Shed runoff flow rate Q has been computed under the Rational Method using the equation:

Q = CiA

for a very long time, but ever so often, a new user would ask if this equation is dimensionally consistent.

In this equation, the units of Q is cfs (cubic feet per second, or ft³/sec). C is the runoff coefficient, which is dimensionless, i is the rainfall intensity in inches per hour (in/hr)), and A is the tributary watershed area, in acres. If the equation were dimensionally consistent, then shouldn’t the units of Q be (in*ac/hr)? If it is, then is in*ac/hr = ft³/sec? This is examined below.

Convert in*ac/hr to ft³/sec as follows:

Thus, strictly speaking, Q = 1.0083*CiA for English units, which is usually rounded to Q = CiA. Thus, Q = CiA is indeed dimensionally consistent. The Ration Method equation, however, slightly underestimates Q, by 0.83 percent, for English units.

Similarly, it may shown that the metric equation:

Q = (1/360)*CiA,

where Q is the watershed runoff flow rate with units of m³/sec, C is the dimensionless runoff coefficient, i is the rainfall rate in mm/hr, and A is the tributary watershed area in hectares, is dimensionally consistent, without the need for rounding. The Rational Method equation does not underestimate (or overestimate) Q for metric units.

BASIC Hydraulics aims to help students both to become proficient in the BASIC programming language by actually using the language in an important field of engineering and to use computing as a means of mastering the subject of hydraulics.

The book begins with a summary of the technique of computing in BASIC together with comments and listing of the main commands and statements. Subsequent chapters introduce the fundamental concepts and appropriate governing equations. Topics covered include principles of fluid mechanics; flow in pipes, pipe networks and open channels; hydraulic machinery; and seepage and groundwater flow.

Each chapter provides a series of worked examples consisting primarily of an introduction in which the general topic or specific problem to be considered is presented. A program capable of solving the problem is then given, together with examples of the output, sometimes for several different sets of conditions. Finally, in a section headed Program Notes the way the program is constructed and operates is explained, and the engineering lessons to be learned from the program output are indicated. Each chapter also concludes with a set of problems for the student to attempt.

This book is mainly intended for the first- and second-year undergraduate student of civil engineering who will be concerned with the application of fundamental fluid mechanics theory to civil engineering problems.

This manual provides guidance for the safe design and economical construction of retaining and flood walls. It is intended primarily for retaining walls which will be subjected to hydraulic loadings such as flowing water, submergence, wave action, and spray, exposure to chemically contaminated atmosphere, and/or severe climatic conditions. For the design of retaining walls which will not be subjected to hydraulic loadings or severe environmental conditions as described above, TM 5-818-1 may be used for computing the loadings and evaluating the stability of the structure.

Types of Walls. This manual presents design guidance for retaining walls and inland and coastal flood walls. Retaining walls are defined as any wall that restrains material to maintain a difference in elevation. A flood wall is defined as any wall having as its principal function the prevention of flooding of adjacent land.

Not specifically covered in this manual are seawalls which are defined as structures separating land and water areas, primarily designed to prevent erosion and other damage due to wave action. They are frequently built at the edge of the water, but can be built inland to withstand periods of high water. Seawalls are generally characterized by a massive cross section and a seaward face shaped to dissipate wave energy.

Coastal flood walls, however, are generally located landward of the normal high water line so that they are inundated only by hurricane or other surge tide and have the smooth-faced cantilever stems shown in this manual.

Types of Foundations. This manual describes procedures for the design of retaining and flood walls on shallow foundations, i.e., bearing directly on rock or soil. The substructure design of pile-founded walls is not included, but is covered in EM 1110-2-2906.

Flood Wall Guidance. A flood wall is treated as a special case of a retaining wall. Unless specifically noted, the guidance herein applies to both retaining and flood walls.

Geotechnical and Structural Aspects. Both geotechnical and structural aspects of wall design are included. Coordination between geotechnical engineers, structural engineers, and geologists in the design of retaining and flood walls is essential.

This manual provides technical guidance for specifying requirements and performing hydrographic surveys of USACE river and harbor navigation projects, water control projects, and shore protection projects.

Hydrographic surveys are performed to provide underwater site plan data for nearly all USACE civil works activities. These projects primarily include channel condition, measurement, payment, and clearance surveys of coastal Federal navigation channels, inland river and intra-coastal navigation projects, reservoirs, and underwater structural surveys at locks and dams. Also included are surveys for various coastal engineering projects, beach re-nourishment and restoration projects, shoreline protection structure construction (breakwaters and jetties), and river stabilization structures.

Hydrographic survey systems developed during the past decade have become increasingly complex, requiring the integration of acoustic multibeam sonar systems with differential GPS positioning systems and inertial vessel orientation/alignment systems. Acoustic depth measurements now utilize sophisticated beam forming phase detection, interferometric, synthetic aperture, and backscatter signal processing methods. The quality control and quality assurance guidance in this manual is intended to increase the overall confidence in reported navigation project clearances and the measured elevations of water control and shore protection projects.

Industry design and construction standards (American Concrete Institute [ACI], American Association of State Highway and Transportation Officials [AASHTO], etc.) are adopted as applicable to provide safe, reliable, and cost effective hydraulic structures for civil works projects.

Reinforced Concrete Hydraulic Structures (RCHS) are directly subjected to submergence, wave action, spray, icing or other severe climatic conditions, and sometimes to a chemically contaminated atmosphere. Satisfactory long-term service requires that the saturated concrete be highly resistant to deterioration due to daily or seasonal weather cycles and tidal fluctuations at coastal sites.

