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WRM Classes - Part II.pdf

  1. Inter-Linkages between Integrated Water Resource Management and Environmental Flows for Ensuring Water Security for All
  2. Water Stress Water stress occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use. Water stress causes deterioration of freshwater resources in terms of quantity (aquifer over-exploitation, dry rivers, etc.) and quality (eutrophication, organic matter pollution, saline intrusion, etc.) Water scarcity refers to the volumetric abundance, or lack thereof, of water supply. This is typically calculated as a ratio of human water consumption to available water supply in the given area. Water scarcity is a physical, objective reality that can be measured consistently across regions and over time. Falkenmark Indicator: An indicator used to measure water scarcity. It measures water scarcity as the amount of renewable freshwater that is available per person per year and proposes a threshold of 1,700 m3 per person per year to identify the regions that suffer from water stress. Source:; As per 2011 Census, per capita water availability in India is 1575 m3 2
  3. Water Resource System • A water resource system encompasses surface water, ground water, riverbed, riverbanks and technical infrastructure, including the occurring plant and animal communities and all associated physical, chemical and biological characteristics and processes • Watershed centric approach is critical for ensuring water security in the urban areas • Water resource system includes three groups of functions: (i) Sink, (ii) Source and (iii) Life Support system Source:;; Sink Source Life Support system 3
  4. Integrated Water Resource Management • IWRM is a process which promotes the coordinated development and management of land, water and related resources in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems • IWRM addresses the three E’s: Economic efficiency, Environmental sustainability and social Equity, including poverty reduction • IWRM acts as the link between the water needs of the ecosystem and the humans 4 Source: Guidelines for IWRM, 2016; Basin Organisation Technology Basin Level Management Activities Stakeholder Involvement Human and Organisational Capacity Science Based Decision Making Policy, Legal and Regulatory Framework Human Water Needs IWRM Availability of fresh water of appropriate quality Aquatic Ecosystem and Biodiversity needs Appropriate Flow to Coastal Areas Climate Geology Vegetation Topography Basin Organisation Technology Basin Level Management Activities Stakeholder Involvement Human and Organisational Capacity Science Based Decision Making Policy, Legal and Regulatory Framework Human Water Needs IWRM Availability of fresh water of appropriate quality Aquatic Ecosystem and Biodiversity needs Appropriate Flow to Coastal Areas Climate Geology Vegetation Topography
  5. Environmental Flow Environmental Flows Ensure Water for Ecosystem needs Maintain water quality at acceptable levels 5 • Environmental Flow is defined as the quantity, timing, and quality of freshwater flows and levels necessary to sustain aquatic ecosystems which, in turn, support human cultures, economies, sustainable livelihoods, and well- being • In India, the scope of environmental flows is limited to the terms called ‘minimum flow’ and ‘flushing flow’ • Under the basic principles of Draft National Water Framework Bill, 2016, it is mentioned that environmental flows adequate to preserve and protect a river basin as a hydrological and ecological system shall be maintained and a portion of river flows should be kept aside to meet ecological needs ensuring that the low and high flow releases are proportional to the natural flow regime, including base flow contribution. • Meeting the aquatic ecosystem needs means those of the groundwater and the surface water dependent ecosystems. If the River dies then it is detrimental to all the water dependent communities, not just rural but also the urban. Source: Brisbane Declaration,2018; Central Water Commission. (2007)
  6. Status of Water Resources in India • For large-scale analyses of water resources, the country is often separated into 19 major river basins/ drainage regions • Basins including Cauvery, Ganga-Brahmaputra, Godavari, Indus, Krishna, Mahanadi, Narmada, Pennar and Tapi have been categorized as “strongly affected” by flow fragmentation and regulation through dam construction Source: NCIWRDP, (Nilsson et al. 2005) Estimation of Water Deficit in the case of India (year 2050) 6
  7. Status of Water Resources in India • Over abstraction of ground water has obstructed the base flow to the surface water bodies thus substantially reducing in turn the environmental flow requirements • Stage of ground water extraction is defined as the ratio of existing ground water extraction for all uses to annual extractable ground water resources represented in percentage • Annual extractable ground water is considered as 90-95% of the annual recharge • Stage of ground water extraction in the range of 0- 70% is considered as safe, 70%-90% as semi- critical, 90%-100% as critical, and >100% as over exploited • Groundwater scenario ranges from semi critical to over exploited in many development blocks concentrated mainly in the western and southern regions 7 Source: C.G.W.B (as on 2017)
  8. Environmental Flow Assessment Methodologies • Environmental flow assessments are performed mainly for the river systems that are already regulated or are the focus of proposed water resource developments • The scale at which the environmental flow assessment is undertaken may also vary widely, from a whole catchment for a large river basin that includes regulated and unregulated tributaries, or a single river stretch • Different methodologies are appropriate over such a broad range in spatial scale and resolution, as well as in accordance with constraints including the time frame for assessment, the availability of data, technical capacity and finances 8 Source: Arthington et al., 2000; King et al., 1999; Tharme, 2003; Arthington et al., 1998;;; important-for-cold-water-fish/;; Hydrologic • Hydrologic Data Hydraulic • Hydraulic Data Holistic • Multidisciplin ary expertise and input Habitat Simulation • Quantity and suitability of instream physical habitats available
  9. Interlinkage between Environmental Flows and IWRM • As far as the environmental flow assessment is concerned, a shift is needed from the concept of ‘minimum flows’ and ‘flushing flows’ to a set of flow variables more accurately representing the natural variations in the flow regime temporally • By maintaining the quality of the drinking water sources such as the rivers and its tributaries at a better level in turn reduces the capital costs incurred for setting up of water treatment infrastructure substantially • Environmental flow assessment findings, if implemented will also be helpful in improving the ground water recharge, as part of the water inundating the floodplains, eventually becomes the ground water • Trade-offs between various water uses such as drinking water, irrigation, ecosystem needs and industrial are required for better determination of environmental flows 9
  10. References • Nilsson, C., et al., (2005). Fragmentation and flow regulation of the world’s largest river systems. Science, 308, 405–408. [Crossref] • Arthington, A. H., & Zalucki, J. M. (1998). Comparative evaluation of environmental flow assessment techniques: Review of methods. LWRRDC Occasional Paper Series 27/98, 141. • Tharme, R. E. (2003). A global perspective on environmental flow assessment: Emerging trends in the development and application of environmental flow methodologies for rivers. River Research and Applications, 19(5–6), 397– 441. • King, J., Tharme, R. E., & Brown, C. (1999). Definition and implementation of instream flows. Thematic Report to the World Commission on Dams. Southern Waters Ecological Research and Consulting, Cape Town, South Africa, 94 p. • Arthington, Angela H., et al. "Environmental flow requirements of the Brisbane River downstream from Wivenhoe Dam." Southeast Queensland Water Corporation and Centre for Catchment and In-Stream Research: Brisbane (2000) • Brisbane Declaration on Environmental Flows (2018) • Central Water Commission. (2016). Guidelines for Integrated Water Resource Management • Central Water Commission. (2007) Report of Working Group on Environmental Flows 10