Sources: Diario El País (Montevideo) and Uruguay public holidays (qppstudio.net). A bill has been introduced to the Parliament of Uruguay which would declare April 17, 2009, a one-off public holiday in Paso de los Toros, to commemorate the 50th anniversary of the 1959 inundations.
Note that law Nº 17.238 of 2000 already makes April 17th an annual Día Nacional de la Solidaridad, but this is only a commemorative day, not a public holiday as the new bill would have it for 2009.