Probability curves of integration and total maximum daily loads (TMDL)on quality management of a urban watershed

Abstract

Inadequate releases of sanitary sewage and solid waste in water resources promote the gradual contamination of the water. This study aimed at the integration of qualitative and quantitative information in a watershed highly urbanized and intense human activity detrimental to water quality. The basin is located in the urban area of the municipality of Santa Maria-RS, with 2.7 km² area. The probability curves were constructed for total BOD and coliforms, E. coli, DO, nitrite and nitrate. The retention curves were used to obtain the TMDLs curves relating to water quality parameters. The results obtained show that the Cancela Tamandaí creek receives daily high loadings of organic matter,TC, EC, nitrite, nitrate and the concentration of DO in 90% of the time is less than 1.0 mg / L. The curves of probability of daily loads together with the TMDL curves are alternatives to the planning of remediation actions in the creek, or are tools thatmay assist in the management of water resources and water quality management in the Cancela-Tamandaí watershed. The TMDL curves have a simple methodology and results can be easily applied, enabling the practical use in water management.