O presente estudo foi desenvolvido para a represa de Nova Ponte, localizada no estado de Minas Gerais. O objetivo deste estudo foi analisar o comportamento e as possíveis causas da concentração de Nitrato na represa de Nova Ponte. Foram empregadas técnicas de Geoprocessamento e avaliando-se o uso do solo, as classes de solos e o aporte por descarga de esgoto bruto das cidades no entorno da represa. Para a realização do trabalho foram coletados cinquenta e nove pontos amostrais distribuídos ao longo de toda a represa onde foram obtidos a concentração de Nitrato em agosto de 2007 e espacializado para a represam empregando-se geoestatistica, foi elaborado o mapa de uso e ocupação do entorno da represa e digitalizado o mapa de solos da região, além da espacialização dos centros urbanos no entorno da represa e a quantificação da distância destes à represa. Analisando conjuntamente o uso do solo, as classes de solo e o aporte de esgoto bruto nos tributários da represa e contrapondo-se às regiões de maiores concentrações de Nitrato, conclui-se que tais concentrações seriam advindas do esgoto bruto e não da agropecuária nesta região. Normal 0 false false false PT-BR X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri",sans-serif; mso-ansi-language:PT-BR; mso-fareast-language:PT-BR;} A B S T R A C T The presence of nitrate in water bodies can promote the appearance of algae and other aquatic plants affecting the quality of these for various uses. Depending on the concentration you can also promote the development of methemoglobinemia, of certain types of cancer, so studies related to determining the concentration and the possible contribution of causes are extremely important. This study was conducted for the dam of Nova Ponte, located in the Minas Gerais states. The aim of this study was to analyze the behavior and the possible causes of the nitrate concentration in the Nova Ponte Dam. It was done using GIS techniques and also evaluating the land use, the soil types and the possible contribution of the raw sewage discharge of the cities surrounding the dam. To conduct the study were collected fifty nine sampling points distributed throughout the dam in August 2007 and spatialized for dam employing geostatistics, and it was prepared the use and occupation of the surrounding map dam and digitized the region of soil map, in addition to the spatial distribution of urban centers in the vicinity of the dam and the quantification of the distance between the cite to the dam. Analyzing together the land use, the soil classes and the raw sewage inflow in the dam tributaries and contrasting to the regions of higher concentrations of nitrate, it is concluded that such concentrations would be coming from the raw sewage and not from the agriculture in this region . Keywords: nitrate, agriculture, sewage, geoprocessing .