Intermittent water supply

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]

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]

  1. ^ a b 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 icon (Open access)
  2. ^ Taylor 2018, p. 25, 32.
  3. ^ a b 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. Free access icon (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. Free access icon (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. ^ a b 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. Limited access icon (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 icon (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. Free access icon (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. Free access icon (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 icon (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 icon (Open access)
  14. ^ 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.