DistrictCover.fm Page 1 Thursday, January 13, 2005 4:24 PM In cooperation with the Texas Department of Transportation Extreme Precipitation Depths for Texas, Excluding the Trans-Pecos Region Water-Resources Investigations Report 98–4099 U.S. Department of the Interior U.S. Geological Survey Extreme Precipitation Depths for Texas, Excluding the Trans-Pecos Region By Jennifer Lanning-Rush, William H. Asquith, and Raymond M. Slade, Jr. U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 98–4099 In cooperation with the Texas Department of Transportation Austin, Texas 1998 U.S. DEPARTMENT OF THE INTERIOR Bruce Babbitt, Secretary U.S. GEOLOGICAL SURVEY Thomas J. Casadevall, Acting Director Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. For additional information write to: District Chief U.S. Geological Survey 8011 Cameron Rd. Austin, TX 78754–3898 Copies of this report can be purchased from: U.S. Geological Survey Branch of Information Services Box 25286 Denver, CO 80225–0286 ii CONTENTS Abstract ................................................................................................................................................................................ 1 Introduction .......................................................................................................................................................................... 1 Purpose and Scope .................................................................................................................................................... 1 Previous Studies and Extreme Storm Data ............................................................................................................... 2 Extreme Precipitation Depths for Texas ............................................................................................................................... 3 Selected References ............................................................................................................................................................. 4 FIGURES 1. Map showing climatic regions of this report and of the National Weather Service, Texas .................................. 2 2–13. Graphs showing extreme precipitation curve for the: 2. 1-day storm in the High Plains and Low Rolling Plains climatic region of Texas .................................... 8 3. 3-day storm in the High Plains and Low Rolling Plains climatic region of Texas .................................... 8 4. 2-day storm in the North Central climatic region of Texas ....................................................................... 9 5. 4-day storm in the North Central climatic region of Texas ....................................................................... 9 6. 1-day storm in the Edwards Plateau climatic region of Texas ................................................................... 10 7. 3-day storm in the Edwards Plateau climatic region of Texas ................................................................... 10 8. 5-day storm in the Edwards Plateau climatic region of Texas ................................................................... 11 9. 2-day storm in the South Texas, South Central, and Lower Valley climatic region of Texas .................... 11 10. 4-day storm in the South Texas, South Central, and Lower Valley climatic region of Texas .................... 12 11. 6-day storm in the South Texas, South Central, and Lower Valley climatic region of Texas .................... 12 12. 2-day storm in the East Texas and Upper Coast climatic region of Texas ................................................. 13 13. 4-day storm in the East Texas and Upper Coast climatic region of Texas ................................................. 13 TABLES 1. Descriptions of notable and extreme storms in Texas .......................................................................................... 14 2. Summary of notable and extreme storms in Texas ............................................................................................... 38 CONTENTS iii Extreme Precipitation Depths for Texas, Excluding the Trans-Pecos Region By Jennifer Lanning-Rush, William H. Asquith, and Raymond M. Slade, Jr. Abstract Texas Department of Transportation, began a 3-year study of precipitation characteristics for Texas. The The U.S. Geological Survey, in cooperation major objectives of this study are (1) to define the with the Texas Department of Transportation, depth-duration frequency of precipitation in Texas, conducted a study of extreme precipitation depths (2) to determine appropriate depth-area precipitation for various durations and storm areas for Texas, relations for Texas, and (3) to investigate extreme excluding the Trans-Pecos region. The extreme precipitation depths for regions of Texas. The focus of precipitation depth is an estimate, from docu- this report is on extreme precipitation depths. mented storms, of the largest precipitation depth expected to occur over a given area. The extreme Purpose and Scope precipitation depth exceeds the precipitation depth associated with recurrence intervals greater than The purpose of this report is to present the 100 years. extreme precipitation depths for Texas, excluding the Storm durations of 1, 2, 3, 4, 5, and 6 days Trans-Pecos region. The climatic regions of this report were investigated for this report. The extreme pre- (fig. 1) are the same as or a combination of 2 or 3 of the cipitation depth for a particular area is estimated 10 National Weather Service (NWS) climatic regions of from an “extreme precipitation curve” (an upper Texas (Carr, 1967). Storm durations of 1, 2, 3, 4, 5, and limit or envelope curve developed from graphs of 6 days were investigated, although the extreme precipi- extreme precipitation depths for each climatic tation depths for all of these durations are not available region). The extreme precipitation curves were for each region. The extreme precipitation depth for a determined using precipitation depth-duration particular area is estimated from an “extreme precipita- information from a subset (24 “extreme” storms) of tion curve” (an upper limit or envelope curve developed 213 “notable” storms documented throughout from graphs of extreme precipitation depth versus area Texas. The extreme precipitation curves can be for each climatic region). The extreme precipitation used to estimate extreme precipitation depth for a (EP) curves were developed from data for 24 “extreme” storms selected from a data base of “notable” storms in particular area. The extreme precipitation depth Texas compiled for the study. The precipitation depths represents a limiting depth, which can provide use- for the 24 selected storms were so large that, for pur- ful comparative information for more quantitative poses of this report, they are referred to as extreme. The analyses. 24 extreme storms are identified along with 189 other notable storms in Texas (table 1 at end of report). The INTRODUCTION description and dates of occurrence for each identified The extreme precipitation depth is an estimate storm are listed in the table. The temporal distribution of of the largest precipitation depth expected to occur the notable and extreme storms by decade or period of over a given area. The extreme precipitation depth occurrence is documented (table 2 at end of report). Dis- exceeds the precipitation depth associated with recur- cussion pertinent to the documentation of storms in rence intervals greater than 100 years. In 1996, the U.S. Texas is presented in the “Extreme Precipitation Depths Geological Survey (USGS), in cooperation with the for Texas” section. Abstract 1 102 o 100 o 36 o High Plains 98o 96o 34 o Low Rolling Plains North Central 106 o 32 o 104 o Trans-Pecos East Texas Edwards Plateau 30 o South Central Upper Coast South EXPLANATION Texas 28 o Climatic regions of this report Boundary of climatic regions of this report and the National Weather Service Boundary of climatic regions of the National Weather Service Lower Valley 26 o 0 50 100 150 200 MILES Figure 1. Climatic regions of this report and of the National Weather Service, Texas. Previous Studies and Extreme Storm Data presents the results of an investigation of extreme flood-peak discharges in Texas. In that study, the rela- Lowry (1934) classified and tabulated data for tions between large flood peaks and contributing drain- 33 storms to develop depth-area curves for durations of 3, 4, and 5 days in Texas. The analysis in Lowry is age area were used to develop upper limit or envelope similar to that presented in this report. No other analyses curves for extreme flood peaks. The analysis in this of extreme precipitation in Texas are known to have report is analogous to that presented by Asquith and been conducted. A study by Asquith and Slade (1995) Slade. 2 Extreme Precipitation Depths for Texas, Excluding the Trans-Pecos Region Data for this report are from past reports of docu- the extreme storms in Texas indicates that the occur- mented storms that have precipitation contour maps rence of extreme storms also is fairly evenly distributed for the storms. Texas storms have been documented in in time, with two exceptions—the 1931–40 decade publications by the U.S. Army Corps of Engineers with 9 extreme storms and the 1951–60 decade with 5 (Tulsa, Okla.); International Boundary and Water extreme storms. Supporting the evidence that the 1931– Commission (El Paso, Tex.); National