The Southern And Eastern Africa Rainwater Network (SEARNET) seeks to promote rainwater harvesting as a risk reduction strategy and means to improve livelihoods through its member national rainwater harvesting associations. SEARNET is an important channel of international donor funding from the Swedish and Dutch governments, and exists to facilitate the sharing of knowledge and experiences of rainwater harvesting through networking. To identify the environmental and organisational issues affecting SEARNET, a questionnaire was sent to SEARNET members that asked open-ended questions about the value of rainwater harvesting to their country and the value of SEARNET to their association. Respondents raised issues that were pertinent to both their association and to SEARNET. Issues were also identified in a survey of Annual Country Status Reports (country reports) presented by national rainwater harvesting associations at the annual SEARNET conferences. Issues included water scarcity and sustainable water supplies; registration as a barrier to funding; a mismatch between donor funding and institutional requirements; and the need for better networking at the SEARNET conference. Several recommendations are made to improve both the promotion of rainwater harvesting by SEARNET members and the networking of SEARNET itself.

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Globally, two-thirds of the population face significant water shortages and eighty percent of the U.S. states' water managers predict water shortages in the near future. Additionally, the current centralized system in the United States is facing significant problems of scarcity, groundwater depletion, high energy consumption and needs a trillion dollars investment in repairs, replacement, and expansion. Furthermore, due to increased urban/suburban development, runoff (stormwater) pollutes our waterways and is causing increased flooding. The status quo is unsustainable in its present form and the water security of the nation is at risk. Fortunately, in recent decades there has been a resurgence in the use of a millenniums old approach, rainwater harvesting (RWH), that if deployed broadly, will mitigate those issues created by the current centralized municipal water system and the expanding development of our cities, suburbs, and towns reducing permeable surface area and lower water security vulnerabilities. This study enlists Multi-Level Perspective (MLP) to examine the transitioning that is occurring from the current centralized municipal water system to one in which it is significantly complemented by an alternative water source, RWH. MLP posits that pressures originating in the broader landscape exerts pressures on the existing regime, as well as the community as a whole, creating an opportunity for the niche to emerge and either replace or change the regime. In the case of RWH, the myriad of pressures are only partially placed on the current centralized water supply regime providing them less pressure to change. Alongside water shortages another significant pressure being placed on the public and governing authorities is increased flooding and pollution resulting in the RWH niche emerging in the construction industry. In response to these pressures a RWH niche formed, largely outside of the existing water supply regime, and grew until it was joined by actors within the regime (e.g., plumbers, plumbing engineers, standards development organizations). This research is framed using MLP's three phases Start-up (niche), Acceleration, and Stabilization. This dissertation does three things. First it shows the internal processes occurring between the MLP levels (landscape, sociotechnical regime, and niche) and mechanisms created that foster the broader adoption of RWH. Secondly, it reveals that while the incumbent regime is not being significantly influenced by the RWH niche, the construction industry is embracing RWH (especially the commercial sector) and following the MLP pathway of Reconfiguration. Third, it looks at RWH in a phase of stabilization. / Doctor of Philosophy / Today the world, as well as the United States, faces significant water problems. These problems include scarcity, groundwater depletion, high energy consumption, and is in need of a trillion dollars to repair or replace US water infrastructure. Additionally, due to urban sprawl and diminishment of permeable surfaces, runoff is a problem causing flooding and pollution. One mitigation is the use of a millennium old technology, rainwater harvesting (RWH). This research uses Multi-Level Perspective (MLP) framework to examine the transition occurring today in the construction industry to build sustainable RWH into new construction, especially commercial buildings. This research examines the dynamic processes and the mechanisms used to grow the RWH niche and then accelerate its adoption. Those mechanisms include building demonstration projects, manuals, standards, and incentive programs. This research also looks at RWH in the U.S. Virgin Islands where RWH has been mandated since 1964. The practical value of this research is to provide policy makers insight into the useful mechanisms aiding a transition to sustainable infrastructure. The theoretical value is that it reveals a transition occurring outside of the dominate regime, the centralized water suppliers, in the construction industry. Additionally, it shows that the creation of RWH standards and the administration of building code has created a new form of water governance.

