 After the Civil War , the Corps of Engineers undertook a program of river and harbor improvements . Raynolds supervised the dredging and improvement of navigation on the Arkansas , Mississippi and Missouri Rivers . He also helped supervise several harbor dredging and construction projects , involving the harbor in Buffalo , New York , the Harbor of Refuge in New Buffalo , Michigan , Erie Harbor in Erie , Pennsylvania , and the river harbors of St. Louis , Missouri and Alton , Illinois . Raynolds sited and oversaw the installation of dozens of lighthouses in the Great Lakes area , where he served as the superintending engineer from 1864 to 1870 . Raynolds was promoted to permanent rank of lieutenant colonel in the Corps of Engineers on March 7 , 1867 . He then supervised lighthouse construction along the Gulf Coast and in New Jersey where he managed the construction of the Hereford Inlet Lighthouse in 1874 . From May 5 to October 7 , 1877 , Reynolds led a procession of American engineers to an engineering conference in Europe . 
