters
• Quality of water entering
Flora and fauna and exiting the waterbody • Secondary reports from forest
department/environment
• Quality of sediment
department/municipal
organisation/lake development
authority regarding flora and
fauna
• Primary survey for flora and
fauna assessment
Values and uses To identify the current • Municipal corporation, lake
services that waterbody development authority
provides. It may include:
• Reconnaissance survey
• Water supply,
• Secondary reports and literature
groundwater recharge,
flood protection, • Primary survey – drainage
livelihood, recreation,
culture, tourism,
ecological values (birds,
fish, vegetation), religious
values.

37
Description Objective Source
Existing pressures To identify natural factors and Refer to the following:
on waterbody human activities affecting the For assessment of land use and land
health of the waterbody. cover changes refer to
These include:
• Appendix C Data sources
• Catchment disturbances –
changes in land use, land For drainage infrastructure
cover impacting quality • Municipal corporation, lake
and/or quality of runoff development authority
• Hydrologic disturbances – • Primary survey for drainage
changes in drainage
Pollution entering waterbody and
infrastructure leading to
groundwater
capacity or connectivity
constraints • Lake water and sediment quality
(Appendix A.1 – Water and
• Point or non-point sources
sediment quality testing of
of pollution – discharge of
waterbody)
treated used water,
untreated used water • Groundwater quality (Appendix
discharges from areas not – A.2 – Groundwater quality)
connected with network, Reconnaissance survey, primary
illegal dumping of waste survey for drainage
in the waterbody’s
peripheral areas – leading Impact of climate change:
to eutrophication and • Long-term trend analyses of
reduction in water carrying rainfall, flood and drought events
capacity
• Impact of climate change –
frequent flooding or
drought instances
Existing water To assess the waterbody’s Refer to data availability listed in
balance of water balance – the amount of Appendix C – Data sources
waterbody. water entering the waterbody
and deducting the minimum
environmental storage of
waterbody (to sustain local
flora and fauna) and any
downstream discharge.
• Inflow to the waterbody
includes – runoff from the

38
Description Objective Source
catchment, direct rainfall,
flow contributed through
treated used water from
upstream, untreated used
water (if any) coming from
settlements that are not
connected with waterbody
and discharging in drains
leading to waterbody
• Waterbody’s
environmental storage
and outflows from the
waterbody includes –
evaporation loss,
minimum environmental
waterbody water storage,
and any downstream
discharge,
Description of To assess the physical form of Bathymetry data – presented in form
waterbody the waterbody, potential of X, Y and Z coordinates, where X
physical form quality of silt deposition, and Y presents the lateral position of
amount of desilting required the given point relative to survey
for storage capacity start point, and Z represents the
enhancement. sediment depth and water depth at
Waterbody physical form the same point.
representation is done using
bathymetry data and plotting
it to generate the lake-bed
profile, and calculating the
waterbody storage capacity at
the outlet level.
Description of To assess the current flora and • Secondary reports from forest
waterbody flora fauna that the waterbody is department/environment
and fauna supporting. department/municipal
condition When studied in conjunction organisation/lake development
(including in with the water and sediment authority regarding flora and
buffer zone) quality outputs, it also informs fauna
based on presence of intrusive • Primary survey for flora and
fauna assessment

39
 Description Objective Source
primary or vegetation species that causes
secondary data infestation of weeds.
The output from this and earlier tasks forms the basis for development of Stage 2 –
Development of Waterbody Rejuvenation Plan.

3.7.2 Stage 2 – Development of Waterbody Rejuvenation Plan

Development of Waterbody Rejuvenation Plan requires a holistic assessment of waterbody as
well as the factors that impact its functioning. It is important to note that the output from Stage
1 forms the basis for developing a comprehensive and holistic Waterbody Rejuvenation Plan.
The key tasks to be undertaken as part of Waterbody Rejuvenation Plan includes:
• Creating a vision for the Waterbody Rejuvenation with identification of specific and
measurable outcomes to achieve it,
• Development of contextual and waterbody specific measures to manage the pressures on
waterbody, while enhancing its social, environmental, and ecological value,
• Development of design for engineering infrastructure along with costs,
• Identification of Operation and Maintenance activities required as part of Waterbody
Rejuvenation,
• Development of project implementation plan, and
• Development of stakeholder engagement and public education & outreach plan.
The following Table 8 presents the description and interventions required as part of
development of Waterbody Rejuvenation Plan.
Table 8: Development of waterbody rejuvenation plan

S. Description Interventions
No.
Description of The vision for the waterbody rejuvenation, and finalisation of
vision for the the measurable outcomes that are aligned with the vision,
waterbody should be developed in consultation with the key stakeholders
of the waterbody. The vision should align with identification of
Identification of
key values and uses that waterbody intends to serve.
specific and
measurable The specific and measurable outcomes may include:
outcomes to
• Water quality targets to be maintained at inlet and outlet
achieve the
vision • Finalising the uses and users that the waterbody will serve

40
S. Description Interventions
No.
• Water carrying capacity of waterbody, and level of flood
protection
• Revenue targets, if any, through specific activities such as
fishing, access to water base activities such as boating,
leasing for community functions
Selected The interventions identified within waterbody, fringe area, and
intervention at the catchment level should improve the overall ecological
measures to help and environmental health of the waterbody and promote strong
manage social value for the communities dependent on it.
pressures on the
• Desilting and de-weeding plan – based on deepening and/or
waterbody,
desilting requirement development of waterbody zonation
reduce impacts
plan, proposed desilting process, de-silting quantity, and
on the
disposal plan (refer to Appendix B1 – Bathymetry and
waterbody, and
Bank Reshaping and Appendix B2 – Desilting, Appendix
improves its
C3 – Aquatic weed management and removal),
overall health
• Constructed wetland, floating wetlands (refer to Appendix
D 2.1 – Constructed wetland and D 2.2 – Floating
wetland)
• Waterbody inlet, outlet and periphery management –
rehabilitation/construction requirement of flow control
structures, silt and pollutant traps, dry weather flow
diversion drains, incoming and outgoing drain desilting and
structural repair requirements, lake bank erosion control
measures, security fencing to prevent waste dumping,
placement of waste bins along the periphery, security guard
room, lighting requirement, community toilets (for flow
management in catchment and within waterbody, refer to
Section A of Appendix B – Potential measures for
waterbody rejuvenation)
• Aquatic and riparian vegetation management (refer to
Appendix C1 – Establishing watershed characteristics
and C2 – Establishing waterbody and meteorological
characteristics)
• Fish population – introduction of locally suitable fish
species for the waterbody based on experimental phase plan
(for one year) and stocking plan (for three years)

41
 S. Description Interventions
No.
Design of The design of engineering infrastructure should be done in
engineering conformance with applicable local codes, guidelines, and water
infrastructure quality standards, supported by necessary drawings,
interventions calculations, maps, hydrologic and hydraulic modelling outputs
required as part (if any), etc. All engineering drawings should be prepared in
of waterbody CAD format. Spatial analyses should be done preferentially in
rejuvenation ArcGIS format. The implementation plan should identify the
key activities along with their implementation timelines with
necessary float as required.
Development of
Bill of Quantities The design, calculation, spatial distribution maps, O&M regime
for capital works etc., should include the following:
and O&M • Calculation of runoff volume
activities
• Design of drainage improvement works, catchment
improvement works
Preparation of
• Design of waterbody inlet and outlet
project
implementation • Wetland design
plan, waterbody • Any primary and secondary treatment system design
monitoring plan,
and stakeholder • Lake-bed profile, and desilting & de-weeding quantities
engagement plan along with disposal plan
• Capital cost of identified interventions
• Operation and maintenance regime and associated cost
• Flow and water quality monitoring plan
• Project implementation plan
• Stakeholder engagement plan to facilitate implementation,
monitoring and evaluation

3.7.3 Description of interventions

As described under Interventions in Table 8, the waterbody rejuvenation include development
of
• Flow management measures which include interception and diversion of dry weather flow,
flow redirection, redistribution, diversion in to the waterbody,
• Physical form measures which include bank reshaping and desilting,

42
• Aquatic & riparian vegetation management which include identification of plant species
suitable for aquatic and riparian planting, as well as removal of aquatic weed,
• Water quality management plan which includes identification of parameters and sample
collection frequency to monitor the health of waterbody.
These interventions are presented under Part C –Interventions for waterbody rejuvenation,
which comprehensively covers and presents the aspects listed above.

43
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44
Part C –Interventions for waterbody rejuvenation

Appendix A – Recommended quality parameters

A.1 – Water and sediment quality testing of waterbody

Table 9: Sampling points for water quality monitoring
Type of Sampling Points Sample Significance
sample collection
zone
Shallow zone Epilimnion 3 Water quality at these locations will
Lake
represent water quality variation between
water Deeper zone Hypolimnion 4 shallow and deeper zones.
Shallow zone Sediment quality at these locations
Lake Sediment
provide indication of health of the
sediment Deeper zone Surface
waterbody.
Water quality at this location will
Inlet to the lake represent quality of water entering the
waterbody.
Water quality at this location will
Inlet to floating
Inlet represent quality of water entering the
wetland (if proposed) Inlet
water floating wetland (if proposed).
Water quality at this location will
Inlet to marshy represent quality of water after floating
wetland (if proposed) wetland. This data will help assess the
floating wetland treatment efficiency.
Outlet
Outlet of the lake. Outlet Quality of water exiting the waterbody.
water
Water quality at this location will
represent quality of water after natural
Outlet Outlet of marshy
Surface treatment. This data will help assess the
water wetland (if proposed)
treatment efficiency of floating, marsh
wetlands and natural treatment as a unit.

