Rethinking Urban Water Management Through Drivers-Pressures-States-Impacts-Responses Framework Application in Chennai, India

1 Rethinking urban water management through Drivers-Pressures-States-Impacts-Responses framework application in Chennai, India Daniel Rosado1,2,3*, Valeria Fárez-Román4, Felix Müller5, Indumathi Nambi2, Nicola Fohrer1 1 Department of Hydrology and Water Resources Management, Institute for Natural Resource Conservation, Kiel University, 24118 Kiel, Germany. 2 Department of Civil Engineering, Indian Institute of Technology Madras, 600036 Chennai, India. 3 Indo-German Centre for Sustainability, Indian Institute of Technology Madras, 600036 Chennai, India. 4 UFZ - Helmholtz Centre for Environmental Research, Department Lake Research, Brückstr. 3a, 39114 Magdeburg, Germany 5 Department of Ecosystem Management, Institute for Natural Resource Conservation, Kiel University, 24118 Kiel, Germany CORRESPONDING AUTHOR: * Department of Hydrology and Water Resources Management, Institute for Natural Resource Conservation, Kiel University, Olshausenstr. 75, D-24118 Kiel, Germany. Tel.: 0049 431 880 4889; Email address: [email protected] (Daniel Jesús Rosado Alcarria). 2 Abstract 1 Cities suffering water scarcity are projected to increase in the following decades. However, 2 the application of standardized indicator frameworks for assessing urban water resource 3 management problems is on an early stage. India is expected to have the highest urban 4 population facing water scarcity in the world by 2050. In this study, the authors assess how 5 the Drivers-Pressures-States-Impacts-Responses framework, a causal framework adopted by 6 the European Environment Agency, can contribute to evaluate water management challenges 7 in cities and apply it to Chennai, India´s fourth-largest urban agglomeration. 8 The framework proved to be a helpful tool for the evaluation of water management challenges 9 in cities by disentangling relationships between environmental indicators and structuring 10 disperse data that allows a better understanding for policy makers. The main drivers identified 11 in Chennai were population growth and economic development which generated impacts such 12 as loss of aquatic ecosystems, low water table, low water quality and reduction of biodiversity 13 and human health. As a response, better urban planning, projects for new water infrastructure, 14 and water bodies restoration have been implemented. Nevertheless, Chennai keeps facing 15 difficulties to achieve a proper water management. The severe hit of COVID-19 pandemic on 16 the Indian economy and its future management will be key for achievements related to water 17 management. 18 19 Keywords 20 Water Resources Management, Land-use change, water scarcity, Environmental causal 21 framework, Urban resilience, South India. 22 23 24 3 1 Introduction 25 Cities around the globe are suffering from water scarcity. In 2009, at the end of the “Millennium 26 Drought”, water storage volumes feeding Melbourne fell to a historic low of 25.6% of capacity 27 (Low et al. 2015; van Leeuwen 2017). In 2013 and 2014, Sao Paulo became dependent on 28 reservoirs with available water percentages in the single digits (Millington 2018). In 2018, Cape 29 Town faced a Day Zero in which pipes went dry and people needed to collect drinking water 30 from distribution points (Zetland 2021). 31 Urban water demand will increase by 80% by 2050, while rapid population growth and 32 urbanization of cities put significant pressure on water resources (Newton 2016) and climate 33 change is altering the timing and distribution of water (Flörke et al. 2018). In this context, the 34 number of large cities facing water scarcity was projected to increase from 193 (37%) to 292 35 (56%) and global urban population facing water scarcity was projected to double from 933 36 million (33%) in 2016 to 1.693–2.373 billion (35–51%) in 2050 (He et al. 2021). Consequently, 37 water insecurity will be one of the most severe crisis the world will face during the next several 38 decades (UNESCO and UN-Water 2020). Cities are also facing a problem of water quality 39 with impacts on health and ecosystems (Chaturvedi 2012). In 2020, at least 2 billion people 40 used a drinking water source contaminated with faeces (WHO World Health Organization 41 2020) and 3.6 billion lacked safely managed sanitation (World Bank 2020). 42 India had the highest number of urban inhabitants facing water scarcity worldwide in 2016 43 (222 million people). This is expected to increase to 550 million in 2050, i.e. 26.7% of the 44 world’s urban population facing water scarcity (He et al. 2021). City development and poor 45 institutional control (Chaturvedi 2012; Hossain et al. 2013) have resulted in the pollution of the 46 majority of surface water bodies with untreated sewage (Chaturvedi 2012) and promoted over47 extraction of ground water (Wada et al. 2012). Chennai, India´s fourth-largest urban 48 agglomeration, exhibits a complex setup around water resources management that generates 49 social, political and environmental tensions, including water-poor areas where human 50 development is limited (Allen et al. 2006). In 2019, the city hit Day Zero when its four major 51 reservoirs dried up and four million people were relying solely on water tankers (Jayaraman, 52 2019; “Water crisis in Chennai", 2019). 53 Traditionally, cities relied on large-scale infrastructure for water management, often with 54 systems operating independently of each other (Brown et al. 2009; Marlow et al. 2013). 