ROUND ROCK RAIn
ROUND ROCK RAInRAINFALL APPLICATION INSTRUCTIONS FOR HYDROLOGIC ANALYSES AND DESIGNSAUGUST 2020CITY OF ROUND ROCKUTILITIES AND ENVIRONMENTAL SERVICES
1.0 SummaryThe City of Round Rock Rainfall Application Instructions for hydrologic analyses anddesigns (RAIn) provides guidance for application of rainfall estimates data and forimplementation of runoff determination methods associated with hydrologic analyses anddesigns in the City of Round Rock.2.0 Rainfall Estimates GuidanceThe National Oceanic and Atmospheric Administration (NOAA) under the United StatesDepartment of Commerce published Volume 11 Version 2.0 (for Texas) of thePrecipitation-Frequency Atlas of the United States (NOAA Atlas 14) in 2018. The City ofRound Rock has determined that the precipitation estimates in NOAA Atlas 14 for thevicinity of Round Rock, Williamson County, and Travis County, Texas are currently the bestdata available; and the NOAA Atlas 14 estimates shall be applicable for hydrologic analysesperformed for infrastructure designs and floodplain determinations subject to City ofRound Rock review and acceptance as they pertain to City of Round Rock developmentregulations and capital improvement projects.Williamson County, Texas has adopted a policy of dividing the county along majorwatershed boundaries and use of NOAA Atlas 14 rainfall estimates determined for thecentroid of a watershed when performing hydrologic analyses for an area within thecorresponding watershed; a map showing the watersheds, NOAA Atlas 14 1% AnnualChance 24-hour rainfall depth estimates isopluvials, and NOAA Atlas 14 1% Annual Chance24-hour rainfall depths at watershed centroids is contained in Appendix A. The City ofRound Rock believes that the Williamson County, Texas policy is sufficiently accurate forhydrologic analyses and will allow the policy to be followed in a similar fashion for the Cityof Round Rock. Alternatively, the design engineer may determine the NOAA Atlas 14 dataspecifically for the area being analyzed and use said data in hydrologic analyses, providedthe data determined and being used is properly and sufficiently justified to the satisfactionof the Utilities and Environmental Services Department Director (UES Director).Rainfall depth and intensity values for selected durations and frequencies extracted fromthe NOAA Atlas 14 data for the centroid of the Brushy Creek Watershed as shown on themap in Appendix A are provided in Tables 1 and 2, respectively; these values may be usedfor hydrologic analyses performed on areas within the Brushy Creek Watershed whenusing the Natural Resources Conservation Service (NRCS) or HEC-HMS methods.2 Page
Table 1: NOAA Atlas 14 Brushy Creek Watershed Centroid Rainfall Depth for selected Durationsand Frequencies (inches); AC Annual ChanceDuration1-yr2-yr5-yr10-yr25-yr(4% AC)50-yr100-yr(1% 5.206.388.179.7011.513.516.719.3Table 2: NOAA Atlas 14 Brushy Creek Watershed Centroid Rainfall Intensity for selected Durationsand Frequencies (inches/hour); AC Annual ChanceDuration1-yr2-yr5-yr10-yr25-yr(4% AC)50-yr100-yr(1% st fit rainfall intensity values at the centroid of the Brushy Creek Watershed for 5 to 30minute durations and selected frequencies as determined by the City’s consultant fromanalyses of the NOAA Atlas 14 data are provided in Table 3; these values may be used forhydrologic analyses within the Brushy Creek Watershed when using the Rational Method.3 Page
Table 3: Best fit NOAA Atlas 14 Brushy Creek Watershed Centroid Rainfall Intensity for 5 to 30-minuteDurations and selected Frequencies (inches/hour); AC Annual ChanceDuration1-yr2-yr5-yr10-yr25-yr(4% AC)50-yr100-yr(1% 69.489.309.13Rainfall depth and intensity values for selected durations and frequencies extracted fromthe NOAA Atlas 14 data for the centroid of the Lake Creek Watershed as shown on themap in Appendix A are provided in Tables 4 and 5, respectively; these values may be usedfor hydrologic analyses performed on areas within the Lake Creek Watershed when usingthe Natural Resources Conservation Service (NRCS) or HEC-HMS methods.4 Page
