Henry Flad was an immigrant born on July 30, 1824 near Heidelberg, Baden. He graduated from the University of Munich in 1846. He was employed by the Bavarian government as a hydraulic worker on the Rhine River. He married Helen Richard in 1848. During the Revolution of 1848-1849 he was a Captain in the Parliamentary Army in Germany. Following the defeat of the Parliamentary Army, he was sentenced to death, but was never captured before he fled the German states in 1849. He served as a draftsman in New York for a while before he left to work as a construction engineer during the building of the New York and Erie Railroad. In 1852 he became resident engineer on the construction of the Ohio and Mississippi Railroad. In 1854 he moved to St. Louis to become the resident engineer of the Iron Mountain Railroad. In the intervening years, his wife Helen died, and he married her sister, Caroline Richard in 1856. When the Civil War broke out in 1861, Flad enlisted as a private in a regiment of the U.S. Reserve Corps. After a few weeks he was commissioned a Captain and transferred to command of Company B, Engineer Regiment of the West. Starting in August 1861, he constructed the fortifications around Cape Girardeau. Later that year he was detailed to General Pope’s staff. He served at Island No. 10, Fort Pillow, Shiloh, and Corinth. Following these battles he was detailed to railroad construction and other engineering work. He served all over the western theater. He was promoted through the ranks to Colonel, commanding the 1st Engineer Regiment, Missouri Volunteers. He was mustered out of service in November 1864. In 1865, he served as assistant engineer for James P. Kirkwood of St. Louis and worked to improve the water supply for St. Louis. He helped design the Chain of Rocks in St. Louis, part of the new metropolitan water system. He was on the Board of Water Commissioners, and served as the Commissioner of Water Works for eight years. In 1868, James B. Eads offered Flad the job of chief assistant engineer for the construction of what later became known as Eads Bridge. He held this position until 1874, at times serving as chief engineer when Eads was away. In 1871 he became a member of the American Society of Civil Engineers. In 1874, he laid out Forest Park in St. Louis, as the chief engineer of the Forest Park Commissioners. In 1876, he was elected first president of the St. Louis Board of Public Improvements. He held this office for 14 years. He was elected president of the American Society of Civil Engineers in 1886. In 1890 he left the Board of Public Improvements to become a member of the Mississippi River Commission, a position he would hold until his death. Henry Flad died on June 20, 1898 from heart failure while visiting a friend in Pittsburgh, Pennsylvania. During his life he was also an avid inventor as well. He invented a water meter and filters, a hydrostatic and hydraulic elevator, a deep sea sounding apparatus, pressure gauges and a pile driver, electromagnetic and straight air brakes, a recording velocimeter, a rheobathometer, a device for indicating the velocity of running fluids, and an automatic airbrake valve controlled by electricity.