This thesis discusses rainwater harvesting systems (RWH systems). It particularly focuses on systems collecting rainwater for domestic consumption in rural areas of developing countries. The main aim of the thesis is to identify factors, which influence the willingness and ability of people to adopt and use properly these RWH systems. I began with a brief introduction into the topic of the good-quality drinking water scarcity and with a discussion of relevant information about the RWH systems. The method used for the research was a systematic review. The relevant literature was systematically searched, selected, evaluated, and the relevant material was then processed with regards to the importance of particular factors influencing the RWH systems adption and utilization. Altogether, 26 influential factors were identified and discussed.

Vatten är en livsnödvändig förutsättning för allt levande och förändringar i vattentillgången kan ha förödande konsekvenser. Därför är det viktigt att hitta ett hållbart sätt att konsumera och återanvända vatten på, särskilt i områden med risk för vattenbrist eller vattenkvalitetsproblem. Sandön är en skärgårdsö med speciell natur och denna studie behandlar en undersökning kring möjligheterna för implementering av regnvatteninsamling på ön för att minska grundvattenuttaget. Studien har omfattat en litteraturgenomgång, insamling, sammanställning och bearbetning av digitala data samt en fältstudie för insamling och kontroll av platsspecifika data. Resultatet av studien visar att möjligheterna för implementering av regnvatteninsamlingslösningar på Sandön är god och olika alternativa lösningar för insamling presenteras. Med den mest kostnadseffektiva lösningen blir den möjliga mängd som går att ersätta med regnvatten 26,7 % av hushållets användning under månaderna juni, juli och augusti, beroende på fastighetens storlek och utrymme för uppsamlingstank samt antalet personer. Den begränsande faktorn är inte potentialen på 23 miljoner liter vatten per år, utan uppsamlingstankens volym som är beroende av fastighetens storlek. Den beräknade optimala totala tankvolymen med avseende på nederbörd och vattenanvändning för Sandön är 3 m3. Vad studien också visar är att grundvattenuttaget på sommaren inte kan täckas upp av enbart regnvatten och att ytterligare lösningar krävs. / Water is a critical necessity for all living creatures and changes in the reservoirs may have disastrous consequences. It is important to find a sustainable way to consume and re-use water, especially in areas with a higher risk of water shortageor quality issues. Sandön is an island in the Swedish archipelago with unique nature and this study includes a survey on the possibilities for implementation of rainwater harvesting on the island in order to decrease the groundwater consumption. The study has covered a literature study on books, reports and articles, collection and processing of digital data and a field study was performed. The result of the study shows that the possibilities of implementation of rainwater harvesting solutions on Sandön is good and different system alternatives are presented. With the most cost-effective system the quantity that is possible to replace with rainwater is 26,7 % of the households use during the months of June, July and August, depending on the properties size, space for placement of tanks and the number of people. The limiting factor is not the potential of 23 millions of liters of water per year, but the volume of the storage tank which is dependent on the size of the property. The optimal total tank volume for Sandön is 3 m3. The study also concludes that the water consumption during the summer can not be covered only by the collection of rainwater and additional solutions are needed.