An emerging field in rainwater harvesting (RWH) is the application of communal rainwater harvesting system. This system's main advantage compared to individual RWH is the centralization of water treatment, which some users of individual RWH find difficult to maintain. Despite alleviating one concern, this communal approach does not increase the RHW system's (RWHS) reliability nor necessarily satisfy all water demands, and hence is not a major improvement in terms of system performance. This research tackles this challenge with a novel approach to communal RWH for single-family houses. Instead of the traditional communal approach to RWH which uses only one storage location, we propose connecting multiple single-family homes' RWHSs to a communal backup tank, i.e., capturing overflow from multiple RWHS, which will increase reliability and water demand met in a way that will significantly improve the current performance of communal RWH. The proposed system will potentially maximize the availability of potable water while limiting spillage and overflow. We simulated the performance of the system in two cities, Houston and Jacksonville, for multiple private and communal storage combination. Results show that volumetric reliability gains, of 1.5% - 6% and 1.5% - 4%, can be achieved for seven to ten and six to seven connected households, respectively, for Houston and Jacksonville if the emphasis is on volumetric reliability (VR). As per total storage capacity, the system achieves higher VR gains for lower total storage capacity in Houston while the system achieves higher VR gains for higher total storage capacities in Jacksonville. With regards to the total cost of ownership per household for the individual system and for the communal storage system, the lifecycle cost of the system was performed using the Net Present Value (NPV) method, with an interest rate of 7% over 30 years. The NPV of the total system costs per household in the city of Houston is lowest for nine to ten connected households, as well as comparable to the base case of a rainwater harvesting system that is not connected to a communal tank for seven and eight connected households. This communal system is more resilient and can be a worthy addition to water and stormwater infrastructures, especially in the face of climate change. / Doctor of Philosophy / An emerging field in rainwater harvesting (RWH) is the application of communal rainwater harvesting system. This system's main advantage compared to individual RWH is the centralization of water treatment, which some users of individual RWH find difficult to maintain. Despite alleviating one concern, this communal approach does not increase the RHW system's (RWHS) reliability nor necessarily satisfy all water demands, and hence is not a major improvement in terms of system performance. This research tackles this challenge with a novel approach to communal RWH for single-family houses. Instead of the traditional communal approach to RWH which uses only one storage location, we propose connecting multiple single-family homes' RWHSs to a communal backup tank, i.e., capturing overflow from multiple RWHS, which will increase reliability and water demand met in a way that will significantly improve the current performance of communal RWH. The proposed system will potentially maximize the availability of potable water while limiting spillage and overflow. We simulated the performance of the system in two cities, Houston and Jacksonville, for multiple private and communal storage combination. Results show that volumetric reliability gains, of 1.5% - 6% and 1.5% - 4%, can be achieved for seven to ten and six to seven connected households, respectively, for Houston and Jacksonville if the emphasis is on volumetric reliability (VR). As per total storage capacity, the system achieves higher VR gains for lower total storage capacity in Houston while the system achieves higher VR gains for higher total storage capacities in Jacksonville. With regards to the total cost of ownership per household for the individual system and for the communal storage system, the lifecycle cost of the system was performed using the Net Present Value (NPV) method, with an interest rate of 7% over 30 years. The NPV of the total system costs per household in the city of Houston is lowest for nine to ten connected households, as well as comparable to the base case of a rainwater harvesting system that is not connected to a communal tank for seven and eight connected households. This communal system is more resilient and can be a worthy addition to water and stormwater infrastructures, especially in the face of climate change.