55 Addressing water management in cities with complex scenarios like Chennai requires an 56 integrated approach, such as the Integrated Urban Water Management (IUWM) process. This 57 approach encompasses water supply, sanitation, stormwater, and wastewater management 58 integrating them with land use planning and economic development (Bahri 2012). The concept 59 of IUWM emerged in the 1980s, highlighting the interconnections between actors, surface 60 water, groundwater, and issues of water quantity and quality and has evolved over the years 61 (Benson et al. 2015; Hoekstra et al. 2018; Manny 2022). In the 1990s, Sustainable Urban 62 Water Management (SUWM) became prominent, driven by growing concerns for ecological 63 health and sustainable development, integrating environmental variables more 64 4 comprehensively into the discussion (Hoekstra et al. 2018; Pluchinotta et al. 2021). In the late 65 2000s, Adaptive Water Management emerged in response to the need for climate change 66 adaptation (Kirono et al. 2014; Hoekstra et al. 2018). Recently, concepts such as Water Risk, 67 Water Resilience, the Water-Food-Energy Nexus, Total Water Cycle Management (Maurya 68 and Singh 2022), and Water Sensitive Urban Design (van der Meulen et al. 2023) have 69 become influential (Hoekstra et al. 2018). In parallel and since around 2000, water security 70 has also emerged as a central concept, broadly encompassing integrated, sustainable, and 71 adaptive aspects (Hoekstra et al. 2018). The relevance of water security is underscored by its 72 recognition and definitions from the Global Water Partnership (GWP 2000), the World Water 73 Council (WWC 2000), and the United Nations (UN-Water 2013). Over time, the term has 74 evolved to include various attributes, such as affordability, human well-being, water-related 75 disasters, hazard, risk, political stability, and resilience (Romero-Lankao and Gnatz 2016; 76 Chapagain et al. 2022). 77 Although IUWM is a crucial process to prevent water crises regardless of water scarcity (Di 78 Baldassarre et al. 2018) and has the highest potential to reduce pressures on water resources 79 (Koop and van Leeuwen 2015a), there is no internationally standardized indicator framework 80 for it (Koop and van Leeuwen 2015a). This situation compromises the achievement of the 81 United Nations Sustainable Development Goals (SDGs) numbers 6 Clean Water and 82 Sanitation and 11 Sustainable Cities and Communities (United Nations 2015; He et al. 2021). 83 Several models and frameworks are used for analyzing water management, environmental 84 issues and socio-ecological systems: causal-chain frameworks, such as the Pressure-State85 Response (PSR), Pressure-State-Impact-Response (PSIR), and the Drivers-Pressures86 States-Impacts-Responses (DPSIR), sustainability assessment frameworks, including the 87 Social-Ecological Systems Framework (SESF) and the Ecosystem Services Framework, and 88 integrated water management frameworks, like the City Blueprint and the Asian Water 89 Development Outlook (AWDO) frameworks. 90 The PSR framework emphasizes the relationship between environmental pressures, the 91 current state of the environment, and societal responses (Maurya and Singh 2022), while the 92 PSIR framework incorporates an "Impact" stage (Van Ginkel et al. 2018). The DPSIR, a causal 93 framework for describing the interactions between society and the environment, provides an 94 organized structure to assessing the causes, consequences, and responses to changes in 95 ecosystems (Gabrielsen and Bosch 2003; European Environment Agency 2020). The SESF 96 is used to diagnose the sustainability of social-ecological systems (Ostrom 2009), while the 97 Ecosystem Services Framework categorizes the benefits humans obtain from ecosystems, 98 with an emphasis on natural resource management (Matzdorf & Meyer, 2014). The City 99 Blueprint framework (van Leeuwen et al. 2012; Koop and van Leeuwen 2015b) uses 24 100 indicators across eight categories, including water security, water quality, sanitation, 101 biodiversity, and governance. It measures integrated water resources management 102 performance implemented by local water authorities (Hoekstra et al. 2018) and includes an 103 additional framework for describing significant trends and pressures that may impact water 104 management (Koop and van Leeuwen 2015b). The AWDO framework (Asian Development 105 5 Bank 2020) assesses water security through five key dimensions: households, economies, 106 cities, the environment, and resilient communities. 107 The DPSIR framework is particularly suitable for urban water management due to its holistic 108 and integrated approach. Simplified frameworks like PSR and PSIR are straightforward, easy 109 to use, and effectively link pressures to state changes and policy responses (Hazbavi et al. 110 2020). This clarity makes them useful for decision-makers. However, they often lack the depth 111 required for comprehensive urban water management by oversimplifying interactions 112 (Niemeijer and De Groot 2008; Levrel et al. 2009). Compared to SESF and the Ecosystem 113 Services Framework, DPSIR not only addresses sustainability and ecosystem services but 114 also analyzes the system with a holistic approach, which is key for complex scenarios like 115 water management in Chennai. The City Blueprint framework provides a detailed structure but 116 is complex, requiring a dual framework that focuses on water resources management 117 performance as well as trends and pressures. This complexity, along with the need for 118 extensive and specific data, can impede its application, especially in developing countries 119 (Hoekstra et al. 2018). The AWDO framework provides a holistic view of water security by 120 addressing interconnected and interdependent dimensions. However, it is primarily designed 121 for national assessments, includes only five urban-specific indicators, and uses averaged data 122 for all urban areas across a country, which limits its usefulness for IUWM (Jensen and Wu 123 2018). 124 Adopted by the European Environment Agency, the DPSIR framework provides an organized 125 structure to assess the causes, consequences, and responses regarding water management 126 (European Environment Agency 2020), that facilitates communication with stakeholders 127 (Tscherning et al., 2012). Additionally, it has been widely applied to assess the environmental 128 state of cities (Kohsaka 2010), rural communities (Gari et al. 2018a) and river basins (Kong et 129 al. 2016; Pagan et al. 2020a), and has demonstrated its utility to describe cause effect 130 relationships in cases with limited data availability (Gari et al. 2018b), and to develop causal 131 chains (Pagan et al. 2020b). 