In a 3-quart saucepan mix blueberries, water, and the 1/2 cup sugar.
Bring to boiling.
Cover, reduce heat and simmer 5 minutes.
Combine flour, 1/4 cup sugar, soda, and salt.
Cut butter into flour mixture till mixture resembles coarse crumbs.
Stir in buttermilk just till flour is moistened.
Drop batter by tablespoonfuls atop bubbling blue berry mixture, making six dumplings.
Cover pan tightly; simmer 15 minutes (don't lift cover).