sustainability Communication Integrated Water Resource Management: Rethinking the Contribution of Rainwater Harvesting Zhe Huang 1, *, Esther Laurentine Nya 2 , Mohammad Azizur Rahman 3 , Tulinave Burton Mwamila 4 , Viet Cao 5 , Willis Gwenzi 6 and Chicgoua Noubactep 7,8,9,10, *   Citation: Huang, Z.; Nya, E.L.; Rahman, M.A.; Mwamila, T.B.; Cao, V.; Gwenzi, W.; Noubactep, C. Integrated Water Resource Management: Rethinking the Contribution of Rainwater Harvesting. Sustainability 2021, 13, 8338. https://doi.org/10.3390/ su13158338 Academic Editor: Fernando António Leal Pacheco Received: 1 June 2021 Accepted: 20 July 2021 Published: 26 July 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 School of Law, Southeast University, Nanjing 211189, China 2 Faculty of Art, Letter and Social Sciences, University of Maroua, Maroua P.O. Box 644, Cameroon; nya.esther@yahoo.fr 3 Technovative Solutions, Manchester Science Park, Manchester M15 6JJ, UK; aziz@technovativesolutions.co.uk 4 Department of Water Supply and Irrigation Engineering, Water Institute, Dar es Salaam P.O. Box 35059, Tanzania; mtulinave@gmail.com 5 Faculty of Natural Sciences, Hung Vuong University, Phu Tho 35120, Vietnam; caoviet@hvu.edu.vn 6 Biosystems and Environmental Engineering Research Group, Department of Agricultural and Biosystems Engineering, University of Zimbabwe, Mt. Pleasant, Harare P.O. Box MP167, Zimbabwe; wgwenzi@yahoo.co.uk 7 Centre for Modern Indian Studies (CeMIS), Universität Göttingen, D-37073 Göttingen, Germany 8 Applied Geology, University of Göttingen, D-37077 Göttingen, Germany 9 Faculty of Health Sciences, Campus of Banekane, Université des Montagnes, Bangangté P.O. Box 208, Cameroon 10 School of Material Energy Water and Environmental Science (MEWES), Department of Water Environmental Science and Engineering (WESE), The Nelson Mandela African Institution of Science and Technology, Arusha P.O. Box 447, Tanzania * Correspondence: maggie_huangzhe@126.com (Z.H.); cnoubac@gwdg.de (CN) Abstract: Rainwater harvesting (RWH) is generally perceived as a promising cost-effective alternative water resource for potable and non-potable uses (water augmentation) and for reducing flood risks. The performance of RWH systems has been evaluated for various purposes over the past few decades. These systems certainly provide economic, environmental, and technological benefits of water uses. However, regarding RWH just as an effective alternative water supply to deal with the water scarcity is a mistake. The present communication advocates for a systematic RWH and partial infiltration wherever and whenever rain falls. By doing so, the detrimental effects of flooding are reduced, groundwater is recharged, water for agriculture and livestock is stored, and conventional water sources are saved. In other words, RWH should be at the heart of water management worldwide. The realization of this goal is easy even under low-resource situations, as infiltration pits and small dams can be constructed with local skills and materials. Keywords: infiltration pits; Kilimanjaro concept; rainwater harvesting; storage tank; water management 1. Introduction In 2015, the United Nations (UN) Sustainable Development Goals (SDGs) were adopted to substantially improve the human well-being by 2030 [1,2]. The UN SDGs consist of 17 goals, of which two focus explicitly on water: (i) Goal 6, “Ensure availability and sustainable management of water and sanitation for all”, and (ii) Goal 14, “Conserve and sustainably use the oceans, seas and marine resources for sustainable development”. Both goals call for: (i) avoiding water pollution, (ii) improving and/or restoring water quality, and (iii) protecting and/or restoring water-related ecosystems worldwide. This implies a reconsideration of water management at all scales, including household, small community, city, and national and international levels. With such an approach, enhancing groundwater recharge and reducing aquatic pollution start at household level, with each individual world citizen being involved, including those living in the slums of Durban Sustainability 2021, 13, 8338. https://doi.org/10.3390/su13158338 https://www.mdpi.com/journal/sustainability