Theme: Catchment perspective
Wednesday, July 1
Evaluating the Hydrologic Performance of Passive and Active Release Systems Retrofitting Rainwater Harvesting Cisterns
Towards an assessment of the quantitative impact of the development of treated wastewater reuse on surface water: mapping the contributions of wastewater treatment plants to low flows in the Rhône river basin
In the context of increase of water scarcity due to climate change, wastewater reuse (REUT) – which involves recovering part of the wastewater after appropriate additional treatment – is one of the solutions proposed to reduce pressure on natural water resources. While it presents a clear opportunity as a non-conventional water source, REUT raises questions concerning low water flows downstream of WWTPs, since WWTP discharges can in some cases contribute significantly to maintaining low water flows in rivers. Based on databases of WWTP discharge flows (Rhône Méditerranée Corse Water Agency), river flows from HydroPortail or simulated using a hydrological model, this study presents a map of the contributions of WWTPs (average discharges during dry weather from July to September) to low flow indicators (VCN10 and QMNA5) across the entire hydrographic network of the Rhône river basin. The results show that these contributions vary, thereby helping to better identify opportunities for diversifying water sources in different territories.
Assessment of urban rainwater harvesting potential in Portugal: A spatial approach using the C index
Climate change increasingly demands robust strategies that can guide society toward more sustainable pathways. Rainwater Harvesting Systems (RWHS) constitute a proven and effective tool in this transition, contributing not only to the preservation of water resources but also to the mitigation of urban flooding and the reduction of demand on public water-supply networks. The present study applied a methodology to assess the potential of each Portuguese municipality for RWHS implementation by calculating the C Index, incorporating built-area typology (Class 1, Class 2, and Class 3), precipitation, and water consumption. All spatial analyses were carried out in QGIS. The results demonstrated the feasibility of RWHS deployment, particularly in municipalities located in northern and central Portugal. A total of 22 Class 1 municipalities and 2 Class 2 municipalities were identified as having the capacity to meet their population’s water demand exclusively through harvested rainwater.