Table 4: NOAA Atlas 14 Lake Creek Watershed Centroid Rainfall Depth for selected Durations andFrequencies (inches); AC Annual ChanceDuration1-yr2-yr5-yr10-yr25-yr(4% AC)50-yr100-yr(1% .296.518.3910.011.914.117.420.3Table 5: NOAA Atlas 14 Lake Creek Watershed Centroid Rainfall Intensity for selected Durationsand Frequencies (inches/hour); AC Annual ChanceDuration1-yr2-yr5-yr10-yr25-yr(4% AC)50-yr100-yr(1% t fit rainfall intensity values at the centroid of the Lake Creek Watershed for 5 to 30minute durations and selected frequencies as determined by the City’s consultant fromanalyses of the NOAA Atlas 14 data are provided in Table 6; these values may be used forhydrologic analyses within the Lake Creek Watershed when using the Rational Method.5 Page
Table 6: Best fit NOAA Atlas 14 Lake Creek Watershed Centroid Rainfall Intensity for 5 to 30-minuteDurations and selected Frequencies (inches/hour); AC Annual ChanceDuration1-yr2-yr5-yr10-yr25-yr(4% AC)50-yr100-yr(1% 810.610.410.2When performing hydrologic analyses on areas of the City of Round Rock within TravisCounty, Texas, the values for the Lake Creek Watershed in Tables 4, 5, and 6 above areconsidered applicable by the City of Round Rock, as appropriate for the method being usedfor runoff determination.3.0 Runoff Determination Guidance3.1 Rational MethodFor small drainage areas being analyzed having times of concentration (T c ) less than orequal to 15 minutes, it is recommended that the Rational Method be used; best fit NOAAAtlas 14 rainfall intensities for durations from 5 to 30 minutes for use with the Rational6 Page
Method for selected storm frequencies are provided in tables 3 and 6 above for thecorresponding watershed containing the area being analyzed.As per the City of Round Rock Drainage Criteria Manual as part of the City of Round RockDesign and Construction Standards (DACS), the Rational Method may be used forwatersheds up to 100 acres in area; however, NOAA Atlas 14 rainfall data will need to bedetermined if any T c is found to be greater than 30 minutes, and such determination willrequire proper and sufficient justification to the satisfaction of the UES Director. Fordrainage areas being analyzed with T C less than 5 minutes, the intensity value for the 5minute duration should be used in the Rational Method.3.2 NRCS and HEC-HMS MethodsFor larger drainage areas where use of the Rational Method is inappropriate, the NRCS orHEC-HMS method should be applied for hydrologic analyses. As per the DACS, the City ofRound Rock has adopted a 24-hour frequency storm for use with these methods.The meteorological model when applying HEC-HMS should use the Frequency Stormprecipitation method included in the program; rainfall depth values for the desiredfrequency analysis as shown in tables 1 or 4 above, depending on the watershedcontaining the area being analyzed, should be entered in the Frequency Stormprecipitation method as required by the program.The computational time interval (time step) should not be less than 5 minutes nor greaterthan 10 minutes when developing hydrographs with the NRCS and HEC-HMS methods. Atime step of 5 or 6 minutes should generally be used in most analyses; but when properlyand sufficiently justified to the satisfaction of the UES Director, a time step up to 10minutes may be used.3.3 NRCS Runoff Curve Number AdjustmentThe Texas Department of Transportation (TxDot) has previously commissioned researchregarding NRCS Runoff Curve Numbers culminating in the Climatic Adjustments of NaturalResource Conservation Service (NRCS) Runoff Curve Numbers Final Report dated November2003; a copy of this report is contained in Appendix B. When applying the NRCS or HECHMS method, the engineer may, but will not be required to, adjust a Runoff Curve Number(CN) shown in the DACS, or a CN not shown in the DACS but included in NRCS publications,in accordance with the report contained in Appendix B if, in the opinion of the engineer,the adjustment is appropriate; but allowance by the City of Round Rock of CN adjustmentdoes not relieve the engineer of his/her responsibilities under the Texas Engineering andLand Surveying Practice Acts and Rules Concerning Practice and Licensure as adopted bythe State of Texas. Furthermore, no CN adjustment shall exceed 15, no CN with an unadjusted value above 40 shall be adjusted such that the result will be less than 40, and anyCN shown in the DACS, or a CN not shown in the DACS but included in NRCS publications,with a published value of 40 or less shall not be adjusted.7 Page