3
The uppermost layer is called the epilimnion and is characterized by relatively warm water where most photosynthesis occurs.
4
The hypolimnion or under lake is the dense, bottom layer of water in a thermally-stratified lake.

45
Table 10: Recommended list of parameters and sampling frequency for water quality
monitoring
S. No Parameters Frequency of sampling
Pre-project During project Post-project
implementation
A – Physico-chemical parameters
1 Ambient temperature Once Bi-Monthly Quarterly
(oC)
2 Water temperature (oC) Once Bi-Monthly Quarterly
3 pH Once Bi-Monthly Quarterly
4 Conductivity, µmho/cm Once Bi-Monthly Quarterly
5 Transparency (m) Once Bi-Monthly Quarterly
6 Total hardness as Once Bi-Monthly Quarterly
CaCO3 (mg/l)
7 Total dissolve solids Once Bi-Monthly Quarterly
(mg/l)
8 Total suspended solids Once Bi-Monthly Quarterly
(mg/l)
9 Total alkalinity as Once Bi-Monthly Quarterly
CaCO3 (mg/l)
10 Dissolved oxygen (DO) Once Bi-Monthly Quarterly
(mg/l)
11 Total organic carbon Once Bi-Monthly Quarterly
(mg/l)
12 Biochemical Oxygen Once Bi-Monthly Quarterly
Demand (BOD5) (mg/l)
13 Chemical oxygen Once Bi-Monthly Quarterly
demand (COD) (mg/l)
14 Total Nitrogen (mg/l) Once Bi-Monthly Quarterly
15 Ammonia (mg/l) Once Bi-Monthly Quarterly
16 Total Kjeldahl Nitrogen Once Bi-Monthly Quarterly
(mg/l)
17 Nitrate (mg/l) Once Bi-Monthly Quarterly
18 Total Phosphorous as P Once Bi-Monthly Quarterly
(mg/l)
B – Biological Parameter
1 Total coliforms Once Bi-Monthly Quarterly

46
S. No Parameters Frequency of sampling
Pre-project During project Post-project
implementation
organism (MPN/100 ml)
2. Faecal Coliforms Once Bi-Monthly Quarterly
(MPN/100 ml)
C – Heavy Metals
1 Lead (Pb) ( µg/l) Once Quarterly Semi-annually
2 Nickel (Ni) (µg/l) Once Quarterly Semi-annually
3 Cobalt (Co) (µg/l) Once Quarterly Semi-annually
4 Zinc (Zn) (µg/l) Once Quarterly Semi-annually
D – Pesticides
1 Total BHC, (µg/l) Once Quarterly Semi-annually
2 Total DDT, (µg/l) Once Quarterly Semi-annually
E – Biodiversity Study
1 Phytoplankton primary Once Quarterly Semi-annually
productivity
(mg C/m3/d) &
Chlorophyll-a (µg/l)
2 Phytoplankton species Once Quarterly Semi-annually
richness & community
abundance
3 Zooplankton species Once Quarterly Semi-annually
richness and community
abundance
4 Macrophytes species Once Quarterly Semi-annually
5 Species composition & Once Quarterly Semi-annually
population dynamics of
fish based on survey of
catch from fisherman

47
Table 11: Recommended list of parameters and sampling frequency for sediment quality
monitoring
S. No Parameters Frequency of Sampling

Pre-project During project Post-project

(once) implementation (At least for 2
years)
A – Physico-chemical parameters
1 Total Nitrogen (mg/l) Once Quarterly Half-yearly
2 Total Kjeldahl Nitrogen Once Quarterly Half-yearly
(mg/l)
3 Total Phosphorous Once Quarterly Half-yearly
(mg/kg)
4 Calcium (mg/kg) Once Quarterly Half-yearly
5 Magnesium (mg/kg) Once Quarterly Half-yearly
B – Heavy Metals
1 Lead (Pb) (µg/kg) Once Quarterly Half-yearly
2 Nickel (Ni) (µg/kg) Once Quarterly Half-yearly
3 Cobalt (Co) (µg/kg) Once Quarterly Half-yearly
4 Zinc (Zn) (µg/kg) Once Quarterly Half-yearly
C –Pesticides
1 Total BHC (µg/kg) Once Quarterly Half-yearly
2 Total DDT ( µg/kg) Once Quarterly Half-yearly

48
A.2 – Groundwater quality
Typical comprehensive test for groundwater abstraction in an urban environment would comprise of the parameters provided below in the Table
12 below. However, the number of parameters can be reduced, subject to the specific risks being considered for any given scheme, and the
actual species detected in the initial rounds of monitoring:
Establish groundwater chemistry
Method: Samples of borehole water using purpose-built observation wells and at nearby third party abstractions
Frequency: Quarterly during operation.
Table 12: Establishment of groundwater chemistry

Basic parameters Major ions Hydrocarbons Trace metals/metalloids Microbiology Pesticides (if
potential
contaminant sources
in catchment)

• pH • Chloride • Mineral oils • Arsenic • Total coliforms • Suite as per

screen National drinking
• Dissolved oxygen • Fluoride • Aluminium (total and • E. coli
water standards
• Total phenol dissolved)
• Temperature • Iron (total and • Cryptosporidium https://law.resourc
dissolved) • VOCs • Boron – (filter sampled) e.org/pub/in/bis/S0
• Conductivity
6/is.10500.2012.pd
• Manganese • SVOCs • Cadmium • Giardia – (filter
• Redox potential f
sampled)
• Nitrate • Chromium (total)
• Odour/visual
appearance • Ammonium • Chromium
(hexavalent)
• Odour • Hardness as
CaCO3 • Copper (dissolved)

49
Basic parameters Major ions Hydrocarbons Trace metals/metalloids Microbiology Pesticides (if
potential
contaminant sources
in catchment)

• Colour • Alkalinity as • Cyanide (total and

HCO3 free)
• Suspended solids
• pH • Lead
• Sulphate • Manganese (total and
dissolved)
• TDS
• Mercury
• Molybdenum
• Nickel
• Selenium
• Zinc

50
Appendix B – Potential measures for waterbody rejuvenation

The following section of Appendix B presents interventions that are applicable to remediate
problems typically identified while implementing a waterbody rejuvenation plan.

Section A. Flow management measures

A1 – Flow interception and diversion around waterbody

Application level Beneficial effect on waterbody health
Catchment  Hydrology and hydraulics 
Incoming channel Physical form
Buffer zone  Water quality 
Waterbody Aquatic and riparian
ecosystems

Application
Interception and diversion of incoming flow is applied to improve the hydrology of a
waterbody (e.g., if the waterbody receives excess water) and/or to improve water quality in
the waterbody by diverting polluted water to a treatment asset. For instance, where dry
weather flows are highly polluted from untreated wastewater, interception and diversion of
dry weather flows around the waterbody to a treatment system may be required. This
intervention generally requires hydraulic structures (e.g., weirs, gates, pits, pipes, bunds,
open channels) to intercept and divert water around the waterbody.

Figure 12. Interception and diversion schematic

Planning and design considerations

51
This intervention requires an understanding of the hydrologic and water quality problems
and requirements of the waterbody. Consideration should be given on the impacts of the
interception and diversion intervention on the hydrologic regime of the waterbody and the
“values and uses” of the waterbody (for instance interception and diversion may reduce
inflow during the dry season and affect amenity value of waterbody). The hydraulic design
of the diversion structure must be carefully undertaken to enable diversion of “low flows”
(e.g., polluted dry weather flows) but enable higher flows (e.g., stormwater runoff) to enter
the waterbody (or another treatment system targeting stormwater pollutants). Furthermore,
diversion of polluted water around the waterbody without treatment does not address
pollution downstream of the waterbody and may in fact worsen water quality downstream.

Open Channel (inlet)

Diversion structure
(mechanically operated
hydraulic gate)
Screens (1st stage)

Towards Treatment

Interception structure to
restrict dry weather Screens (2nd stage)
flow entering the lake

Figure 13. Interception & Diversion structure at Mahadevapura Lake, Bangalore (Source:
CDD India)
Operations and maintenance considerations
As such interventions are largely hydraulic structures, maintenance activities include clean-
out of sediment and litter accumulated within the infrastructure, and to fix erosion issues of
earthen bunds when they arise. Additionally, care must be taken to ensure all levers of
hydraulic gates are functioning adequately, especially before monsoon, to ensure smooth
operation.

