CREATE TABLE table_62074 ("Dam constructed" TEXT, "Year completed" FLOAT, "Impounded body of water" TEXT, "Reservoir capacity" TEXT, "Dam wall height" TEXT, "Dam type" TEXT)

Which Year completed has a Dam type of concrete gravity, and an Impounded body of water of deep creek reservoir?
SELECT MIN("Year completed") FROM table_62074 WHERE "Dam type" = 'concrete gravity' AND "Impounded body of water" = 'deep creek reservoir'
SELECT MIN("Year completed") FROM "table_62074" WHERE "Dam type" = 'concrete gravity' AND "Impounded body of water" = 'deep creek reservoir'