Antonio Carlos Zuffo

Estimation and calibration of Manning’s roughness coefficients for ungauged watersheds on coastal floodplains

ABSTRACT Knowledge of hydrodynamic behaviour is imperative for the water resource management and the sustainable development of basins. Hydraulic and hydrologic modelling are essential tools for the simulation of this behaviour. However, lack of basin assessment makes modelling input data scarce. This is the case for the Juqueriquere River basin, which comprises the major floodplains of the northern coastline of Sao Paulo State, Brazil. This region is susceptible to floods and is under pressure from real estate speculation, gas exploitation, and infrastructure development for port facilities. The purpose of this study was to estimate and calibrate Manning’s roughness coefficients of the Juqueriquere River basin, as they are mandatory data for hydraulic modelling. The estimation of Mannings n values was based on field observations. These data were inserted into the Hydrologic Engineering Centers River Analysis System (HEC-RAS) model for the calibration of the roughness coefficients in a trial and error process. The findings of this study proved that the estimation and calibration methods were efficient, with mean absolute deviations lower than 10% in the studied sections.

Contributions to increase the availability of water supply in regions of water shortage: the case study of São Paulo, Brazil

Discussions over water availability increase, as society perceives the shortage of this good essential to human life. However, there is still a long way to go to ensure the efficient and equitable distribution of water. To increase the availability of water, often utilities consider catchment from new sources that constitutes supplyside water management. Currently, new sources of drinking water are scarce. An alternative is the planning based on the demand-side which is the rational management of water in its various uses through greater control measures and use of efficient equipment, water loss reduction, and public awareness. Here, we identify and prioritize relevant criteria to increase water availability via demandside management in the state of Sao Paulo, Brazil. Based on interviews with experts in the field, the criteria for increasing water availability were defined and divided into groups that structure water demand and water supply management. The results highlight the priorities for water reuse and individualized micromeasurements.

Derivation of Design Rainfall and Disaggregation Process of Areas with Limited Data and Extreme Climatic Variability

In a sustainable urbanisation process, the infrastructure has to be designed taking into consideration the hydrological behaviour of the respective catchment. It is mandatory to predict the climatic events accurately to understand the hydrological impacts of urban developments. It is very challenging for hydrologists to model extreme events when there are limited data available. The current study proposed a methodology to calculate the design rainfalls in the coastal region of Sao Paulo, Brazil. The gamma-function distribution used the annual maximum daily rainfalls in a probabilistic approach. The achieved 24-h-design rainfalls were compared to the results from other intensity–duration–frequency equations in different time-series. The rainfall disaggregation used regional and national conversion ratios. The fluctuation of the annual maxima revealed that the study area was affected by the Noah and Joseph erratic processes. Subsequently, the detected extreme event time-series were also used for the derivation of the 24-h-design rainfalls. The outcomes of the study showed that the gamma-function distribution provides reliable results, enhanced by the use of representative disaggregation ratios and proper time-series.