text: In 1925, a study on the phenomena of oxidation and reaeration in the Ohio River in the US was published by the sanitary engineer, Harold Warner Streeter and the consultant, Earle Bernard Phelps (1876–1953). The study was based on data obtained from May 1914 to April 1915 by the United States Public Health Service under supervision of Surg. W.H. Frost.
  More complex versions of the Streeter–Phelps model were introduced during the 1960s, where computers made it possible to include further contributions to the oxygen development in streams. At the head of this development were OConnor (1960) and Thomann (1963). OConnor added the contributions from photosynthesis, respiration and sediment oxygen demand (SOD). Thomann expanded the Streeter–Phelps model to allow for multi segment systems.