Gambia is the smallest country on the African mainland, surrounded by Senegal on all it's borders except the coastal one. Gambia faces a pressing issue with water supply shortages, along with more than one third of the world’s population. The aim of this study is to propose a system that will solve water supply shortage through a local water supply system. The method mainly consisted of a literature review, aimed to provide an overview of the subject as well as to highlight existing gaps within today’s research about rainwater harvesting systems. Furthermore, a case study was used to determine the best way to design the rainwater harvesting system. The results of the study are showcased through a tank and pipe system, where water is collected on the roof of the residential homes and stored in a polyethylene tank on the ground. The results from the survey, asking questions related to the inhabitants’ water usage habits, were analyzed and represented through a table. In Brikama rainwater can be used for laundry, cooking and watering plants. The positive effects it brings include, but are not limited to, reduction of soil erosion, restoring the ground water cycle, as well as making people become more self-sufficient. In this study, a system for Brikama can be optimized by using Solvatten technology in combination with conventional rainwater harvesting methods. The tank volume suggested by Mun and Han (2011) is a feasible premiss, however it can not be directly applied to Gambian rainwater conditions as there are differing presumptions between the reference country Korea, and Gambia. Additionally, the validity of the study is affected as the reference studies suggest using computer simulations, as well as computer models as a basis for the operational and input data. / Gambia är det minsta landet på det afrikanska fastlandet, omgivet av Senegal på alla dess gränser utom den kustnära. Gambia står inför ett akut problem med vattenbrist, tillsammans med mer än en tredjedel av världens befolkning. Syftet med denna studie är att föreslå ett system som löser problematiken med vattenförsörjning genom ett lokalt vattenförsörjningssystem. Metoden bestod huvudsakligen av en litteraturöversikt, som syftade till att ge en överblick över ämnet samt att lyfta fram befintliga luckor inom dagens forskning om system för uppsamling av regnvatten. Dessutom användes en fallstudie för att bestämma det bästa sättet att designa systemet för uppsamling av regnvatten. Resultatet av studien visas genom ett tank- och rörsystem, där vatten samlas upp på taket av bostadshusen och lagras i en polyetentank på marken. Resultatet från undersökningen, med frågor relaterade till invånarnas vattenanvändningsvanor, analyserades och representerades genom en tabell. I Brikama kan regnvatten användas för tvätt, matlagning och vattning av växter. De positiva effekter det medför inkluderar, men är inte begränsade till, minskning av jorderosion, återställande av grundvattnets kretslopp, samt att få människor att bli mer självförsörjande. I denna studie kan ett system för Brikama optimeras genom att använda Solvatten-teknik i kombination med konventionella metoder för uppsamling av regnvatten. Tankvolymen som föreslagits av Mun och Han (2011) är en genomförbar premiss, men den kan inte tillämpas direkt på gambiska regnvattenförhållanden eftersom det finns olika antaganden mellan referenslandet Korea och Gambia. Dessutom påverkas studiens validitet eftersom referensstudierna föreslår att man använder datorsimuleringar, samt datormodeller som underlag för drift- och indata.

Self supply is an emerging approach to water supply which focuses on fostering household investment in incremental improvements to their water sources. When successful, it can lower costs and increase sustainability by offering users a larger share of ownership in their own supply, and harnessing the already existing strengths of a community rather than trying to impose an external perspective. In addition to well upgrading and source protection, one of the key self supply areas is rainwater harvesting. Uganda has a diverse selection of rainwater storage options, but many of them are scattered and disparate. The objective of this study was to create a comprehensive collection of well-established Ugandan rainwater storage options, and to demonstrate the geographical disparities in availability, particularly for Rakai District, where the author lived and worked as a Water and Sanitation Engineer for two years. Data was gathered by interviewing key stakeholders in rainwater harvesting at the national, regional, and district level in order to gather their collective knowledge in rainwater harvesting storage techniques. In order to understand the availability and pricing of manufactured products, a survey of Rakai District hardware stores determined the prices and range of volumes at which different manufactured products were available. The study found 11 distinct technologies widely used for rainwater storage: three informal or traditional, three manufactured, and five built-in-place by skilled artisans. The traditional/informal technologies consisted of clay pots, pots and basins, and brick mortar tanks. The manufactured products were plastic tanks ranging from 60 to 24,000 liters, corrugated iron tanks, and 55-gallon metal drums. The built-in-place tank technologies were mortar jars, tarpaulin tanks, ferrocement tanks, partially below ground ferrocement tanks, and interlocking stabilized soil brick tanks. The study also found that while the manufactured products are well distributed, built-in-place options have not spread beyond where they were originally introduced by NGO's trying to promote certain technologies. With regard to costs, tanks with storage volume less than 1,000 liters had costs that ranged from 182 to 724 UGX/liter, with small plastic tanks being least expensive. For volumes between 1,000 and 10,000 liters, costs ranged between 42 and 350 UGX/liter, with tarpaulin tanks providing the largest storage per unit cost. Above 10,000 liters of storage, tanks ranged from 35 to 341 UGX/liter, with tarpaulin tanks again ranking first by cost per unit volume. In order for self supply to flourish, these technologies need to be implemented in such a way that fosters a thriving private sector and independent uptake of rainwater harvesting. This research provides a starting point by laying out the technologies, costs, and volumes available.

