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Pacheco F.A.L.,Chemistry Research Center | Pacheco F.A.L.,Royal University | Santos R.M.B.,Center for the Research and Technology of Agro Environment and Biological science | Sanches Fernandes L.F.,Center for the Research and Technology of Agro Environment and Biological science | And 3 more authors.
Science of the Total Environment | Year: 2015

A study on nitrate yields was conducted in forested watersheds of mainland Portugal. The prime goal was to rank parameters in descending order of their contribution to the export of nitrate towards streams and lakes. To attain the goal, variables like soil loss, rainfall intensity, topography, soil type, forest composition and environmental disturbances such as hardwood harvesting or wildfires were organized in a conceptual yield model. Because some parameters were potentially collinear, a robust multivariate statistical technique was selected to execute the conceptual model and perform the aforementioned ranking, namely Partial Least Squares (PLS) regression. This technique was tested with a sample of 60 forested watersheds (>. 70% of forest occupation), being subject to a double-validation process to ensure prediction capability. According to final regression coefficients, soil erosion seems to regulate nitrate distribution across the basins, because soil loss and type, rainfall intensity and topography explained around 60% of nitrate yield variance. The major importance of erosion is followed by a moderate role of biochemical processes such as nitrification or nutrient uptake, which accounted for approximately 15% of nitrate yield variance. In this case, deciduous forests and scrubland seem to behave as net sinks of nitrate while coniferous and mixed forests seem to act dually, as net sources or sinks. The least important parameters are the environmental disturbances, explaining no more than 5% of nitrate yield variance. The results of PLS regression were coupled in a scenario analysis with measures designed to protect soil from erosion and surface water from eutrophication. These interventions are to be implemented until 2045, according to regional plans of forest management. Considering the key role of erosion in explaining nitrate dynamics across the catchments, it was not surprising to verify that soil protection measures may reduce nitrate yields by some 35% of their current values. © 2015 Elsevier B.V.

Santos R.M.B.,Royal University | Santos R.M.B.,Center for the Research and Technology of Agro Environment and Biological science | Sanches Fernandes L.F.,Royal University | Sanches Fernandes L.F.,Center for the Research and Technology of Agro Environment and Biological science | And 6 more authors.
Journal of Hydrology | Year: 2014

Within the period 1978-2006, climate change and human interferences produced noticeable impacts on the hydrology of a small watershed, known as the Beça River basin. Climate change was characterized by a persistent raise in temperature (+0.78°Cdecade- 1) and a drop in the annual rainfall (-300mmdecade- 1). Human interferences included the construction of a dam for electric power generation, in 1998, and since then the transference of Beça River flows from the dam lake to the adjacent Tâmega River. The impacts on catchment hydrology comprised a decline of aquifer hydraulic conductivity and effective porosity, by approximately one order of magnitude, related to a water table lowering of about 17m within the bedrock aquifer composed of weathered and fractured Hercynian granites and Paleozoic metassediments and of saprolite layers derived therefrom. Aquifer property estimates were compared across spatial scales, namely the Beça River and the nested sub-basins scale. Sub-basin aquifers are more porous and permeable than the basin aquifer because corresponding hydraulic circuits are shallower. Comparisons were also made between aquifer properties derived from measured and simulated stream flows, which revealed effects of modeling uncertainties on the results. River flows also suffered a substantial decrease in the course of climate change and human interference, especially the overland flows (4/5 decrease) and the base flows (2/3 decrease). The inter flows were less affected (1/3 decrease) because they were partly fed with water from the aquifer storage, which in turn underwent depletion. The hydrologic changes in the Beça River basin anticipate important impacts on the local use of natural water. In this context, the aforementioned water table lowering may have caused limited access to shallow groundwater for activities such as crop irrigation from dug wells, whereas the severe decline in overland flows and base flows had certainly reduced the availability of surface water for the refilling of dam lakes and of groundwater for the supply of public and private boreholes. © 2014 Elsevier B.V.

