WEYBURN, Sask. - Water levels are expected to rise another half metre in the already flooded southeastern Saskatchewan communities of Estevan and Roche Percee.

The Saskatchewan Watershed Authority is releasing more water from dams on the Souris River because of additional rainfall over the weekend.

Some area residents have said they don't understand why floodgates on the dams are being opened when communities down stream are already under water.

But authority spokesman Dale Hjertaas says the reservoirs simply can't hold back the huge amount of water.

Environment Canada says Estevan has had 287 millimetres of rain since May 1, making this the wettest May-June period since records began in 1945.

The agency says 112 millimetres of rain has fallen in Weyburn since Friday and more rain is expected today.