| Title | Assessing Transmission Losses through Ephemeral Streams: A Methodological Approach Based on the Infiltration of Treated Effluents Released into Streams |
| Abstract | Climate change and anthropogenic pressures are the main drivers of the quantitative and qualitative depletion of water bodies, worldwide. Nowadays, in many urban areas, discharging effluents from wastewater treatment plants (WWTPs) into surface water bodies is a management solution to face the problem of water scarcity and sustain environmental flows. Although this practice can cause some concerns in public opinion about possible ecological side-effects and impairment of quality on receiving streams, it is an important contribution to the environmental baseflow of ephemeral streams, but also to groundwater recharge, especially during dry seasons, and in semi-arid and arid regions. This latter occurs through losing reaches along the streambed, though many factors may affect the infiltration rate, such as spatial distribution of streambed sediments and bedrock or the presence of channel lining. Moving from such premises, this study focuses on the Canale Reale River, an effluent-fed stream located nearby the city of Brindisi on the south-eastern side of the Apulia Region, in Italy. The Canale Reale flows through the Torre Guaceto protected wetland, located along the Adriatic coast. It collects effluents from four WWTPs with wastewater contributing for about 16.5% of the annual volume of channel drainage (i.e., 3.82 Mm(3) out of 23.02 Mm(3) along its 50 km long course). Within the framework of a complex geological setting, the Canale Reale River crosses different lithologies, which implies different streambed infiltration conditions. Using the Reach Length Water Balance method (RLWB), the transmission losses between the watercourse and the underlying aquifers were investigated. Particularly, the method allowed for the estimation of a spatially-average value of the riverbed's infiltration rate applicable to the whole river course as well as the minimum, average, and maximum potential transmission losses (TLP) from the river to the underlying groundwater systems. Combining the estimated TLP values and the Flow Duration Curve (FDC) allowed for the inferring of the Transmission Loss Duration Curves (TLDC). Finally, the water volume infiltrating during an average hydrological year was estimated to be 6.25 Mm(3), 61% of which was due to treated wastewater discharge. The results obtained confirm that the practice of increasing the river flow rates with WWTP effluents reduces the dry riverbed periods, with potential improvements to the river's ecological sustainability and relevant enhancement of groundwater recharge. |
| Source | Water (Basel) 14 (22) |
| Keywords | surface-groundwater interactionseffluent-fed riverReach Length Water Balance method |
| Journal | Water (Basel) |
| Editor | Molecular Diversity Preservation International, Basel, |
| Year | 2022 |
| Type | Articolo in rivista |
| DOI | 10.3390/w14223758 |
| Authors | Portoghese, Ivan; Brigida, Silvia; Masciale, Rita; Passarella, Giuseppe |
| Text | 483668 2022 10.3390/w14223758 ISI Web of Science WOS 000887720000001 surface groundwater interactions effluent fed river Reach Length Water Balance method Assessing Transmission Losses through Ephemeral Streams A Methodological Approach Based on the Infiltration of Treated Effluents Released into Streams Portoghese, Ivan; Brigida, Silvia; Masciale, Rita; Passarella, Giuseppe Water Research Institute, National Research Council IRSA CNR , viale F. De Blasio 5, 70132 Bari Climate change and anthropogenic pressures are the main drivers of the quantitative and qualitative depletion of water bodies, worldwide. Nowadays, in many urban areas, discharging effluents from wastewater treatment plants WWTPs into surface water bodies is a management solution to face the problem of water scarcity and sustain environmental flows. Although this practice can cause some concerns in public opinion about possible ecological side effects and impairment of quality on receiving streams, it is an important contribution to the environmental baseflow of ephemeral streams, but also to groundwater recharge, especially during dry seasons, and in semi arid and arid regions. This latter occurs through losing reaches along the streambed, though many factors may affect the infiltration rate, such as spatial distribution of streambed sediments and bedrock or the presence of channel lining. Moving from such premises, this study focuses on the Canale Reale River, an effluent fed stream located nearby the city of Brindisi on the south eastern side of the Apulia Region, in Italy. The Canale Reale flows through the Torre Guaceto protected wetland, located along the Adriatic coast. It collects effluents from four WWTPs with wastewater contributing for about 16.5% of the annual volume of channel drainage i.e., 3.82 Mm 3 out of 23.02 Mm 3 along its 50 km long course . Within the framework of a complex geological setting, the Canale Reale River crosses different lithologies, which implies different streambed infiltration conditions. Using the Reach Length Water Balance method RLWB , the transmission losses between the watercourse and the underlying aquifers were investigated. Particularly, the method allowed for the estimation of a spatially average value of the riverbed s infiltration rate applicable to the whole river course as well as the minimum, average, and maximum potential transmission losses TLP from the river to the underlying groundwater systems. Combining the estimated TLP values and the Flow Duration Curve FDC allowed for the inferring of the Transmission Loss Duration Curves TLDC . Finally, the water volume infiltrating during an average hydrological year was estimated to be 6.25 Mm 3 , 61% of which was due to treated wastewater discharge. The results obtained confirm that the practice of increasing the river flow rates with WWTP effluents reduces the dry riverbed periods, with potential improvements to the river s ecological sustainability and relevant enhancement of groundwater recharge. 14 Published version https //doi.org/10.3390/w14223758 Articolo in rivista Molecular Diversity Preservation International 2073 4441 Water Basel Water Basel Water Basel Water. Basel BRIGIDA SILVIA giuseppe.passarella PASSARELLA GIUSEPPE ivan.portoghese PORTOGHESE IVAN rita.masciale MASCIALE RITA TA.P04.005.008 Integrazione di metodologie per il monitoraggio e la modellizzazione per la gestione delle risorse idriche |