ROUND ROCK RAInAPPENDIX AWilliamson County, Texas Watersheds Map
North(Not to Scale)d10.61210. 811.6D11.411.211.2"Salado Creek10.9"D San Gabriel RiverLake Creek11.9"11.811DDBrushy Creek11.5"Watershed CentroidSan Gabriel River WatershedSalado Creek WatershedLake Creek WatershedBrushy Creek WatershedNOAA Atlas 14 1% annual chance 24-hour rainfall isopluvial (inches)NOAA Atlas 14 Precipitation Estimates atWilliamson County, Texas Watershed Centroids
ROUND ROCK RAInAPPENDIX BClimatic Adjustments of Natural Resource Conservation Service(NRCS) Runoff Curve Numbers Final Report
Climatic Adjustments of NaturalResource Conservation Service(NRCS) Runoff Curve Numbers:Final ReportDavid B. Thompson, H. Kirt Harle, Heather Keister,David McLendon, and Shiva K. SandranaDepartment of Civil EngineeringTexas Tech UniversityCenter for Multidisciplinary Research inTransportationSubmitted to:Texas Department of TransportationReport No. 0-2104-2October 2003
1. Report No.:TECHNICAL REPORT DOCUMENTATION PAGE2. Government Accession No.:3. Recipient’s Catalog No.:TX -00/0-2104-24. Title and Subtitle:“Climatic Adjustments of Natural Resource Conservation Service(NRCS) Runoff Curve Numbers”7. Author(s):David B. Thompson, H. Kirt Harle, Heather Keister, David McLendon,and Shiva K. Sandrana9. Performing Organization Name and AddressTexas Tech UniversityDepartment of Civil EngineeringBox 41023Lubbock, Texas 79409-102312. Sponsoring Agency Name and Address:Texas Department of TransportationResearch and TechnologyP. O. Box 5080Austin, TX 78763-50805. Report Date:November 20036. Performing OrganizationCode:TechMRT8. Performing OrganizationReportNo.0-2104-210. Work Unit No. (TRAIS)11. Contract or Grant No.:Project 0-210413. Type of Report and PeriodCovered: Final Report14. Sponsoring Agency Code:15. Supplementary Notes:Study conducted in cooperation with the Texas Department of Transportation.Research Project Title: “Climatic Adjustments of Natural Resource Conservation Service (NRCS) RunoffCurve Numbers”16. Abstract:The purpose of this report is to present results and recommendations from Project Number 0-2104, ClimaticAdjustments of Natural Resource Conservation Service (NRCS) Runoff Curve Numbers. The literature was reviewedfor previous research pertinent to the project. Several other studies had been conducted that, while dealing with curvenumbers, were not directly transferable to the subject project. However, they did provide important technology forthe development of project curve numbers and the means to provide adjustments to the curve number to reflect Texashydrology. Based on the literature and computations involving some 1600 measured rainfall-runoff events, a mapwas developed that can be used by TxDOT hydraulic designers to adjust the runoff curve number by geographiclocation. It is recommended that the tool become a part of the hydraulic design process, but not to the exclusion ofother tools available to the designer.17. Key Words:Hydrology, rainfall-runoff, NRCS curve number,SCS curve number, modeling, hydrographs19. Security Classif. (of this report)UnclassifiedForm DOT F 1700.7 (8-72)18. Distribution Statement:No restrictions. This document is available to thepublic through the National TechnicalInformation Service, Springfield, Virginia 2216120. Security Classif. (of this page)Unclassifiedi21. No. of Pages3522. Price
CLIMATIC ADJUSTMENTS OF NATURAL RESOURCECONSERVATION SERVICE (NRCS) RUNOFF CURVE NUMBERSFINAL REPORTbyDavid B. Thompson, Ph.D., P.E.,Graduate Students: H. Kirt HarleHeather Keister, David McLendon, and Shiva K. SandranaResearch Report Number 0-2104-2conducted forTexas Department of Transportationby theCENTER FOR MULTIDISCIPLINARY RESEARCH IN TRANSPORTATIONTEXAS TECH UNIVERSITYNovember 2003ii
IMPLEMENTATION STATEMENTThis project (0-2104) resulted in the development of a map to be used by TxDOT hydraulic designersfor adjustment of the NRCS runoff curve number. This tool can be used to reduce the runoff fromdesign events for a significant portion of the state. The research findings can be used by TxDOTanalysts to 1) reduce cost of new drainage facilities, 2) to assess a more reasonable estimate of thecapacity of existing drainage works, and 3) to make decisions on appropriate amounts of additionalhydraulic capacity, if in the judgment of the analyst such additional hydraulic capacity is warranted.iii
