Land use impacts on water resources of the Manacás Lake Basin, Minas Gerais, Brazil

The 134.68 ha campus of the Federal University of Juiz de Fora (UFJF) is in urban area impacted by new developments. The population of 27,600 consumers causes the loss of green areas and generates increasing waste and sewage water. This study evaluated the impact of UFJF Campus activities on water quality, emphasizing the Manacás Lake Basin (MLB). The evaluation was based on five monitoring points: a spring (P1) and the four mouths of the streams that flow into Manacás Lake (P2 to P5). Water samples were collected monthly between November 2013 and October 2014, and pH, DO, COD, Conductivity and Turbidity were analyzed. The results showed that the DO increases from the spring (P1) to the mouth (P2), with low values at the other points, and a median of 1.3 mg L-1 at P5. COD does not follow a pattern, registering medians higher than 6 mgO2 L-1 at all points, highlighting P4 with 25.5 mgO2 L-1, the sub-basin which contains most of the Labs. Worse turbidity was found at P5, with 39.42 UNT, coinciding with the sub-basin most affected by construction. Conductivity gradually increased from P1 to P2, and medians were not statically different for P3, P4, and P5. Manacá Lake is Class 2 according to CONAMA resolution Nº 357/2005, but the results showed that the DO at P4 and P5 has values of Class 4 water, with frequent anaerobiosis.O Campus da Universidade Federal de Juiz de Fora, com 134,68 ha, está inserido em área urbana com grande crescimento imobiliário e com uma população de 27.600 usuários, acarretando a perda de áreas verdes, aumentando a geração de resíduos e efluentes. O objetivo desse artigo foi avaliar os impactos das atividades do Campus da UFJF na qualidade da água da Bacia de Contribuição do Lago dos Manacás (BCLM). Foram escolhidos cinco pontos para o monitoramento, considerando uma nascente (P1) e as fozes dos quatro córregos que deságuam no Lago dos Manacás (P2 a P5). As amostras foram coletadas mensalmente, durante o período de novembro de 2013 a outubro de 2014. Foram medidos pH, Oxigênio Dissolvido (OD), Demanda Química de Oxigênio (DQO), Condutividade Específica e Turbidez. Os resultados mostraram que o OD aumenta da nascente de um córrego (P1) para sua foz (P2) com valores baixos nas demais fozes, destacando uma mediana de 1,3 mg L-1 no P5; a DQO não segue um padrão, ficando com as medianas maiores que 6 mg O2 L-1 em todos os pontos, com destaque para o P4 com 25,5 mg O2 L-1, sub-bacia na qual estão localizados a maioria dos laboratórios da universidade; a Turbidez ficou pior no P5 com 39,42 UNT, coincidindo com a sub-bacia mais afetada por obras e movimentação de terra; a Condutividade Específica aumentou gradativamente de P1 até P2, não diferenciando estatisticamente as medianas entre P3, P4 e P5. O Lago dos Manacás enquadra-se na Classe 2 e, de acordo com a Resolução CONAMA nº 357/2005, há uma desconformidade entre os padrões estabelecidos e os resultados encontrados, com destaque para o OD nas seções 4 e 5, com valores atuais compatíveis com a Classe 4 de frequente anaerobiose

Impactos do uso do solo nos recursos hídricos da bacia de contribuição do Lago dos Manacás, Minas Gerais, Brasil

The 134.68 ha campus of the Federal University of Juiz de Fora (UFJF) is in urban area impacted by new developments. The population of 27,600 consumers causes the loss of green areas and generates increasing waste and sewage water. This study evaluated the impact of UFJF Campus activities on water quality, emphasizing the Manacás Lake Basin (MLB). The evaluation was based on five monitoring points: a spring (P1) and the four mouths of the streams that flow into Manacás Lake (P2 to P5). Water samples were collected monthly between November 2013 and October 2014, and pH, DO, COD, Conductivity and Turbidity were analyzed. The results showed that the DO increases from the spring (P1) to the mouth (P2), with low values at the other points, and a median of 1.3 mg L-1 at P5. COD does not follow a pattern, registering medians higher than 6 mgO2 L-1 at all points, highlighting P4 with 25.5 mgO2 L-1, the sub-basin which contains most of the Labs. Worse turbidity was found at P5, with 39.42 UNT, coinciding with the sub-basin most affected by construction. Conductivity gradually increased from P1 to P2, and medians were not statically different for P3, P4, and P5. Manacá Lake is Class 2 according to CONAMA resolution Nº 357/2005, but the results showed that the DO at P4 and P5 has values of Class 4 water, with frequent anaerobiosis