Making the Hidden Visible
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FULL TEXT VERSION OF: Everard, M., Ahmed, S., Gagnon, A.S., Kumar, P., Thomas, T., Sinha, S., Dixon, H. and Sarkar, S. (2020). Can nature-based solutions contribute to water security in Bhopal? The Science of the Total Environment, 723 138061. DOI: https://doi.org/10.1016/j.scitotenv.2020.138061. 1 Can nature-based solutions contribute to water 2 security in Bhopal? 3 4 Dr Mark Everard, University of the West of England (UWE), Coldharbour Lane, 5 Frenchay Campus, Bristol BS16 1QY, UK. (E: [email protected], M: +44-(0)- 6 7747-120019). Corresponding author 7 8 Prof. Shakeel Ahmed, Department of Geography, Faculty of Natural Sciences, 9 Jamia Millai Islamia, New Delhi-110025, India. (E: [email protected]; M: +91- 10 9849919496). 11 12 Dr Alexandre S. Gagnon, School of Biological and Environmental Sciences, 13 Liverpool John Moores University, Liverpool L3 3AF, UK. (E: [email protected]; 14 M: +44-7871-088198) 15 16 Dr Pankaj Kumar, Department of Earth and Environmental Sciences, Indian 17 Institute of Science Education and Research Bhopal, By-Pass Road, Bhauri, Bhopal 18 – 462066, M.P., India. (E: [email protected]; M: +91-7974975701). 19 20 Dr T. Thomas, National Institute of Hydrology, Central India Hydrology Regional 21 Centre, Bhopal, M.P., India. (E: [email protected]; M: +91-9893686808. FULL TEXT VERSION OF: Everard, M., Ahmed, S., Gagnon, A.S., Kumar, P., Thomas, T., Sinha, S., Dixon, H. and Sarkar, S. (2020). Can nature-based solutions contribute to water security in Bhopal? The Science of the Total Environment, 723 138061. DOI: https://doi.org/10.1016/j.scitotenv.2020.138061. 22 23 Dr Sumit Sinha, Institute for Climate and Atmospheric Science, School of Earth and 24 Environment, University of Leeds, Leeds LS2 9JT, UK. (E: 25 [email protected]; M: +44-7715-302376). 26 27 Prof. Harry Dixon, Centre for Ecology & Hydrology, Maclean Building, Benson 28 Lane, Wallingford, OX10 8BB, UK. (E: [email protected]; T: +44-1491-692254) 29 30 Dr Sunita Sarkar, Centre for Ecology & Hydrology, Maclean Building, Benson Lane, 31 Wallingford, OX10 8BB, UK. (E: [email protected]; T: +44-1491-692254) 32 33 34 Abstract 35 36 Bhojtal, a large man-made lake bordering the city of Bhopal (Madhya Pradesh state, 37 central India), is important for the city’s water supply, connoted the lifeline of the city. 38 Despite the dry though not arid and markedly seasonal climate, soil impermeability 39 hampers infiltration into the complex geology underlying the Bhojtal catchment. 40 Rural communities in the catchment are nonetheless high dependent on underlying 41 aquifers. This paper develops baseline understanding of trends in the ecology, 42 water quality and uses of Bhojtal, discussing their implications for the long-term 43 wellbeing of the Bhopal city region. It highlights increasing dependency on water FULL TEXT VERSION OF: Everard, M., Ahmed, S., Gagnon, A.S., Kumar, P., Thomas, T., Sinha, S., Dixon, H. and Sarkar, S. (2020). Can nature-based solutions contribute to water security in Bhopal? The Science of the Total Environment, 723 138061. DOI: https://doi.org/10.1016/j.scitotenv.2020.138061. 44 diverted from out-of-catchment sources, and also abstraction across the Bhojtal 45 catchment in excess of replenishment that is depressing groundwater and 46 contributing to reported declining lake level and water quality. Despite some nature- 47 based management initiatives, evidence suggests little progress in haltering on- 48 going groundwater depression and declines in lake water level and quality. 49 Significant declines in ecosystem services produced by Bhojtal are likely without 50 intervention, a major concern given the high dependency of people in the Bhopal 51 region on Bhojtal for their water supply and socio-economic and cultural wellbeing. 52 Over-reliance on appropriation of water from increasingly remote sources is currently 53 compensating for lack of attention to measures protecting or regenerating local 54 resources that may provide greater resilience and regional self-sufficiency. 55 Improved knowledge of catchment hydrogeology on a highly localised scale could 56 improve the targeting and efficiency of water harvesting and other management 57 interventions in the Bhojtal catchment, and their appropriate hybridisation with 58 engineered solutions, protecting the catchment from unintended impacts of water 59 extraction or increasing its carrying capacity, and also providing resilience to rising 60 population and climate change. Ecosystem service assessment provides useful 61 insights into the breadth of benefits of improved management of Bhojtal and its 62 catchment. 63 64 65 Graphical abstract FULL TEXT VERSION OF: Everard, M., Ahmed, S., Gagnon, A.S., Kumar, P., Thomas, T., Sinha, S., Dixon, H. and Sarkar, S. (2020). Can nature-based solutions contribute to water security in Bhopal? The Science of the Total Environment, 723 138061. DOI: https://doi.org/10.1016/j.scitotenv.2020.138061. 