Life cycle and hydrologic modeling of rainwater harvesting in urban neighborhoods: Implications of urban form and water demand patterns in the US and Spain

Abstract

Water management plays a major role in any city, but applying alternative strategies might be more or less feasible depending on the urban form and water demand. This paper aims to compare the environmental performance of implementing rainwater harvesting (RWH) systems in American and European cities. To do so, two neighborhoods with a water-stressed Mediterranean climate were selected in contrasting cities, i.e., Calafell (Catalonia, Spain) and Ukiah (California, US). Calafell is a high-density, tourist city, whereas Ukiah is a typical sprawled area. We studied the life cycle impacts of RWH in urban contexts by using runoff modeling before (i.e. business as usual) and after the implementation of this system. In general, cisterns were able to supply >75% of the rainwater demand for laundry and toilet flushing. The exception were multi-story buildings with roofs smaller than 200m, where the catchment area was insufficient to meet demand. The implementation of RWH was environmentally beneficial with respect to the business-as-usual scenario, especially because of reduced runoff treatment needs. Along with soil features, roof area and water demand were major parameters that affected this reduction. RWH systems are more attractive in Calafell, which had 60% lower impacts than in Ukiah. Therefore, high-density areas can potentially benefit more from RWH than sprawled cities.

An Analysis of the Effectiveness of Two Rainwater Harvesting Systems Located in Central Eastern Europe

“…The tank capacity adopted for the academic facilities was supported by the results of simulation tests on the model. This amount was not intended to store all the rainwater delivered to the tank during the rainy season in order to be used later in the dry season, and this assumption is identical with other publications [48]. Depending on the year, the capacity of the reference tanks allowed for retention of 63% to 82% (average 74%) and from 73% to 97% (average 85%) rainwater runoff from the roof to the tank for Nemcova dormitory and Ikar dormitory, respectively.…”

Expanding the Distributed Generation Concept: Toward Decentralized Energy and Water Supply

“…In general, high‐density urban areas will benefit more from rainwater harvesting than low‐density areas; with less water retrieved from the centralized water system, and lower amount of water entering the sewer network to eventually end up as wastewater requiring chemical and biological treatment in wastewater depurators …”

“…To encourage the use of solar disinfection, the same team suggested that plastic bottles need to be provided to households, though water quality concerns exist from long-term leaching of toxic chemicals from the plastic bottles, which significantly increases with storage time and temperature. [35] In general, high-density urban areas will benefit more from rainwater harvesting than low-density areas; [36] with less water retrieved from the centralized water system, and lower amount of water entering the sewer network to eventually end up as wastewater requiring chemical and biological treatment in wastewater depurators. [37] Large-scale successful approaches include those demonstrated, for example, in South Korea or in Malaysia.…”

Identifying eco-efficient year-round crop combinations for rooftop greenhouse agriculture

“…In addition, UA promotes resource efficiency in urban areas. The use of rainwater recovery systems can become an adaptive strategy to mitigate the repercussions of climate change in high-density areas when applied to UA while increasing water supply (Angrill et al 2012;Petit-Boix et al 2018b). The re-use of nutrients recovered from urban organic waste (Bryld 2003) and wastewater (de-Bashan and Bashan 2004;Sengupta and Pandit 2011) also offers possibilities to improve the efficiency of UA.…”