52
A2 – Flow diversion into waterbody
Application level Beneficial effect on waterbody health
Catchment  Hydrology and hydraulics 
Incoming channel Physical form
Buffer zone  Water quality 
Waterbody Aquatic and riparian
ecosystems

Application
Flow diversion into a waterbody may be required for several reasons including to top up
the waterbody, or to improve water quality by improving flow circulation, turnover of
water in the waterbody, or to lower pollutant concentration (dilution) in the waterbody.
This intervention generally requires hydraulic structures (e.g., weirs, gates, pits, pipes,
open channels) to divert water to the waterbody.

Figure 14. Schematic of flow diversion into waterbody

Planning and design considerations
This intervention requires an understanding of the hydrologic and water quality problems
and requirements of the waterbody. A water balance analysis is required to be undertaken
to understand the inflows and losses from the waterbody. The amount, quality, flow rate,
position of the inlet and direction of the flow in the waterbody are fundamental elements to
consider ensuring effectiveness of this technique. It generally requires introduction of large
volumes of water into the waterbody. It can also be capital cost intensive because of the
water diversion infrastructure. However, it can also be cost effective if there is a supply of
good quality water and the costs of facilities and their maintenance for delivering water to
waterbody are not high. This technique has been successfully used in small waterbodies.

53
The hydraulic design of the diversion structure must be carefully undertaken to enable
diversion of the required volume and flow rate, and to allow diversion to be stopped if
needed (e.g., using gates).
Operations and maintenance considerations
As such interventions are largely hydraulic structures, maintenance activities include
clean-out of sediments and litter accumulated in the diversion infrastructure, and fixing
erosion issues of earthen bunds when they arise. Additionally, care must be taken to ensure
all levers of hydraulic gates are functioning adequately, especially before monsoon, to
ensure smooth operation.
Where water is diverted from a nearby treatment plant, water quality monitoring must be
undertaken to ensure that the quality of water entering the waterbody adheres to
requirements that support its desired values and uses.

54
A3 – Flow mixing and aeration
Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics 
Incoming channel Physical form
Buffer zone Water quality 
Waterbody  Aquatic and riparian
ecosystems
Application
Mixing and aeration should aim to promote both convection (movement of water within
the waterbody) and oxygenation of water. Effective mixing devices are typically one of
two types:
• Floating or submersible pump systems which pumps and circulates water from poorly
mixed areas (e.g., stagnant areas) to well-mixed areas (including from the base of the
waterbody to the surface).
• Aerators – these systems release air bubbles at the base of the waterbody to promote
both convection and oxygenation.
Mixing and aeration can also be used to disrupt layers of stratification that often occur in
deep and still waterbodies. Stratification occurs when there is a significant difference in
density where water layers at the bottom are heavier than the surface water which prevents
the different layers from mixing. The lack of mixing between layers means that oxygen
does not make it through to the bottom water layers which changes the way nutrients are
processed in the waterbody sediments. As a result, nutrients are more readily released into
the water column which can lead to algal blooms. By breaking down the stratification
layer, oxygen makes it to the bottom layers creating conditions where nutrients can break
down more naturally.

Figure 15. Mixing and aeration

Planning and design considerations
Mixing and aeration is a well-established technique but is generally feasible for application
in small waterbodies. Capital and operational costs can become prohibitive when applied
over a large waterbody or for waterbodies with extensive deep zones. Where low dissolved
oxygen in a waterbody is a problem, this intervention alone may not address the problem –

55
measures to improve water quality entering the waterbody (see section D) may also be
required.
Operations and maintenance considerations
Sub-surface pumps and aerators require maintenance to remove build-up of organic
material, algae, sludge, and sediments collected on their motors and other mechanical
parts. Without maintenance, the build-up will become thick over time and cause motors to
strain, over-heat and perform less effectively.

56
A4 – Flow redirection
Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics 
Incoming channel Physical form
Buffer zone Water quality 
Waterbody  Aquatic and riparian
ecosystems

Application
This intervention is about improving flow distribution in the waterbody to reduce
occurrence of short-circuits and stagnant zones in the waterbody. The shape of a waterbody
and the locations of its inlets and outlets influence how water moves in the waterbody. For
instance, waterbodies that have a low length to width ratio with a single inlet and outlet
point can suffer from poor flow distribution resulting in short-circuits and stagnant zones.
Short-circuit flow paths are typically narrower and deeper channels within the waterbody
(often not visible) that carry a sizeable proportion of the flow compared to the rest of the
waterbody. Short-circuits occur due to channelisation of the flow, which may be promoted
by zones of sparse vegetation, erosion, or funnelling of flow between features (e.g., islands,
accumulated sediment, and litter, etc).
Construction of flow bunds or baffles within the waterbody is a useful technique to
promote flow distribution within the waterbody (and reduce channelisation) by directing
water along a longer flow path. The use of flow bunds and baffles can also improve water
quality by avoiding stagnant zones. Similarly, a flat bathymetry perpendicular to the flow
path can ensure an even flow distribution across the flow width rather than channelisation
along a deeper section (see also B1 – Bathymetry and bank reshaping).

Figure 16. Schematic of flow redirection in a waterbody using flow bunds or bafflers
Planning and design considerations

57
This technique requires an understanding of hydraulic (water movement) problem within
the waterbody. It requires the waterbody (or sections of the waterbody) to be dewatered so
that the bunds can be constructed. This technique has been successfully applied in small- to
medium-sized waterbodies where it is feasible and acceptable to drain the waterbody to
facilitate construction of bunds.
Operations and maintenance considerations
As such interventions are largely earthen bunds, maintenance activities mostly relate to
fixing erosion issues that arise with the earthen bunds.

58
A5 – Flow recirculation
Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics 
Incoming channel Physical form
Buffer zone Water quality 
Waterbody  Aquatic and riparian
ecosystems

Application
Another effective method to promote mixing of water in a waterbody is to install a
recirculation system which pumps and circulates water from poorly mixed areas (e.g.,
stagnant areas) to well-mixed areas. There may be areas of the waterbody that are poorly
flushed and do not receive flowing water. These are often isolated and deep areas of open
water that become stagnant and are sometimes accompanied by odour or algal growth.

Figure 17. Schematic of flow recirculation in a waterbody

Planning and design considerations
This technique requires an understanding of where poorly flushed zones are in the
waterbody and understanding the volume of water in these zones. The aim of recirculation
is to move volume of water in the dead zones every 2-3 days. For example, a 2 m deep, 20
m2 zone equates to a volume of 40,000 litres of water. For this water to be pumped out in 3
days (4320 mins), it would require a pumping rate of 10 L/min. Given the low flow rates, a
solar powered recirculation system can often be used.
Recirculating water from the waterbody through a constructed treatment wetland can be
used to improve water quality in the waterbody. This method is often used to manage algal
bloom in a waterbody. Constant recirculation through the treatment wetland improves
water quality in the long term and thereby reducing likelihood of algal bloom in the

59
waterbody. Consideration must be given to the design of constructed treatment wetlands
that receive both inflows and recirculated waterbody flows.
Operations and maintenance considerations
Sub-surface pumps require maintenance to remove build-up of organic material, algae,
sludge, and sediments collected on their motors and other mechanical parts. Without
maintenance, the build-up will become thick over time and cause motors to strain, over-
heat and perform less effectively.
Useful resources
Water by Design (2013), Waterbody Management Guideline, Healthy Waterways Ltd,
Brisbane, Australia (https://waterbydesign.com.au/)

60
A6 – Flow (stormwater) retention in the catchment
Application level Beneficial effect on waterbody health
Catchment  Hydrology and hydraulics 
Incoming channel Physical form 
Buffer zone Water quality 
Waterbody Aquatic and riparian 
ecosystems
Application
The creation of impervious surfaces in a waterbody catchment significantly increases the
volume and frequency of stormwater runoff entering the waterbody which can lead to
erosion and scouring of banks and beds and change the hydrologic regime of the
waterbody (and in turn impacting on aquatic ecosystems). Conventional approaches to
stormwater management focus on drainage and flood protection and do not address the
issue of diffuse pollution and hydrologic disturbances in waterbodies from stormwater
runoff. The table below presents structural measures that can be applied to reduce the
volume and frequency of stormwater runoff generated in the waterbody catchment. Such
measures may be appropriate in urban greenfield or retrofit areas, on public and private
lots, and/or within the waterbody buffer zone.
Planning and design considerations

Figure 18: Rainwater and stormwater harvesting

Rainwater and stormwater harvesting capture and store runoff from impervious surfaces
for water supply. Additional benefits include regulating stormwater runoff volume and
frequency (benefitting waterbodies) and reducing peak flows (for flood protection). As
rainwater and stormwater contains pollutants, some of which are harmful to humans
including pathogens and micropollutants, rainwater and stormwater harvesting schemes
should be designed to safely collect, treat, and store water.

61
Figure 19: Porous pavement
Porous pavements are permeable surfaces that allow water to seep into the ground.
Benefits include regulating stormwater runoff volume and frequency (benefitting
waterbodies), reducing peak flows (for flood protection) and groundwater recharge.
They often have an underlying storage reservoir filled with aggregate material that
provides temporary storage prior to infiltration into the underlying soils. Porous
pavements take on many forms – from permeable pavers to pebble material loosely
bound together with resins that allow penetration of water. Porous pavements are not
recommended in areas with high water table, and for soils that are saline, sodic and have
high shrink/swell characteristics.

