Bonifacio Fernández

Models for Data Generation in Hydrology: Univariate Techniques

Most approaches suggested for modelling and generation of multisite hydrological series fall within the general framework of multivariate ARMA models. Formal modelling procedures suggest a three-stage iterative process, namely: model identification, parameter estimation and diagnostic checks. In general, it is not an easy task, especially if high order vector ARMA models are used. However, simpler models, such as the contemporaneous model, may be sufficient for most applications in water resources. Modelling approaches based on these models are reviewed and examples of modelling bivariate and trivariate streamflow series are included.

Hydrological model for urban catchments – analytical development using copulas and numerical solution

Abstract 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 catchments 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 Chillán 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. Citation Zegpi, M. & Fernández, B. (2010) Hydrological model for urban catchments – analytical development using copulas and numerical solution. Hydrol. Sci. J. 55(7), 1123–1136.

Drenaje de aguas lluvias urbanas en zonas semiáridas

La urbanizacion progresiva del suelo se relaciona con muchos conflictos del habitat contemporaneo. Las inundaciones, agravadas por la incapacidad de los suelos pavimentados para absorber las lluvias, son un ejemplo potente de esta interaccion. En el contexto de la aridez santiaguina, los temas de erosion, riqueza del suelo y napas subterraneas estan directamente vinculados a la expansion urbana; nuevos paradigmas al respecto plantean salidas a estos problemas.

Laboratory study of mixture proportioning for pervious concrete pavement

The present research shows the results of an equation that allows to dose pervious concrete in function of water to cement ratio and the required interconnected void content in hardened concrete. Eighteen different mixtures - with w/c ratio between 0.29 and 0.41- were analyzed using this equation. The samples were made in the laboratory and compacted with a heavy roller simulating site conditions. The results allow a good characterization of these mixtures both mechanical and hydraulic behavior. Relationships between void contents, infiltration rate and flexural strength were found.