Intermittent water supply

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A piped water supply and distribution system is intermittent when water continuity is for less than 24 hours a day or not on all days of the week. [1] [2] During this continuity defining factors are water pressure and equity. [3] [4] At least 45 countries have intermittent water supply (IWS) systems. [5] It is contrasted with a continuous or "24/7" water supply, the service standard. [6] [7] No system is intentionally designed to be intermittent, but they may become that way because of system overexpansion, leakage and other factors. [8] [9] As of 2022, there was no feasible method for modelling IWS, including no computer-aided tools. [1] Contamination issues can be associated with an intermittent water distribution system. [10] Global public health impact includes millions of cases of infections and diarrhea, and 1560 deaths annually. [11]

Contents

A continuous supply is not practical in all situations. [3] In the short term, an IWS may have some benefits. [12] These may include addressing demand with a limited supply in a more economical manner. [13] An intermittent supply may be temporary (e.g., when water reserves are low) or permanent (e.g., where the piped system cannot sustain a continuous supply). [6] Associated factors resulting from an intermittent supply include water extraction by users at the same time, resulting in low pressure and a possible higher peak demand. [14]

Prevalence

About 41 percent of urban water supply systems around the world are intermittent; a critical misutilization considering the fact that these systems are designed to run continuously (i.e., 24 hours a day). [15] [16] About 1.3 billion people have a piped supply that is intermittent, including large populations in Africa, Asia, and Latin America and the Caribbean. [1] [14] This does not include those who do not get piped water at all, about 2.7 billion people. [1] Countries with intermittent supply in some areas and continuous supply in others include India [17] and South Africa. [18] In India, various cities are at various stages of constructing 24/7 supply systems, such as Chandigarh, [19] Delhi, [20] Shimla, [21] and Coimbatore. [22] In Cambodia, Phnom Penh increased coverage from 25% to 85% and duration from 10 to 24 hours a day between 1993 and 2004. [23]

Storage

Installation of storage and pumps at residences may offset the intermittency of the water supply. [6] Roof tanks are a common feature in countries where the water supply is intermittent. [24] In Jordan, most houses have one or more ground or roof tanks. An intermittent supply can be supplemented with other non-piped sources such as packaged drinking and cooking water bought from local shops or delivered to the house. [25]