132 Hence, this study aims to address the following research questions: (i) How can the DPSIR 133 framework contribute to evaluate water management challenges in cities with wicked water 134 problems? (ii) What are common limitations for effective water management in cities located 135 in developing countries and facing resource scarcity? These questions will be addressed 136 through the application of the DPSIR framework to the city of Chennai, India. 137 138 6 2 Materials and methods 139 2.1 Study area 140 Chennai, known as Madras until 1996, is the capital of the Indian state of Tamil Nadu. It is 141 located on the southeastern coast of India (13o05′N and 80o18′E), on the Bay of Bengal (Figure 142 1). Nowadays, the Chennai city limits coincide with the Chennai district (Government of Tamil 143 Nadu 2020). According to the 2011 Indian census, the Chennai district had 7,088,000 144 inhabitants in an area of 426 km2 (Directorate of Census Operations Tamil Nadu 2011). 145 Chennai city is governed by the Greater Chennai Corporation (Chennai District 2020). 146 The Chennai city district together with parts of Tiruvallur, Kanchipuram and Chengalpattu 147 districts constitute the Chennai Metropolitan Area (CMA) with an extension of 1189 km2 148 (CMDA 2020a) and 8.70 million inhabitants according to the 2011 Indian census (Directorate 149 of Census Operations Tamil Nadu 2011). The Chennai Metropolitan Development Authority is 150 in charge of urban planning in this area. 151 152 Figure 1. Chennai location and water bodies. Source: Authors. Note: India on the globe 153 image, Wikimedia Commons, 2014 (https://creativecommons.org/licenses/by-sa/3.0). CC 154 BY-SA 3.0 155 156 7 Chennai has a tropical wet and dry climate (Köppen: Aw) with a relative constant temperature 157 (Rajanikanth and Rajini Kanth 2020). In the period 1971-2000, highest and lowest average 158 monthly temperatures showed annual variations ranging from 28.9 to 37.1oC and from 21.2 to 159 28.0oC and the average monthly rainfall ranged from 2.2 to 407.4 mm (Selvaraj et al. 2016). 160 The hottest part of the year is late May and early June and the coolest is January (Prakash 161 and Punyaseshudu 2015). The average annual precipitation is around 1,400 mm (Rajanikanth 162 and Rajini Kanth 2020). The lowest precipitations occurred in February, during the pre163 monsoon season, and the highest from mid–October to mid–December in the northeast 164 monsoon (NE) season (Selvaraj et al. 2016). Regarding climate change, mean temperatures 165 have risen (maximum, 1.6°C; annual, 1.3°C; minimum, 1.0°C) from 1951 to 2010 (Jeganathan 166 and Andimuthu 2013) while rainfall tendency is unclear (Ramachandran and Anushiya 2015; 167 Rangarajan et al. 2018). Concerning floods, Oldenborgh et al. (2016) found no signal for a 168 positive trend in extreme one-day precipitation at the southeastern coast of India over 1900169 2014. 170 Chennai is situated on a flat area known as the Eastern Coastal Plains with an average 171 elevation of 6.7 m.a.s.l. and a highest point of 60 m.a.s.l. (Pulikesi et al. 2006). The rivers of 172 Chennai flow from west to east, draining into the Bay of Bengal, and divide the city into north– 173 south sections. Two major rivers are the Cooum River, located in the center of the city, and 174 the Adyar River to the south. A third river, the Kortalaiyar, flows through the northern fringes 175 of the city before draining into the sea, at Ennore. The three rivers are connected by the 176 Buckingham Canal, a fresh water artificial waterway parallel to the Coromandel Coast. 177 Additionally, there are four reservoirs called Poondi, Cholavaram, Puzhal, and 178 Chembarambakkam (Mariappan 2014) and many artificial lakes, locally called tanks that 179 traditionally stored water during the monsoon season that was used for irrigation during the 180 dry season (Devi et al. 2020). 181 The Chennai ecosystem has been dominated by Palmyra and Phoenix palms interspersed 182 with thickets with a mixture of grasses and short herbs in the intervening spaces; allowing free 183 surface water flows and preventing flooding. Trees were sparse and local (Ranjit-Daniels et 184 al. 2020). Pallikaranai Marsh stand out with multiple species of plants, fish, birds, butterflies, 185 and reptiles (Surya 2016) although it has been heavily urbanized within the last 30 years 186 (Coelho 2018). 187 188 8 2.2 Application of the DPSIR framework 189 In this work, we applied the DPSIR framework (Gabrielsen and Bosch 2003; Kristensen 2004; 190 European Environment Agency 2020) and, consequently, defined its components (drivers, 191 pressures, states, impacts, and responses) and its causal chain in relation to water 192 management in the city of Chennai, India. The components of the DPSIR framework and their 193 linkages are depicted in Figure 2 while their definitions can be found in the literature (Smeets 194 and Weterings 1999; Gabrielsen and Bosch 2003; Kristensen 2004; Semeoshenkova et al. 195 2017). 196 197 Figure 2. The components of the DPSIR framework and their connections. 198 The application of the DPSIR framework and the definition of its components involved an 199 extensive literature research in Scopus, Web of Sciences core collection and Google Scholar 200 (Patrício et al. 2016). Also, data reports and other documents provided by public 201 administrations. Thus, the websites of the Chennai Metropolitan Water Supply and Sewerage 202 Board (CMWSSB, also known as Metrowater), Chennai Metropolitan Development Authority 203 (CMDA), Tamil Nadu Water Supply and Drainage (TWAD) Board, Tamil Nadu Pollution 204 Control Board, Central Pollution Control Board, Central Ground Water Board (CGWB) were 205 consulted, as well as the second edition of the master plan of Chennai and renowned 206 newspapers. 