author = "Wrublack, Suzana C. and Mercante, Erivelto and Vilas Boas, Marcio 
                         A. and Prudente, Victor Hugo Rohden and Silva, Jefferson L. G.",
          affiliation = "{Universidade Estadual do Oeste do Paran{\'a}} and {Universidade 
                         Estadual do Oeste do Paran{\'a}} and {Universidade Estadual do 
                         Oeste do Paran{\'a}} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Universidade Estadual do Oeste do 
                title = "Variation of water quality along a river in agricultural watershed 
                         with support of geographic information systems and multivariate 
              journal = "Engenharia Agr{\'{\i}}cola",
                 year = "2018",
               volume = "38",
               number = "1",
                pages = "74--81",
                month = "jan.",
             keywords = "geoprocessing, mapping land use and occupation, water quality.",
             abstract = "This study demonstrates using remote sensing, geographic 
                         information systems and multivariate statistics to study water 
                         quality in an agricultural watershed. The monitoring of water 
                         quality in the watershed of Lontrass river in the southwestern 
                         region of the State of Paran{\'a} had been done in 2012 and 2013 
                         with a multi-parameter probe in ten sites that were defined 
                         upstream and downstream watershed, during four different seasons. 
                         Mosaicked images were used from Google Earth, Digital Elevation 
                         Model and soil types of maps, defined as the explanatory 
                         variables. The definition of the areas of influence and 
                         multivariate statistical techniques, particularly the Redundancy 
                         Analysis (RDA), were used for the correlation between variables. 
                         In a spring area, located upstream watershed, the contribution on 
                         water quality variation has gotten smaller, when compared with the 
                         other monitoring sites. There was interference in water quality in 
                         downstream sites that has become greater due to the effects of 
                         diffuse pollution. The RDA enabled synthesizes the data 
                         variability structure and the relationship of multidimensional 
                         variables. These statistical techniques added to products 
                         resulting from the GIS contributed to a better understanding of 
                         the variation of water quality in the watershed.",
                  doi = "10.1590/1809-4430-Eng.Agric.v38n1p74-81/2018",
                  url = "http://dx.doi.org/10.1590/1809-4430-Eng.Agric.v38n1p74-81/2018",
                 issn = "0100-6916",
             language = "en",
           targetfile = "wrublack_variation.pdf",
        urlaccessdate = "25 jul. 2021"