Figure 20: Infiltration system

An infiltration system (e.g., gravel trenches) collects stormwater runoff and allow it to
slowly infiltrate into the surrounding soils. Benefits include regulating stormwater runoff
volume and frequency (benefitting waterbodies), reducing peak flows (for flood
protection) and groundwater recharge. Infiltration systems can include surface systems

62
 such as infiltration ponds and sub-surface systems such as gravel trenches. Minimum
buffer distances are required to protect structural integrity of infrastructure such as
buildings. Infiltration systems are not recommended on slopes > 5%, for areas with high
water table, and for soils that are saline, sodic and have high shrink/swell characteristics.

Operations and maintenance considerations

A key maintenance activity for rainwater and stormwater harvesting systems is to remove
accumulated litter, sediment and organic water in the storages, pipes entering and leaving
the storages, and in any filter screens installed. Infiltration systems require removal
accumulated litter, sediment (coarse and fine) and organic water that accumulate at the
inlets or on the surface. Porous pavement may require vacuuming with a commercial
cleaning unit (or a combination of low-pressure water and vacuuming) to remove fine
sediments which can clog the infiltration layer overlying the storage.
Useful resources
CSIRO (2005), Water Sensitive Urban Design (WSUD) Engineering Procedures –
Stormwater, CSIRO Publishing, Australia.

63
Section B. Physical form measures

B1 – Bathymetry and bank reshaping

Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics 
Incoming channel Physical form 
Buffer zone Water quality 
Waterbody  Aquatic and riparian 
ecosystems
Application
The shape of a waterbody including the profile of its base (bathymetry) influences flow
movement in the waterbody amongst several other factors. Poor flow distribution and
short-circuits can result in areas within the waterbody that are poorly flushed, becoming
stagnant and isolated and sometimes accompanied by odour or algal growth.
The base and banks of a waterbody can be reshaped or reprofiled to 1) improve water
movement in the waterbody (which in turn can improve water quality in the waterbody), 2)
achieve the desired water depths to support aquatic and riparian vegetation and other
“values and uses” (such as increased water storage to meet water supply requirements), and
3) improve safety at edges of waterbodies.
Planning and design considerations
The design of the bathymetry should aim to achieve suitable water depths to ensure
establishment and long-term viability of emergent aquatic vegetation. The tolerance of
aquatic vegetation to inundation depth varies significantly across species, and growth
declines as water depths increases. For instance, many emergent species can be sensitive to
water depths, with growth difficulties in permanent water depths greater than 0.3 m. The
range in water depths and the inundation frequency and duration should be studied to
inform suitable plant species in the waterbody (noting species native to the local region are
recommended).
Waterbodies with depths > 3 m and steep edges are also vulnerable to stratification and
weed infestation. Shallow systems tend to be more resilient and stable compared to deep
systems. Shallow waterbodies (< 3 m) with gradually sloping edges provide ideal
conditions for aquatic vegetation to grow, and also improve safety at edges of waterbodies.

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Figure 21. Example of bathymetry and bank reshaping

Compared to shallow zones, deep water provides inferior nutrient removal, with reduced
nitrification and oxidation of organic matter by dissipating flow momentum and mixing.
However, the low velocity in deep zones does assist with sediment removal and helps to
break short circuits. Hence it is important for the bathymetric design to allow water to flow
through a mix of shallow zones and deeper zones. As part of bathymetry reshaping, some
zones can be “filled” to ensure shallower water depths for establishment of aquatic
vegetation (Figure 20). Similarly, infilling of stagnant zones which are prone to poor water
quality can also be considered. The slope of the waterbody “underwater banks” can also be
modified with a gentler profile (instead of a steep profile) to promote establishment of
aquatic vegetation on the banks. The banks can also be shaped to create submerged
“benches” for aquatic planting.
Operations and maintenance considerations
Maintenance includes clean out of sediments, litter and organic material that accumulates
at the base of the waterbody and along the banks. This is to ensure the desired profile of the
waterbody base and banks is maintained (see B2 – Desilting).

65
B2 – Desilting
Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics 
Incoming channel Physical form 
Buffer zone Water quality 
Waterbody  Aquatic and riparian
ecosystems
Application
Desilting is a maintenance activity to clean out sediments, litter and organic material that
accumulates at the base of the waterbody and along the banks. Desilting ensures the desired
profile of the waterbody base and banks is maintained, as well as its water holding capacity.
Desilting can also play a role in improving water quality of the waterbody by removing
material and pollutants that have accumulated at the base of the waterbody over time. Whist
regular desilting is an important activity to undertake at the waterbody, measures should also
be considered to manage pressures that cause the problem (e.g., unmanaged erosion in the
catchment and sediment runoff from construction sites). These measures will reduce the
frequency of desilting required in the waterbody.

Figure 22. Desilting of Sembakkam Lake, Chennai (Source: The Nature Conservancy)
Planning and design considerations

66
Understanding the depth of silt deposition is essential in planning any desilting activity. A
bathymetry survey can provide insights on the level of silt accumulation by comparing the
historic water depth and the existing water depth of the waterbody. It is often difficult to
identify the historic depth of a waterbody but consultation with the local community can
provide insights. Sediment samples at varying depths can also be collected and analysed for
silt content. Generally, as sample depth increases, silt content in the samples reduces and the
soil characteristics would start exhibiting that of the surrounding geology.
To undertake desilting, two broad approaches are followed:
• Wet Dredging: In this approach, the sediments are removed without dewatering the
waterbody using dredgers installed over a floating platform/barge. This technique is
commonly applied in large waterbodies where either diversion of incoming runoff or
dewatering is not possible. One major challenge is the re-suspension sediments into
the water column which can affect water quality.
• Dry Dredging: In this approach, the incoming water to the waterbody is diverted and
the waterbody is dewatered to facilitate the removal of silt using mechanical
excavators. Sometimes, temporary bunds are created within waterbody to allow for
smooth desilting activity and movement of heavy machinery. Desilting is widely
adopted in arid parts of India where urban and peri-urban waterbodies are usually dry
before the monsoon. It is worth noting that use of heavy machinery can compact the
bed of the waterbody and reduce infiltration/groundwater recharge.

Spot desilting can also be undertaken in priority areas of the waterbody such as inlet zones
where sedimentation is highest, or areas where there is minimal disruption to livelihood
activities (fishing/irrigation), or where there is ease of access, or areas where impacts on flora
and fauna can be minimised or avoided.
Testing of sediment quality is recommended to inform disposal or reuse of the material. This
is because contaminants from urban catchments which can accumulate in the waterbody bed
sediments can be harmful to humans and to the environment if disposed or reused
inappropriately.
Operations and maintenance considerations
Desilting is not a one-time activity and needs to be undertaken at regular intervals. If
desilting has not been undertaken for a long time, desilting can form part of a broader activity
to reshape the bathymetry and banks of the waterbody (see B1 - Bathymetry and bank
reshaping).

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Section C. Aquatic and riparian vegetation management

C1 – Aquatic planting
Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics
Incoming channel  Physical form
Buffer zone Water quality 
Waterbody  Aquatic and riparian 
ecosystems
Application
Aquatic planting can be applied within the waterbody or within the incoming channels,
rivers or drains. Aquatic planting is applicable for all types and sizes of waterbodies,
although wetlands can be expected to have large coverage of aquatic vegetation already.
Existing aquatic vegetation of high value should be protected during waterbody
rejuvenation works. Additional planting can be undertaken once earthworks are completed
such as reprofiling of the waterbody bathymetry and banks.
Aquatic vegetation, especially emergent and submerged plants, within a waterbody plays
an significant role in managing water quality in the waterbody (Figure 22). Planting
permanent emergent vegetation around the perimeter of a waterbody intercepts pollutants
in runoff from the land immediately surrounding the waterbody. It also provides several
other services including habitat provision, bank stabilisation, and nutrient uptake.
Similarly, submerged aquatic vegetation in waterbodies provide multiple services including
habitat provision, sediment stabilisation (restraining resuspension of bottom sediments into
water column), and nutrient uptake.

68
Figure 23. Different categories of aquatic planting (Source: ksuweb.kennesaw.edu/)
Planning and design considerations
Planting permanent emergent vegetation around the perimeter of a waterbody is relatively
low cost and easy to implement. Planting of submerged vegetation can also be carried out
in the shallow margins of open water zones with relative ease. Planting should take place
during the dry season to ensure a high success rate of plant survival and establishment. The
waterbody water level can also be lowered temporarily to facilitate planting.
The bathymetry of the waterbody may need to be modified to achieve suitable water depths
to ensure establishment and long-term viability of emergent aquatic vegetation (see B1 –
Bathymetry and bank reshaping). The tolerance of aquatic vegetation to inundation depth
varies significantly across species, and growth declines as water depths increases. For
instance, many emergent species can be sensitive to water depths with growth difficulties
for permanent water depths greater than 0.3 m.
Aquatic vegetation may require netting during the plant establishment phase to reduce
grazing from birds.

