The municipal government of Dallas underwent two significant changes in its structure during its history. The first change was made in 1907 where the city voted to change from an alderman structure to a commission form of government. Stephen J. Hay was the first mayor elected in this new form of government, demonstrating the success of the highly debated commission form of government and contributing to the development of White Rock Lake in response to a water shortage in 1910. The second major government change was made in 1930, altering the commission form of government to specifically be a council-manager form. The mayor to serve following that change was Tom Bradford, a successful grocer who was a significant financial contributor to the Bradford Memorial Hospital for Babies, the preliminary institution to the Children's Medical Center Dallas. He died after suffering a major heart attack in 1932 and was the first mayor of Dallas to die in office.