Teexas Hydraulic Design Manual The purpose of this drainage manual is to establish design procedures necessary for the control of storm water runoff for the IH 635 Freeway improvements from Luna Road to US 80 (referred to in this manual as IH 635 corridor). Also included is IH 35E from Royal Lane to Valwood Parkway. The design factors, formulas, graphs, and procedures are intended for use as engineering guides in the solution of drainage problems involving determination of the quantity, rate of flow and conveyance of storm water. The procedures defined herein should be applied by experienced professional drainage Engineers who are ultimately responsible for the design of drainage systems within the IH 635 corridor.
Hydraulic Design Manual Revised November 2002 © by Texas Department of Transportation (512) 416-2055 all rights reserved Hydraulic Design Manual November 2002 Manual Notices Manual Notice 2002-2 To: Districts, Divisions and Offices From: Mary Lou Ralls, P.E Manual: Hydraulic Design Manual Effective Date: November 1, 2002 Purpose This manual provides guidance and recommended procedures for the design of Texas Department of Transportation drainage facilities This revision updates various equations and references to them, updates the procedure for conduit design, and corrects minor errors Instructions Revisions are distributed online only This 2002-2 version supersedes the 2002-1 version Contents The manual contains fourteen chapters: ♦ Manual Introduction ♦ Policy and Guidelines ♦ Types of Documentation ♦ Data Collection, Evaluation, and Documentation ♦ Hydrology ♦ Hydraulic Principles ♦ Channels ♦ Culverts ♦ Bridges ♦ Storm Drains ♦ Pump Stations ♦ Reservoirs ♦ Storm Water Management, and ♦ Conduit Strength and Durability Contact For more information regarding any chapter or section in this manual, please contact the Hydraulics Branch of the Bridge Division Manual Notice 2002-1 To: Districts, Divisions and Offices From: Mary Lou Ralls, P.E Manual: Hydraulic Design Manual Effective Date: April 3, 2002 Purpose This manual provides guidance and recommended procedures for the design of Texas Department of Transportation drainage facilities This revision adds English measurement equivalents to the metric units provided in a previous version of the manual It also updates examples, eliminates an unnecessary section on wave runup analysis, streamlines the organization of the manual, and corrects minor errors Instructions Revisions are distributed online only This 2002-1 version supersedes the 2001-1 version Contents The manual contains fourteen chapters – Manual Introduction; Policy and Guidelines; Types of Documentation; Data Collection, Evaluation, and Documentation; Hydrology; Hydraulic Principles; Channels; Culverts; Bridges; Storm Drains; Pump Stations; Reservoirs; Storm Water Management; and Conduit Strength and Durability Contact For more information regarding any chapter or section in this manual, please contact the Hydraulics Branch of the Bridge Division Manual Notice 2001-1 To: Districts, Divisions and Offices From: Kirby W Pickett, P.E Deputy Executive Director Manual: Hydraulic Design Manual Effective Date: October 1, 2001 Purpose This manual will provide guidance and recommended procedures for the design of Texas Department of Transportation drainage facilities Instructions This manual replaces the Bridge Division Hydraulic Manual, Third Edition Contents The manual contains fourteen chapters – Manual Introduction; Policy and Guidelines; Types of Documentation; Data Collection, Evaluation, and Documentation; Hydrology; Hydraulic Principles; Channels; Culverts; Bridges; Storm Drains; Pump Stations; Reservoirs; Storm Water Management; and Conduit Strength and Durability Contact For more information regarding any chapter or section in this manual, please contact the Hydraulics Branch of the Bridge Division Chapter Manual Introduction Contents: Section — About This Manual 1-3 Purpose .1-3 Conventions and Assumptions 1-3 Organization 1-4 Feedback 1-4 Section — Introduction to Hydraulic Design 1-5 Description 1-5 Hydraulic Design Manual 1-1 TxDOT 11/2002 Chapter — Manual Introduction Hydraulic Design Manual Section — About This Manual 1-2 TxDOT 11/2002 Chapter — Manual Introduction Section — About This Manual Section About This Manual Purpose Hydraulic facilities include open channels, bridges, culverts, storm drains, pump stations, and storm-water quantity and quality control systems Each can be part of a larger facility that drains water In analyzing