Figure 24. Establishment of aquatic emergent vegetation around the perimeter of

waterbody (Source: Coimbatore Lake restoration)
Whist aquatic vegetation generally has a beneficial effect on values and uses such as water
supply, recreation, amenity, and ecological values, it can also have a negative effect on
recreational values by impacting access to the waterbody for instance. This impact can be
minimized by managing aquatic vegetation close to the banks where access to water is
desired or by avoiding emergent vegetation where water-based recreation is desired.
Aquatic vegetation can also worsen flooding by reducing flood storage within the

69
waterbody. This impact can be avoided by offsetting the loss of storage from aquatic
planting with additional air space for flood detention within the waterbody (e.g., by raising
the flood bunds).
Operation and maintenance considerations
Low-skilled personnel can perform routine maintenance activities such as removal of
weeds, clean out sediment and rubbish, and replacement of plants as necessary. Another
consideration is to draw down the water level to enable drying out of aquatic vegetation for
a short period of time, as this can assist with plant regeneration and growth as well as
access to shallow zones for maintenance.
Useful resources
Water by Design (2013), Waterbody Management Guideline, Healthy Waterways Ltd,
Brisbane, Australia (https://waterbydesign.com.au/)

70
C2 – Riparian planting
Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics
Incoming channel  Physical form
Buffer zone  Water quality 
Waterbody Aquatic and riparian 
ecosystems
Application
The riparian or buffer zone of the waterbody is the land that adjoins the waterbody and
directly influences or is influenced by the body of water. In this document, the riparian
zone is defined as the area between the water edge and the surrounding built environment
(houses, buildings, roads, etc.).

Figure 25: Role of riparian vegetation (Source: Adapted by Jean Miller, DNR)
Riparian planting can be applied within the waterbody buffer zone or along the buffer
zones of incoming channels, rivers, or drains. Riparian planting is applicable for all types
and sizes of waterbodies. Existing riparian planting should be protected during waterbody
rejuvenation earthworks. Additional planting with the buffer zone can be undertaken as
soon as earthworks or any planned disturbances within that zone are completed.
Planting a healthy riparian zone benefits the health of a waterbody by protecting its water
quality and supporting the aquatic ecosystem. It protects water quality by regulating
nutrient and sediment inputs from the adjacent land into the waterbody. It supports the

71
aquatic ecosystem by providing habitat such as overhanging branches, leaves, branches,
and logs.
Riparian zones often provide a dense and diverse vegetation community in comparison
with other landscapes and support a much higher number and density of terrestrial animals
compared to surrounding landscapes. This is largely because the zone provides a water
supply in addition to food sources associated with water such as semi-aquatic insects.
Riparian zones also provide a corridor that allow animals to move through the landscape to
disperse and to access resources. In urban environments, where habitat is fragmented, the
role of riparian zones in providing connectivity both along the riparian corridor and to core
habitat patches outside the riparian corridor is critical.
Riparian zone also provides a range of other services such as supporting amenity and
aesthetics, and stabilising waterbody banks by preventing erosion which can cause
sedimentation, reduce habitat availability, impact water quality, and slow the flow of water.
Riparian corridors can also improve well-being by providing pathways for active travel,
active recreation facilities such as playgrounds, cultural and social facilities, and passive
opportunities to recreate and connect with nature.
Planning and design considerations
Planting riparian vegetation is relatively low cost and easy to implement. It is critical that
suitable species are planted in correct zones so that the plants are subject to conditions
which are suitable to their requirements. Soil moisture availability and inundation pattern
(frequency and duration) are particularly important with species selection transitioning
from aquatic/semi-aquatic species closer to the water’s edge where the soil is moist and
inundation is seasonal and can last for a long duration, to dry tolerant species where the
soil is well-drained, and inundation is infrequent and last for a short duration (Figure 25).
The slope of the waterbody banks can be modified where possible with a gentler profile
(instead of a steep profile) to promote establishment of riparian vegetation on the banks
and improve safety along the water’s edges. The creation of “benches” above the water’s
edge is another technique to facilitate establishment of riparian vegetation (refer to B1 –
Bathymetry and bank reshaping).
Hard infrastructure should be restricted in the riparian/buffer zone. Infrastructure such as
paths, benches, playgrounds, constructed treatment wetlands may be allowed.
Riparian zones also play an important role in flood conveyance and attenuation by
detaining runoff from the catchment and reducing the magnitude of flood pulses
downstream. However, in urban areas, increasing riparian vegetation on the floodplain can
make flooding worse. This impact can be avoided by offsetting the loss of storage from
riparian planting with additional air space for flood detention within the waterbody (e.g.,
by raising the flood bunds) or by ensuring a healthy riparian vegetation across the
catchment so that the magnitude of flood pulses is reduced upstream in the catchment
before reaching the waterbody.

72
Figure 26. Zoning to guide riparian planting based on soil moisture and inundation
pattern.
Operation and maintenance considerations
Low-skilled personnel can perform routine maintenance activities such as removal of
weeds, clean-out of sediment and rubbish, and replacement of plants as necessary.
Useful resources
Melbourne Water (2019), Constructed Waterway Design Manual, Australia,
(https://www.melbournewater.com.au)

73
C3 – Aquatic weed removal and management
Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics 
Incoming channel Physical form
Buffer zone Water quality
Waterbody  Aquatic and riparian 
ecosystems
Application
Problematic aquatic weed is an issue in its own right but it is usually symptomatic of
broader issues such as poor water quality in the waterbody. The presence of aquatic weeds
may be due to several factors including:
• Weed infestation in the upstream catchment
• Excess sediment accumulation in the waterbody
• High nutrient concentrations in the waterbody
• Seed dispersal
• Lack of regular maintenance

Investigation should be undertaken to confirm the proportion and species of weeds present,
and the causes of the weed infestation. Understanding a weed’s biology or ecology may
influence the timing of the control method. For example, it may be beneficial to control a
particular weed before it seeds to prevent further spread of the infestation.
There is a range of methods commonly used to control weeds. An integrated approach,
where several control methods are used in a co-ordinated manner, is often the most
effective long-term strategy. This section discusses mechanical harvesting to remove large
infestations of aquatic weeds from waterbodies. Mechanical harvesting is the application of
floating harvesters, excavators, or draglines (chains) to remove floating or submerged
aquatic weeds. It can be applied to any size or types of waterbodies. Mechanical harvesting
is an effective short-term control of aquatic weeds but unlikely to eradicate them. Use of
chemicals (herbicides) and biological controls (e.g., insects) to manage aquatic weeds need
specialist advice and is not covered in this advisory.
Planning and design considerations

74
Specialised floating harvesters can remove floating aquatic weeds or cut and remove weed
biomass at a fixed depth below the water surface. An excavator can remove floating and
submerged aquatic weeds from open water areas. This normally involves scooping plants
from the water with a bucket. If using excavators, use floating booms to concentrate
floating aquatic weeds. Long-reach draglines, such as chains or nets, can remove floating
or submerged aquatic weeds. This involves pulling the chain or net through the water using

a tractor. Only use this method when other methods of weed control are unfeasible as
draglines can damage desirable macrophytes.
Figure 27. Mechanical removal of aquatic weeds in Rankala lake (Source: GHONE, A. S.,
& SINGAL, S. K. Performance Evaluation of Deweeding Operations Implemented for
Conservation of Rankala Lake, India.)
Operations and maintenance considerations
As it is a short-term solution, mechanical harvesting needs to be regularly repeated.

75
Section D. Treatment measures
Treatment measures are generally implemented as part of a treatment train. A treatment train is
a meaningful combination and sequencing of treatment assets each targeting specific pollutants
in order to achieve the overall treatment objectives. For waterbody rejuvenation, a treatment
train usually consists of pre-treatment, primary treatment, and secondary treatment measures.
For instance, constructed wetlands are often implemented as part of a treatment train (Figure 27
and Figure 28).
• Pre-treatment – refers to the removal of coarse solids such as sand, plastics, and litter with
the aim to protect downstream treatment assets from accumulation of solids. Pre-treatment
uses physical removal mechanisms. Measures include screens and floatation systems.
• Primary treatment – refers to the stage of the treatment process that focuses on removal of
solids, sediments, and organic matter mostly by the process of sedimentation. Measures
include settling tanks, sedimentation ponds, sediment ponds, and Anaerobic Baffled
Reactors.
• Secondary treatment – refers to the stage of the treatment process that focuses on removal of
biodegradable organic matter, suspended solids, and nutrients (phosphorus and nitrogen).
In urban areas, flows into waterbodies are usually contaminated with untreated wastewater.
Where high organic material is present in the incoming flows, the primary treatment measure
should be carefully designed to enhance removal and digestion of organic matter.

Figure 28. Constructed wetland installed at Rajokri lake, Delhi (Source: Srivastava and
Prathna, 2021)

76
Figure 29. Schematic of a treatment train (Source: Srivastava and Prathna, 2021)

77
D1 – Primary treatment

D1.1 – Settling tank

Application level Beneficial effect on waterbody health
Catchment  Hydrology and hydraulics
Incoming channel Physical form
Buffer zone  Water quality 
Waterbody Aquatic and riparian
ecosystems
Application
A settling tank is one of several primary treatment options for wastewater treatment. It
targets removal of solids and organic matter by sedimentation process. It can be applied at
the inflow points to a waterbody or at any location in the catchment where discharge of
wastewater is a problem. The low velocity in a settler allows settleable solids to sink to the
bottom and material lighter than water to float to the surface. Settlers can achieve reduction
in suspended solids of 50-70% and reduction in Biochemical Oxygen Demand (BOD) of
20-40%.