See also

References

Bibliography
Citations
  1. 1 2 3 4 Sarisen, Dondu; Koukoravas, Vasilis; Farmani, Raziyeh; Kapelan, Zoran; Memon, Fayyaz Ali (1 December 2022). "Review of hydraulic modelling approaches for intermittent water supply systems". Journal of Water Supply: Research and Technology-Aqua. 71 (12): 1291–1310. doi:10.2166/aqua.2022.028. hdl: 10871/132852 . ISSN   0003-7214. S2CID   253616080. Open Access logo PLoS transparent.svg (Open access)
  2. Taylor 2018, p. 25, 32.
  3. 1 2 Vairavamoorthy, Kala; Elango, K. (2002). "Guidelines for the design and control of intermittent water distribution systems" (PDF). Waterlines. 21 (1): 19–21. doi:10.3362/0262-8104.2002.041 via IRCWash. Lock-green.svg (Free to read)
  4. Nishimura, Érica; Roma, Woodrow (2018). "The lack of standard definition for intermittent water supply system: An overview of definitions used in the literature and by Brazilian Regulatory Agencies". Revista de Gestão de Água da América Latina. 15 (1): 9. doi: 10.21168/rega.v15e9 . S2CID   194318870. Lock-green.svg (Free to read)
  5. Kumpel 2013, p. 1. cited to : van den Berg, C. and A. Danilenko (2011). The IBNET Water Supply and Sanitation Performance Blue Book: The International Benchmarking Network for Water and Sanitation Utilities Databook. Washington, DC: World Bank.
  6. 1 2 3 Laspidou, Chrysi; Spyropoulou, Alexandra; Charalambous, Bambos (2017). "1". In Charalambous, Bambos; Laspidou, Chrysi (eds.). Dealing with the Complex Interrelation of Intermittent Supply and Water Losses . Scientific and Technical Report No. 25. IWA Publishing. pp. xxv, 1–3. ISBN   978-1-78040-706-7 via Google Books. Lock-gray-alt-2.svg (Limited pages accessible, free registration required for complete access.)
  7. Ray, I.; Billava, N.; Burt, Z.; Colford, J. M.; Ercümen, A.; Jayaramu, K. P.; Kumpel, E.; Nayak, N.; Nelson, K.; Woelfle-Erskine, C. (2018). "From Intermittent to Continuous Water Supply A Household-level Evaluation of Water System Reforms in Hubli–Dharwad". Economic and Political Weekly. 53 (49): 39–48. ISSN   0012-9976 via eScholarship, University of California. Open Access logo PLoS transparent.svg (Open access)
  8. Kumpel 2013, p. 7. To our knowledge, no systems have been intentionally designed to provide intermittent supply ... the system became limited by excessive leakages and/or unchecked network expansion.
  9. McIntosh, Arthur C. (2014). Urban Water Supply and Sanitation in Southeast Asia. A Guide to Good Practice (PDF). Philippines: Asian Development Bank. p. 37. ISBN   978-92-9254-555-0. The primary cause of intermittent water supply is the extension of distribution systems beyond their hydraulic capacity to provide service to more customers. Lock-green.svg (Free to read)
  10. Dubasik, Frank B. (2017). Planning for intermittent water supply in small gravity-fed distribution systems: Case study in rural Panama (Master of Science in Environmental Engineering thesis). Houghton, Michigan: Michigan Technological University. doi: 10.37099/mtu.dc.etdr/498 . pp. 3. Lock-green.svg (Free to read)
  11. Taylor 2018, p. 24. cited to Bivins, Aaron W.; Sumner, Trent; Kumpel, Emily; Howard, Guy; Cumming, Oliver; Ross, Ian; Nelson, Kara; Brown, Joe (2017). "Estimating Infection Risks and the Global Burden of Diarrheal Disease Attributable to Intermittent Water Supply Using QMRA". Environmental Science & Technology. 51 (13): 7542–7551. Bibcode:2017EnST...51.7542B. doi:10.1021/acs.est.7b01014. hdl: 1983/bcbdf2db-44bb-40b6-93e5-a123d10566c4 . ISSN   0013-936X. PMID   28582618. S2CID   206568606.
  12. Irving, Tyler (9 July 2019). "U of T researcher proposes new model to analyze world's 'intermittent' water systems". University of Toronto News. Retrieved 5 January 2023. Open Access logo PLoS transparent.svg (Open access)
  13. Tong, Yan; Fan, Liangxin; Niu, Haipeng (2022). "Identification of pathways that lead to continuous or intermittent water supply by conducting a qualitative comparative analysis of rural water utilities in China". Journal of Water Supply: Research and Technology-Aqua. 71 (7): 801–815. doi: 10.2166/aqua.2022.052 . ISSN   0003-7214. S2CID   250394031. Open Access logo PLoS transparent.svg (Open access)
  14. 1 2 Loubser, Carlo; Basson, Suzanne Esther; Jacobs, Heinz Erasmus (2020). "A conceptual index for benchmarking intermittent water supply in a water distribution system zone". Water SA. 46 (1 January): 12, 15. doi:10.17159/wsa/2020.v46.i1.7873. hdl: 10019.1/124436 . ISSN   1816-7950. S2CID   213294175.
  15. Mohan, S; Abhijith, GR (22 February 2021). Hayward, Keith (ed.). "Intermittent water supply interventions for India's cities". The Source. Retrieved 2 January 2023.
  16. Andey, Subhash P; Kelkar, Prakash S. (2007). "Performance of water distribution systems during intermittent versus continuous water supply" . Journal (American Water Works Association). 99 (8): 99–106. Bibcode:2007JAWWA..99h..99A. doi:10.1002/j.1551-8833.2007.tb08011.x. ISSN   0003-150X. JSTOR   41312830. S2CID   116175326.
  17. Vairavamoorthy, Kala (22 February 2021). Hayward, Keith (ed.). "Closing the SDG access gap – the challenge of intermittent supply". The Source. Retrieved 9 January 2023.
  18. Loubser, Carlo; Chimbanga, Bubala Mwiinga; Jacobs, Heinz (January 2021). "Intermittent water supply: a South African perspective". Water SA. 47 (1 January). doi: 10.17159/wsa/2021.v47.i1.9440 . ISSN   1816-7950. S2CID   234071186.
  19. "24x7 water supply in Chandigarh: MoU signed with French loaning agency". Hindustan Times. 15 September 2022. Retrieved 9 January 2023.
  20. "Delhi divided into three zones for 24X7 water supply project". Business Standard. Press Trust of India. 5 September 2021. Retrieved 9 January 2023.
  21. "Shimla to get 24X7 water supply by 2025". The Tribune India. 8 October 2022. Retrieved 9 January 2023.
  22. Raj, Aravind (2 January 2023). "Coimbatore: 24x7 water supply project to drag on till '25". The New Indian Express. Retrieved 9 January 2023.
  23. Seetharam, K. E.; Bridges, Geoffrey (2005). "Helping India Achieve 24x7 Water Supply Service by 2010" (PDF). Asian Development Bank. Water Sector Technical Note # 1.
  24. Hernandez-Lopez, R. D.; Tzatchkov, V. G.; Martin-Dominguez, A.; Alcocer-Yamanaka, V. H. (2016). "Study of hydraulics and mixing in roof tanks used in intermittent water supply". Journal of Water, Sanitation and Hygiene for Development. 6 (4): 547–554. doi: 10.2166/washdev.2016.147 . ISSN   2043-9083.
  25. Rosenberg, David E.; Talozi, Samer; Lund, Jay R. (2008). "Intermittent water supplies: challenges and opportunities for residential water users in Jordan". Water International. 33 (4): 488–504. Bibcode:2008WatIn..33..488R. doi:10.1080/02508060802474574. ISSN   0250-8060. S2CID   153670339.

Further reading