Santos R.M.B.,Center for the Research and Technology of Agro Environment and Biological science | Sanches Fernandes L.F.,Center for the Research and Technology of Agro Environment and Biological science | Sanches Fernandes L.F.,Royal University | Pereira M.G.,Center for the Research and Technology of Agro Environment and Biological science | And 3 more authors.
Science of the Total Environment | Year: 2015

Situated in the north of Portugal, the Beça River basin is subject to recurrent wildfires, which produce serious consequences on soil erosion and nutrient exports, namely by deteriorating the water quality in the basin. In the present study, the ECO Lab tool embedded in the Mike Hydro Basin software was used for the evaluation of river water quality, in particular the dissolved concentration of phosphorus in the period 1990-2013. The phosphorus concentrations are influenced by the burned area and the river flow discharge, but the hydrologic conditions prevail: in a wet year (2000, 16.3km2 of burned area) with an average flow of 16.4m3·s-1 the maximum phosphorus concentration was as low as 0.02mg·L-1, while in a dry year (2005, 24.4km2 of burned area) with an average flow of 2m3·s-1 the maximum concentration was as high as 0.57mg·L-1. Phosphorus concentrations in the water bodies exceeded the bounds of good ecological status in 2005 and between 2009 and 2012, water for human consumption in 2009 and water for multiple uses in 2010. The River Covas, a right margin tributary of Beça River, is the most appropriate stream as regards the use of water for human consumption, because it presents the biggest water potential with the best water quality. Since wildfires in the basin result essentially from natural causes and climate change forecasts indicate an increase in their frequency and intensity in the near future, forestry measures are proposed to include as a priority the conversion of stands of maritime pine in mixed stands of conifer and hardwood species. © 2015 Elsevier B.V.

Pacheco F.A.L.,Chemistry Research Center | Pacheco F.A.L.,Royal University | Sanches Fernandes L.F.,Center for the Research and Technology of Agro Environment and Biological science
Science of the Total Environment | Year: 2016

Environmental land use conflicts are uses of the land that ignore soil capability. In this study, environmental land use conflicts were investigated in mainland Portugal, using Partial Least Squares (PLS) regression combined with GIS modeling and a group of 85 agricultural watersheds (with >. 50% occupation by agriculture) as work sample. The results indicate a dominance of conflicts in a region where vineyards systematically invaded steep hillsides (the River Douro basin), where forests would be the most appropriate use. As a consequence of the conflicts, nitrate concentrations in rivers and lakes from these areas have increased, sometimes beyond the legal limit of 50. mg/L imposed by the European and Portuguese laws. Excessive nitrate concentrations were also observed along the Atlantic coast of continental Portugal, but associated to a combination of other factors: large population densities, and incomplete coverage by sewage systems and inadequate functioning of wastewater treatment plants. Before this study, environmental land use conflicts were never recognized as possible boost of nitrate concentrations in surface water. Bearing in mind the consequences of drinking water nitrate for human health, a number of land use change scenarios were investigated to forecast their impact on freshwater nitrate concentrations. It was seen that an aggravation of the conflicts would duplicate the number of watersheds with maximum nitrate concentrations above 50. mg/L (from 11 to 20 watersheds), while the elimination of the conflicts would greatly reduce that number (to 3 watersheds). © 2016 Elsevier B.V.

