Valerio C. Andrés-Valeri

A fuzzy stochastic multi-criteria model for the selection of urban pervious pavements

Multi-criteria decision making methods (MCDM) have been widely used throughout the last years to assist project contractors in selection processes related to the construction field. Sustainable urban drainage systems (SUDS) are an especially suitable discipline to implement these techniques, since they involve important impacts on each branch of sustainability: economy, environment and society. Considering that pervious pavements constitute an efficient solution to manage urban stormwater runoff as a source control system, this paper presents a multi-criteria approach based on the Integrated Value Model for Sustainable Assessments (MIVES) method to facilitate their proper selection. Given the lack of accurate information to shape the behavior of the alternatives regarding some of the criteria defining the decision-making environment, a series of variables are modeled by executing stochastic simulations based on the Monte Carlo methods. Additionally, a group of ten experts from various sectors related to water management was requested to provide their opinions about the importance of the set of selected criteria, according to the comparison levels of the Analytic Hierarchy Process (AHP). These judgments are converted into triangular fuzzy numbers, in order to capture the vagueness that human attitude entails when making judgments. A case of study in which the three major types of pervious pavements (porous asphalt, porous concrete and interlocking concrete pavers) are evaluated is presented to demonstrate the potential of the model.

Laboratory Study on the Stormwater Retention and Runoff Attenuation Capacity of Four Permeable Pavements

AbstractHydrological behavior of pervious pavements during rainfall events is a complex process that is affected by many factors such as surface type, nature of aggregates, layer thickness, rainfall height, rainfall intensity, and the preceding dry period. In order to determine the influence of construction materials on the runoff attenuation capacity of pervious pavements, 16 laboratory models were created with four different cross sections obtained by combining two pervious surfaces and two subbase aggregate materials. Successive rainfall simulations were applied over the laboratory models, measuring lag times, retained rainfalls, and times to peak, and peak outflows were registered for the simulated rainfalls. The results obtained were grouped depending on the materials used and statistically analyzed in order to compare their stormwater retention and runoff attenuation capacities. Both surface type and subbase aggregate characteristics were proven to influence the attenuation capacity of pervious pave...

Comparative analysis of the outflow water quality of two sustainable linear drainage systems

Three different drainage systems were built in a roadside car park located on the outskirts of Oviedo (Spain): two sustainable urban drainage systems (SUDS), a swale and a filter drain; and one conventional drainage system, a concrete ditch, which is representative of the most frequently used roadside drainage system in Spain. The concentrations of pollutants were analyzed in the outflow of all three systems in order to compare their capacity to improve water quality. Physicochemical water quality parameters such as dissolved oxygen, total suspended solids, pH, electrical conductivity, turbidity and total petroleum hydrocarbons were monitored and analyzed for 25 months. Results are presented in detail showing significantly smaller amounts of outflow pollutants in SUDS than in conventional drainage systems, especially in the filter drain which provided the best performance.

Relationship between Urban Runoff Pollutant and Catchment Characteristics

Much research has been done to determine levels of contamination in runoff from urban and rural catchment areas. Some authors compare their results with other authors or look for relationships between the variations of pollutant concentration and the catchment characteristics, but they seldom focus on determining the statistical significance of their results. This paper presents a review of 37 papers selected from a total of 169 papers consulted about runoff-water quality throughout the world (America, Asia, and Europe). The results presented in these 37 papers have been reviewed and statistically analyzed to evaluate the influence of catchment-area characteristics (location, size, average daily traffic, and type of land use) on the storm water runoff pollution. For the cases studied, most of the results about the polluting agents studied are comparable and no important element of the catchment characteristics had significant influence on the pollutants’ concentration.

Characterization of wash-off from urban impervious surfaces and SuDS design criteria for source control under semi-arid conditions

Knowledge about pollutant wash-off from urban impervious surfaces is a key feature for developing effective management strategies. Accordingly, further information is required about urban areas under semi-arid climate conditions at the sub-catchment scale. This is important for designing source control systems for pollution. In this study, a characterization of pollutant wash-off has been performed over sixteen months, at the sub-catchment scale for urban roads as impervious surfaces. The study was conducted in Valencia, Spain, a city with a Mediterranean climate. The results show high event mean concentrations for suspended solids (98mg/l), organic matter (142mgCOD/l, 25mgBOD5/l), nutrients (3.7mgTN/l, 0.4mgTP/l), and metals (0.23, 0.32, 0.62 and 0.17mg/l for Cu, Ni, Pb, and Zn, respectively). The results of the runoff characterization highlight the need to control this pollution at its source, separately from wastewater because of their different characteristics. The wash-off, defined in terms of mobilized mass (g/m2) fits well with both process-based and statistical models, with the runoff volume and rainfall depth being the main explanatory variables. Based on these results and using information collected from hydrographs and pollutographs, an approach for sizing sustainable urban drainage systems (SuDS), focusing on water quality and quantity variables, has been proposed. By setting a concentration-based target (TSS discharged to receiving waters <35mg/l), the results indicate that for a SuDS type detention basin (DB), an off-line configuration performs better than an on-line configuration. The resulting design criterion, expressed as SuDS volume per unit catchment area, assuming a DB type SuDS, varies between 7 and 10l/m2.

Clogging potential evaluation of porous mixture surfaces used in permeable pavement systems

Abstract Service life of permeable pavements is strongly influenced by the infiltration capacity reduction produced due to the progressive clogging of the interconnected pores. This study focused on the effect of rainfall intensity and duration as well as the pavement slope, on the clogging and de-clogging processes of permeable pavements. For this purpose, a rainfall simulator was used in order to test porous asphalt and pervious concrete samples with void contents of 15, 20 and 25%. In order to simulate the permeability reduction in permeable pavements during their service life, test samples were clogged using three different sediment concentrations: 0.5, 1.0 and 2.0 kg/m2. Three different rainfall intensities (50, 100 and 150 mm/h) and two different rainfall durations (15 and 30 min) were tested over the test samples. The infiltration capacity of the test samples was assessed in newly built conditions, and for each clogging scenario before and after rainfall simulations. Results showed that rainfall patterns as well as pavement slope significantly affect the infiltration capacity of clogged permeable materials, being higher after longer and intense rainfall events and for lower pavement slopes. Overall, PC mixture showed a best performance in terms of infiltration capacity and self-cleaning capabilities.