Floods of April 28, 1966 in the Northern Part of Dallas, Texas
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Floods of April 28, 1966 In the Northern Part of Dallas, Texas GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1870-B Prepared in cooperation with the city of Dallas Floods of April 28, 1966 In the Northern Part of Dallas, Texas By WILLARD B. MILLS and ELMER E. SCHROEDER FLOODS OF 1966 IN THE UNITED STATES GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1870-B Prepared in cooperation with the city of Dallas UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1969 UNITED STATES DEPARTMENT OF THE INTERIOR WALTER J. HICKEL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Abstract___ _____________________________________________________ Bl Introduction. _____________________________________________________ 1 Acknowledgments _________________________________________________ 2 The study area__________________________________________________ 2 Flood history.____________________________________________________ 11 Rainfall____________________________________________________ 12 Antecedent rainfall_____________________________________________ 12 Rainfall on April 28, 1966__________________________________ 12 General description of the April 28, 1966, flood______________________ 19 Inundation _______________________________________________________ 22 Flood damage.____________________________________________________ 23 Determination of flood discharge.___________________________________ 23 Summary_ _ ______________________________________________________ 24 Streamflow data.___-________-____-______-__-______-_______-_-_---- 27 Explanation of data._________________________________________ 27 Station data._________________________________________________ 29 Joes Creek at Walnut Hill Lane, Dallas, Tex______________.___ 29 Joes Creek at State Highway 114, Dallas, Tex ________________ 29 Bachman Branch at Walnut Hill Lane, Dallas, Tex____________ 30 Slaughter Branch at Walnut Hill Lane, Dallas, Tex____________ 30 Bachman Branch at Northwest Highway, Dallas, Tex__________ 30 Bachman Branch at Midway Road, Dallas, Tex_______________ 31 Bachman Branch at Webbs Chapel Road, Dallas, Tex_________ 31 Bachman Branch at Bachman Lake, Dallas, Tex______________ 31 Turtle Creek below McFarlin Boulevard, Dallas, Tex__________ 32 Turtle Creek at Dallas, Tex___._______________.____-_-_.-- 32 White Rock Creek at Keller Springs Road, Dallas, Tex_ _______ 32 Spanky Branch at McCallum Lane, Dallas, Tex___-_________-- 33 Armstrong Branch at Melrose Drive, Richardson, Tex_________ 33 Cottonwood Creek at Forest Lane, Dallas, Tex-______-----___. 34 Floyd Branch at Valley View Road, Dallas, Tex__ _ ____________ 34 Floyd Branch at Forest Lane, Dallas, Tex____________________ 34 White Rock Creek at Greenville Avenue, Dallas, Tex__________ 34 White Rock Creek at White Rock Lake, Dallas, Tex_________ 35 Ash Creek at Highland Drive, Dallas, Tex_ _ ________________ 35 Forney Creek at Lawnview Avenue, Dallas, Tex_____________ 36 White Rock Creek at Scyene Road, Dallas, Tex_____________ 36 Selected references.._______________________________________________ 37 m IV CONTENTS ILLUSTRATIONS Page PLATE 1. Map showing areas flooded in the north Dallas area, Texas____________.__________________________ In pocket 2. Maps and graphs showing cumulative rainfall at 30- minute intervals and total rainfall for the storm of April 28, 1966, north Dallas area, Texas________ In pocket FIGURE 1. Map showing location of watersheds._________________ B3 2-7. Flood profiles: 2. Joes Creek________________________._________ 5 3. Bachman Branch.___________________________ 6 4. Turtle Creek_______________________ 8 5. Upper White Rock Creek_________________ 9 6. Cottonwood Creek___________________________ 10 7. Floyd Branch-_________-_.______________ 13 8. Graph showing accumulated rainfall, April 13-28, 1966, at rain gage 6-W_______.__-____________._________ 14 9. Graph showing comparison of maximum point rainfall intensity at gage 12-W with the rainfall intensity- duration-frequency curves for Dallas.____-.__.__ 15 10-12. Graphs showing comparison of rainfall intensities on watersheds with the rainfall intensity-duration- frequency curves for Dallas: 10. Bachman Branch watershed._________________ 16 11. Joes Creek watershed______________________ 17 12. Turtle Creek watershed____________________ 18 13. Rainfall-runoff hydrographs for storm on Joes Creek and Bachman Branch watersheds._______________ 19 14. Rainfall-runoff hydrographs for storm on Turtle Creek and White Rock Creek watersheds________________ 21 15-17. Photographs of flood damage: 15. Joes Creek at Walnut Hill Lane. _-_-.__ __ _ _ 23 16. Bachman Branch___________________________ 24 17. Turtle Creek at Fitzhugh Avenue.