or designing drainage facilities, your investment of time, expense, concentration, and task completeness should be influenced by the relative importance of the facility This manual provides procedures recommended by the Texas Department of Transportation (TxDOT) for analyzing and designing effective highway drainage facilities Version 2001-1 2002-1 Publication Date October 2001 April 2002 2002-2 November 2002 Manual Revision History Summary of Changes New manual; replaced 1985 Bridge Division Hydraulic Manual Revision adding English measurement units, deleting unnecessary section on wave runup analysis, streamlining organization, and correcting minor errors Revision updating equations in Chapters 4, 5, and 8; providing new equations on pavement drainage ponding and curb inlets in sag configurations; updating the procedure for on-grade slotted drain inlets, and correcting minor errors Conventions and Assumptions This manual provides information, where possible, in both English standard measurement units and in metric measurement units This manual assumes that hydraulic designers have access to programmable calculators, computer spreadsheets, and specific hydraulic computer programs Hydraulic Design Manual 1-3 TxDOT 11/2002 Chapter — Manual Introduction Section — About This Manual Organization This manual is organized as follows: ♦ Chapter 1: Manual Introduction – Overview of the material covered in this manual ♦ Chapter 2: Policy and Guidelines – Considerations regarding highway drainage design for TxDOT ♦ Chapter 3: Documentation – Formal documentation required by highway drainage analysis and design ♦ Chapter 4: Data Collection, Evaluation, and Documentation – Data sources and data management during highway drainage analysis and design ♦ Chapter 5: Hydrology – Methods used by TxDOT for discharge determination or estimation, guidelines and examples for development of runoff hydrographs, and discussion of design frequency requirements and considerations ♦ Chapter 6: Hydraulic Principles – Basic hydraulic concepts and equations for open channels, culverts, and storm drains ♦ Chapter 7: Channels – Overview of channel design, methods, and guidelines governing location and need to subdivide cross sections ♦ Chapter 8: Culverts – Discussion of culvert analysis and design procedures and concerns, equations for various culvert operating conditions, and appurtenances such as improved inlets and erosion velocity protection and control devices ♦ Chapter 9: Bridges – Overview of stream-crossing design, bridge hydraulic considerations, bridge scour and channel degradation concerns, and design by risk assessment ♦ Chapter 10: Storm Drains – Discussion of storm drain planning, components, calculation tools, and other guidelines ♦ Chapter 11: Pump Stations – Discussion of the function of pump stations and flood routing approach ♦ Chapter 12: Reservoirs – Overview of factors affecting highways either crossing or bordering reservoirs ♦ Chapter 13: Storm Water Management – Guidance on storm water management practices, including erosion and sediment control, maintenance of erosion control measures, storm water runoff collection and disposal, and storm water pollution abatement ♦ Chapter 14: Conduit Strength and Durability – Information on conduit durability, estimating service life, classes of bedding for reinforced concrete, RCP strength specifications, and jacked pipes Feedback Direct any questions or comments on the content of the manual to the Director of the Bridge Division, Texas Department of Transportation Hydraulic Design Manual 1-4 TxDOT 11/2002 Chapter 14 — Conduit Strength and Durability Section — Estimated Service Life Section Estimated Service Life Corrugated Metal Pipe and Structural Plate Determine the service life of corrugated metal structure by calculating the service life of the exterior and interior of the pipe using the site characteristics for the soil and water discussed in the previous section The overall service life will be the lesser of the interior service life or exterior service life The service life of a corrugated metal conduit is expressed by the sum of the base metallic coating, post applied coating, and paving or lining service life, as in Equation 14-1 and Equation 14-2: Equation 14-1: SL INT = å SL BMCI + SL PACI + SL LI Equation 14-2: SL EXT = å SL BMCE + SL PACE where: SLINT = service life of the interior of the pipe SLEXT = service life of the exterior of the pipe SLBMCI = service life of the base metallic coating interior SLBMCE = service