Regression analysis applied to time series on suspended and settleable solids transported in an urban river in Brazil

Abstract

Solids transport by river waters bears diurnaloscillations caused by the production regime of solid matter,and hydrodynamic fluctuations of fluvial regimes. Diurnalvariation patterns were identified for different types ofsediment concentrations on a river crossing the Greater SãoPaulo, Brazil, subject to strong diurnal seasonality (sanitaryand industry discharges contain solids). Two dry-weathercampaigns were conducted (July-2006; June-2007) in orderto provide a considerable data basis, at every two hours. Astrong correlation resulted between serial extremes (localmaxima and minima) of settleable solids, on the one hand,and suspended solids, on the other. Conclusions were:similar efforts to recognise diurnal patterns on urban riversolids transport shall continue (so helping to plan futuremonitoring campaigns); similar care must apply whenmonitoring transient events due to heavy storm. Also, asettling/ressuspension oscillatory mechanism was noticed onsettleable solids due to fluctuations in river hydrodynamics.

Index Terms - Solids concentrations correlation, sedimenttransport, river sediments, diurnal oscillation pattern.