207 Pressures Drivers States Responses Impacts 9 3 Results 208 3.1 Overview 209 210 Figure 3 presents the components and causal chain of DPSIR analysis of water management 211 in Chennai. Also, a table shows the indicators used in this study in the supplementary material 212 (Table S1). 213 214 Figure 3. Components and causal chain of DPSIR analysis of the water management in 215 Chennai, India. 216 3.2 Drivers 217 3.2.1 Population growth 218 Chennai is today a cosmopolitan megacity due to a transformation that started in the last 219 century and continues in the present. The 20th century brought to Chennai an accelerated 220 16 GW 40-68 63-107 110-357 3-9 (2017) Pallikaranai marshland SW 0.002– 0.14 0-0.02 0.03–1.13 0-0.019 0-1.52 0.10–1.52 0-0.60 Karpagavalli et al. (2012) SD 149.4 102 36.6 1.6 0.58 30,201 382 85 Jayaprakash et al. (2010) Ground water City area GW 26-130 1.2-141.6 71-1,200 3-36 Krishna Kumar et al. (2015) Ennore creek PVa 4.658 3.289 0.761 0.416 8.957 Vasanthi et al. (2017) PVb 3.378 3.098 0.892 0.315 7.987 358 17 3.4.4 Biodiversity status 359 Encroachment and pollution of natural and artificial water bodies has affected Chennai’s 360 aquatic biodiversity. Amali et al. (2019) found that the wetlands located within the coastal 361 districts of Tiruvallur, Chennai and Kancheepuram were only 15.8% of the total area in 2016. 362 In the Pallikaranai marshland species diversity has been reduced due to wetland occupation 363 and wastewater and solid waste pollution. According to Azeez et al. (2007) and Vencatesan 364 (2007), 114 plant and 223 animal species can be found in the wetland, including endangered 365 species. Plants include two endemics to Peninsular India (Cynodon barberi and Iseilema 366 enthephroides), and exotic plants like water hyacinth (Eichhornia crassipes) and water lettuce 367 (Pistia stratiotes). 115 bird, 46 fish, 21 reptile, 10 amphibian, 10 mammal, 9 mollusk, 5 368 crustacean and 7 butterfly species have been reported. Raj et al. (2010) reported 101 species 369 of resident and migratory birds. Knight and Devi (2010) found 75 fish species on the freshwater 370 habitats around Chennai. 371 3.5 Impacts 372 3.5.1 Loss of aquatic ecosystems 373 Urbanization involved occupation, mismanagement and drainage of wetlands and the 374 abandonment of water tanks (Amirtham et al. 2009; Meenatchi Sundaram 2011; Murawski 375 2015). Therefore, water bodies shrank by 30.6%, i.e. an average annual reduction of 1.25% 376 (Mathan and Krishnaveni 2020). 377 The Pallikaranai marshland drained about 250 km2 and occupied an area of 56 km2 over 378 today’s residential localities such as Velachery, Thoraipakkam, Perungudi and Pallikaranai 379 until 1980 (Vencatesan 2007; Sree Sharmila and Swathika 2016). Construction in this area 380 reduced its extension to only 6 km2 (Steinbruch and Hörmann 2015; Sree Sharmila and 381 Swathika 2016). In 2005, 0.57 km2 were used as a dumpsite and 1.37 km2 were impacted by 382 garbage and sewage (Vencatesan 2007). In 2007, 3.17 km2 were declared as a Reserve 383 Forest (Vencatesan 2007). Nowadays, there are two garbage-dumping yards in its outskirts. 384 Into the bargain, untreated or partially treated sewage enters the wetland due to direct 385 discharge or the Perungudi sewage treatment plant (The Hindu 2019). 386 Shifting drinking water supply from surface water to ground water sources in the past resulted 387 in the degradation and abandonment of water tanks (Ariza et al. 2007; Palanisami et al. 2008; 388 Adelina 2015). The Tamil Nadu administration tried to change this situation with the Protection 389 of Tanks and an Eviction of Encroachment Act, in October 2007. However, this law has not 390 been fully implemented (Lavanya 2013). Approximately 15% of the water storage capacity of 391 the tanks in Adyar basin was lost due to heavy siltation (Massuel et al. 2014). 392 3.5.2 Low water table 393 Groundwater over-extraction and reduced groundwater recharge due to dense urbanization 394 and increase of paved areas have caused declining groundwater levels (Srinivasan et al. 395 18 2013). Subsequently, aquifers are salinized due to seawater intrusion (Butterworth et al. 2007; 396 Brunner et al. 2014; John 2015). 397 According to the Central Groundwater Board, 80% of Chennai's groundwater has been 398 depleted (Balan et al. 2012) and all of the 20 groundwater assessment units in Chennai are 399 over-exploited. In May 2019 (pre-monsoon), 64% of 11 monitored wells presented a water 400 level of 5 to 10 m and 36% of 2 to 5 m (Central Ground Water Board 2020). Any further 401 exploitation could lead to severe salt water intrusion (Balan et al. 2012). In peri-urban areas, 402 groundwater over-extraction has caused a decline of the groundwater table: the pre-monsoon 403 and post-monsoon groundwater level fluctuation varied from 2–6 m to 0–5 m, respectively, 404 during 1971–2007 (Packialakshmibb et al. 2011). An evaluation of the total change in 405 groundwater storage across the state of Tamil Nadu from 2002 to 2012 concluded that 406 groundwater depletion rate is 8% higher than the annual recharge rate (Chinnasamy and 407 Agoramoorthy 2015). 408 3.5.3 Low water quality 409 The estimated 1073 MLD of sewage directly discharged into water bodies, together with 410 industrial waste water produced a poor quality status of the aquatic ecosystems of Chennai 411 (Amirthalingam 2003). 412 The Adyar river suffers from agricultural pollution upstream Nandambakkam, where it starts 413 to receive untreated sewage (Venugopal et al. 2009; Lakshmi and Deepa 2011). This river is 414 not perennial and only carries enough water during the rainy season. The rest of the year is 415 almost stagnant due to the lack of water and the formation of sand bars near the mouth 416 (Lakshmi 2011), transporting undiluted effluents from sewage treatment plants (CMDA 2008). 