life of the base metallic coating exterior SLPACI = service life of the post applied coating interior SLPACE = service life of the post applied coating exterior SLLI = service life of the paving or lining interior Hydraulic Design Manual 14-6 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Estimated Service Life Corrugated Steel Pipe and Steel Structural Plate The base metallic coating data provided in this section are limited to the following values for galvanized metals: ♦ < pH < ♦ resistivity ≥ 2,000 ohm-cm ♦ soft waters considered hostile when resistivity ≥ 7,500 ohm-cm For aluminized type 2, the following values apply: ♦ 5.0 < pH < 9.0; Resistivity > 1,500 ohm-cm ♦ soft waters not considered to be a problem Estimate the service life for the interior base metallic coating using Equation 14-3 Equation 14-3: SL BMCI = (basic interior service life) × (thickness multiplier) The basic interior service life for 18-gage corrugated galvanized metal pipe is provided in the table following Equation 14-4 for pH values of 7.3 and lower and using the equation for pH values in excess of 7.3 0.41 Equation 14-4: L i = (1.25)(1.47)R where: Li = interior years R = resistivity (ohm-mm) Hydraulic Design Manual 14-7 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Estimated Service Life Exterior Coating Estimate the service life for the basic exterior base metallic coating using Equation 14-5 Equation 14-5: SL BMCE = (basic exterior service life) × (thickness multiplier) The basic exterior service life (Le) for 18-gage corrugated galvanized metal pipe is provided in the table following Equation 14-6 for pH values of 7.3 and lower and using the equation for pH values in excess of 7.3 0.41 Equation 14-6: L e = (2.0)(1.47)R Exterior Durability for 18-Gage CMP (years) Resistivity (ohm-cm) pH 7.3 7.0 6.5 6.0 5.8 5.5 5.0 1,000 54.8 34.6 23.9 18.0 16.2 13.8 10.4 1,500 59.6 39.4 28.8 22.9 21.0 18.6 15.3 2,000 63.1 42.9 32.2 26.3 24.5 22.1 18.7 2,500 65.8 45.6 34.9 29.0 27.2 24.8 21.4 3,000 67.9 47.7 37.1 31.2 29.3 26.9 23.6 4,000 71.4 51.2 40.5 34.6 32.8 30.4 27.0 5,000 74.1 53.9 43.2 37.3 35.5 33.1 29.7 7,500 78.9 58.7 48.0 42.1 40.3 37.9 34.5 10,000 82.4 62.2 51.5 45.6 43.8 41.4 38.0 Heavier gage metal has more sacrificial metal and, therefore, a longer anticipated life under given conditions The table below provides coating thickness/gage multipliers for use in Equation 14-1 and Equation 14-2 for the respective gage and metallic coating The resulting values are not exact but allow a systematic comparison of relative durability of the various metals and gages used in design Thickness Multipliers for Steel Conduit Item 460 - CMP Item 461 - Structural Plate Gauge 18 16 14 12 10 Thickness in (mm) 0.052 (1.32) 0.064 (1.63) 0.079 (2.01) 0.109 (2.77) 0.138 (3.50) 0.168 (4.27) ** ** ** ** Hydraulic Design Manual Factor Galv Alt 1.3 1.6 2.2 2.8 3.4 ** ** ** ** 3.6 3.9 4.2 4.8 5.4 ** ** ** ** 14-8 Thickness Factor in (mm) Galv ** ** ** ** ** ** 0.109 (2.77) 2.24 0.138 (3.50) 2.84 0.168 (4.27) 3.54 0.188 (4.78) 3.81 0.218 (5.54) 4.42 0.249 (6.32) 5.05 0.280 (7.11) 5.68 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Estimated Service Life Corrugated Aluminum Pipe and Aluminum Structural Plate The service life of aluminum pipe and aluminum structural plate is a function of the pitting rate of the aluminum, which is less than 0.013 millimeter per year in the following environmental limits: ♦ 4.0 ≤ pH ≤ 9.0 ♦ resistivity ≥ 500 ohm-cm ♦ resistivity ≥ 25 ohm-cm (provided a free draining backfill material) ♦ no upper resistivity limits; soft waters not a problem Estimate interior service life (SLBMCI) and exterior service life (SLBMCE) using Equation 14-7 SL BMCI = SL BMCE = Equation 14-7: (metal thickness) 0.0005 in yr or 0.0127 mm yr The following table shows gage thickness and available structural plate thickness Aluminum Pipe Gage Thickness Item 460 – CMP Item 461 – Structural Plate Gage Thickness Gage Thickness (in) (mm) (in) (mm) 18 0.048 1.22 ** ** ** 16 0.06 1.52 ** ** ** 14 0.075 1.91 ** ** ** 12 0.15 2.67 ** 0.1 2.54 10 0.135 3.43 ** 0.125 3.18 0.164 4.17 ** 0.15 3.81 ** ** ** ** 0.175 4.45 ** ** ** ** 0.2 5.08 ** ** ** ** 0.225 5.72 ** ** ** ** 0.25 6.35 Hydraulic Design Manual 14-9 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Estimated Service Life Post-applied Coatings and Pre-coated Coatings The following table provides anticipated additional service life for post-applied and precoated coatings (SLPACI and SLPACE) for use in Equation 14-1 and Equation 14-2 