The 11-year period from July 1, 1928, to June 30, 1939, was one of violent contrasts , both naturall and man-made; great floods and severe droughts occurred and great industrial activity 'W'as· succeeded by deep and persistent depression which droughts made even more devastating. It spans the· time from the first year of 50-50 cooperation with the States, to the last year that Nathan C. Grover was Chief of the Branch.