Thesis (M.Sc.(Agronomy)) --University of Limpopo, 2015 / The changes in climate, especially poor rainfall patterns and distributions are key issues posing major agricultural challenges for food security and threaten the rural livelihoods of many communities in the Limpopo Province. Rainfall (P) is low and limited. These limited P is mostly lost through runoff and evaporation, which result in low soil moisture availability and possible crop failure. Therefore, techniques that reduce these water losses are important for improving dryland crop production and rainwater productivity (RWP). The objectives of this study were to determine the potential and effectiveness of rainwater harvesting and conservation techniques (RWH&CT’s) to conserve and improve plant available water (PAW) for dryland maize production and also determine the efficiency of the RWH&CT’s to improve dryland maize yield and RWP compared to conventional tillage (CON). The study was conducted over a period of two growing seasons (2008/09; 2009/10) using maize as indicator crop at the Towoomba Research Station of the Limpopo Department of Agriculture in the Limpopo Province of South Africa, on an Arcadia ecotope. The experiment was laid out in a randomized complete block design, with four replications and five treatments. The five treatments used in the study were; conventional tillage (CON), No-till (NT), In-field rainwater harvesting (IRWH), Mechanized basins (MB) and Daling plough (DAL). The IRWH and DL were classified as rainwater harvesting techniques (RWHT’s), whilst MB and NT were classified as water conservation techniques. Two access tubes were installed at each treatment to measure the soil water content (SWC) at four different soil depths of 150, 450, 750 and 1050 mm using the neutron water meter. The data collected included climatic data, soil and plant parameters. The data were subjected to analysis of variance through NCSS 2000 Statistical System for Windows and GENSTAT 14th edition. Mean separation tests were computed using Fisher's protected least significant difference test. The SWC of IRWH, DAL and MB were about 510 and 490 mm higher compared to CON and NT treatment during the 2008/09 and 2009/10 seasons, respectively. The PAWT of the IRWH, MB and DAL was significantly different from the CON treatment during the 2008/09 season. For both seasons the biomass yield of the IRWH treatment was significantly different from the NT treatment, producing 23 and 50% more biomass in the 2008/09 and 2009/10 growing seasons, respectively. The grain yield under IRWH was significantly different from the NT treatment during both 2008/09 and 2009/10 seasons. The highest maize grain yield of IRWH was achieved during the 2009/10 season with 56% higher grain yield than the NT treatment. RWP from various RWHT’s were significantly different from the NT treatment. These results indicate that IRWH and DAL were 12 and 2% more effective in converting rainwater into harvestable grain yield than the CON treatment. R2 values of 68.6 and 78.4% for SWC and transpiration (Ev) were obtained when correlated with maize grain yield respectively. This indicates the importance of moisture conservation for improved dryland maize production under low P areas. Therefore, the use of appropriate RWHT’s by smallscale farmers maybe crucial to improve dryland maize production. IRWH outperformed all other treatments in terms of the soil parameters and plant parameter measured during the period of this study. Therefore, these results suggest IRWH has potential of sustaining maize yields under low rainfall conditions. Key words: Rainwater harvesting, conservation techniques, ecotope, rainwater productivity, maize yield, precipitation use efficiency.

As water infrastructure in urban Ontario strains to meet the demands of a growing population, alternatives to the conventional water supply approach that complement demand management strategies are important to enable more sustainable water use at the household level. The adoption of rainwater harvesting (RWH), for indoor and outdoor uses by single-family households can reduce a households withdrawals on municipal water by 30% if rainwater is used for toilet flushing, laundry and outdoor uses (Despins 2009). The amount of potable water savings because of RWH is influenced by the rate of adoption and the allowed uses of rainwater at the individual household scale. The adoption of RWH systems would lead to reductions in potable water demand, which, in turn would lead to reduced demands on municipal water sources (e.g., groundwater or surface water), and storm water infrastructure resulting in overall reduced ecosystem stress and increased resiliency for climate change adaptation. Greater onsite storm water retention would mimic natural processes and would help reduce excess overland runoff that can result in water contamination. Presently, RWH systems tend to be more accepted and utilized in rural areas. However, there is a history of cistern use in rural and non-rural Waterloo. This history and capacity seems to be largely forgotten or unknown by urban citizens and local government officials. Century houses’ cisterns are often removed or filled in due to: a perceived lack of need, safety concerns and disrepair because of disuse. The increasing popularity of “green” building features and certifications have added some RWH systems for indoor and outdoor use to the urban environment, however, these remain limited instances. Moving RWH forward requires commitment from the Provincial and municipal government. Municipalities’ actions must support the sustainability objectives often referenced in their legislation and policy. This study establishes the drivers of RWH and examines the barriers to practice in the urban environment by examining existing examples and academic literature RWH systems within Canada and internationally. Results from a survey conducted in the City of Waterloo are used to reflect the systems user’s perspective. Interviews with municipal officials and RWH experts further highlight the drivers and barriers to RWH in urban Ontario. Based on the surveys, participants were generally willing to consider adopting RWH systems and a greater use of rainwater in the house, although a lack of information acts as significant barrier. However, Waterloo municipal officials who participated in the interviews described a much less enthusiastic attitude towards RWH. Although barriers identified in this research, including: legislative barriers, risk tolerance, perceptions of water abundance and economic realities shape the willingness to adopt RWH, this study indicates the barriers are surmountable through education and economic signaling.