Post-applied and Pre-coated Coatings Guide to Anticipated Service Life Add-On (additional years) Coating Interior (SLPACE) Exterior (SLPACE) Abrasion Level Level Level Level Level Bituminous 8-10 5-8 0-2 30 Polymer 10/10 28-30 10-15 0-5 30 Paving and Lining The following table provides additional service life for applied paving and lining (SLl) for use in Equation 14-1 Post-applied Paving and Lining Guide to Anticipated Service Life Add-On Paved Or Lined Interior Exterior Abrasion Level (SLLL) Level Level Level Level Bituminous Paved Invert 25 25 25 N/A Concrete Paved Invert 40 40 40 25 N/A 100% Bituminous Lined 25 25 25 N/A 100% Concrete Lined 50 50 50 35 N/A Hydraulic Design Manual 14-10 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Estimated Service Life Reinforced Concrete There is little technical data on methods to estimate service life for reinforced concrete In department experience when cast-in-place and precast reinforced conduit is used in appropriate environments, service life exceeds the original design life of the project (typically in excess of 50 years) Durability of reinforced concrete can be affected by acids, chlorides, and sulfate concentrations in the soil and water If the pH value is 6.5 or less, the use of porous concrete pipe with shell thickness of in (25 mm) or less is not advisable If the pH value is 5.5 or less, use of reinforced concrete without a protective coating of epoxy or other acceptable coating is not advisable Salt content of the soil and water can have a detrimental effect on reinforced concrete because the salt (with its chloride constituent) can permeate the concrete in time, threatening the embedded reinforcing steel Sulfate content in the soil or water can have a detrimental effect on reinforced concrete facilities The following table presents a guide for adjusting cement type and factor for sulfate content in soils and runoff Guide for Sulfate Resisting Concrete Water-soluble sulfate in Sulfate in water sample Type of Cement factor soil sample (%) (ppm) cement - 0.20 - 2,000 II Minimum required by specifications 0.20 - 0.50 2,000 - 5,000 V Minimum required by specifications II sacks 0.50 - 1.50 5,000 - 15,000 V Minimum required by specifications II sacks over 1.50 over 15,000 V sacks Plastic Pipe To date, the department has minimal long-term experience with plastic pipe applications More information will be provided as the department becomes aware of appropriate information However, this lack of information should not preclude the possible use of plastics that conform to AASHTO and ASTM specifications if there is solid indication that the particular installation will meet service life expectations Hydraulic Design Manual 14-11 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Installation Conditions Section Installation Conditions Introduction Pipe has four basic installation conditions, as illustrated in Figure 14-1 Figure 14-1 Pipe Installation Conditions Trench Trench installation of conduit is most preferred from the standpoint of structural advantage and long term operational costs In order to establish trench conditions, the minimum trench shapes must conform to the diagrams shown in Figure 14-2 Hydraulic Design Manual 14-12 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Installation Conditions Figure 14-2 Permissible Trench Shapes Positive Projecting (Embankment) Positive projecting installation, sometimes termed “embankment installation,” is the simplest technique and has the most economical first cost However, operationally, it does not serve to relieve any structural loading from above the conduit and may result in failure or high maintenance costs during the life of the structure Negative Projecting (Embankment) Negative projecting conditions are more costly than the positive projecting conditions Negative projection provides some loading relief from the conduit due to the frictional interface between the trench boundaries and the backfill See Figure 14-1 for a schematic of this effect Negative projection conditions normally become cost-effective only when fill heights approach 30 ft (10 m) Hydraulic Design Manual 14-13 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Installation Conditions Imperfect Trench The imperfect trench condition is usually more costly than any of the other three installation conditions shown As with negative projection installation, imperfect trench installation normally becomes cost-effective only when fill heights approach 30 ft (10 m) Bedding for Pipe Conduits