Influência das fossas no aquífero freático do Bairro Novo, Cidade de Quelimane

Abstract

In the Bairro Novo region, due to the low cost and ease of drilling wells, not only, but also the unavailability of drinking water for the entire population, the abstraction of water from the free aquifer, although more vulnerable to contamination by septic tanks/ cesspool due to horizontal and vertical distance that separates the two environments, have been the option of many residents of that neighborhood. However, the present study aimed to analyze the influence of the septic tanks in the aquifer of the Bairro Novo, Quelimane City. A well was drilled to collect and analyze samples of water and sediments, where it was found that the water of the Bairro Novo is contaminated and that the aquifer of the place is made up by means of very fine sand. The granulometric analysis indicated that, in general, the sediments found in all stratigraphic horizons are composed of thick silt, medium and fine sand, where the silt is larger than the other sediments. The well method was used to determine the hydraulic conductivity of the soil at a depth of 2.57 m, where the final result was 7.74 x 10-4 m / s and classified as moderate low. All 4 wells surveyed have total coliform contamination and although they have a countable or moderate number of coliforms, they are all outside the standards established by MISAU and water is inadequate to consumption. The relationship verified between the presence of coliforms and the hydraulic conductivity is direct since both parameters presented moderate characteristics or behaviors.