417 The situation is similar in the Cooum river (Dhamodharan et al. 2019). Beyond Vanagram up 418 to its mouth, the river is highly polluted due to its perennial state, siltation, sand bar formation 419 and almost stagnant state (Mukhopadhyay et al. 2020), and the discharges of untreated 420 sewage and industrial waste water (Nethaji Mariappan et al. 2017). Also in the Buckingham 421 Canal, that receives sewage and industrial effluents during its course through the city and the 422 silting up of the canal has left the water stagnant (Jayaprakash et al. 2012). Encroachment in 423 some sections of the central area has shrunk its width from 100 m to 10 m (2019b). 424 The lakes and the Pallikaranai marshland have suffered from encroachments, dumping, 425 burning of wastes and sewage and industrial waste water discharge (Shahina et al. 2020). 426 The Pallikaranai marshland is additionally polluted by the non-isolated Perungudi dumpsite 427 (Padmavathi 2007). High concentrations of Cd, Hg, Cr, Cu, Ni, Pb, and Zn were found in its 428 sediments (Jayaprakash et al. 2010). Sea water has intruded up to 16.5 km inland in Minjur - 429 Panjetty area due to over exploitation of groundwater (Government of India 2017). 430 Seawater is polluted nearby the river mouths of the Adyar and the Cooum rivers by high 431 concentrations of nutrients, low dissolved oxygen, high biochemical oxygen demand (BOD) 432 and chemical oxygen demand (COD), high total suspended matter, high trace elements 433 (Shanmugam et al. 2007; Mishra et al. 2015), high level of coliforms, Vibrio and Pseudomonas, 434 (Santhiya et al. 2011), and presence of antibiotic resistant pathogens (Vignesh et al. 2012) 435 19 and microplastics (Kumar et al. 2016). 436 3.5.4 Reduction of biodiversity and human health 437 Amali et al. (2019) found that the wetlands located within the coastal districts of Tiruvallur, 438 Chennai and Kancheepuram have decreased to 31.6%, from 23.1% in 1988 to 15.8% in 2016, 439 i.e. an average annual reduction of 1.35%. 440 The degradation of aquatic ecosystems in Chennai has impacted its biodiversity. Invasive 441 species, like the ornamental fish suckermouth, have been introduced and affected local 442 species population (Oppili 2017). Water hyacinth colonized and significantly affected the 443 biodiversity in Pallikaranai Marshland (Surya 2016). The construction of roads fragmented the 444 marshland and limited the movement of animals (Azeez et al. 2007), with a reduction of 445 resident birds in general (Vencatesan 2007) and the Black-winged Stilt in particular from 836 446 individuals in 2000 (Subramanian 2000) to 150 in 2010 (Raj et al. 2010). 447 For Buckingham Canal, the changes in the water quality reduced the primary productivity, 448 affecting the entire aquatic ecosystem (Kumar et al. 2018). In Ennore estuary, 15 species were 449 found dead in large numbers in August 2014 (Sachithanandam et al. 2017). High 450 concentrations of Fe, Mn, Zn, Cu, Pb and Cd in Mugil cephalus fish and ultrastructural 451 alterations on the green mussel Perna viridis have been found (Arockia Vasanthi et al. 2013; 452 Vasanthi et al. 2017). At the discharge site of the power plant located in Ennore, the population 453 density of phytoplankton and zooplankton is reduced by 64% and 93%, respectively (Prince 454 Prakash Jebakumar et al. 2018). 455 The pollution of water resources has also adversely affected Chennai’s inhabitants health. 456 The stagnant water in Buckingham canal creates an attractive habitat for malaria-spreading 457 mosquitoes (Jayaprakash et al. 2012). Water-borne diseases like Diarrhea and Typhoid are 458 common (Sethuram 2014). Drinking water in some areas was highly contaminated with 459 coliforms, Cryptosporidium and Isospora (Anbazhagi et al. 2007; Lavanya 2013; Chopra and 460 Dworkin 2013), including sachet water but not bottled water (Venkatesan et al. 2014). 461 3.6 Responses 462 3.6.1 Urban planning 463 Chennai has had two master plans for urban planning. The First Master Plan for Chennai 464 Metropolitan Area was approved in 1976 and the Second is in force since September 2008 465 (CMDA 2020b). Nevertheless, the urban form of the Chennai Metropolitan Area has been 466 dictated by developments along the major roads and rail links radiating from the center of 467 Chennai into the peri-urban regions (CMDA 2008). The second Plan included chapters for 468 infrastructure for water supply and sanitation, with a recommendation to allocate water to 469 areas within the city and outside, and for environment, with a recommendation to reduce 470 pollution levels to acceptable standards in the waterways of Chennai. Recently, the 471 elaboration of a third master plan with long-term vision document produced through a 472 participatory approach has been announced, being planned to be implemented from 2026 and 473 20 to last for two decades (Shivakumar 2020). 474 3.6.2 Water infrastructure 475 Chennai has developed a big water infrastructure consisting on dams and interbasin transfers, 476 groundwater pumping, rainwater harvesting, desalination plants and water tankers. 477 Over 90% of the water supply of Chennai is covered by water stemming from reservoirs 478 (Brunner et al. 2014; Sakthivel et al. 2015). Surface water is provided mostly through two 479 systems of interconnected reservoirs. The oldest system has three reservoirs at Poondi (91.5 480 hm3) and Cholavaram (25 hm3), that discharge into Puzhal (93.5 hm3), also called Red Hills. 481 This water is treated at Puzhal (300 million liters per day, MLD), Kilpauk (270 MLD) and 482 Surapet (14 MLD) (CMDA 2006; CMWSSB 2020b). The newest system has 483 Chembarambakkam reservoir (103,2 hm3) and Chembarambakkam Water Treatment Plant 484 (530 MLD) (CMDA 2006; CMWSSB 2020b). 485 When water is scarce, around 500 MLD water from the Srisailam reservoir in the Krishna 486 River, can be diverted towards Poondi Lake through a series of 400 km-long inter-linked 487 canals called the Telugu Ganga project (CMDA 2006). Also, Veeranam lake and Vadakuthu 488 Water Treatment Plant (180 MLD) are added to the system. In total, the capacity of the cited 489 water treatment plants is 1,294 MLD (CMWSSB 2020c). 