In general, bedding for a conduit should comprise select, compact material that conforms to the external curvature of the conduit it supports This is important for both flexible and rigid conduits For a flexible conduit, irregularities or imperfections in the bedding usually can be accommodated by minor shape deformations in the conduit without damage to the structural integrity of the pipe For a rigid conduit, such irregularities or imperfections in the bedding cannot be accommodated because the conduit cannot reshape itself without structural failure Due to the compressive/tensile characteristics of rigid pipe under a load, critical shear zones can fail if bedding geometry is not in conformance with specifications See Figure 14-3 for a schematic illustration of this characteristic Figure 14-3 Critical Shear Stress Zones for Rigid Pipe Planned bedding should be supported thoroughly by specifications Bedding affects required reinforced concrete pipe strength The four recognized classes of bedding are shown in Figures 14-4 through 14-7 The most common classes of bedding are Class B and Class C Class C is the most economical and Class A the most expensive However, for a given fill height, Class A bedding requires the lowest reinforced concrete Hydraulic Design Manual 14-14 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Installation Conditions pipe strength, and Class C requires the greatest strength Base selection of bedding on designing the most cost-effective facility Figure 14-4 Class A Bedding Figure 14-5 Class B Bedding Hydraulic Design Manual 14-15 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Installation Conditions Figure 14-6 Class C Bedding Figure 14-7 Class C Bedding on Rock Foundation Hydraulic Design Manual 14-16 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Structural Characteristics Section Structural Characteristics Introduction Flexible pipe and rigid pipe have some common structural characteristics The following information provides general guidance on selecting appropriate strength of conduit However, you may need to coordinate efforts with structural designers to ensure structural adequacy and compatibility Corrugated Metal Pipe Strength Corrugated metal pipe (CMP) is structurally designed in accordance with AASHTO Section 12 Fill height tables are presented in the Conduit Strength and Durability document These fill height tables are based on the following minimum parameters: ♦ AASHTO Section 12 Design Guide - Service Load Design ♦ soil unit mass of 120 lb./cu.ft (1,922 kilograms per m3) ♦ 90% standard density proctor AASHTO T99 ♦ minimum internal factor of safety: wall area = 2.0, buckling = 2.0, and seam strength = 3.0 ♦ maximum height for pipe arch limited to 39,146 lb./sq.ft (191,531 kilograms per m2) of corner bearing pressure ♦ HS 20 and HS 25 live loading For structures not represented by tables and conditions outside of above referenced conditions, contact the Bridge Division, Structures Section Hydraulic Design Manual 14-17 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Structural Characteristics Concrete Pipe Strength The final design of reinforced concrete pipe walls is not specified in detail on the plans The required strength of the concrete pipe is indicated on the plans by the D-load that the pipe will be required to support in the test for acceptance With this designated loading, the manufacturer can determine the most economical structural design of the pipe walls and reinforcement that comply with the applicable American Society for Testing and Materials (ASTM) specification The D-load is written as a number followed by (-D) For example, consider the shorthand notation of 1350-D, which represents 1350 lb./ft of pipe length per foot of pipe diameter (lb./ft./ft.) For this example, multiply 1350 by the pipe diameter (in ft.) for the total allowable loading per foot of pipe length (65-D represents 65 N/m of pipe length per millimeter of diameter (N/m/mm) For this example, multiply 65 by the pipe diameter in mm to obtain the total allowable loading per meter of pipe length.) Design load (D-load) values have been computed for a range of conditions and are tabulated in the Conduit Strength and Durability document The D-load values depend primarily on the following: ♦ soil unit weight and height of fill above the pipe (dead load) ♦ live loads ♦ installation conditions ♦ trench widths ♦ bedding The soil weight used for preparing the tables is 120 lb./cu.ft (18,857 kN/m3) Live loads are determined using