Search results for "Environmental engineering"
showing 10 items of 2674 documents
Using Beerkan experiments to estimate hydraulic conductivity of a crusted loamy soil in a Mediterranean vineyard
2019
Abstract In bare soils of semi-arid areas, surface crusting is a rather common phenomenon due to the impact of raindrops. Water infiltration measurements under ponding conditions are becoming largely applied techniques for an approximate characterization of crusted soils. In this study, the impact of crusting on soil hydraulic conductivity was assessed in a Mediterranean vineyard (western Sicily, Italy) under conventional tillage. The BEST (Beerkan Estimation of Soil Transfer parameters) algorithm was applied to the infiltration data to obtain the hydraulic conductivity of crusted and uncrusted soils. Soil hydraulic conductivity was found to vary during the year and also spatially (i.e., ro…
A review of preferential water flow in soil science
2018
A better understanding of preferential water flow is important because water-related crises, i.e., water scarcity and security, are strongly associated with water retention rates in different landscapes. This review aims to evaluate significant advances in the main themes of preferential water flow to establish the inconsistent roles of preferential water flow in eco-hydrology and suggest promising areas for future work. Results showed that preferential water flow studies have made significant advances in our understanding of certain parameters functioning at multiple scales but that most studies focus on preferential water flow in the vadose zone, whereas few studies on the soil surface. …
Unsaturated Soil Hydraulic Properties
2016
In the first part of this chapter, the tension infiltrometer (TI) technique is illustrated. After having described apparatus and instruments as well as the operative procedures in the field, the solutions based on the Wooding’s equation for steady-state flow are presented. Specific focus is given to the multi-potential approaches that allow determination of unsaturated soil hydraulic conductivity, K 0, corresponding to a sequence of pressure head values, h 0, imposed on the soil surface. The analytical model proposed by Haverkamp et al. (1994) to describe three-dimensional transient infiltration from a circular source is introduced and a single-test approach is presented that allows estimat…
Remote sensing of cyanobacterial blooms in a hypertrophic lagoon (Albufera of València, Eastern Iberian Peninsula) using multitemporal Sentinel-2 ima…
2018
Eutrophy in Albufera of Valencia (Eastern Iberian Peninsula) is a quite old problem since after the intense eutrophication processes throughout the 1960s. The system shifted to a turbid stable state consolidated by the virtual disappearance of macrophytes by the early 1970s. The lagoon has been studied extensively since the 1980s, but efforts to revert the system to a clear state have not yielded the expected results because cultural eutrophication due to the growth of population in its area of influence and the effects of climate change, decreasing rainfall and increasing evaporation. This has driven to an increase in water retention times in the lagoon in recent years, resulting in a phyt…
Distribution patterns of particulate trace metals in the water column and nepheloid layer of the Gulf of Riga.
2004
The dynamics (fate) of trace metals in suspended particulate matter within the Gulf of Riga has not yet been adequately addressed in the scientific literature. Therefore, during a two year period (2001-2002) samples of suspended particulate matter and surface sediments for trace metal analysis were collected in the Gulf of Riga and the Daugava river, and these data were combined with background information from the national marine monitoring program in Latvia. This paper presents a descriptive study of solid phase trace metals (aluminium, iron, cadmium, chromium, copper, manganese, nickel, lead and zinc) dynamics and their spatial distribution within the Gulf of Riga based on Principal Comp…
The Influence of Seasonality on the Economic Efficiency of Wastewater Treatment Plants
2010
Many tourist areas are often characterized with seasonal water demand. The influence of seasonality on water management is more intensive in the context of water scarcity. Thus the use of so-called non-conventional water resources in these areas becomes a key aspect. In this sense, efficient performance, both in technical and cost terms, favors water reuse possibilities and, therefore, increases the supply of non-conventional resources. In tourist areas, seasonality is a determining factor in the efficiency of wastewater treatment plants (WWTPs) as these are operating at full capacity only during the summer season while the rest of the year they have under-utilization problems. Using the Fr…
Energy, water and environmental balance of a complex water supply system
2015
The present paper describes the analysis of water and energy balance in a complex urban water supply system. The analysis was carried out employing Life Cycle Analysis (LCA) methodologies. The LCA approach was integrated with the analysis of the system energy and water balance. For a real size water supply system, based on the results of the individual LCAs, the current baseline was constructed highlighting the water, energy and environmental (in terms of CO2eq emissions in the atmosphere) costs of supplied water. Then, three different mitigation measures have been evaluated: the first is based on energy production by installation of photovoltaic systems; the second is based on energy recov…
ECONOMIC AND TECHNICAL EFFICIENCY OF WASTEWATER PLANTS: A BASIC REQUISITE TO THE FEASIBILITY OF WATER REUSE PROJECTS
2006
The water reuse could be considered essential both from a social and also an environmental and health point of view. In light of the growing importance of water reuse as an alternative source of water resources in many regional areas, the objective of this paper is to analyse the efficiency of wastewater treatment plants. Efficient performance, both in technical and economic terms favours reuse possibilities and, therefore, increases the water supply. An analytical benchmarking methodology based on non-radial measures gives us an efficiency indicator for each input considered in the wastewater treatment process. These indicators, obtained by means of mathematical programming techniques, are…
The Intervention of Hydrogeophysics in the Economics of Groundwater Exploitation and Management in Sicily
1989
Abstract The problem of the preservation of water resources in Sicily presents various aspects, some of which have been treated by a number of works. Among the different applied methodologies, the geophysical ones occupy an important place. Their contribution, directed to an economic and efficient exploitation and management of groundwaters, can be useful for selected “risk” areas as well as for more regional programmes. In fact, uncontrolled drillings on relatively rich aquifers occur in several zones of this island; the economically disadvantageous exploitation causes also heavy impoverishment and pollution phenomena. The fragmentation of charges and the lack of a planning Regional Body m…
An assessment of the BEST procedure to estimate the soil water retention curve: A comparison with the evaporation method
2018
The Beerkan Estimation of Soil Transfer parameters (BEST) procedure is an attractive, easy, robust, and inexpensive way for a complete soil hydraulic characterization but testing the ability of this procedure to estimate the water retention curve is necessary as relatively little information is available in the literature. In this investigation the soil water retention curve was predicted for four differently textured soils by applying three existing BEST algorithms (i.e., slope, intercept and steady) and the results compared with those measured by the standard Wind evaporation method. A sensitivity analysis of the infiltration constants, beta and gamma, was also carried out and their impac…