Influence of Design Variables on the Financial Feasibility of Rainwater Harvesting Systems

Abstract

Extensive implementation of rainwater harvesting (RWH) systems can promote substantial improvement in urban water resource management. Therefore, establishing the financial feasibility of RWH systems is imperative for their dissemination. This study evaluated the influence of rainfall time series indicators (average annual rainfall, seasonality index and behaviour of periods without precipitation) and design variables (catchment area, rainwater demand, number of inhabitants, potable water demand and rainwater tank size) on the financial feasibility of RWH systems in eight Brazilian cities. Correlations between rainfall indicators and financial feasibility were introduced, along with sensitivity analysis of design variables. Financial feasibility was obtained in 30% to 70% of the simulated scenarios. Initial investment and operating costs varied significantly among the eight cities according to local prices. Systems with a catchment area of 200 m2 were capable of supplying, on average, 90.5% of the maximum rainwater consumption observed in this study. Local variation of potable water tariff schemes affected the financial feasibility of RWH systems. The number of inhabitants was the most influential design variable on the financial feasibility of RWH systems, followed by the rainwater tank size. Places with lower rainfall seasonality indexes and lower incidence and duration of dry periods are likely to lead to greater financial feasibility.

Sustainable Rainwater Management and Life Cycle Assessment: Challenges and Perspectives

“…In this country, the return on investment times varied between seven and twenty years for tank capacities between 1500 and 10,000 L, considering the tariff policy practised at the time of the study by the local utility. For example, Istchuk and Ghisi [94] studied which variables correlated to the feasibility of domestic rainwater harvesting systems in Brazil. The authors found that tank capacities were the second most crucial design variable, in which the number of inhabitants and rainwater consumption came first.…”

“…This matches the study of Li et al [77], where the tank capacity was an important variable in the overall feasibility of the systems. Istchuk and Ghisi [94] also assessed the importance of rainfall distribution in the feasibility indicators; the authors found that places with low seasonality indexes have a higher probability of obtaining feasibility.…”

Exploring bundle bamboo split technique in bending dendrocalamus asper for landscape structure

“…However, it should be noted that the latter exhibits exceptional hardness [32] , rendering it more suitable for outdoor construction purposes. [6] [20] [24] The discussion also aims to determine the most appropriate BTM (Bamboo Treatment Method) that can be utilized to achieve the desired curvature, as previously mentioned. Various techniques, such as employing a bamboo slash with a 'V' notch on its culm, are being explored as potential methods for bending bamboo.…”

“…It is renowned for its flexibility, as it is capable of bending without breaking. [5] Additionally, bamboo exhibits remarkable strength, comparable to that of steel [6] . Its elegant and organic shape further adds to its aesthetic appeal.…”