Prepared in cooperation with the Texas Department of Transportation and the U.S. Department ofTransportation, Federal Highway Administration.iv
AUTHOR’S DISCLAIMERThe contents of this report reflect the views of the authors who are responsible for the facts and theaccuracy of the data presented herein. The contents do not necessarily reflect the official view ofpolicies of the Department of Transportation or the Federal Highway Administration. This reportdoes not constitute a standard, specification, or regulation.PATENT DISCLAIMERThere was no invention or discovery conceived or first actually reduced to practice in the course of orunder this contract, including any art, method, process, machine, manufacture, design or compositionof matter, or any new useful improvement thereof, or any variety of plant which is or may bepatentable under the patent laws of the United States of America or any foreign country.ENGINEERING DISCLAIMERNot intended for construction, bidding, or permit purposes. The engineer in charge of the researchstudy was David B. Thompson, Ph.D, Texas Tech University.TRADE NAMES AND MANUFACTURERS’ NAMESThe United States Government and the State of Texas do not endorse products or manufacturers.Trade or manufacturers’ names appear herein solely because they are considered essential to theobject of this report.v
vi
TABLE OF CONTENTSTECHNICAL DOCUMENTATION PAGE . iTITLE PAGE . iiIMPLEMENTATION STATEMENT . iiiFEDERAL-DEPARTMENT CREDIT . ivDISCLAIMER .vMETRIC SHEET . viTABLE OF CONTENTS. viiLIST OF FIGURES . viiiLIST OF TABLES. ixINTRODUCTION .1Background .1Objectives .1RESEARCH METHODS .3Database.3Observed Curve Numbers.5Predicted Curve Numbers .8RESULTS AND DISCUSSION .11Predicted and Observed Curve Numbers.11Hailey and McGill .14Design Tool .18Conclusions and Recommendations .20References .21APPENDIX I.23vii
LIST OF FIGURESFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8Figure 9Location of study watersheds .Plot of rainfall and runoff, rainfall and curve number, and runoff and curvenumber for Alazan Creek in San Antonio. .Observed curve numbers from study watersheds .A watershed near Dublin, Texas with computed curve numbers derivedusing the automated procedures developed for this project. .Predicted curve numbers from study watersheds .Mean difference between CNobs and CNpred overlain on map of averageannual precipitation. Negative values indicate that CNobs is less than CNobs .Mean differences between CNobs and CNpred and mean annual temperature.Negative values indicate that CNobs is less than CNobs. .14Comparison of Hailey and McGill adjusted curve numbers, CNH&M, with CNobs.Negative differences indicate that CNH&M ,is larger than CNobs. .Suggested design aide based on difference between CNobsand CNpred.1719viii46791013
LIST OF TABLESTable 1Table 2APPENDIX ITable I.1Table I.2Table I.3Table I.4Table I.5Summary statistics of CNobs , CNpred and the difference betweenCNobs , and CNpred. .Comparison of project CNobs with observed curve numbers computed byHailey and McGill (1983). .(Humphrey 1996) .Observed and predicted curve numbers for the Austin region .Observed and predicted curve numbers for the Dallas region.Observed and predicted curve numbers for the Fort Worth region.Observed and predicted curve numbers for the San Antonio region.Observed and predicted curve numbers for the small rural watersheds .ix1115162324242526
CLIMATIC ADJUSTMENTS OF NATURAL RESOURCECONSERVATION SERVICE (NRCS) RUNOFF CURVE NUMBERS:TXDOT PROJECT NUMBER 0-2104INTRODUCTIONBackgroundThe Natural Resource Conservation Service (NRCS), formerly the Soil Conservation Service (SCS),developed the curve number procedure in 1954 as a method for estimating runoff. This procedurewas developed for application to hydrologic design activities associated with small agriculturalwatersheds. Since its development, the curve number method has become a widely used procedurefor estimating runoff. Because of the endorsement by NRCS as a federal agency, engineers use theprocedure for a wide range of applications.The Texas Department of