66 67 NBS in Bhopal GRAPHIC (ME 2020-02-28) 68 69 70 Research highlights 71 72 Bhojtal contributes significantly to Bhopal’s water supply, but is degrading 73 Despite adequate rainfall, soil impermeability and complex geology hamper 74 recharge 75 Increasing abstraction across the Bhojtal catchment is depressing 76 groundwater 77 Declines in ecosystem services are likely without appropriate interventions FULL TEXT VERSION OF: Everard, M., Ahmed, S., Gagnon, A.S., Kumar, P., Thomas, T., Sinha, S., Dixon, H. and Sarkar, S. (2020). Can nature-based solutions contribute to water security in Bhopal? The Science of the Total Environment, 723 138061. DOI: https://doi.org/10.1016/j.scitotenv.2020.138061. 78 Localised knowledge of hydrogeology can optimise catchment management 79 interventions 80 81 82 Key words 83 catchment management; hydrogeology; water resources; ecosystem services; 84 groundwater recharge; RAWES 85 86 87 1. Introduction 88 Water has been a constant limiting factor for the development of India’s booming 89 population – 33 million at Independence in 1947, 1.37 billion in 2019 (a 42-fold 90 increase), and is still rising at 1.08% per annum (worldometers.info, 2019) – and 91 will remain so as part of the water-food-energy nexus subject to population, 92 globalisation, urbanisation and climate change trends. The vitality of pressurised 93 aquatic resources, both on the surface and underground, need to be increasingly 94 safeguarded through positive management as a primary resource supporting 95 continuing human wellbeing. 96 97 Madhya Pradesh state in central India is generally dry though not arid; mean annual 98 rainfall varies from 650 to 1400 mm across the state with 1260 mm for Bhopal 99 (CGWB, 2016). Centres of dense population and other demands place significant FULL TEXT VERSION OF: Everard, M., Ahmed, S., Gagnon, A.S., Kumar, P., Thomas, T., Sinha, S., Dixon, H. and Sarkar, S. (2020). Can nature-based solutions contribute to water security in Bhopal? The Science of the Total Environment, 723 138061. DOI: https://doi.org/10.1016/j.scitotenv.2020.138061. 100 pressures on locally available surface and groundwater resources across the state. 101 Bhopal, the state capital, is known as the ‘City of Lakes’ owing to the multitude of 102 natural and man-made lakes in the vicinity. 14 lakes in the city act as water 103 recharge units and, in conjunction with perennial river systems, formerly dense forest 104 cover and low relief, have created a unique urban microclimate (Burvey et al., 2017). 105 However, rapid urban expansion is eroding ecosystems surrounding the city. The 106 vegetative cover of Bhopal declined from 92% in 1977 to 21% in 2014, with further 107 predicted declines to 11% by 2018 and 4% by 2030 (Bharath Aithal, 2016). The 108 Kerwa Forest Area (KFA) located at 10 km from Bhopal faces severe anthropogenic 109 pressure compromising its critical roles as a carbon sink and source of water and 110 other contributions to environmental quality for the residents of Bhopal city (Dwivedi 111 et al., 2009). 112 113 Bhojtal, formerly known as Upper Lake or Bada Talab (‘Big Pond’), is the largest 114 local lake, abutting Bhopal city. Local folklore attributes the lake’s construction to 115 Paramara Raja Bhoj, king of Malwa from 1005 to 1055, when establishing the city of 116 Bhojpal to secure the eastern frontier of the kingdom. Bhojpal, named after the king, 117 was subsequently renamed Bhopal. The name of the lake was changed from Upper 118 Lake to Bhojtal in 2011 to honour its creator. Bhojtal was formed by constructing an 119 earthen dam across the Kolans River, which rises approximately 16 km from the 120 head of Bhojtal (Figure 1). The earthen dam retaining Bhojtal was replaced in 1965 121 by an 11-gate dam, known as Bhadbhada, situated at the southeast corner of Bhojtal FULL TEXT VERSION OF: Everard, M., Ahmed, S., Gagnon, A.S., Kumar, P., Thomas, T., Sinha, S., Dixon, H. and Sarkar, S. (2020). Can nature-based solutions contribute to water security in Bhopal? The Science of the Total Environment, 723 138061. DOI: https://doi.org/10.1016/j.scitotenv.2020.138061. 122 where it controls the outflow from Bhojtal into the Kaliasote River. Bhadbhada also 123 forms the western edge of the city of Bhopal (comprising both Old Bhopal and New 124 Bhopal). Van Vihar National Park borders Bhojtal to the South. Scattered human 125 settlements and resorts occur in the eastern and northern shores, and agricultural 126 fields lie to the West. 127 128 Figure 1: Map of Bhojtal catchment and associated cities and towns 129 130 A range of studies on the quality and uses of Bhiojtal and its catchment have been 131 undertaken, and are integrated into the Results and Discussion sections of this 132 paper. However, there appears to be only a single ecosystem service study of the 133 Bhoj Wetland by Verma et al.