As water infrastructure in urban Ontario strains to meet the demands of a growing population, alternatives to the conventional water supply approach that complement demand management strategies are important to enable more sustainable water use at the household level. The adoption of rainwater harvesting (RWH), for indoor and outdoor uses by single-family households can reduce a households withdrawals on municipal water by 30% if rainwater is used for toilet flushing, laundry and outdoor uses (Despins 2009). The amount of potable water savings because of RWH is influenced by the rate of adoption and the allowed uses of rainwater at the individual household scale. The adoption of RWH systems would lead to reductions in potable water demand, which, in turn would lead to reduced demands on municipal water sources (e.g., groundwater or surface water), and storm water infrastructure resulting in overall reduced ecosystem stress and increased resiliency for climate change adaptation. Greater onsite storm water retention would mimic natural processes and would help reduce excess overland runoff that can result in water contamination. Presently, RWH systems tend to be more accepted and utilized in rural areas. However, there is a history of cistern use in rural and non-rural Waterloo. This history and capacity seems to be largely forgotten or unknown by urban citizens and local government officials. Century houses’ cisterns are often removed or filled in due to: a perceived lack of need, safety concerns and disrepair because of disuse. The increasing popularity of “green” building features and certifications have added some RWH systems for indoor and outdoor use to the urban environment, however, these remain limited instances. Moving RWH forward requires commitment from the Provincial and municipal government. Municipalities’ actions must support the sustainability objectives often referenced in their legislation and policy. This study establishes the drivers of RWH and examines the barriers to practice in the urban environment by examining existing examples and academic literature RWH systems within Canada and internationally. Results from a survey conducted in the City of Waterloo are used to reflect the systems user’s perspective. Interviews with municipal officials and RWH experts further highlight the drivers and barriers to RWH in urban Ontario. Based on the surveys, participants were generally willing to consider adopting RWH systems and a greater use of rainwater in the house, although a lack of information acts as significant barrier. However, Waterloo municipal officials who participated in the interviews described a much less enthusiastic attitude towards RWH. Although barriers identified in this research, including: legislative barriers, risk tolerance, perceptions of water abundance and economic realities shape the willingness to adopt RWH, this study indicates the barriers are surmountable through education and economic signaling.

