Search results for "hydrology"
showing 10 items of 1041 documents
Ordination analysis and bioindices based on zoobenthos communities used to assess pollution of a lake in southern Finland
1990
The suitability of an ordination method, detrended correspondence analysis (DCA), was tested in assessing the degree of pollution of a large lake on the basis of the zoobenthos communities. Lake Etela-Saimaa, in southern Finland, was originally oligotrophic but is now heavily loaded by effluents from the wood-processing industry. Comparison between areas was complicated by variation in the water depths of the lake sub-basins. A horizontal pollution gradient could, however, easily be detected by means of the DCA in both the profundal and sublittoral zones. The benthic quality index (BQI) based on the composition of the profundal chironomid fauna failed at some stations because the indicator …
Groundwater nitrate risk assessment using intrinsic vulnerability methods: A comparative study of environmental impact by intensive farming in the Me…
2015
Abstract Groundwater contamination by nitrate and other nutrients is a major problem throughout the world, often occurring as the result of anthropogenic activities, lack of management, and over-exploitation of groundwater resources. In the last few decades in the majority of the Italian regions, the nitrate concentrations in groundwater have dramatically increased, mainly as a consequence of the large-scale agricultural application of manure and fertilizers. This excessive use of chemicals and fertilizers increases the risk of surface and groundwater pollution from diffuse sources, which have an important impact on human health and the environment. Sicily is located in the central Mediterr…
Hydrochemical evolution and environmental features of Salso River catchment, central Sicily (Italy)
2000
A hydrogeochemical study of the Salso River highlighted the chemical and isotopic space-time evolution along its flow path and the main contamination processes. Within the basin, three different hydrogeochemical facies have been individuated: (1) Ca-Mg-HCO3, (2) Ca-Mg-SO4 and (3) Na-Cl. The first facies reflects the chemical composition of the groundwaters hosted in the carbonate reliefs that belong to the Madonie Mountains. The second and the third facies are the result of the interaction processes between surface waters and the gypsum and salty clays, respectively. Two pollution sources have been also located in the basin downstream from the salt mine and downstream from a discharge area …
Evaluation of Local Scale PM Pollution Levels in Typical Street Canyon in Riga
2013
The present study describes long term PM10 and PM2.5 changes in typical street canyon with particular emphasis on seasonal, diurnal variations in context with meteorological data. In order to understand PM10 pollution sources during 28 April 2007-31 December 2007, chemical composition measurements were done with particular emphasis on heavy metals (As, Cd, Ni, and Pb), crustal material (Ca, Mg, Na, and K) and anions (sulphates, nitrates, chlorides). Meteorological data used for this evolutional analysis were measured close to traffic related stations and several meteorological parameters were analyzed in relation to particulate measurements. Keep in mind that atmospheric aerosols are genera…
Geomorphing effect of sand fences in primary dunes of Gulf of Riga
2022
Finding a the most appropriate solution for the problems caused by coastal eros ion is very important, as erosion prevention and habitat management measures must promote the restoration of the natural balance (order of things before anthropogenic disturbances) and restore the coastal status quo as much as possible [6; 2].Dune fences are a very widespread erosion management tool on developed sandy coastal areas due to ease of installation, inexpensiveness, and generally positive public attitude [1]. Effectiveness and impact of fences have also been studied in many places around the world, however previous studies in Latvia have been very limited and episodic [16].This article shows the obser…
Thorium-234 derived information on particle residence times and sediment deposition in shallow waters of the south-western Baltic Sea
2009
Abstract Activities of the naturally occurring, short-lived and highly particle-reactive radionuclide tracer 234 Th in the dissolved and particulate phase were measured at three shallow-water stations (maximum water depths: 15.6, 22.7 and 30.1 m) in Mecklenburg Bay (south-western Baltic Sea) to constrain the time scales of the dynamics and the depositional fate of particulate matter. Activities of particle-associated (> 0.4 μm) and total (particulate + dissolved) 234 Th were in the range of 0.08–0.11 dpm L − 1 and 0.11–0.20 dpm L − 1 , respectively. The activity ratio of total 234 Th and its long-lived and conservative parent nuclide 238 U was well below unity (range: 0.09–0.19) indicating …
Comparing theoretically supported rainfall-runoff erosivity factors at the Sparacia (South Italy) experimental site
2018
Interpreting rainfall‐runoff erosivity by a process‐oriented scheme allows to conjugate the physical approach to soil loss estimate with the empirical one. Including the effect of runoff in the model permits to distinguish between detachment and transport in the soil erosion process. In this paper, at first, a general definition of the rainfall‐runoff erosivity factor REFe including the power of both event runoff coefficient QR and event rainfall erosivity index EI30 of the Universal Soil Loss Equation (USLE) is proposed. The REFe factor is applicable to all USLE‐based models (USLE, Modified USLE [USLE‐M] and Modified USLE‐M [USLE‐MM]) and it allows to distinguish between purely empirical m…
Green roof effects on the rainwater response in the Mediterranean area: first results of a Sicilian case study
2021
<p>Over the last decades, we have been witnessing an increasing frequency of urban floods often attributed to the interaction between intensification of rainfall extremes due to climate change and increasing urbanization. Consequently, many studies have been trying to propose different new alternatives to mitigate ground effects of ever more frequent and severe extreme rainfall events in a context of growing urbanization, such as rain gardens, green roofs, permeable parking lots, etc., which are commonly referred to as green infrastructures.</p><p>With this regard, one of the most promising mitigation solutions is represented by multilayer green roo…
Anthropogenic processes in the evolution of a soil chronosequence on marly-limestone substrata in an Italian Mediterranean environment
2007
Due to anthropic pressure, many areas of the world are affected by a process of soil “entisolization” that leads to the formation of “anthropogenic soils”. In order to investigate Man's role in soil evolution, a survey was carried out in Southeastern Sicily (Italy), where, for years, there have been wide farming areas with anthropogenic soils. A chronosequence of anthropogenic soils in a vineyard area, cultivated for 22 years, was investigated. The first stage of the chronosequence was made by the original soils which, in the study area, had been undisturbed till the 1980's. These soils, classified as Entic Haploxerolls under the American Soil Taxonomy (ST) or Calcaric Kastanozem according …
Rainfall erosivity over the Calabrian region
1997
Abstract Following the results of a study carried out for the neighbouring Sicilian region, this paper reports a study of the applicability of the annual value, Faj, of the Arnouldus index to represent the erosion risk in Calabrian region. Firstly, By using 214 values of the mean annual value of the erosivity index, FF, and a Kriging interpolation method, an isoerosivity map is plotted. Then, in order to predict the erosion risk for an event of any return period, the probability distribution of the Faj index is studied. An in situ statistical analysis, carried out by using candidate distributions with two parameters (Gauss, LN2, EV1 and Weibull distribution), showed that the EV1 and LN2 law…