Search results for "Subsurface flow"
showing 10 items of 23 documents
Transboundary Basins Need More Attention: Anthropogenic Impacts on Land Cover Changes in Aras River Basin, Monitoring and Prediction.
2020
Changes in land cover (LC) can alter the basin hydrology by affecting the evaporation, infiltration, and surface and subsurface flow processes, and ultimately affect river water quantity and quality. This study aimed to monitor and predict the LC composition of a major, transboundary basin contributing to the Caspian Sea, the Aras River Basin (ARB). To this end, four LC maps of ARB corresponding to the years 1984, 2000, 2010, and 2017 were generated using Landsat satellite imagery from Armenia and the Nakhchivan Autonomous Republic. The LC gains and losses, net changes, exchanges, and the spatial trend of changes over 33 years (1984–2017) were investigated. The most important drivers of the…
Effects of Irrigation with Different Sources of Water on Growth, Yield and Essential Oil Compounds in Oregano
2020
Aromatic plants can benefit from the use of treated wastewater to satisfy their water requirements, but the effects on the essential oil yield and quality need an assessment. The aims of this study were to assess the effects of freshwater and treated wastewater obtained from a Sicilian (Italy) pilot-scale horizontal subsurface flow constructed wetland system on plant growth and yield, essential oil yield and composition of oregano (Origanum vulgare ssp. hirtum (Link) Ietswaart) and soil characteristics. The system had a total surface area of 100 m2 and was planted with giant reed and umbrella sedge. An experimental open field of oregano was set up close to the system. Two years and two diff…
Reuse of urban-treated wastewater from a pilot-scale horizontal subsurface flow system in Sicily (Italy) for irrigation of Bermudagrass (Cynodon dact…
2016
Constructed wetlands (CW) are one of the most important biological technology for the treatment and reuse of wastewaters. The aim of this study was to evaluate the reuse of treated wastewater (TWW) from CW for irrigation of Bermudagrass turf (Cynodon dactylon (L.) Pers.) and assess the effects of TWW on the biometric and qualitative parameters of the turfgrass and on chemical–physical soil properties. The research was carried out in Sicily (Italy) in a pilot-scale horizontal subsurface flow system which was fed with urban TWW following secondary treatment from an activate sludge wastewater treatment plant. The pilot-system included three separate parallel units. The outflow TWW flowed downh…
Water balance and pollutant removal efficiency when considering evapotranspiration in a pilot-scale horizontal subsurface flow constructed wetland in…
2016
Abstract In constructed wetland systems (CWs) for wastewater treatment, the performance of the system is affected by evapotranspiration (ET). This study shows the results of a series of water balance and pollutant removal efficiency analyses taken from a pilot horizontal-subsurface flow system (HSSFs) in the West of Sicily (Italy). The system comprised three separate units, one planted with Cyperus alternifolius L., one planted with Typha latifolia L. and an unplanted unit. The system was fed with urban wastewater from an activated-sludge wastewater treatment plant. The aims of the study were to determine water balance and pollutant removal rates when considering evapotranspiration in two r…
Subsurface flow and large-scale lateral saturated soil hydraulic conductivity in a Mediterranean hillslope with contrasting land uses
2017
Abstract The lateral saturated hydraulic conductivity, Ks,l , is the soil property that mostly governs subsurface flow in hillslopes. Determinations of Ks,l at the hillslope scale are expected to yield valuable information for interpreting and modeling hydrological processes since soil heterogeneities are functionally averaged in this case. However, these data are rare since the experiments are quite difficult and costly. In this investigation, that was carried out in Sardinia (Italy), large-scale determinations of Ks,l were done in two adjacent hillslopes covered by a Mediterranean maquis and grass, respectively, with the following objectives: i) to evaluate the effect of land use change o…
Evaluation of clogging in full-scale subsurface flow constructed wetlands
2016
Abstract Treatment processes that occur in constructed wetlands can result in gradual clogging of the porous medium. Clogging may result in hydraulic malfunction and/or reduced treatment performance. The aim of this study was to analyze the hydraulic aspects of horizontal subsurface flow (H-SSF) constructed wetlands (CWs), and, in particular, to investigate the clogging phenomena through in situ measurements of hydraulic conductivity of the gravel bed, quantification of accumulated clog matter and flow paths visualization by means of tracer tests. Removal efficiencies of chemical and physical contaminants were also assessed. Experiments were carried out in three full-scale H-SSF CWs in Sici…
An insight into water stable isotope signatures in temperate catchment
2020
Abstract Stable isotopes are used to decipher hydrological processes in watershed research. A two-year monthly monitoring of hydrogen and oxygen stable isotope ratios (δ2H and δ18O) in a temperate catchment in Norther Europa, Latvia was undertaken. Isotope ratios in common water types – raised bog, confined groundwater, unconfined groundwater and surface water – were measured. We found characteristic signatures of isotope ratios for each of these four water types. The average isotope ratios of different water types ranged from −80.8 to −68.3‰ for δ2H and −11.46 to −8.76‰ for δ18O, with standard deviations from 18 to 25‰ and 0.10 to 1.59‰, respectively. The isotope ratios of the stream base …
Hydrological effects of a layer of vegetation ash on underlying wettable and water repellent soil
2012
Abstract Hydrological processes after a wildfire may take place under soil conditions altered by heat and by the presence of ash. Soil and ash interact as a two-layer system with poorly understood hydrological properties, especially when ash covers water repellent soil. Here we quantify the effect of an ash layer (0, 5, 15 and 30 mm depth) covering wettable and water repellent soil on (i) the hydrological response and the mechanism of runoff generation and (ii) the water repellency dynamics, for a rainfall event followed by different drying periods and a second rainfall event. Laboratory rainfall simulation experiments (82.5 mm h − 1 during 40 min) at small plot-scale (0.09 m 2 ) were perfo…
EHSM: a conceptual ecohydrological model for daily streamflow simulation
2013
A parsimonious conceptual lumped model is here presented with the aim of simulating daily streamflow in semi-arid areas. The model, processing daily rainfall and reference evapotranspiration at basin scale, reproduces surface and subsurface runoff, soil moisture dynamics, and actual evapotranspiration fluxes. The key elements of this numerical model are the soil bucket, where rainfall, evapotranspiration, and leakage drive soil moisture dynamics, and two linear reservoirs working in parallel with different characteristic response times. The surface reservoir, able to simulate the fast response of the basin, is fed by rain falling on impervious area and by runoff generated with excess of sat…
Effects of karst processes on surface water and groundwater hydrology at Skaistkalne Vicinity, Latvia
2012
The Skaistkalne area in Latvia is one of the places where karst processes in gypsum strata occurs. The Iecava and Memele rivers border the area with extensive surface karst features such as sinkholes and karst lakes. Earlier investigations suggested a hydraulic connection between the Iecava and Memele rivers exists via the karst conduits due to the water level (WL) difference in the rivers. A set of methods was performed to study the possible connection: dye tracer was applied in the Iecava river and its occurrence was visually observed at the karst lakes and Memele river; the current velocity was measured and discharge of rivers calculated at several profiles; surface water and groundwater…