http://ww1.sema.rs.gov.br/upload/Resolu%C3%A7%C3%A3o%20CRH%20n%C2%BA%20111-2012%20-%20Aprova%20o%20enquadramento%20das%20aguas%20superficiais%20da%20Bacia%20do%20Rio%20Ijui.pdf