This atlas presents data pertaining to the regimen of flooding along White Rock Creek and its tributaries, Spanky Branch, Floyd Branch, and Cottonwood Creek at Dallas, Texas. The map and flood data were prepared to aid those concerned with, and responsible for, the safe and yet extensive use of the floodplain along White Rock Creek and its tributaries. The flood map is shown in two parts—A, north half, and B, south half.
The map shows areas inundated by the flood of September 21, 1964, along White Rock Creek and Spanky Branch and by the flood of October 8, 1962, along Cottonwood Creek and Floyd Branch.
The flood of September 21, 1964, is known to be the greatest since at least 1886 on White Rock Creek upstream from the Texas and Pacific Railroad (mile 6.6). Downstream from the Texas and Pacific Railroad, White Rock Creek has been subject to inundation from backwater from the Trinity River. The greatest known flood on Trinity River occurred May 25, 1908. Because of extensive flood-control works built since 1908 in the upper Trinity River basin, the degree of flooding resulting from a storm of the magnitude of the 1908 catastrophe probably would be substantially different today. No backwater from Trinity River occurred during the flood of September 21, 1964.
The greatest flood since at least 1892 on Cottonwood Creek and Floyd Branch occurred June 14, 1949. The storm of October 8, 1962, caused flood heights at Forest Lane to be comparable to those of June 14, 1949, on Cottonwood Creek and about 1 foot lower on Floyd Branch. The greatest flood since at least 1917 on Spanky Branch was that of September 21, 1964. Greater floods than those delineated are possible.