490 Groundwater’s contribution has significantly diminished due to overexploitation 491 (Packialakshmibb et al. 2011; Sakthivel et al. 2015) from a maximum of 25% to around 6% 492 during the 2000’s (Brunner et al. 2014). Because of low water level in the inner-city, 493 Metrowater started to hire private peri-urban agricultural wells in 2000 that yielded 77 MLD in 494 2005 compared to only 5.99 MLD of previous wells (CMDA 2006). Currently, Metrowater 495 continues extracting in peri-urban areas: Minjur, Panjetty, Tamaraipakkam Poondi and 496 Kannigaiper (CMWSSB 2020d). In fact, most of the agricultural wells in the villages in the 497 Chennai Metropolitan Area feed the inner city water market through water tankers 498 (Packialakshmibb et al. 2011) depriving peri-urban farmers of irrigation water (Butterworth et 499 al. 2007). In the southern peri-urban interface, 17.1 MLD are extracted by private water tankers 500 and 19.2 MLD by packaged water industries (Packialakshmibb et al. 2011). Also many 501 households in Chennai have in-house wells (Ruet et al. 2007). 502 To improve this situation, installation of Rain Water Harvesting (RWH) structures became 503 mandatory for new buildings in 2002 (CMWSSB 2020d). Since then, 38,218 structures have 504 been constructed (CMWSSB 2020d) with high acceptance by the public (Vivek 2016) but 505 maintenance issues were reported (Ministry of Water Resources and Government of India 506 2011). 507 Since 2010, a 100 MLD seawater desalination plant is operating at Minjur, north of the city, 508 and a similar 100 MLD plant at Nemmeli, south of the city, since 2013 (CMWSSB 2020e). A 509 third 150 MLD plant is expected to be completed by April 2023 (Lakshmi 2022) and a fourth 510 400 MLD at Perur by 2024 (Lakshmi 2019). 511 Tanker-based water supply is estimated to be 21% of the total water supplied in Chennai 512 21 (Maheshwari et al. 2020) i.e. around 125 MLD (Venkatachalam 2015), that would be delivered 513 by up to 20,000 daily tanker loads of water (The Hindu 2018). About 80% of households in the 514 Chennai Metropolitan Area consume packaged drinking water instead of piped water (The 515 Hindu 2018). About 15-20 MLD of packaged drinking water are sold in the city daily (Srinivasan 516 2008). 517 3.6.3 Sewage treatment 518 The total installed wastewater treatment capacity in Chennai reaches 727 MLD in 12 sewage 519 treatment plants, however, it is estimated that nearly 1073 MLD of sewage are directly 520 discharged into water bodies (Arappor Iyakkam 2017). The 12 treatment plants are divided in 521 zones from I to V and their treatment capacity ranges from 12 to 120 MLD. In Nesapakkam, 522 Koyambedu and Kodungaiyur, plants use activated sludge process and in Villivakkam an 523 aerated lagoon (CMDA 2020b). In 2005 and 2006, the Chennai City River Conservation 524 Project (CCRCP) invested Rs. 7201.5 million to increase the sewage treatment capacity, 525 prevent overflow of sewage into the city waterways and renovate part of the system (CMDA 526 2006). 527 3.6.4 Restoration of water bodies 528 There are several projects to restore Chennai’s water bodies. The Chennai Rivers Restoration 529 Trust, founded in 2006 by Government of Tamil Nadu as Adyar Poonga Trust, have three 530 projects: the Eco-Restoration of Adyar Creek (58 acres), the Eco-Restoration of the Adyar 531 Creek and Estuary (300 acres) and the Integrated Cooum River Eco-Restoration Plan 532 (Chennai Rivers Restoration Trust 2020). 533 The non-governmental organizations (NGOs) Care Earth Trust and The Nature Conservancy, 534 among others, have developed wetland restoration projects introducing a sustainability and 535 community participation focus. Care Earth Trust has successfully completed the restoration of 536 the Narayanapuram Lake, the Perungalathur Periya Eri, the Puduthangal Lake, Thazhambur 537 Eri, the Sembakkam Lake, the Puducheri Keni kulam and the Odai keni kulam (Care Earth 538 Trust 2020). 539 In the Pallikaranai marshland, 317 ha of its southernmost portion were declared as a bird 540 sanctuary on April 2007 (Vencatesan 2007; Steinbruch and Hörmann 2015) and its declaration 541 as Ramsar site is in progress (Shekhar 2020). 542 3.6.5 Water governance 543 The Chennai Metropolitan Water Supply and Sewerage Act, 1978, amended in 1997, also 544 known as Tamil Nadu Act 28 of 1978 founded Metrowater and gave it the mission to provide 545 the Chennai Metropolitan Area an adequate supply of good quality water and a safe disposal 546 of waste water at a reasonable price (CMWSSB 2020f). Metrowater subsidizes its residential 547 customers by overpricing its industries (Gopakumar 2009). According to their data, 830 million 548 liters per day (MLD) of drinking water are produced in Chennai, whereas the treatment 549 capacity reaches 1,494 MLD. The expansion to cover the whole Chennai Metropolitan Area is 550 22 in progress (CMWSSB 2020c). A few years later, the Chennai Metropolitan Area Ground 551 Water (Regulation) Act, 1987 came into force to preserve ground water and gave Metrowater 552 the power to authorize permits to sink wells and licenses for extraction and the obligation of 553 keeping well registers and the use of groundwater for agricultural purposes (The Chennai 554 metropolitan area groundwater (regulation) act 1987 1987). Furthermore, The Tamil Nadu 555 Pollution Control Board is responsible for setting, monitoring and enforcement of 556 environmental regulations and standards (Roumeau et al. 2015). 557 Current approaches to water governance struggle to meet Chennai’s demands for water. 558 Legislation exists but for political, institutional and social reasons it is not always enforced 559 (Janakarajan and Lakshmi 2005). 560 The insufficient supply of water by public entities has made private owned tankers and the 561 packaged water vendors critical actors in water governance (Roumeau et al. 2015). Many 562 farmers have left their agricultural activities to sell groundwater directly to private tankers 563 following a greater revenue (Packialakshmibb et al. 2011; Roumeau et al. 2015). Other 564 stakeholders are water suppliers in the private sector, farmers, and the civil society (Roumeau 565 et al. 2015) as well as multiple NGOs dealing with water and environmental issues, like 566 Environmentalist Foundation of India or the Care Earth Trust. 