Abstract  The use of alternative water resources such as rainwater where drinking water quality is dispensable is an important measure towards a more sustainable water management. Despite raised awareness of future water scarcity, and despite a growing field of theoretical and practical competence, the development of rainwater reuse is progressing slowly in Sweden compared to other European countries. The following essay aims to investigate drivers and barriers concerning increased implementation of rainwater reuse, or RWH (Rainwater harvesting), in Sweden. Data collection was made by interviews with respondents from municipality, construction and from REWAISE, a project aiming to decrease drinking water usage and by notes from meetings, webinars and workshops with participants from relevant fields. The theoretical framework consisted of the keywords knowledge, legislation, economy, political influence and environmental engagement and urban environmental transition theory and was used in order to understand why alternative water sources are chosen, or neglected, in construction plans. The results showed that entrepreneurs often found the legislation to be confusing and wanting, and that RWH was associated with economic risks. Initiatives were also hampered by unclear legislation, and by shortages in the exchange of knowledge within the field. Builders and city planners ask for more explicit general outlines and for shared burden of responsibilities. Personal environmental engagement showed to be an important driver, but best effect was reached when it was combined with political support.

Rainwater harvesting (RWH) in the UK has seen a low level of uptake relative to similar settings such as Australia and Germany. The relatively low cost of municipal water in the UK limits the financial savings associated with RWH systems, especially in a domestic setting. Although financial benefits can be relatively low (in terms of reduced water bills), academic and practitioner studies have demonstrated the potential for RWH to significantly reduce potable water demands at typical UK houses. Hence, increased uptake of RWH has potential to contribute to mitigating droughts in water scarce regions. Stormwater management in the UK is receiving increasing attention at all levels; from grass-roots sustainable drainage systems (SuDS) such as downpipe disconnections and raingardens; through to implementation of urban realm attenuation schemes and continued development of guidance from UK policy makers. The public realm nature of most SuDS presents a need for partnership approaches to be fostered between infrastructure mangers and the general public. The application of RWH as a technology within the SuDS management train has been limited in the UK as policy makers have taken the view that RWH tanks may be full at the start of a design storm, and thus the potential for attenuation and peak discharge reduction has been largely ignored. However, in the last few years there has been a shift in emphasis; from RWH perceived purely as a water demand management technology to a focus on its wider benefits e.g. mitigating surface water flooding through improved stormwater management. RWH systems examined in this thesis are now available which offer multiple benefits to both end-users and water service providers. The application of RWH in a dual purpose configuration (to displace potable water demands and control stormwater discharges) has seen increasing interest during the development of this thesis. However, the successful design of RWH as a stormwater management tool requires a series of calculations to be completed. To date, practitioners have frequently relied upon low-resolution heuristic methods which lead to a small range of configurations being deployed, with minimal demonstrable stormwater control benefits. In this thesis, full details of novel and traditional RWH technologies were identified and described. Empirical data was collected, both in laboratory conditions and at field sites, to identify the real world operating characteristics of a range of RWH configurations. Additionally a new time series evaluation methodology was developed to enable RWH systems to be designed and analysed. This method quantifies water demand benefits and also focusses on stormwater management metrics (i.e. largest annual discharge and total discharge volume per year). The method was developed to enable a range of RWH configurations to be evaluated at a given site. In addition, a decision support tool (RainWET) was developed and tested which enabled the methods to be deployed in real world settings. The application of the RainWET software allowed a UK-wide, time series analysis of RWH configurations to be completed and the holistic benefits of a range of dual purpose RWH systems to be analysed and described. Evidence from the UK study suggests that a traditional RWH installation (3000l storage, 300l/day demand and 60m2 roof) installed at a house in a water scarce region (London, SAAR 597mm) was able to fully mitigate stormwater overflows over a 20 year analysis whilst providing a mean water saving of 31,255l/annum. An equivalent system located in the wettest region studied (Truro, SAAR 1099mm) saw mean reductions in the largest annual storm of 62% (range 35-86%) whilst satisfying a mean rainwater demand of 50,912l/annum. The study concluded that suitably designed dual purpose RWH systems offered better stormwater management benefits than those designed without a stormwater control device. In addition, the integration of smart RWH controls were shown to maximise stormwater control benefits with little or no reduction in a system’s ability to satisfy non-potable water demands.

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