Pacheco F.A.L.,Royal University | Pacheco F.A.L.,Chemistry Research Center | Sanches Fernandes L.F.,University of Trás os Montes e Alto Douro | Sanches Fernandes L.F.,Center for the Research and Technology of Agro Environment and Biological science
Journal of Hydrology | Year: 2013

An assessment of aquifer intrinsic vulnerability was conducted in the Sordo river basin, a small watershed located in the Northeast of Portugal that drains to a lake used as public resource of drinking water. The method adopted to calculate intrinsic vulnerability was the DRASTIC model, which hinges on a weighted addition of seven hydrogeologic features, but was combined with a pioneering approach for feature reduction and adjustment of feature weights to local settings, based on a multivariate statistical method. Basically, with the adopted statistical technique-Correspondence Analysis-one identified and minimized redundancy between DRASTIC features, allowing for the calculation of a composite index based on just three of them: topography, recharge and aquifer material. The combined algorithm was coined vector-DRASTIC and proved to describe more realistically intrinsic vulnerability than DRASTC. The proof resulted from a validation of DRASTIC and vector-DRASTIC by the results of a groundwater pollution risk assessment standing on the spatial distribution of land uses and nitrate concentrations in groundwater, referred to as [. NO3-]-DRASTIC method. Vector-DRASTIC and [. NO3-]-DRASTIC portray the Sordo river basin as an environment with a self-capability to neutralize contaminants, preventing its propagation downstream. This observation was confirmed by long-standing low nitrate concentrations in the lake water and constitutes additional validation of vector-DRASTIC results. Nevertheless, some general recommendations are proposed in regard to agriculture management practices for water quality protection, as part of an overall watershed approach. © 2012 Elsevier B.V.

Pacheco F.A.L.,Royal University | Pacheco F.A.L.,Chemistry Research Center | Pires L.M.G.R.,Royal University | Santos R.M.B.,Chemistry Research Center | And 3 more authors.
Science of the Total Environment | Year: 2015

Evaluation of aquifer vulnerability comprehends the integration of very diverse data, including soil characteristics (texture), hydrologic settings (recharge), aquifer properties (hydraulic conductivity), environmental parameters (relief), and ground water quality (nitrate contamination). It is therefore a multi-geosphere problem to be handled by a multidisciplinary team. The DRASTIC model remains the most popular technique in use for aquifer vulnerability assessments. The algorithm calculates an intrinsic vulnerability index based on a weighted addition of seven factors. In many studies, the method is subject to adjustments, especially in the factor weights, to meet the particularities of the studied regions. However, adjustments made by different techniques may lead to markedly different vulnerabilities and hence to insecurity in the selection of an appropriate technique. This paper reports the comparison of 5 weighting techniques, an enterprise not attempted before. The studied area comprises 26 aquifer systems located in Portugal. The tested approaches include: the Delphi consensus (original DRASTIC, used as reference), Sensitivity Analysis, Spearman correlations, Logistic Regression and Correspondence Analysis (used as adjustment techniques). In all cases but Sensitivity Analysis, adjustment techniques have privileged the factors representing soil characteristics, hydrologic settings, aquifer properties and environmental parameters, by leveling their weights to ≈. 4.4, and have subordinated the factors describing the aquifer media by downgrading their weights to ≈. 1.5. Logistic Regression predicts the highest and Sensitivity Analysis the lowest vulnerabilities. Overall, the vulnerability indices may be separated by a maximum value of 51 points. This represents an uncertainty of 2.5 vulnerability classes, because they are 20 points wide. Given this ambiguity, the selection of a weighting technique to integrate a vulnerability index may require additional expertise to be set up satisfactorily. Following a general criterion that weights must be proportional to the range of the ratings, Correspondence Analysis may be recommended as the best adjustment technique. © 2014 Elsevier B.V.

Telmo C.,Royal University | Lousada J.,Center for the Research and Technology of Agro Environment and Biological science
Biomass and Bioenergy | Year: 2011

The Higher Heating Value (HHV) of 17 wood fuels was correlated with their Klason lignin (L) and extractive contents (Ext). There was a highly significant correlation between higher heating value, Klason lignin and extractive contents. The HHV (MJ/kg) of wood fuels as a function of lignin and extractive contents can be calculated using the following equation: qv,gr,d = 14.3377 + 0.1228 (L) + 0.1353 (Ext). The correlation coefficient (r) was 0.915. The standard error for Klason lignin was 0.017 and to extractive contents of 0.024. The proportion explained by Klason lignin was 56.4% and explained by extractive contents was 43.6%. © 2011 Elsevier Ltd.