Figure 30. Illustration of a settling tank (Tilley et al., 2014)

Planning and design considerations
Settlers are typically designed with a hydraulic retention time of 1.5-2.5 hours. The tank
should be designed to ensure satisfactory treatment performance at peak flow. The sizing
of the tank depends on the wastewater characteristics, retention time and sludge removal
rate.

78
Operation and maintenance considerations
Access should be provided for a truck to access the location as the sludge must be regularly
removed.
Useful resources
Manual on Constructed Wetland as an Alternative Technology for used water management
in India.

79
D1.2 – Sedimentation pond
Application level Beneficial effect on waterbody health
Catchment  Hydrology and hydraulics
Incoming channel Physical form
Buffer zone  Water quality 
Waterbody Aquatic and riparian
ecosystems
Application
A sedimentation pond is one of several primary treatment options for used water treatment. It
targets removal of solids and organic matter by sedimentation process. It can be applied at the
inflow points to a waterbody or at any location in the catchment where discharge of used
water is a problem. It can also be applied as the primary treatment asset for stormwater
treatment targeting removal of sediments by sedimentation process (also referred to as
“sediment ponds”).
Sedimentation pond works by slowing water allowing settleable solids to sink to the bottom
and material lighter than water to float to the surface. Settlers can achieve reduction in
suspended solids of 50-70% and reduction in BOD of 20-40%.

Figure 31. Illustration of a sedimentation pond (Tilley et al., 2014)

Planning and design considerations
Settlers are typically designed with a hydraulic retention time of 1.5-2.5 hours. The tank
should be designed to ensure satisfactory treatment performance at peak flow. The sizing of
the tank depends on the used water characteristics, retention time and sludge storage volume
and removal rate.
For stormwater treatment, the sediment pond should be designed to capture most of the target
coarse sediment (typically 125 µm or larger). It should only capture a small number of finer
particles and contaminants, which should be removed by secondary treatment assets
downstream. Key design consideration includes the design flow rate, volume of storage for
sediment capture and frequency of sediment removal.
Operation and maintenance considerations

80
Access should be provided for a truck to access the location as the sludge or accumulated
sediments must be regularly removed. The sedimentation pond can be drained of water to
allow access. An excavator can reach from the side or may need to enter the pond.
Useful resources
Manual on Constructed Wetland as an Alternative Technology for used water management in
India.
CSIRO (2005), Water Sensitive Urban Design (WSUD) Engineering Procedures –
Stormwater, CSIRO Publishing, Australia.

81
D1.3 – Anaerobic baffled reactor
Application level Beneficial effect on waterbody health
Catchment  Hydrology and hydraulics
Incoming channel Physical form
Buffer zone  Water quality 
Waterbody Aquatic and riparian
ecosystems
Application
An anaerobic baffled reactor is one of several primary treatment options for used water
treatment. It targets removal and digestion of organic matter in used water. It can be
applied at the inflow points to a waterbody or at any location in the catchment where
discharge of used water is a problem.
Used water is forced to flow through a series of baffles which increases contact time with
active biomass (bacteria in accumulated sludge) and enhances removal and digestion of
organic matter. BOD can be reduced by up to 90%.

Figure 32. Illustration of an Anaerobic baffled reactor (Tilley et al., 2014)

Planning and design considerations
This technology is most suitable where there is a constant amount of incoming used water.
The majority of settleable solids are removed in the sedimentation chamber (settler). A
separate pre-treatment settler can also be included in the design. Typical inflows can range
from 2 to 200 m3 per day. The hydraulic retention time can range between 48 to 72 hours.
Operation and maintenance considerations

82
 Access should be provided for a truck to access the location as the sludge must be regularly
removed (particularly from the settler). Accessibility to all chambers is required for
maintenance, and the tank should be vented for release of odorous and harmful gases.
Useful resources
Manual on Constructed Wetland as an Alternative Technology for used water management
in India.

D2 – Secondary treatment

D2.1 – Constructed wetland

Application level Beneficial effect on waterbody health
Catchment  Hydrology and hydraulics
Incoming channel * Physical form
Buffer zone  Water quality 
Waterbody  Aquatic and riparian
ecosystems
* See D4 – In-situ drain treatment for horizontal flow filter which operates based on the same
processes as in constructed wetlands.
Application
Constructed wetland forms the secondary stage for treatment of used water or stormwater. It
targets removal of suspended solids, organic matter, and nutrients (nitrogen and phosphorus) and
to some extent pathogens in used water. It can also be applied for treatment of stormwater to
target removal of suspended solids, organics, and nutrients and, to some extent, pathogens.
Constructed wetlands are man-made engineered system consisting of macrophytes grown in a
natural or imported substrate designed to remove pollutants from incoming flows. Constructed
wetlands are a well-established intervention and are applicable for all types and sizes of
waterbodies. It can be applied at the inflow points to a waterbody, within a waterbody (attractive
when land availability is a constraint), or at any location in the catchment for treatment of used
water or stormwater.
Constructed wetlands can be designed and integrated in the landscape, and therefore enhance
amenity of the waterbody with minimal impact on the community uses. Constructed wetlands can
also enhance the aquatic ecosystem of the waterbody by supporting native vegetation and aquatic
organisms.

83
Figure 33. Treatment processes in a constructed wetland (Payne et al, 2015)
Processes
The main pollutant removal processes for sediments, organic matter and nutrients in constructed
wetlands including sedimentation, decomposition, filtration, adsorption, plant assimilation, and
nitrogen transformation. Apart from denitrification, which is a pathway for permanent removal of
nitrogen, all other processes serve to contain pollutants within the wetland substrate and plant
tissues. Pollutants that are not contained are eventually exported from the wetland.
Dominant processes include:
• Decomposition of organic compounds to simpler forms consuming oxygen in the process.
• Settlement of suspended solids, and nutrients and organic compounds in particulate forms
to the base of the wetland into the substrate.
• Assimilation of inorganic nutrients in plants and algae in their tissues.
• Adsorption of ammonium and phosphorus to soil particles and organic matter
• Transformation of ammonium to nitrates under aerobic conditions (nitrification process)
and subsequently from nitrates to nitrogen gas under anaerobic conditions (denitrification
process) by bacteria.

Pathogens may also be retained via adsorption, sedimentation of particulates, natural die-off,
burial and sunlight exposure.
Planning and design considerations
Constructed wetlands should be constructed once primary treatment measures are in place (See
D1 – Primary Treatment) to protect the macrophyte zone from accumulation of solids and ensure

84
effective treatment. The macrophyte zone generally requires 3-5 days contact time of polluted
water with the plants, substrate, and associated microbial community. Constructed wetlands have
effective pollutant removal performance as long as the system is designed and sized to manage
the pollutant loading.
There are various design configurations for constructed wetlands which can broadly be
categorised into 1) surface flow and 2) sub-surface flow systems (see Figure 33 and Figure 34).
In surface flow systems, water flows above the substrate. The wetland base is generally lined
with clay and covered with a substrate with native vegetation (e.g., cattails, reeds and/or rushes).
In sub-surface flow systems, water flows through the substrate (generally gravel or sand) either in
a vertical direction (vertical flow) or horizontal direction (horizontal flow). The substrate acts as
a filter for removing solids with the microbial community supported by the substrate/plant-root
matrix responsible for other pollutant removal processes.
A surface flow constructed wetland is generally simpler to construct (than a sub-surface flow
wetlands) using locally available materials and can achieve high removal of suspended solids and
moderate removal of pathogens, nutrients, and heavy metals. It is appropriate for used water with
low pollutant loading after some type of primary treatment. It can tolerate variable water levels
and nutrient loads. It is also appropriate for stormwater treatment. Good design and maintenance
can prevent such systems becoming breeding grounds for mosquitoes and can minimise safety
risk including contact with polluted water from standing water.

Figure 34. Illustration of a surface flow constructed wetland (Tilley et al., 2014).
A sub-surface horizontal flow constructed wetland is used for secondary treatment of used water
after some type of primary treatment. The bed is lined to prevent leaching and the wetland is
shallow to maximise water contact with vegetation roots. Clogging is a common problem and
hence primary treatment is important as well as selection of substrate (gravel or sand is generally
suitable but sand is more prone to clogging). It is not appropriate for blackwater. As water flows
below the surface, human and wildlife contact with polluted water is minimised and mosquito
breeding is reduced as there is no standing water.

85
Figure 35. Illustration of a sub-surface horizontal flow constructed wetland (Tilley et al., 2014)
The planning and design of constructed wetlands requires expertise in civil, hydrology and
hydraulics, stormwater and used water management, landscape design and plant species selection
targeted for pollutant removal with tolerance to polluted water.
Constructed wetland systems can also be installed within the catchment to treat used water at the
source (e.g. at the lot or neighbourhood scale such as in Figure 35). Components of the treatment
train generally include a settler tank and/or an anaerobic baffled reactor, a sub-surface horizontal
flow planted gravel filter, and in some instances a polishing pond depending on uses.

