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Bhutan Journal of Natural Resources and Development

College of Natural Resources


Assessment of Water Shortage and Potential for Rooftop Rainwater Harvesting in Rural Development Training Centre, Zhemgang Town, Bhutan

Dorji,, Choiney .;  Tashi , Sonam .;  Chhetri, Rekha.; 

DOI: https://doi.org/10.17102/cnr.2020.43

Abstract

Rainwater harvesting is one of the promising alternatives to supplement surface water resources in areas where existing water supply is inadequate to meet the demand. The water shortage in Zhemgang is a recurring problem. This study was conducted to assess the water shortage in Zhemgang town and the potential for Rainwater Harvesting (RWH) in the Rural Development Training Centre (RDTC). A total of 318 households were assessed for the water shortage and knowledge, attitude and practices on RWH. Additionally data were collected once in 24 hours in the rainy season from June through September from five rooftops in RDTC premises. The study revealed that the Zhemgang Municipal supplies 469.02 litres of water per day per household resulting in residents facing potable drinking water deficit of about 54.48 litres/ day/ household as the average requirement is 523.50 ± 110.48 (mean ± SD) litres/day/household. Zhemgang town receives a mean annual rainfall of 1,412.50 ± 208.90 (mean ± SD) mm with an intra-annual variability range of 0.95 and 0.97 mm and interannual variability of 0.15 mm. The low variability in rainfall, ranging from 0.29 mm to 0.41 mm during the rainy season, indicates a reliable condition for RWH and guarantees the return on investment. The RWH potential for RDTC was 7,790,220.00 m3 and the average rainwater runoff collection from the experimental sites was 633,000 L during the rainy season from the rooftop catchment area of 456.14 m2. The daily collections of rainfall in 1,000 L from the month of June through September were 3.4 L, 8.9 L, 3.6 L, and 4.9 L respectively. The water was used to irrigate field crops such as maize, oats, vegetable, pasture field and fruits trees. The study identifies RWH as an alternative means to supplement the water supply scheme. The quality of RWH from CGI roofing after the first flush had all physical parameters within the permissible limit.



Keywords

rooftop rainwater harvesting, water quality, water shortage, Zhemgang

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Reference

Adugna, D., Jensen, M.B., Lemma, B., and Gebrie, G.S. (2018). Assessing the Potential for Rooftop Rainwater Harvesting from Large Public Institutions. International Journal of Environmental Research and Public Health, 15, 336.doi: 10.3390/ijerph15020336.

Aladenola, O.O., and Adeboye, O.B. (2010). Assessing the Potential for Rainwater Harvesting. Water Resour Manage, 24, 2129–2137.doi:10.1007/s11269-009-9542-y.

Charles, M.J. (2007). Rainwater harvesting systems for communities in developing countries. Michigan technological university.

Che-Ani, A.I., Shaari, N., Sairi, A. (2009). Rainwater Harvesting as an Alternative Water Supply in the future. European Journal of Scientific Research, 34(1), 132–140.

Dorji, Y. (Ed.). (2016). Water: securing Bhutan’s future. Thimphu: Asian Development Bank/National Environment Commission.

Engida, M. (1999). Annual Rainfall and Potential Evapo-Transpiration in Ethiopia. Ethiop. J. Natl. Resour., 1, 137-154.

Fang, C.L., Bao, C., and Huang, J.C. (2007). Management Implications to Water Resources Constraint Force on Socio-economic System in Rapid Urbanization: A Case Study of the Hexi Corridor, NW China. Water Resour Manage, 21, 961-982.

Gleick, P.H. (1996). Basic Water Requirements for Human Activities: Meeting Basic Needs. Water International, 21, 83-92.

GNHC. (2013). Eleventh Five Year Plan Document. Gross National Happiness Commission. Royal Government of Bhutan. Thimphu, Bhutan.

Hofman, J.M., & Paalman, M. (2014). Rainwater harvesting, a sustainable solution for urban climate adaptation? Knowledge for Climate, 142.

IPCC. (2007). Summary for policymakers: An Assessment of the Intergovernmental Panel for Climate Change. Valencia, Spain.

Kumar, A. (2019). Hydraulic Rubber Dam. Water Conservation Technologies.

Kucezera, G. (2007). Regional Impacts of Roof Water Harvesting-Supplementing Public Water Supply. Rainwater Colloquium in Kuala Lumpur: Kuala Lumpur, Malaysia.

Nasr, M. (1999). Assessing Desertification and Water Harvesting in the Middle East and North Africa: Policy Implications. Germany: Zentrumfur Entwick lungs for schung (ZEF), 59.

NCHM. (2019). Analysis of Historical Climate and Climate Projection for Bhutan. National Center for Hydrology and Meteorology Royal Government of Bhutan, PO Box: 2017, Thimphu, Bhutan.

NEC. (2016). Bhutan Drinking Water Quality Standard.National Environment Commission, Royal Government of Bhutan, Post Box No. 466, Thimphu, Bhutan.

Park, D., and Um, M.J. (2018). Sustainability Index Evaluation of the Rainwater Harvesting System in Six US Urban Cities. Sustainability, 10, 280.doi:10.3390/su10010280.

Rijsberman, F.R. (2006). Water scarcity: Fact or fiction? Agriculture Water Management, 80(1-3), 5-22. Sendanayake, S. (2016). Rainwater Harvesting for Urban Living. South Asian Institute of Technology and Medicine, Malabe, Sri Lanka.

Thomas, T.H., and Martinson, D.B. (2007). Roof water Harvesting: A Handbook for Practitioners. Technical Paper Series, no. 49, IRC International Water and Sanitation Center: Delft, The Netherlands, 160 pp.

Tidwell, V.C., Passell, H.D., Conrad, S.H., and Thomas, R.P. (2004). System dynamic modeling for community-based water planning: Application to the Middle Rio Grande. Aquatic Sciences, 66(4): 357-372.