This is the second census of drainage. The first was taken in 1920. The data collected on the special drainage schedule cover the 35 States reporting organized drainage enterprises. The statistics are relative to character of enterprise, purpose of drainage, area and condition of land in enterprises, capital invested and financing of enterprises, drainage works, operation and maintenance, arrears and delinquency, and flood protection by outside agencies.
Only those enterprises having drainage works completed or partially completed on January 1, 1930, were included in the 1930 census. Drainage works include all varieties of underground conduits, pipes, or lines of tile; all open ditches, canals, and pumping equipment for drainage; and all necessary levees, dikes, dams, weirs, and gates, and other devices for draining away or controlling surface and soil waters.
Census statistics date back to 1790 and reflect the growth and change of the United States. Past census reports contain some terms that today’s readers may consider obsolete and inappropriate. As part of our goal to be open and transparent with the public, we are improving access to all Census Bureau original publications and statistics, which serve as a guide to the nation's history.