Figure 36. Schematic of a decentralised used water treatment system installed at Arvind Eye
Hospital, Pondicherry (Source: CDD Society)
Operation and maintenance considerations
Low-skilled personnel are required for key maintenance activities including removal of
accumulated solids and material, removal of solid waste, cut back and thinning of vegetation,
harvesting and replacement of plants, and maintaining flow paths through the entire width of the
macrophyte zone and ensuring no short-circuits. Replacement of substrate at the inlet zone for
sub-surface systems is required generally every 10 or more years.
Useful resources

86
Manual on Constructed Wetland as an Alternative Technology for used water management in
India.
Central Pollution Control Board (CPCB). (2019). Manual on Constructed Wetland as an
Alternative Technology for Used water Management in India. Ministry of Science & Technology,
Ministry of Environment, Forest & Climate Change. Government of India. Retrieved from:
https://dbtindia.gov.in/sites/default/files/Print_Version_of_CW_Manual-23_May-2019.pdf
UN-HABITAT, 2008. Constructed Wetlands Manual. UN-HABITAT Water for Asian Cities
Programme Nepal, Kathmandu. Retrieved from:
https://sswm.info/sites/default/files/reference_attachments/UN%20HABITAT%202008%20Cons
tructed%20Wetlands%20Manual.pdf
CSIRO (2005), Water Sensitive Urban Design (WSUD) Engineering Procedures – Stormwater,
CSIRO Publishing, Australia.
Melbourne Water (2020), Wetland Design Manual, Australia,
(https://www.melbournewater.com.au)

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D2.2 – Floating wetland
Application level Beneficial effect on waterbody health
Catchment Hydrology and hydraulics
Incoming channel Physical form
Buffer zone Water quality 
Waterbody  Aquatic and riparian
ecosystems
Application
Floating wetlands are purpose-built devices consisting of emergent macrophytes growing
on a floating platform in a waterbody’s open water. The floating platform consists of a
buoyant mat and structures (e.g., PVC pipes, fibreglass, bamboo). Plants are established
directly into the floating platform with roots growing into the water column.
Application of floating wetlands is usually targeted at polishing water quality or for low to
moderately polluted waterbodies. For waterbodies that are highly polluted (e.g., high levels
of nutrients and BOD), application of floating wetlands alone will not be sufficient to
address the problems, with primary and secondary treatment measures to capture pollutants
before it enters the waterbody also required. Floating wetlands can also be applied for
algae and mosquito control in a waterbody.
A key advantage is that it can be implemented within the footprint of the waterbody
requiring no land take and excavation. Another advantage is that the buoyancy of the
structure adjusts with varying water depths in the waterbody – plants are therefore less
sensitive to changing water depths. They also enhance the aquatic ecology and aesthetics
of a waterbody.
Processes
The main pollutant removal processes occur largely within the submerged plant root mat
and its biofilm:
• Decomposition of organic compounds to simpler forms consuming oxygen in the
process
• Assimilation of inorganic nutrients in plants and algae in their tissues
• Adsorption of ammonium and phosphorus
• Transformation of ammonium to nitrates under aerobic conditions (nitrification
process) and subsequently from nitrates to nitrogen gas under anaerobic conditions
(denitrification process) by bacteria

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Figure 37. Schematic of a floating treatment wetland (Source: Department of Environment
and Science, Queensland Government, Australia).

Figure 38. Application of floating macrophyte bed at Neknampur Lake, Hyderabad

(Source: The Hindu).
Planning and design considerations
Several design aspects must be taken into consideration such as the functionality,
durability, anchoring system, weight, buoyancy, and plant species selection. The ability to
keep the asset anchored during high flow velocities, wave action or strong winds needs

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consideration to protect the asset and prevent damage to other infrastructure. Consideration
should be given to the plants’ ability to withstand variation in water quality as floating
wetlands cannot be placed offline during a severe pollution event. Plant species selection
should consider pollutant removal effectiveness, aesthetics, endemicity and robustness
(noting that issues can arise from excessive bird grazing and nesting). Phragmites australis
(common reed) has been found to be highly effective at uptake of nitrogen and phosphorus
in floating wetland systems. There are products available on the market currently, however
floating wetland systems can also be constructed from locally available material.
Operation and maintenance considerations
Low-skilled personnel are required for key maintenance activity including weed removal,
plant cutting back and thinning, pest control and plant replacement. Harvesting plant
material may be required so that they do not release nutrients back into the water column
when they senesce (particularly in eutrophic waterbodies where nutrient mitigation and
removal is the objective). Studies suggest that biofilms that form on plant roots continue to
remove nutrients after plants start to senesce.
Useful resources
Niti Ayog. (2022). Urban Used water Scenario in India–. Water Security, 16, 100119.
Government of India (GOI). https://www.niti.gov.in/sites/default/files/2022-09/Waste-
Water-A4_20092022.pdf

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D2.3 – In-situ drain treatment
In-situ drain treatment measures have been developed to target treatment of used water in
drains. Examples include microbial dosing, horizontal flow filters, floating wetland cells, and
vertical flow filters. These measures can assist with improving water quality before it enters
downstream waterbodies or downstream treatment assets (e.g., constructed wetlands).

Application level Beneficial effect on waterbody health

Catchment Hydrology and hydraulics
Incoming channel  Physical form
Buffer zone Water quality 
Waterbody Aquatic and riparian
ecosystems

D2.3.1 – Microbial dosing

Microbial dosing refers to the application of naturally occurring microbes in the drain to
degrade organic matter generally from untreated used water thus reducing concentration of
organic pollutants entering downstream waterbodies or treatment assets. The microbes
delivered into the drain use the nutrients in the water for their growth and digest the organic
matter (i.e., food source) using oxygen to produce carbon dioxide and water. Microbes are
usually applied to flowing water with contact created at barriers of stones and boulders to
ensure uniform mixing and oxygenation of the water. A key advantage of this technique is
that it can be applied without disturbing the drain structure.
Microbial dosing has been implemented as several sites in India and has shown successful
reduction in BOD. Expertise is required in designing the dosing system, selecting the right
product, determining the dosing program, and monitoring performance. However low-skilled
personnel are required to operate the system once installed. Capital cost is required upfront
for setting up the dosing facility as well as on-going costs from regular application. Because
they are naturally occurring microbes, they are safe to the environment and people.

D2.3.2 – Horizontal flow filter

This technique refers to installation of “bridges” constructed across the drain or in a zig-zag
manner using locally available material (gravel, sand, and soil) with plants grown within the
upper layer of the bridge (Figure 38). Flow and pollutant removal processes are similar to a
sub-surface horizontal flow wetland (see D2 – Constructed wetland). Screens are installed
upstream of the “bridges” to capture suspended and floating materials and litter. Pollutant
removal processes at the bridges include sedimentation, filtration, adsorption, plant
assimilation, nitrogen transformation, and microbial degradation. The length of bridges can
be optimised for pollutant removal depending on the characteristics of the pollutants and
pollutant loading. Disadvantages of this technique are the impact of the barriers on the flow
carrying capacity of the drains and potential scouring of the upper soil layer and vegetation

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from high flow velocities (noting that application in India have often excluded the vegetation
and upper soil layer). Other similar horizontal flow filter products which are modular, mobile
and available in portable units have also been developed such as the PhytoTrap by NEERI.

Figure 39. Schematic of a horizontal flow filter installed in a drain (Source: Satyendra et al.,
2023).

Figure 40. Application of horizontal flow filter in canal leading to Udai Sagar Lake in
Udaipur (Source: Vikalpsangam)

D2.3.3 – Floating wetland cell

This technique refers to devices purpose-built for installation in drain that have the same
features, benefits, advantages and pollutant removal processes as floating wetland (see D3-
Floating wetland). Products have been developed that are modular and available in portable
units such as Phyto-floraft by NEERI (Figure 40).

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Figure 41. Installation of floating wetlands cells in a drain (Source: NEERI)

D2.3.4 – Vertical flow filters

This technique relies on diversion of water from a drain to a vegetated filter media with water
passing through the biologically active filter media in a vertical direction (Figure 41).
Gravity fed systems are generally low cost and require low skilled personnel to perform
routine operation and maintenance such as removal of accumulated material at the surface of
the filter. Vertical flow filters are generally installed adjacent to the drains to stay offline
during high flows (to prevent scouring and damage).

Figure 42. Schematic of a vertical flow filter (Source: NEERI Satyendra et al., 2023)

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D2.4 – Biofiltration system
Application level Beneficial effect on waterbody health
Catchment  Hydrology and hydraulics
Incoming channel Physical form
Buffer zone  Water quality 
Waterbody  Aquatic and riparian
ecosystems
Application
Biofiltration system forms the secondary stage for treatment of stormwater. It targets
removal of suspended solids, organics, nutrients (nitrogen and phosphorus) and to some
extent pathogens in stormwater. A typical biofiltration system consists of a vegetated sand-
based filter media which receive stormwater at the surface with water flowing vertically
down the filter media and collected in a drainage pipe or allowed to infiltrate into the
surrounding soils for groundwater recharge (Figure 42).

