Rainwater Harvesting Potential and Management Strategies for Sustainable Water Supply in Tanzania

Abstract

Over the years in Tanzania, rainwater harvesting (RWH) demonstration projects have been conducted within communities under facilitation of either government or international organizations or nongovernmental organizations. The goal has been to empower local citizens to take charge of their own water supply challenges and to increase water service coverage. However, to date, the adoption of this technology is still infrequent. High investment cost creates challenges, and where RWH is practiced, concerns about insufficient water quantity during the dry season and poor water quality, have been raised. The aim of this study was to introduce RWH technology as a potential water supply source in Tanzania, and address the challenges of current RWH practices. During this research, a RWH demonstration project was conducted at Mnyundo Primary School in Mtwara Region of Tanzania to address the schools drinking water challenges. Recently established innovative ideas, parameters, and strategies within the technical, economic, and social perspectives were incorporated. These include performance assessment parameters, a water level monitoring strategy, self-financing initiatives, treatment, and monitoring components. These showed improvement in management and availability of rainwater (RW) during the dry season. In addition, the quality of RW was enhanced and better than current alternative sources. Furthermore, high potential for empowering, knowledge transfer, raising sense of ownership, and financial stability was shown. Moreover, field observations of water supply practices in households within Mtiniko village of the Mtwara rural district were made. Through quantity modeling and quality testing, it was determined that challenges existed with the villages domestically relied on surface runoff water. The challenges were water shortages during the dry season and microbiologically contaminated water. Therefore, this study presents strategies that would contribute to boosting the villages water supply practices, ensuring them sufficient water quantity even during the dry season and safe water for drinking purposes. This will be possible through the incorporation of improved RWH technology as an additional water supply source, and adopting improved management strategies of current water supply practices. Rainfall in Tanzania is well distributed and occurs in sufficient quantity. Through analytical interpretation of recent RWH potential study for Tanzania by using GIS, it was established that there is good potential for adopting RWH technology. RWH is capable of serving as the sole water supply source in some areas and considered in combination with other water sources in places with low rainfall. Considering discussed cases of RWH adoption in households and institution, RW can meet over 35% of annual demand, at least 40 L/person/d. Hence, through these decentralized systems the load on the government can be reduced. Technical design guidelines addressing issues of quantity estimation and quality maintenance have been provided. A modeling tool for guiding storage capacity estimation has been introduced, which includes options of variable daily demand, and daily or monthly data input. In addition, recommendations on important RWH components have been provided for better practical management of the system. Water conservation practices have been suggested as well. Additionally, an action and work plan for ensuring RWH technology sustainability and adoption in Tanzania has been suggested. The plans main strategies include, regulation establishment for technology restriction, formation of research centers for technology sustenance and development, financial empowerment for individuals so they can afford to construct and maintain their own systems, and lastly, improving factors for better planning and execution of demonstration projects. Finally, establishing RWH regulations to enforce the technology are recommended. In addition, water resources research centers should be established to sustain the RWH technology and improve indigenous technologies. The government should invest in promoting RWH technology through demonstration projects, incentives, subsidies provision, training, and the media. Moreover, an action plan should guide the implementation to achieve sustainability in the water supply with RWH.