____________ 25 18. Photograph of flooding on White Rock Creek at Scyene Road____________--.-..__________.____ 26 TABLE Page TABLE 1. Flood stages and discharges ______________________ B28 FLOODS OF 1966 IN THE UNITED STATES FLOODS OF APRIL 28, 1966, IN THE NORTHERN PART OF DALLAS, TEXAS By WILLARD B. MILLS AND ELMER E. SCHRQEDER ABSTRACT The floods of April 28, 1966, in the northern part of Dallas, Tex., caused heavy damage to a relatively small area. Flood damage was estimated at $2,500,000; and of this amount, $1,330,000 damage was along Bachman Branch, which has a drainage area of 12.3 square miles. At least seven persons died as a direct result of the floodwaters. The flood was caused by a 5-hour storm in the early hours of April 28. Antece dent rainfall had so saturated the area that the intense, but relatively low, total rainfall (less than a 50-year return period) caused historical floods to be exceeded at many points. A peak runoff rate of 3,160 cubic feet per second per square mile occurred on a 1.5 square-mile area within the watershed. INTRODUCTION A rainstorm in the northern part of Dallas during the early hours of April 28,1966, produced up to 6.7 inches of rain in a 6-hour period; 4.9 inches of rain fell within 1 hour. The intensity of the rainfall exceeded a 100-year return period by a considerable amount for dura tions of 30 minutes to 2 hours, as indicated by U.S. Weather Bureau Technical Paper 25. Because almost 8 inches of rain had fallen during the preceding 2 weeks, the watershed was well saturated, and all storage areas were full. In addition, most of the area is urbanized. This combination of intense rainfall and other hydrologic conditions favorable to high runoff resulted in flood flows greater at some points than the highest flood flows ever recorded on small streams in Dallas. A peak runoff rate of 3,160 cfs per sq mi (cubic feet per second per square mile) occurred on a 1.5 square mile area. This is the second highest peak rate of runoff per square mile recorded by the U.S. Geological Survey in Texas. The highest peak runoff rate recorded, 3,350 cfs per sq mi, occurred on June 30, 1936, on the 4.12 square mile drainage area of Bunton Branch near Kyle, 20 miles southwest of Austin. Bl B2 FLOODS OF 1966 IN THE UNITED STATES Flood damage in Dallas was extensive. Bridges were washed away; more than 270 homes and at least 40 businesses were severely damaged; lawns, gardens, and cemeteries were inundated; and seven lives were lost. Flooding on Bachman Branch, one of the watersheds in north Dallas, caused damages estimated at $1,330,000. This report describes the flood event of April 28, 1966, for the fol lowing watersheds in north Dallas: Joes Creek, Bachman Branch, Turtle Creek, Cottonwood Creek, and Floyd Branch. This flood event is described in terms of rainfall (magnitude, intensity, frequency, and distribution), peak discharge at selected points, flood profiles, inun dated areas, comparison with previous floods, effects of channel changes on flood profiles, and property damage and loss of life due to the flood. The flood on the main stem of White Rock Creek is also described, but in less detail. Figure 1 shows the location of the watersheds, and plate 1 shows the flooded areas. In August 1961 the U.S. Geological Survey, in cooperation with the city of Dallas, began a program of continuing investigations de signed to evaluate the hydrologic factors affecting floods on several small streams in Dallas. Supporting data and computations are in the files of the U.S. Geological Survey, Water Resources Division, Room 647, Federal Building, 300 East 8th Street, Austin, Tex. The height of a flood at any location is generally stated in terms of the stage, which is the elevation of the water surface above a se lected datum plane. In this report, flood heights (stages) are expressed in feet above mean sea level. The rate of flow of a stream is the volume of water that passes a particular point in a given period of time. Discharge rates are given in cubic feet per second. The peak discharge is the maximum instantane ous rate of flow for a given flood. ACKNOWLEDGMENTS The aid of personnel from the city of Dallas who furnished data and assistance for this report is gratefully acknowledged. H. H. Stirman, Director of Public Works, Dallas, Tex., and his staff worked closely with the field engineers to aid in collecting the most accurate data. On the morning of April 28, 1966, Public Works crews were in the flood area and flagged highwater marks. These marks were very helpful in establishing elevations for the flood profiles. THE STUDY AREA The study area comprises about 150 square miles in or near Dallas. Most of the study area is in the 136-square-mile drainage area of White Rock Creek, a tributary