de Vasconcelos M.d.C.B.M.,Center for the Research and Technology of Agro Environment and Biological science | Bennett R.N.,Center for the Research and Technology of Agro Environment and Biological science | Quideau S.,University of Bordeaux 1 | Jacquet R.,University of Bordeaux 1 | And 2 more authors.
Industrial Crops and Products | Year: 2010

The chestnut fruit processing generates large amounts of residues as pericarp (outer shell; 8.9-13.5%) and integument (inner shell; 6.3-10.1%). These materials clearly have the potential as sources of valuable co-products. The analyses of the pericarp and integument of four Portuguese chestnut cultivars (Judia, Longal, Martaínha and Lada) revealed significant contents of total phenolics, low molecular weight phenolics (gallic and ellagic acid), condensed tannins and ellagitannins including castalagin, vescalagin, acutissimin A and acutissimin B. The integument tissues had the highest levels of total phenolics and condensed tannins. The most efficient extraction solvent for the total phenolics, total condensed tannins and low molecular weight phenolics (in Longal) was 70:30 acetone:water at 20 °C. The pericarp and integument tissues of the cultivar Longal were richest in gallic acid and castalagin. It is clear that these materials could be used for the extraction of valuable phenolics. © 2009 Elsevier B.V. All rights reserved.

Santos M.,Center for the Research and Technology of Agro Environment and Biological science | Cabral J.A.,University of Trás os Montes e Alto Douro
Applied Ecology and Environmental Research | Year: 2011

A simple methodology was applied with the purpose of understanding the effects of anthropogenic disturbances in the biodiversity of landscape patches, namely by using Soil Surface Dwelling Arthropods as relevant indicators in changing scenarios. The goal of the present paper is to apply and extend the above academic concepts to landscape management, and to demonstrate the potential of a Stochastic Dynamic Methodology in implementing the respective actions. Since many of the ecosystem phenomenological aspects are the result of whole-system properties, the main purpose of the Stochastic Dynamic Methodology is to promote a mechanistic understanding of the holistic ecological processes, based on statistical parameter estimation methods. In this perspective, the proposed protocol is compatible with most activities undertaken by conventional ecological science, i.e., pattern seeking, the ability to explain past and present states, and the ability to predict future states. Additionally, in contexts relating to landscape management, the results of the Stochastic Dynamic Methodology applied to monitoring and restoration activities are intuitive and can be easily communicated to non-experts (ranging from students to resource users and senior policy makers). © 2011, ALÖKI Kft., Budapest, Hungary.

Pinto A.,University of Porto | Fernandes L.F.S.,Center for the Research and Technology of Agro Environment and Biological science | Maia R.,University of Porto
Water Resources Management | Year: 2016

The success of the river rehabilitation process depends not only on the intervention project but also on the attention given to the monitoring and evaluation of the implemented measures. In spite of the recent efforts on the quantification and sharing of interventions’ results, there are still very few written records documenting that information. The present work proposes a monitoring methodology for riverbanks’ stabilization interventions by comparing the results obtained by monitoring the implemented technical solutions with the corresponding theoretical time-expected performance. For this purpose, two case studies located in the south of Portugal were analysed. For each of those case studies, the dominant factors that influenced the temporal evolution of the observed outcomes were assessed. It was possible to verify that, depending on the implemented technical solution type and on the specific characteristics of the intervention site, monitoring actions can be fundamental to achieve the expected technical and ecological efficiency, namely when bioengineering technical solutions are involved. This work led to the development of a database structure that will gather information on the application of the proposed methodology over time and that shall be improved with the analysis of the behaviour of other riverbanks’ stabilization interventions. The development of this database will surely contribute to enable choosing and applying the most adequate riverbank protection solutions. © 2016 Springer Science+Business Media Dordrecht

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