Browsing by Author "Fernandez, Bonifacio"

Now showing 1 - 4 of 4
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    Experimental Analysis and Modeling of a Stormwater Perlite Filter
    (WATER ENVIRONMENT FEDERATION, 2008) Gironas, Jorge; Adriasola, Jose M.; Fernandez, Bonifacio
    This paper presents the study of a mixed porous media composed of expanded perlite and a nonwoven needle-punched geotextile used to reduce the suspended solids load and concentration in urban runoff. Laboratory procedures were designed to quantify the suspended solids removal efficiency and variation in time of filtration rate. Different grain-size distributions of expanded perlite, diverse suspended solids concentrations, and different hydraulic and geometric conditions were tested to determine the most effective filter media. A dimensionless parameter, termed Global Performance Index (GPI), was developed to reach this objective. Measured data were also used to build a dimensional and a regression model to represent the performance of the filter media mathematically. The theory, derivation, and performance of both models are presented and compared with an existent empirical model. The dimensional model better reproduces the observations, becoming a useful tool for the design, operation, and evaluation of commercial porous media filters. Water Environ. Res., 80, 524 (2008).
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    Hydrological model for urban catchments - analytical development using copulas and numerical solution
    (TAYLOR & FRANCIS LTD, 2010) Zegpi, Macarena; Fernandez, Bonifacio
    A model based on analytical development and numerical solution is presented for estimating the cumulative distribution function (cdf) of the runoff volume and peak discharge rate of urban floods using the joint probability density function (pdf) of rainfall volume and duration together with information about the catchment's physical characteristics. The joint pdf of rainfall event volume and duration is derived using the theory of copulas. Four families of Archimedean copulas are tested in order to select the most appropriate to reproduce the dependence structure of those variables. Frequency distributions of runoff event volume and peak discharge rate are obtained following the derived probability distribution theory, using the functional relationship given by the rainfall runoff process. The model is tested in two urban catchments located in the cities of Chillan and Santiago, Chile. The results are compared with the outcomes of continuous simulation in the Storm Water Management Model (SWMM) and with those from another analytical model that assumes storm event duration and volume to be statistically independent exponentially distributed variables.
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    Integrated Water Resource Management and Energy Requirements for Water Supply in the Copiapo River Basin, Chile
    (MDPI, 2014) Suarez, Francisco; Munoz, Jose F.; Fernandez, Bonifacio; Dorsaz, Jean Marc; Hunter, Christian K.; Karavitis, Christos A.; Gironas, Jorge; CEDEUS (Chile)
    Population and industry growth in dry climates are fully tied to significant increase in water and energy demands. Because water affects many economic, social and environmental aspects, an interdisciplinary approach is needed to solve current and future water scarcity problems, and to minimize energy requirements in water production. Such a task requires integrated water modeling tools able to couple surface water and groundwater, which allow for managing complex basins where multiple stakeholders and water users face an intense competition for limited freshwater resources. This work develops an integrated water resource management model to investigate the water-energy nexus in reducing water stress in the Copiapo River basin, an arid, highly vulnerable basin in northern Chile. The model was utilized to characterize groundwater and surface water resources, and water demand and uses. Different management scenarios were evaluated to estimate future resource availability, and compared in terms of energy requirements and costs for desalinating seawater to eliminate the corresponding water deficit. Results show a basin facing a very complex future unless measures are adopted. When a 30% uniform reduction of water consumption is achieved, 70 GWh over the next 30 years are required to provide the energy needed to increase the available water through seawater desalination. In arid basins, this energy could be supplied by solar energy, thus addressing water shortage problems through integrated water resource management combined with new technologies of water production driven by renewable energy sources.
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    RETURN PERIOD AND RISK OF HYDROLOGIC EVENTS. II: APPLICATIONS
    (ASCE-AMER SOC CIVIL ENGINEERS, 1999) Fernandez, Bonifacio; Salas, Jose D.
    A mathematical formulation to estimate return periods and risks of failure of complex hydrologic events such as those arising from dependent floods and droughts have been examined in the first part of this paper. Specifically, some relationships and algorithms for computing return periods and associated risks for runs arising from independent and dependent events assuming that dependence is represented by a two-state Markov chain have been proposed. The applicability of these procedures is illustrated herein, considering several types of hydrological events with emphasis on those where dependence is important. First, meteorological droughts based on annual precipitation are considered as examples of events consisting of runs in independent trials. Then, minimum streamflows and maximum annual lake outflows are included as examples of dependent events, assuming that dependence is represented by a simple Markov chain. Also, hydrological droughts based on annual streamflow series are considered. In addition, the estimation of return period and risk are illustrated by data generation.