In drought-prone arid and semi-arid areas, limited plant available water exerts a tremendous negative effect on crop production, leading to undesirable low crop productivity, untold food insecurity, and never-ending poverty. In-field rainwater harvesting (IRWH or In-field RWH) is specifically designed to trap rainfall within the field and optimise its use to benefit crop yield and quality, and improve water use efficiency (WUE) in these regions. Two RWH-crop field experiments were established in the semi-arid area of the Hatfield Experimental Farm, University of Pretoria, South Africa. The first RWH-potato experiment was conducted during the 2009/2010 growing season while the second RWH-Swiss chard experiment was carried out during the 2010/2011 growing season. Three cropping systems were involved: (1) conventional tillage (CT), (2) tied-ridges (TR), and (3) IRWH with three different design ratios of runoff area to cropping area (1:1, 2:1 & 3:1). The runoff area of each design ratio was either bare (B) or plastic-covered (P) and this resulted in six IRWH treatments. Therefore, there were a total of eight treatments: CT, TR, 1:1B, 1:1P, 2:1B, 2:1P, 3:1B and 3:1P. For both growing seasons, the total plot area yields and WUEs of TR and CT were in general higher than those of the IRWH treatments. This is because TR and CT had more plants per plot than the IRWH treatments and the rainfall recorded for the specific seasons were sufficient, so there was little advantage in collecting/harvesting additional water. In terms of yields and WUEs expressed on the net cropped area, the IRWH treatments had higher yields and WUE than CT and TR because they captured more runoff than the latter treatments. Field trials are expensive, laborious and time consuming, therefore models were developed to predict potential runoff and crop growth and yield of different RWH techniques or design ratios. During the current investigation, runoff models such as the linear regression, curve number (CN) and Morin and Cluff (1980) models were used to describe and simulate runoff generation from this ecotope. The empirical rainfall-runoff linear regression model indicated that runoff efficiency declined as runoff length increased. The statistics revealed that the CN and Morin and Cluff (1980) models simulated runoff very well. Moreover, the use of a generic crop growth Soil Water Balance model (SWB) showed potential to simulate crop growth and yield for different RWH techniques and design ratios. During the present study, the SWB model was modified by incorporating linear runoff simulation models in order to predict the soil water balance and crop yield under different RWH design scenarios. Field data collected on the study ecotope contributed to the parameterization and calibration of the SWB model for the crops involved. The SWB model was in general, successfully calibrated for the potato crop, while the calibration for the Swiss chard crop was generally not as successful, most probably because of the continuous growing and harvesting system followed (approach for pastures). The scenario simulation results for potato suggested that for the study ecotope, if land is limiting, CT, TR and smaller design ratios (1:1) are the best options in terms of yield per total plot area. However, if land is not limiting, larger design ratios (2:1 and 3:1) are better options, according to the yields per net cropped area outcomes. The SWB model shows promise as a useful tool to assist in the selection of the best RWH strategy and the ideal planting date under specific conditions with minimal input requirements. However, there is a need to upgrade it to a 2D SWB model for better accuracy under a range of conditions. / Dissertation (MScAgric)--University of Pretoria, 2014. / lk2014 / Plant Production and Soil Science / MScAgric / Unrestricted

Vattenbrist är ett stort problem i många delar av världen. En lösning som tar vara på nederbörden och eventuellt kan säkerställa vattenförsörjningen lokalt är rainwater harvesting metoden. Det som denna rapporten analyserar är huruvida det finns potential att implementera rainwater harvesting system på Storsudret, på södra Gotland. Projektet inleddes med en litteraturstudie över befintliga metoder för rainwater harvesting. En sammanställning och utvärdering har gjorts för vad som lämpar sig för området. Detta tillsammans med data från lokala myndigheter, SMHI och Lantmäteriet har analyserats och sammanställts med hjälp av programmen Excel och ArcMap för att bedöma potentialen. Resultatet av rapporten visar att, utifrån de beräkningar och kartanalyser som gjorts, potential finns för rainwater harvesting metoder på Storsudret, Gotland. De bidragande faktorerna till hur stor potential metoden har är nederbördens fördelning över året, den totala mängden nederbörd samt boendesituationen som råder på Storsudret. Boendesituationen handlar främst om storleken på takytor i relation till antalet människor som är bosatta i de fem socknar som utgör området. Slutsatsen av i hur stor grad rainwater harvesting lösningar kan påverka det enskilda hushållets vattenförsörjning är individuellt, och beror på främst på hushållens förbrukning, takyta och lagringspotential. Lösningar som denna bidrar inte enbart med minskad belastning på grundvattendepåerna, utan hjälper även de hushåll där vattnet är otjänligt och/eller där det kommunala vattennätet inte är tillgängligt. Rainwater harvesting är därför en ingenjörsteknik som kan vara en del av det vattenbristproblem som råder, inte bara på Storsudret, utan även på andra platser i Sverige och världen med vattenbrist på grund av gällande hydrogeologiska förutsättningarna. / Many places around the world, including parts of Sweden, suffers from seasonal lack of water. This can be dealt with by storing precipitation in times when the availability is good. One example of such an area is Storsudret on the southernmost part of Gotland. The focus of this report was to analyze the potential of implementing rainwater harvesting methods in Storsudret. The project was initiated with a literature study of existing methods for rainwater harvesting and an evaluation was made whether or not they were suited for the area and data from SMHI and Lantmäteriet was analyzed and compiled in Excel and ArcMap to assess the potential for rainwater harvesting. What this report shows, according to the calculations and map analysis made, is that there is potential in applying rainwater harvesting methods to the area Storsudret, Gotland. The main factors include the meteorological conditions, more specifically, the general spread of precipitation over a year and to the total amount of precipitation in a year. This together with the other factors is needed to evaluate if rainwater harvesting is a viable option for water supply at Storsudret. The other factors are mainly the size of rooftops in relation to the amount of people living in this area. Depending on each households’ own conditions, mainly water usage, rooftop size and storage capacity, the extent of which rainwater harvesting can be applied, varies. These types of solutions can not only help with a less stress on the groundwater storage, but it can also help those households that doesn’t have acceptable groundwater quality or cannot be connected to the municipal water systems. What this comes to show is that rainwater harvesting is an engineering technique that could help solve problems concerning shortage of water, not only at Storsudret, but also in other places in Sweden or in the world.

