Jorge Luiz Steffen

Caracterização morfométrica de bacias hidrográficas através de dados SRTM

Visa-se, neste trabalho, avaliar os dados Shuttle Radar Topography Mission (SRTM) na caracterizacao morfometrica de bacias hidrograficas, atraves da comparacao das caracteristicas obtidas a partir de dados SRTM e de cartas topograficas, processados em Sistema de Informacao Geografica (SIG). O estudo foi realizado tomando-se por base a bacia hidrografica do Ribeirao Salobra, com area aproximada de 540 km2. A diferenca percentual obtida nos dados morfometricos entre os metodos estudados foi inferior a 11%, exceto no indice de circularidade (22%) e declividade media (55%). A utilizacao de dados SRTM em ambiente SIG permite a caracterizacao morfometrica de bacias hidrograficas, podendo auxiliar a gestao e o gerenciamento dos recursos hidricos, mostrando-se uma alternativa pratica e viavel ao minimizar custos e tempo na execucao dos trabalhos.

Model for Estimating the Time of Concentration in Watersheds

The time of concentration for a watershed is an essential parameter to the design of any hydrological project. In this study, a time of concentration estimation-model that uses variables obtained by monitoring rainfall-runoff events in a rural watershed of a tropical climate is proposed. In developing the model, the relationship between the time of concentration and independent variables was verified using a linear correlation matrix. Two variables with the highest correlation coefficient were selected to derive a model that can estimate the time of concentration. The Harmony Search (HS) optimization algorithm was employed to optimize the model parameters. The performance of the model was evaluated based on the Nash–Sutcliffe (NS) coefficient, which yielded a value greater than 0.80. The proposed model allows one to estimate the time of concentration using only the hydrograph of an event at the base level of a watershed, without the use of rainfall data.

Hydraulic and hydrological aspects of an evapotranspiration-constructed wetland combined system for household greywater treatment

ABSTRACT Constructed wetlands systems demand preliminary and primary treatment to remove solids present in greywater (GW) to avoid or reduce clogging processes. The current paper aims to assess hydraulic and hydrological behavior in an improved constructed wetland system, which has a built-in anaerobic digestion chamber (AnC), GW is distributed to the evapotranspiration and treatment tank (CEvaT), combined with a subsurface horizontal flow constructed wetland (SSHF-CW). The results show that both the plants present in the units and the AnC improve hydraulic and volumetric efficiency, decrease short-circuiting and improve mixing conditions in the system. Moreover, the hydraulic conductivity measured on-site indicates that the presence of plants in the system and the flow distribution pattern provided by the AnC might reduce clogging in the SSHF-CW. It is observed that rainfall enables salt elimination, thus increasing evapotranspiration (ET), which promotes effluent reduction and enables the system to have zero discharge when reuse is unfeasible.