Water Dynamics and Role of Groundwater in the 'Lagoa dos Barros', South of Brazil

Priscila Kayani Ghellere Vanzella

Key information

Authors:

Priscila Kayani Ghellere Vanzella (Priscila Kayani Ghellere Vanzella)

Supervisors:

Ramiro Joaquim De Jesus Neves (Ramiro Joaquim De Jesus Neves); Ana Isabel Baião Ramos de Oliveira (Ana Isabel Baião Ramos de Oliveira)

Published in

09/22/2021

Abstract

Lagoa dos Barros is located in the Litoral Medio basin, in the coastal plain of Rio Grande do Sul, Brazil. The lagoon covers 92 km2 of fresh water and is extremely important for the economic activities of the region, especially agriculture with irrigated rice crops that use pond water during the summer. However, by the end of 2019, eutrophication begins to be visible in the lagoon, reaching its peak in May 2020. Thus, the wastewater treatment plant, which was set up in 2009, but which started its operation in late 2018, was considered the main possible cause due to the discharge of its effluents without tertiary treatment, which removes nutrients, into the water body. Thus, the focus of this study was to identify the primary sources of water for Lagoa dos Barros so that it would be easier to identify the most likely cause of Eutrophication that occurred in 2020. Different approaches were applied to interpret the dynamics of the complex area. The physical model together with different approaches such as water balance and aquifer recharge estimation are applied to evaluate the relationships between aquifer and lake systems. Then, check that the contribution of groundwater to the Lagoa dos Barros is not potentially a source of nutrients that could have been involved in the cause of the high concentration of nutrients that causes the blooming of algae in the period in which it was observed.