Para superar o problema de disponibilidade de água e preservar os recursos hídricos, têm sido buscadas fontes alternativas de água para as atividades humanas. Dentre as soluções encontradas está a captação da água de chuva. Esta técnica é possível através da captação da precipitação em áreas impermeáveis e de seu armazenamento em reservatórios para viabilizar seu uso. Como o reservatório é, em geral, a parte mais dispendiosa para a implantação desse tipo de sistema, é necessário avaliar qual método de dimensionamento é o mais adequado. Para tanto, este trabalho analisou os métodos de dimensionamento de reservatórios para sistemas de captação de água de chuva sugeridos pela Associação Brasileira de Normas Técnicas (ABNT), apresentados na norma NBR 15527/07. A partir dos resultados obtidos, foi constatado que o Método Simulação Mensal se destaca por resultar em volumes de reservatórios com garantias de abastecimento elevadas e com capacidades não exageradas. Este método de dimensionamento foi utilizado para desenvolver uma ferramenta eletrônica no Excel®, a fim de auxiliar a tomada de decisão em relação ao pré-dimensionamento de cisternas, localizadas no estado de São Paulo. A ferramenta, denominada SIMCAP, traz como resultados informações técnicas relativas ao volume de reservatório sugerido pelo usuário e a economia resultante da implantação do sistema. Para tanto, a ferramenta necessita que sejam preenchidas as informações sobre a localização, a categoria da edificação e a parcela do consumo a ser abastecido pela captação da água pluvial. A SIMCAP foi testada em estudos de caso com diferentes cenários de consumo de água para uma mesma edificação. Com isso, foi possível concluir que a ferramenta disponibiliza resultados relevantes à tomada de decisão por facilitar a estimativa dos benefícios econômicos e por apresentar a garantia de abastecimento do reservatório analisado. / To overcome the problem of availability of water and to preserve the water resources, there have been sought alternative sources of water for human activities. Among the solutions founded is rainwater harvesting. This technique is based on capturing rainfall in impermeable areas and storing it in reservoirs to enable its use. As the reservoir is usually the most expensive part of the rainwater harvesting system it is necessary to evaluate which method for tank sizing is the most appropriate. Therefore, this paper analyzed the tank sizing methods for rainwater harvesting systems suggested by the Brazilian Association of Technical Standards (Associação Brasileira de Normas Técnicas - ABNT), regulated by NBR 15527/07. From the results obtained, the Simulation Monthly Method stands out since it results in volumes of reservoirs with high supply reliability and non exaggerated capabilities. This method of design was used to develop an electronic tool in Excel®, to assist decision-making in relation to presizing tanks, located in the state of São Paulo. The tool, named SIMCAP, brings as results technical information about the volume of reservoir suggested by the user and the savings results from its implementation. Therefore, this tool requires the information regarding the location of this system, the category of the building and the water consumption to be supplied with rainwater. The SIMCAP was tested in case studies with different scenarios of water consumption for the same building. In conclusion, the tool results are relevant for decision making by facilitating the estimation of the economic benefits and by providing the reliability of supply of the evaluated reservoir.