567 4 Discussion 568 Different studies have assessed the DPSIR framework in terms of its application for 569 sustainable development studies (Carr et al. 2009), determination of causal relationships 570 (Niemeijer and De Groot 2008) and its feasibility for supporting decision making (Tscherning 571 et al. 2012). These authors enunciate that the DPSIR presents drawbacks regarding to its 572 hierarchical structure, the establishment of unidirectional relationships and, in some studies, 573 the lack of integration of decision makers into the participative process. Nevertheless, they 574 also stress the DPSIR’s potential to emphasize causality between environmental indicators 575 and to structure disperse data to provide meaningful explanations of complex environmental 576 issues to policy makers (Niemeijer and De Groot 2008; Tscherning et al. 2012) that facilitates 577 communication and comparison (Patrício et al. 2016). Since the development of the DPSIR, 578 25 derivatives in more than 152 studies have been proposed in the literature (Taft and Evers 579 2016; Patrício et al. 2016). However, none has been adopted by the scientific community as 580 a replacement for the DPSIR nor by international institutions as the original DPSIR framework 581 was by the European Union and European Environment Agency (European Comission 1999). 582 Through the application of the DPSIR in Chennai, the authors agree on its advantages and its 583 potential to be connected with the SDGs 6 and 11. The application of the DPSIR involves 584 indicators regarding water resources and pollution, waste, land use change, and loss of 585 biodiversity among others (Smeets and Weterings 1999; Kristensen 2003; European 586 Environment Agency 2005, 2014) that are also included in the SDGs 6 and 11, like the 587 indicators 6.3.1 Proportion of domestic and industrial wastewater flows safely treated, 6.3.2 588 Proportion of bodies of water with good ambient water quality or 6.6.1 Change in the extent of 589 water-related ecosystems over time and 11.3.1 Ratio of land consumption rate to population 590 23 growth rate (United Nations 2022a, b). 591 The application of the DPSIR framework also found limitations on water management. First, 592 water management requires to be faced from several perspectives and considering a large 593 number of variables. Today, decision-makers and stakeholder work in many cases 594 independently with contradictory interests. Therefore, a deeper integration of the public 595 administration bodies involved in water management and a better cooperation of different 596 stakeholders is necessary. Secondly, poor law enforcement hinders efficient water 597 management. For example, groundwater over-extraction in periurban areas. Thirdly, data 598 scarcity or difficult access impedes to develop new efficient policies adapted to the city needs. 599 In the Indian context, the implementation of effective policies to manage water challenges in 600 cities is limited by inaccessible and unreliable data, limited coordination between stakeholders, 601 non-implementation of policies and projects, environmental legislation violations, unclear or 602 overlapped responsibilities, inadequate maintenance of water infrastructure (Aartsen et al. 603 2018). The Organisation for Economic Cooperation and Development (OECD 2015) provides 604 a framework to understand water governance systems’ performance. In addition, the 605 implementation of adaptive management approaches has been stated as a comprehensive 606 solution for improving decision making and managing water resources (Pahl-Wostl 2008; 607 Kattel 2019a). For instance, Kattel, 2019, has proposed six key elements for enhancing water 608 security in river basins i.e. the implementation of early warning systems, water footprints 609 management, groundwater aquifers management, increased water stewardship and 610 governance, enhanced resilience of social and ecological systems of freshwaters and the 611 promotion of the water-energy-food nexus. 612 Chennai and its metropolitan area are expected to keep facing water stress and difficulties to 613 implement the SDGs 6 and 11. The current water supply system has proven to be insufficient 614 even with average weather conditions, with a gap of 342 MLD between estimated demand 615 (1173 MLD) and supply (831 MLD) in 2014 (Government of Tamil Nadu 2014) and with a 616 supply of only around 90 liters per capita a day (CMDA 2006). Chennai needs to urgently find 617 new water sources to meet the always increasing demand. 618 Conventional surface water sources, like new reservoirs, are fed by Northeast Monsoon and 619 would face a similar trend of drought (Chennai Metropolitan Development Authority, 2006). 620 Catchments depending on the Southwest Monsoon are far from Chennai and would require 621 high costs to build and operate long channels and tensions between communities would 622 emerge, like in the Telugu Ganga project. Groundwater is unable to supply sufficient water in 623 a sustainable manner. Recharging the aquifers by water harvesting would contribute to a more 624 stable and reliable water supply. The two new seawater desalination plants (2x500 MLD) 625 planned for 2024 can cater more than 2 million people, although a final affordable water price 626 has to be granted for poorer areas. Otherwise, water bills could remain unpaid as it happens 627 in the rest of the state of Tamil Nadu (Gopakumar 2009). Furthermore, management of brine 628 produced by desalination plants requires to be considered. 629 Chennai’s water bodies are being polluted because of the lack of waste water treatment plants. 