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Under the climate crisis and rapid urbanisation, rainwater harvesting (RWH) is more pertinent than ever. In Bangladesh, the full potential of rainwater use, especially for the urban poor, has not been explored. This study reviewed the recently-executed national plans to assess the RWH provisions, explored literature to map RWH practice, showed the alignment between the plans and the practices, and assessed the provision of RWH in the currently-implemented plans, with a particular focus on the urban poor. Although the past plans recognised RWH, the study found that these did not emphasise the implementation process nor offer provisions for the urban poor. RWH was, however, widely practised in the urban, peri-urban, and rural parts of the country by utilising different catchment structures. Building on the experiences of other countries, the study assessed the feasibility of RWH for the urban poor to meet their sanitation and hygiene needs under the changing climate. The study concluded that a detailed 'Rainwater Harvesting and Management Plan' supporting the adoption and promotion of community-led models to mitigate RWH-related challenges in the urban slums and integrating multi-storied buildings to harvest rainwater for the poor neighbourhoods could ensure efficient and equitable rainwater management for the urban poor. [ABSTRACT FROM AUTHOR]

Urban growth leads to geographically concentrated demand for water and food - and to growing volumes of wastewater and organic waste. Left unattended by city authorities, both local and planetary resources boundaries for water and nutrients will be transgressed. A novel partly dynamic 'flexible water balance' is developed to explore ways to address a looming water crisis. A systems-based flow chart shows how rainwater, groundwater and recycled water interact. Measures from supply-, demand-, and reuse management are combined to manipulate the water flows. Water management in Bangalore, India, focused on supply management over the period 1964 to 2015, tapping distant rivers. This mind-set was challenged by a Water Disputes Tribunal and international financiers. Residents and industry were losing faith in the erratic water supply, and met part or all their water needs by digging or drilling wells. The 'flexible water balance' is tested on Bangalore for the year 2050 when the population has increased from 8 to 20 million. New housing complexes can provide opportunities for effective arrangements to recycle water and nutrients, save energy, and reduce water pollution and air emissions. The 'flexible water balance' indicates that Bangaloreans can get enough household water without tapping river water and still recharge groundwater. [ABSTRACT FROM AUTHOR]

The objective of the paper is to evaluate the potential of tank-based rainwater harvesting systems in free standing houses as the source control method to mitigate peak roof runoff due to rainfall in urban areas. To this aim, the water balance simulation of the rainwater tank was carried out using both high resolution rainfall series and toilet water demand data extracted from the database of results built in a previous field campaign involving six experimental households in southern Italy. Simulations show that significant potential for runoff peak reduction exists, basically depending on the rainwater tank size and on the characteristics of the water demand in the house. [ABSTRACT FROM AUTHOR]

Rainwater harvesting to irrigate small-scale gardens enhances food self-sufficiency to overcome rural poverty. So far rainwater harvesting is not encouraged by the Namibian National Water Supply and Sanitation Policy nor supported financially by the Namibian government. This study proposes two rainwater harvesting facilities to irrigate gardens; one collects rain from household roofs with tank storage, the second collects rain on a pond roof with pond storage. The aim of this paper is to assess the benefits of rainwater harvesting-based gardening and to propose policy and financing implications for the Namibian government. We investigate the benefits of rainwater harvesting through a literature review, a cost--benefit analysis, monitoring of project pilot plants and a comparison with the existing irrigation and drinking water infrastructure. The results indicate that rainwater harvesting offers numerous benefits in technological, economic, environmental and social terms. The facilities have a positive net present value under favourable circumstances. However, material investment costs pose a financing problem. We recommend that government fund the rainwater harvesting infrastructure and finance privately garden and operation and maintenance costs. Integrating these aspects into a national rainwater harvesting policy would create the conditions to achieve the benefits of an up-scale of rainwater harvesting based gardening in Namibia. [ABSTRACT FROM AUTHOR]