The often relatively massive members of RCHS must have adequate density and impermeability, and must sustain minimal cracking for control of leakage and for control of corrosion of the reinforcement. Most RCHS are lightly reinforced structures (reinforcement ratios less than 1%) composed of thick walls and slabs that have limited ductility compared to the fully ductile behavior of reinforced concrete buildings (in which reinforcement ratios are typically 1% or greater).

Typical RCHS are: stilling basin slabs and walls; concrete lined channels; submerged features of powerhouses and pump stations; spillway piers; spray and training walls; floodwalls; submerged features of intake and outlet structures (towers, conduits and culverts); lock walls; guide and guard walls; and submerged retaining walls and other structures used for flood barriers, conveying or storing water, generating hydropower, water borne transportation, and for restoring the ecosystem.

This manual describes typical loads for the design of RCHS. Load factors are provided. The load factors resemble those shown in ACI 318, but are modified to account for the serviceability needs of hydraulic structures and the higher reliability needed for critical structures.

RCHS typically have very long service lives. A service life of 100 years is the basis for the requirements of this manual. RCHS shall be designed with the strength design method in accordance with the ACI Standard and Report 318-14, Building Code Requirements for Structural Concrete and Commentary (ACI 318), except as specified hereinafter.

This manual provides guidance for the selection and use of waterstops and other preformed joint materials for preventing passage of excessive amounts of water, water-borne matter, gases, other fluids, and other unwanted substances into or through the joints of concrete structures.

Most concrete structures have contraction, expansion, and construction joints. Joints can be a path for unwanted matter, liquids, solids, and gaseous substances to enter and pass through the concrete joint and possibly cause damage to the integrity and serviceability of the structure. Waterstops and other preformed joint materials are a primary line of defense against the passage of excessive amounts of these substances. This manual provides information and data on the various waterstops, preformed compression seals, and other preformed joint materials; their shapes, sizes, and the physical properties that are available to the designers of concrete structures.

This manual provides guidance for stability analysis of concrete gravity structures. Stability refers to resistance to sliding and floatation, limits on the eccentricity of the resultant of the applied loads, and limits on the bearing capacity of the foundation materials. The manual applies to all types of structures founded on rock or soil, such as: dams, outlet works, navigation locks, floodwalls, and pumping stations. It is not applicable to piles or caissons, or to structures founded on these elements.

The manual is written to be compatible with risk-based planning and design methods currently being implemented within USACE. It consolidates and standardizes stability requirements, which were previously contained in several other publications. Changes contained in Chapters 3 and 4 will provide adequate safety factors for all types of structures and loading conditions, while reducing excess conservatism for infrequent loadings of short duration. This will result in project cost savings when compared to some structures designed using previous criteria. Stability criteria in other manuals is being revised to be consistent with this manual. In the interim, where there are conflicting stability criteria, the provisions of this manual shall govern.

This manual covers requirements for static methods used in stability analyses of hydraulic structures. The types of concrete structures addressed in this manual include dams, locks, retaining walls, inland floodwalls, coastal floodwalls, spillways, outlet works, hydroelectric power plants, pumping plants, and U-channels. The structures may be founded on rock or soil and have either flat or sloped bases. Pile-founded structures, sheet-pile structures, and footings for buildings are not included.

These requirements apply to all potential failure planes at or slightly below the structure/foundation interface. They also apply to certain potential failure planes within unreinforced concrete gravity structures. This manual defines the types and combination of applied loads, including uplift forces due to hydrostatic pressures in the foundation material. The manual defines the various components that enable the structure to resist movement, including anchors to the foundation. Most importantly, the manual prescribes the safety factors, which govern stability requirements for the structure for various load combinations. Also, guidance is provided for evaluating and improving the stability of existing structures.

The objective of this manual is to develop a guide for design and construction of levees. The manual is general in nature and not intended to supplant the judgment of the design engineer on a particular project.

The term levee as used herein is defined as an embankment whose primary purpose is to furnish flood protection from seasonal high water and which is therefore subject to water loading for periods of only a few days or weeks a year. Embankments that are subject to water loading for prolonged periods (longer than normal flood protection requirements) or permanently should be designed in accordance with earth dam criteria rather than the levee criteria given herein.

This engineer manual (EM) was written to provide guidance for determining if precipitation, coagulation, flocculation (PIC/F) systems are applicable and guidance on how to properly design, specify, and operate P/C/F systems to remove dissolved heavy metals from aqueous waste streams.

Chemical precipitation is the most common technique used for treatment of metal-contaminated waters (Patterson and Minear 1975, EPA 625/8-80-003, EPA 600/8-80- 042c, Peters et al. 1985, Patterson 1988). Chemical precipitation of heavy metals has long been used as the primary method of treating wastewaters in industrial applications, such as metal finishing and plating. Owing to this past success, chemical precipitation is often selected to remediate hazardous, toxic, and radioactive waste (HTRW) sites containing ground water contaminated by heavy metals or landfill leachate, or both.

For the precipitation process to be effective, an efficient solids removal process must be employed. To separate the solid and liquid phases of the wastestream, coagulation, flocculation, and clarification or filtration, or both, are typically used along with precipitation. Precipitation/coagulation/ flocculation (P/C/F) systems are often used as a pre-treatment step to stop metals from interfering with subsequent treatment processes (e.g., UV–oxidation or air stripping). Depending on the required treatment standards, a P/C/F system may also be used as the final stand-alone treatment.

This manual presents guidelines for calculation of the bearing capacity of soil under shallow and deep foundations supporting various types of structures and embankments. This information is generally applicable to foundation investigation and design conducted by Corps of Engineer agencies.

Principles for evaluating bearing capacity presented in this manual are applicable to numerous types of structures such as buildings and houses, towers and storage tanks, fills, embankments and dams. These guidelines may be helpful in determining soils that will lead to bearing capacity failure or excessive settlements for given foundations and loads.