Transportation (TxDOT) conducts design of a large number of drainagestructures each year. For small watersheds (those with drainage areas less than 200 acres), TxDOTuses the rational method for estimation of peak hydraulic loads. For watersheds with drainage areasthat exceed 20 square miles, regional regression equations are used to estimate design discharges.However, for watersheds with drainage areas between those values, hydrograph methods are used byTxDOT to estimate design discharges.The development of a design discharge using hydrograph methods requires three components: 1) Adesign rainfall depth and temporal distribution, 2) a procedure for converting incoming rainfall torunoff (sometimes called effective precipitation), and 3) a unit hydrograph that represents theintegrated response of a watershed to a unit pulse of effective precipitation with a particular duration.Given these three things, a tool such as HEC-HMS can be used to compute the hydrograph of runofffor the design event.For application of the hydrograph method, TxDOT currently specifies the NRCS curve numberprocedure as the preferred method for sizing hydraulic structures when watershed drainage areasexceed about 200 acres but are less than about 20 square miles. As a result TxDOT engineers acrossthe entire state of Texas have adopted this method in their designs. While curve number calculationswere designed to account for variations in soil textural classification, and for variations in land useand land cover (LULC) type, they do not take into consideration the possibility that differences ineffective curve number might arise in response to differences in climate, particularly rainfall. It wasthe opinion of some TxDOT analysts that standard estimates of curve number resulted inoverprediction of runoff volume, and hence over prediction of peak discharge. There was a suspicionthat effective curve number might be less than the standard values because of variations in rainfallamounts by location across Texas. Therefore, a problem statement to study the relation betweenclimate and curve number was developed so that the effect of these variations could be studied. Inresponse to the request for proposal, researchers from Texas Tech University and U.S. GeologicalSurvey (USGS) prepared a proposal and won the project.ObjectivesTxDOT initiated a research project, TxDOT Project Number 0-2104, Climatic Adjustments of NaturalResource Conservation Service (NRCS) Runoff Curve Numbers, to investigate the need (or lackthereof) for developing a standard procedure for adjusting results of the current method of computinga NRCS curve number. Therefore, the primary objective of this study was to determine if theProject 0-2104Page 1 of 26
standard curve number is representative of rainfall-runoff processes for Texas watersheds, and, if not,to develop a method to adjust the NRCS curve number for use on Texas watersheds.Because of the available records of rainfall and runoff for select watersheds in Texas, a task of thisstudy was to compute the deviations between the observed curve number (calculated from rainfallrunoff data) and the NRCS curve number (or predicted curve number) for each of the selectwatersheds. The computed deviations were then to be analyzed with respect to geographic location ofthe study watershed in Texas.The final objective of this study was to compare the deviations generated from the project andobserved data to a curve number adjustment procedure developed by Hailey and McGill (1983). Intheir procedure, they used observations of rainfall and runoff for a large number of watersheds tocompute an observed curve number. They related average annual precipitation and average annualtemperature into a climatic index, and used the derived climatic index to estimate an effective curvenumber. This work will be brought into the discussion in the Results and Discussion section of thisreport.Project 0-2104Page 2 of 26