Figure 43. Application and schematic of a biofiltration system

Biofiltration system is a well-established technique for stormwater treatment and are
applicable for all types and sizes of waterbodies where stormwater runoff is a primary cause
of poor water quality in the waterbody. It can be applied at the inflow points to a waterbody,
within a waterbody (attractive when land availability is a constraint), or at any location in
the waterbody buffer zone or catchment for treatment of stormwater runoff. They require
smaller footprint than stormwater constructed wetlands for the same pollutant removal
performance and are highly flexible and scalable and therefore suitable for dense urban
spaces.

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 • Small biofiltration systems applied at the street scale or lot-scale are referred to as
‘raingardens’
• Linear biofiltration systems are referred to as “biofiltration swales’
• Larger biofiltration systems applied at end-of-pipe or at inflow points of waterbodies
are referred to as ‘biofiltration basins’

Figure 44. Application of biofiltration technology – Street scale raingarden (left), street
scale linear swale (middle) and end-of-pipe biofiltration basin (Source:Spiire)
Processes
The following treatment processes take place in biofiltration systems:
• As stormwater enters the biofiltration system, soil particles and particulates to settle
out on the surface of the filter media by sedimentation process. In addition,
particulates are filtered from the water as it percolates down through the filter media
(mechanical straining).
• The filter media contains clay minerals and other chemically active compounds that
bind dissolved pollutants (sorption)
• Decomposition of organics
• Adsorption of ammonium and phosphorus to soil particles and organic matter
• Transformation of ammonium to nitrates under aerobic conditions (nitrification
process) and subsequently from nitrates to nitrogen gas under anaerobic conditions
(denitrification process) by bacteria
• Vegetation and the associated microbial community assimilate nutrients and some
other pollutants (e.g. plant and microbial uptake)

Design and planning considerations

Key design considerations include pre-treatment measures for removal of coarse solids such
as sand, plastics and litter to protect the biofiltration system from accumulation of solids.
Construction activities in particularly can generate high sediment loads which can clog the
biofiltration system. Pre-treatment measures can include sediment ponds (see D1.2 –
Sedimentation pond), swales and sediment forebays (Figure 44).

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A key design consideration is sizing the system appropriately for the catchment flows. A
starting point is sizing the biofiltration system with a surface area that is 2% of the
impervious area of the contributing catchment. However, sizing needs to also take into
consideration ponding depth, infiltration rate and vegetation health in the long term.
Oversizing may not provide sufficient flows to sustain vegetation health.
It is important to select a filter media that provides a balance of adequate infiltration rate and
adequate moisture retention to support plant health during the dry season. It is also
important to plant the biofiltration system densely to enhance pollutant removal.
It is also worth considering a submerged zone in the design (by raising the outlet) to provide
anaerobic conditions for permanent removal of nitrogen (via denitrification process) and
water storage to sustain plants during the dry season (Figure 42).

Figure 45. Pre-treatment measures for biofiltration system and other stormwater treatment
assets – Sediment ponds (left) and swales (right)
Operation and maintenance considerations
Typical maintenance activities should focus on health and coverage of vegetation, the filter
media, and hydraulic aspects of the system:
• A strong healthy growth of vegetation is critical to the treatment performance. The
most intensive period of maintenance is during the plant establishment period when
weed removal and replanting may be required. Care during this period will reduce
long-term maintenance requirements.
• The surface of the biofilter is vulnerable to erosion, scour, sediment, and litter
accumulation, clogging and moss growth. These compromise the function of the
system, in terms of the infiltration rate and the capacity to treat stormwater volumes.
Repair minor accumulation of sediment by scarifying the surface between plants and
if feasible, manual removal of accumulated sediment. Repair erosion and infill using
filter media and add features for energy dissipation (e.g., rocks and pebbles at inlets).
Litter removal should be undertaken regularly and manual scraping to remove moss
may also be required.

Useful resources

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Central Public Health and Environmental Engineering Organisation (CPHEEO). (2019).
Manual on Storm Water Drainage Systems, Volume – I, Part A: Engineering Design (First
edition). Ministry of Housing and Urban Affairs (MoHUA). Government of India. Retrieved
from: https://cpheeo.gov.in//cms/manual-on-storm-water-drainage-systems---2019.php
CPHEEO. (2019). Manual on Storm Water Drainage Systems, Volume – II, Part B-
Operation & Maintenance and Part C-Management. MoHUA. GOI. Retrieved from:
https://cpheeo.gov.in//cms/manual-on-storm-water-drainage-systems---2019.php
Adoption Guidelines for Stormwater Biofiltration Systems
(https://watersensitivecities.org.au/wp-
content/uploads/2016/09/Adoption_Guidelines_for_Stormwater_Biofiltration_Systems.pdf)

97
Appendix C – Data sources

C1 – Establishing watershed characteristics

Land use and land cover

Data type Source

Land use Municipal corporation, regional development authority

BHUVAN Portal (https://bhuvan.nrsc.gov.in/home/index.php)
Land cover
Procured satellite images from National Remote Sensing Centre
(NRSC)

Hydrogeology

Data type Source

Hydrogeological Central Groundwater Board (http://cgwb.gov.in/aquifer-atlas)

Aquifer Atlas and Maps – Aquifer Systems of India
State wise Aquifer Atlas and Maps (as on Sep 23) – Chhatisgarh,
Karnataka, Kerala, Himachal Pradesh, Meghalaya, Goa, Andhra
Pradesh, Madhya Pradesh, Tamil Nadu

Soil Map Soil & Land Use Survey of India

Catchment and topography

Data type Source

Drainage network Municipal corporation, regional development authority

Primary data – collected through topography survey

Watershed/Micro- Soil & Land Use Survey of India

watershed Watershed delineation and corresponding natural drainage pattern
can also be derived through Arc GIS using Digital Elevation Model
(DEM). The gridded tiles for DEM downloaded from Bhuvan has a
vertical accuracy of 8m at 90% confidence.
Higher resolution DEM can be purchased from NRSC.

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Incoming flow to waterbody

Data type Source

Flow from the catchment Chapter 4: Runoff Estimation, Manual on Storm Water Drainage
System, Volume -I (Part A: Engineering Design), 2019. Published
by Central Public Health and Environment Engineering
Organisation (https://mohua.gov.in/publication/manual-on-storm-
water-drainage-systems--2019.php)
Using tools such as Arc Hydro (https://www.esri.com/en-
us/industries/water-resources/arc-hydro), SWAT
(https://swat.tamu.edu/), BASINS
(https://www.epa.gov/ceam/better-assessment-science-integrating-
point-and-non-point-sources-basins), PCSWMM
(https://www.pcswmm.com/).

Other sources of flow Incoming flow from upstream Used water treatment plants
discharging into the waterbody. Collect the outflow discharges
from the utility/organisation operating the plant.
Untreated used water from areas not connected with network
discharging into the drains leading to waterbody. Install flow
meters at the inlet of the waterbody.

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C2 – Establishing waterbody and meteorological characteristics
Bathymetry with waterbody inlet and outlet survey

Data type Source

Waterbody bathymetry Primary data collection. It is recommended to collect the data at

10 m × 10 m grid. It will include surveying of the waterbody inlet
and outlet.

Water and Sediment Quality

Data type Source

Physico-chemical data of Kindly refer to Appendix A – Recommended quality parameters

lake water and sediment
quality

Meteorological Data

Data type Source

Rainfall and Evaporation Indian Meteorological Department

Data Rainfall – recommended data is at hourly resolution preferably for
the rain gauge with long duration (30 years or more) data
availability.
Evaporation – daily evaporation data.
If the nearest available rain gauge station from the waterbody does
not have long term data, consider closest gauge station with long
meteorological data record.

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Credits
This Advisory on Waterbody Rejuvenation is an outcome of dedicated efforts by individuals
who were part of creating this document under the aegis of AMRUT 2.0 Mission of Ministry of
Housing and Urban Affairs (MoHUA).

Team’s heartfelt thanks to Ms D Thara, Addl. Secretary and Mission Director AMRUT 2.0
(MoHUA) whose vision and commitment has made it possible to incorporate Waterbodies as an
integral part of thriving Urban Water Ecosystem. Mr. Lavnya Kumar, Director (IC), MoHUA,
and Ms Tanvi Garg, Dep. Secretary, MoHUA, who provided their unwavering support and
valuable guidance through preparation of this advisory.

Dr Harry Virahsawmy, Urban Water Specialist at Alluvium, and to the project team – Advait
Madav, Aksheyta Gupta, Tony Weber, Parth Gohel and Shivani – for the guidance, research
and inputs in preparing this advisory.

Mr. Gaurav Bhatt, Water Lead – ARUP’s AIWASI Team, for his technical inputs and writing
of the report.

The Australian Department of Foreign Affairs and Trade (DFAT), and the team from Australian
High Commission New Delhi – Ms Belinda Costin, First Secretary (AHC), and Mr.
Nagasreenivas Kanchi, Senior Technical Advisor, for their support through the preparation of
this advisory.

It is hoped that this Advisory on Waterbody Rejuvenation will serve as a valuable guidance
document for cities to embark on a transformative journey of sustainable and resilient Urban
Waterbody Management.

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