630 24 The likely 1073 million liters per day (MLD) gap between treated (550 MLD) and non-treated 631 (1500-2000 MLD) sewage is directly discharged into water bodies (Arappor Iyakkam 2017; 632 CMWSSB 2020a). However, it is insufficient to cover the present and future sewage 633 generation. The authorities need to find funds to build new sewage treatment plants and an 634 efficient waste management system, including the closure of the current two main open 635 dumpsites. The ability of the institutions to implement urban plans that consider sewage 636 treatment and waste management systems will be key for pollution prevention of water bodies 637 at a lower cost. The third master plan of Chennai brings a new and promising focus with a 638 long-term vision document produced through a participatory approach. 639 Biodiversity in the Pallikaranai marshland and other water bodies has been reduced due to 640 increased water pollution and invasive species like the water hyacinth (Oppili 2017). NGOs 641 like Care Earth Trust, The Nature Conservancy and Environmentalist Foundation of India play 642 a major role in the restoration of aquatic ecosystems. Restoration success relies significantly 643 on the interest of the institutions to implement this kind of projects on their own or with the help 644 of NGOs and also in the ability of these NGOs to achieve external funds. 645 Environmental regulations need to meet international standards and to be enforced to ensure 646 the protection of the aquatic ecosystems (Janakarajan and Lakshmi 2005). In May 2020, a 647 new draft of the Environment Impact Assessment Notification 2020, under the Environment 648 (Protection) Act, 1986 came into force. It set aside several essential provisions such as public 649 consultation and introduced ex-post facto clearance for many projects, including some 650 irrigation and hydroelectric projects, all inland waterway projects, and others (Ananthakrishnan 651 2020). This sets a worrying precedent that could affect other environmental regulations. 652 The severe hit of COVID pandemic on Indian economy dropped investment growth in the year 653 2020 to 10% (United Nations 2021) and this will probably delay many of the mentioned 654 projects. 655 5 Conclusions 656 This study applied the DPSIR Framework to water management in Chennai, South India. The 657 study provides answers to the research questions raised in the introduction section. First, the 658 DPSIR proved to be a valuable tool to evaluate water challenges in cities by disentangling 659 relationships between environmental indicators and structuring disperse data that allows 660 policy makers for a better understanding. The indicators used for the DPSIR framework can 661 be also easily aligned with the indicators of the Sustainable Development Goals 6 and 11. 662 Second, limited integration of decision-makers and stakeholders, poor law enforcement and 663 scarcity of data limit effective water management in Chennai, which can be applied to other 664 cities with similar scenarios. 665 As a result of the DPSIR analysis, the unplanned population growth fueled by the rapid 666 economic development were identified as the two main drivers. They brought pressures such 667 as rapid land use change, groundwater over-extraction to partially cover the higher water 668 demand, and bigger volumes of solid wastes and untreated sewage that are discharged into 669 water bodies. This situation headed to low values of indicators related to the status of 670 25 urbanization, water availability, water quality and biodiversity and visible environmental 671 impacts within the city: loss of aquatic ecosystems and encroachment, low water table levels, 672 low water quality, that reduces aquatic biodiversity and human health. Urban planning and the 673 third Chennai master plan was identified as a key response. Stakeholders executed numerous 674 water infrastructure projects that increased drinking water availability with conventional (dams 675 and interbasin transfers, groundwater pumping) and non-conventional (desalination plants, 676 water tankers, rainwater harvesting) techniques. They also built sewage treatment plants, 677 restored ecosystems and improved water governance. 678 679 32 of Cooum Sub Basin, Chennai. Nat Environ Pollut Technol 16:969–974 952 Newton D (2016) The Global Water Crisis: a reference Handbook. 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Main indicators considered for every component of the Drivers-Pressures-States1137 Impacts-Responses analysis of water management in Chennai in this study. 1138 Indicator Value Years Source Drivers Population growth Average annual population growth (%) 0.75 2001-2011 Directorate of Census Operations Tamil Nadu (2011) Economic development Average annual growth of per capita net state domestic product in rupees at constant prices in Tamil Nadu (%) 6.59 1998-1999 to 2018-2019 Reserve Bank of India (2020) Pressures Land use change Average annual increase of urban area (%) 1.92 1988-2017 Mathan and Krishnaveni (2020) Groundwater over-extraction Average groundwater extracted (million liters per day) 200 2015 Venkatachalam (2015) Liquid and solid waste mismanagement Waste water treated (%) 33.90 2017 Arappor Iyakkam (2017) States Urbanization status Urban area over the total of the Chennai Metropolitan Area (%) 48.7 2017 Mathan and Krishnaveni (2020) Water availability Water supply (liter/inhabitant/day) 90 2014 Government of Tamil Nadu (2014) Water quality Biochemical oxygen demand (mg oxygen/l) 9-375 2015-2019 Kumar et al. (2019); Dhamodharan et al. (2016); Nethaji Mariappan et al. (2017); Kumar et al. (2018); Raji and Abraham (2018); Krishna Kumar et al. (2015) Biodiversity status Wetland area over the total of the Chennai Metropolitan Area (%) 15.80 2016 Amali et al. (2019) Impacts Loss of aquatic ecosystems Average annual reduction in water surface (%) 1.25 1988-2016 Mathan and Krishnaveni (2020) Low water table Water extracted of the aquifer (%) 80 2012 Balan et al. (2012) Low water quality Untreated waste water discharged (million liters per day) 1073 2017 Arappor Iyakkam (2017) Reduction of biodiversity and human health Average annual reduction in wetlands (%) 1.35 1988-2016 Amali et al. (2019) 1139 1140