Ademir Paceli Barbassa

Avaliação da construção e operação de técnicas compensatórias de drenagem urbana: o transporte de finos, a capacidade de infiltração, a taxa de infiltração real do solo e a permeabilidade da manta geotêxtil

Este trabalho avaliou aspectos da construcao e operacao de tecnicas compensatorias em drenagem urbana e seu efeito na taxa de infiltracao das unidades em escala real. Para tal, foram estudados dois sistemas, a saber: i) filtro-vala-trincheira de infiltracao (FVT) e ii) poco de infiltracao (PI). A infiltracao do solo foi avaliada por meio de ensaios de campo (ensaios de duplo anel e poco invertido) e por medidas das unidades experimentais. Alem disso, foram investigados o teor de material pulverulento e a permeabilidade de amostras do geotextil utilizado no FVT e PI, nas condicoes pre e pos-instalacao. A despeito das protecoes instaladas, houve transporte de finos para o interior das unidades e que esses influenciaram na permeabilidade da manta geotextil (reducao de 30 a 90% para o FVT e de 40 a 70% para o PI) e nas taxas de infiltracao nas unidades em escala real (de 4,7 x 10-6 a 10-5 m.s-1).

Indicators for commercial urban water management: the cases of retail parks in Spain and Brazil

The use of planning and management tools for water management in urban environments is a promising area. This paper focuses on the description of two indicators, Water Intensity of a Purchase (WIP) and Potential Water Self-Sufficiency (PWSS) from rainwater harvesting, for the expanding sector of Retail Parks (RP). The WIP measures the water that is consumed per average customer and purchase, whereas the PWSS quantifies the potential capacity of the system to satisfy its water demand from rainwater. These tools have been checked in two case studies in Spain and Brazil. The results show a WIP of 8.0 and 22.9 litres, respectively, which measures the (in)efficiency of water use. This water demand, mainly of low quality, is met with the potable water supply network, while stormwater runoff is lost to sewage. The PWSS results, 3.0 for Spain and 1.4 for Brazil, indicate that RP could satisfy their needs with rainwater and even have a surplus of water. The combined use of both WIP and PWSS can be useful for the planning, design, evaluation and monitoring of RP.

Estimativa de área impermeabilizada diretamente conectada e sua utilização como coeficiente de escoamento superficial

This paper presents a study of characterization of land occupation and its use in the city of Ribeirao Preto (Sao Paulo), as well as a detailed analysis of the urban imperviousness and hydraulic connectivity of the plots. The runoff coefficient (C) for siz sub-basins was evaluated on the basis of three different definitions. The peaks of outflow for the sub-basins were calculated using the Rational Method with the estimated values of C. It was identified that the imperviousness increases as the area of the plot decreases. The estimative of the C show important differences in its values, influencing the outflow. The use of tables with detailed and maximal C values beyond its superior limitation is equivalent to the values estimated with CDCIA. It is recommended that the CDCIA relative to the area be estimated based on the plot or field researches.

Poço de infiltração para controle de enchentes na fonte: avaliação das condições de operação e manutenção

Neste estudo foram investigados os seguintes aspectos relativos a avaliacao de um poco de infiltracao construido em escala real: i) tampa/filtro de entrada; ii) permeabilidade do geotextil interno ao poco; e iii) tempos de esvaziamento. O poco de infiltracao com volume de 3,6 m³ drena area de 241,8 m². A tampa/filtro foi composta de camadas de areia, brita e geotextil dispostos sobre a estrutura metalica. Os aneis de concreto que compoem a estrutura lateral do poco foram revestidos com manta geotextil intercalada com blocos cerâmicos. O poco permaneceu em constante operacao, entretanto foram simulados eventos especificos para o tempo de esvaziamento. Realizaram-se ensaios da permeabilidade de amostras de geotextil, do teor de materiais pulverulentos dos agregados ao poco, ou seja, a brita e a areia que compoem a tampa/filtro. O geotextil apresentou reducao media da permeabilidade de 50,7%, 7,7% e 21,2% nas amostras do fundo, paredes e tampa do poco respectivamente. A areia do filtro da tampa reteve 34,8% de finos, enquanto a brita reteve 0,13% de finos no mesmo periodo. A capacidade hidraulica media do poco foi 34,7 mm/h. O coeficiente de determinacao para os tempos de esvaziamento calculados e medidos foi de 0,97.

Exploring the Use of Low Impact Development Strategies in a Low-Income Settlement in São Carlos, Brazil

The challenges of applying integrated stormwater management strategies in developing countries such as Brazil are particularly complex due to economic, environmental, and wider social issues in these localities. Factors like housing deficits, real estate speculation, urban land costs, massive demand for affordable housing, and the attempt to associate economic development with environmental preservation have led researchers in the drainage field to seek different models of urbanization. In this context, the present work aims to explore the possibilities of using low impact development (LID) strategies in a low-income settlement in the city of Sao Carlos, Brazil for the runoff management (two-year return period). To evaluate the feasibility and hydrological performance of the proposals, three scenarios were simulated in Storm Water Management Model (SWMM): Scen.CONV, a conventional urbanization and storm sewer drainage system; Scen.WELL, a conventional urbanization associated with the use of an infiltration well to disconnect the lots; and Scen.LID, which uses vegetative swales and infiltration trenches associated with urbanistic changes such as land use/imperviousness coefficients and roads typologies. Comparing Scen.CONV with Scen.WELL, the results indicated a potential 18% reduction in the linear length of buried conduits and a 40% reduction in the number of curb inlets. In the Scen.LID, the use of combined LID strategies allowed for the source control of all of the surface runoff, excluding the need for conventional drainage systems. The results also indicated a decrease of 60% in the peak flows of Scen.CONV in comparison with Scen.WELL and of 100% in relation to Scen.LID.

Modeling Infiltration Wells in SWMM and Comparing Its Performance with a Real-Scale Well

The low impact development (LID) controls are increasingly encouraged to control the urbanization drainage impacts. A particularly interesting LID control for densely urbanized areas is an infiltration well (IW), as it occupies a small area and is efficient in recharging groundwater. The Storm Water Management Model (SWMM) is a hydraulic-hydrological modeling software program for urban areas that has been widely used and accepted. Its most recent versions already allow the modeling of some LID controls. However, despite their importance, IWs have not been studied yet. In this context, the goal of this article is to present a way to model the IW in SWMM using the available tools. For this purpose, infiltration trench (IT) input parameters were used. They were adapted to represent the IW stored volume and outflow. The water levels (WLs) calculated by the proposed model were compared to the WLs from a real-scale IW in the city of Sao Carlos, Brazil. The WLs were measured in the field by six controlled tests. The results showed a good fit between the WLs obtained by SWMM and the monitoring data, with an R2 between 0.96 and 0.97 and a Nash-Sutcliffe efficiency coefficient (NS) between 0.79 and 0.84. These results validate the procedures adopted, which allows the IW modeling in the current version of SWMM.