AASHTO methods, and the design loads for the various pipe diameters and corresponding fill heights are based upon the American Concrete Pipe Association Design Manual (Rev 1978) High Strength Reinforced Concrete Pipe When the required pipe strength exceeds a D-load of 3000 lb./ft./ft (140 N/m/mm), the structural design of the pipe can fall into a special design category This can increase the cost because such pipe is usually not a standard stock item with the manufacturer Often, refinement of parameters for high-strength pipe, such as bedding, soil weight, and/or trench width, is warranted because the cost of stronger pipe justifies a more refined analysis For such cases, even the use of Class A bedding may prove to be cost-effective Contact the concrete pipe manufacturer for assistance with estimates for the various design alternatives when earth loads require pipe strength greater than 3000 lb./ft./ft (140 N/m/mm) Hydraulic Design Manual 14-18 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Structural Characteristics Recommended RCP Strength Specifications Pipe strengths should be specified, as indicated in table below, to reduce the number of bid items and to simplify the administration of the project Recommended RCP Strength Specifications (Metric) For D-loads (lb./ft./ft.) from… …use …or Equivalent Class to 800 800 I 801 to 1,000 1,000 II 1001 to 1,350 1,350 III 1,351 to 2,000 2,000 IV 2001 to 3,000 3,000 V Recommended RCP Strength Specifications (Metric) For D-loads (N/m/mm) from… …use …or Equivalent Class to 40 40.0 I 40.1 to 50.0 50.0 II 50.1 to 65.0 65.0 III 65.1 to 100.0 100.0 IV 100.1 to 140.0 140.0 V For some projects, it may be justified to indicate the actual computed D-load for bidding purposes without adhering to the suggested increments above Generally, deviate from the suggested specification increments only when sufficient quantity of a pipe size warrants the special manufacturer of a specific D-load Manufacturing conditions vary from company to company Therefore, potential manufacturers should be contacted to confirm any suspected advantage Hydraulic Design Manual 14-19 TxDOT 4/2002 Chapter 14 — Conduit Strength and Durability Section — Structural Characteristics Strength for Jacked Pipe Pipe that must be jacked under an existing roadway embankment must endure an additional loading not considered for pipe that is simply placed during roadway construction For jacked pipe, there is the additional load of the axial or thrust load caused by the jacking forces applied during the construction Often, ordinary reinforced concrete pipe will serve for the purpose of jacked pipe Under some conditions, it may be worthwhile to consider specially fabricated fiberglass or synthetic material pipe for jacked pipe Become acquainted with the availability of various special pipe types in the project area For axial loads, the cross-sectional area of a standard concrete pipe wall is adequate to resist stresses encountered in normal jacking operations, if the following construction techniques are used To prevent localized stress concentrations, it is necessary to provide relatively uniform distribution of the axial loads around the periphery of the pipe This requires the following: ♦ pipe ends be parallel and square for uniform contact ♦ jacking assembly be arranged so that the jacking forces are exerted parallel to the pipe axis If excessive jacking pressures are anticipated due to long jacking distances, intermediate jacking stations should be provided Reinforced Concrete Box The Bridge Division issues and maintains culvert standard details for cast-in-place and precast reinforced concrete culverts These accommodate a range of fill heights from direct traffic up to as high as about 30 ft (9 m) for some boxes Consult the Bridge Division for conditions not covered by the standards Plastic Pipe Consult the Bridge Division concerning strength requirements for plastic pipe Hydraulic Design Manual 14-20 TxDOT 4/2002 ... Introduction to Hydraulic Design 1-5 Description 1-5 Hydraulic Design Manual 1-1 TxDOT 11/2002 Chapter — Manual Introduction Hydraulic Design Manual Section — About This Manual. . .Hydraulic Design Manual November 2002 Manual Notices Manual Notice 2002-2 To: Districts, Divisions and Offices From: Mary Lou Ralls, P.E Manual: Hydraulic Design Manual Effective... in this manual, please contact the Hydraulics Branch of the Bridge Division Manual Notice 2002-1 To: Districts, Divisions and Offices From: Mary Lou Ralls, P.E Manual: Hydraulic Design Manual