RESEARCH METHODSDatabaseThe first step to achieve project objectives was to assemble the database. In addition to this project,researchers from Texas Tech University and USGS were joined by researchers from LamarUniversity and the University of Houston on a pair of research projects to develop a unit hydrograph(TxDOT project 0-4193) and a rainfall hyetograph (TxDOT project 0-4194) for use in executingTxDOT designs. These agencies pooled personnel resources to enter data representing 1659 stormsand runoff hydrographs for 100 watersheds. These data were extracted from USGS small-watershedstudies (220 paper reports) stored in USGS archives (Asquith, in press). The resulting database washoused on a Tech workstation with regular backups to USGS Austin-based computers. The majorityof the study watersheds are located in west central Texas near the I-35 corridor; a few others arelocated in the eastern and western regions of the state, and along the Gulf coast. The locations ofstudy watersheds are shown on Figure 1.Project 0-2104Page 3 of 26
Figure 1 Location of study watersheds.Project 0-2104Page 4 of 26
Observed Curve NumbersFor the purposes of this study, the term observed curve number (CNobs) refers to the estimate ofeffective curve number for a watershed that is derived for paired observations of rainfall depth andrunoff depth. Typically, CNobs is estimated by inverting the NRCS rainfall-runoff relation andcomputing the curve number for each event. That is, the rainfall and runoff from a particular event isassumed to have the same exceedance probability. Given a number of observations from a particularwatershed, then an
The City of Round Rock Rainfall Application Instructions for ydrologic analyses and h designs (RAIn) provides guidance for application of rainfall estimates data and for implementation of runoff determination methods associated with hydrologic analyses and designs in the City of Round Rock. 2.0 Rainfall Estimates Guidance
Alannah Myles Atlantic Rock Avril Lavigne Let go Rock Beau Dommage Capitol Rock Bon Jovi Crush Rock Bon Jovi This ain't a Love Song Rock Boom Desjardins Boom Desjardins Rock Boston Greatest hits Rock Chuck Berry Hail! Hail! Rock'N'Roll Rock Creed Weathered Rock Dany Bédar Fruit de ma récente nuit blanche Rock
Base Controller Brand Base Controller Model Add-on Brand Add-on Model Based Controllers Add-on Qualifying Products List as of Aug 01, 2021 . Rain Bird ESP-LXME Rain Bird IQ4G-USA Rain Bird ESP-LXME Rain Bird IQNCC4G Rain Bird ESP-LXME Rain Bird IQNCCEN Rain Bird ESP-LXME Rain Bird IQNCCRS. Page 5 of 5
What is acid rain? Acid rain is defined as rain with a pH of below 4.0 - 4.5. Normal rain has a pH of about 5.6, which is slightly acidic. What are the effects of acid rain? Acid rain increases the acidity levels of rivers, lakes and seas. This can poison fish. Acid rain increases the acidity levels of soils. This can slow or even kill plant .
The Corpus Christi Hooks picked up a dramatic 2-1 walkoff victory over the Round Rock EXHIBITION SERIES HISTORY 2019 Overall: 0-1 In Round Rock: 0-0 In Corpus Christi: 0-1 Streak: L1 One-Run Games: 0-1 Extra-Inning Games: 0-0 All-Time Series: Round Rock leads 7-4-1 All-Time Record in Round Rock: 2-3-1 All-
Rock&Soul Basic Rock B. B. Rock English Rock Hard Rock Memphis R&Blues Rock Ballad Rock Shuffle Soul Usa Rock . 090 Warmness 091 Score 092 Space Control 0 - Value 0 Control 0 - Value 1 Control 0 - Value 2 . (whit Voice Tab Off) - Program Change 1-64 Only Global and Right MIDI Channel] 6 7 DRUM 1 [Program Change 1-128] 001 Standard 009 Folk
(Rock Classification) describes a process for naming rock. The second part of the guide (Structural Characteristics of Rock) is a discussion of the elements of rock mass description and structural rock mapping. Finally, the last part of the guide (Structural Rock Mapping Procedures) provides the methodology for field structural rock mapping.
RAIN GARDEN TECHNICAL ASSISTANCE PROGRAM . RAIN GARDEN EDUCATION WORKSHOP . HAMILTON TOWNSHIP . MERCER COUNTY . dripline of trees 7. Provide adequate space for rain garden p. 17 . . landscape fabric) Completed Rain Gardens . Roof Runoff . Design . Installed Rain Garden . Parking Lot Runoff .
The nonlinear springs are defined using API p–y curves at regular depth . intervals, where p represents the lateral soil resistance per unit length of the pile and y is the lateral deflection of the pile (API, 2007). As it was discussed before response of a single pile is different from response of a pile in a pile group due to group effect. One of the most common methods of accounting for .
