This document provides an overview of topics to be covered in a 3-week professional engineering exam review session on hydrology and hydraulics. It will cover key aspects of hydrology including the hydrologic cycle, precipitation, runoff analysis using the Curve Number method, and peak discharge calculations. Hydraulics topics will include flow through common structures like weirs, orifices, and pipes. Example problems will be worked through for each major topic to illustrate concepts and calculations. Attendees are advised to review references and practice additional example problems.
This document discusses hydrograph concepts including:
- Defining a hydrograph as a graph showing variations in stream discharge over time.
- Components of a single peaked hydrograph from an isolated storm.
- Separating surface runoff, interflow, and groundwater flow.
- Estimating the concentration time of a catchment using the Izzard and Kirpich formulas.
- Defining valley storage as water temporarily stored in stream channels.
- Working through an example problem to calculate time of concentration and peak runoff rate.
1. Waves are disturbances that transfer energy through a medium, such as water. They can be regular (single frequency/height) or irregular/random (variable frequency/height).
2. Important wave parameters include wavelength, period, frequency, speed, height, amplitude, and water elevation.
3. Ocean waves are classified based on their period/frequency and include capillary, gravity, and infragravity waves.
4. Wind generates waves by transferring energy and momentum to water. Wave characteristics depend on wind speed, fetch (distance over which wind blows), and duration. Fully developed seas occur when energy input balances dissipation.
This document summarizes a study that used GIS and the Natural Resources Conservation Service Curve Number (NRCS-CN) method to estimate runoff in the Kardeh watershed in Iran. The study aimed to determine runoff depth using the NRCS-CN method with GIS and examine the effect of slope on runoff generation. Land use, soil, and slope maps were generated in GIS and used to assign CN values. Estimated runoff depths were compared to observed data and a positive correlation was found, though some estimated values differed from observed by over 50%. The results supported using the NRCS-CN method with GIS to estimate runoff in ungauged watersheds in the region.
This document provides an overview of reservoir engineering fundamentals including:
- Three types of reservoir fluids based on compressibility: incompressible, slightly compressible, and compressible.
- Three flow regimes in reservoirs: steady-state, unsteady-state, and pseudosteady-state.
- Common reservoir geometries that influence fluid flow including radial, linear, spherical, and hemispherical.
- Darcy's law and its applications to steady-state fluid flow in reservoirs, including for different fluid types and geometries.
Hec ras flood modeling little river newburyportWilliam Mullen
This document describes a HEC-RAS 2D flood modeling case study of the Little River in Newburyport and Newbury, Massachusetts. It summarizes the advantages of 2D modeling, details the HEC-RAS model setup including terrain and hydrologic inputs, and presents calibration results from a historic 2006 rainfall event. Next steps include running additional storm simulations and using the model to evaluate potential flood mitigation measures under future sea level and climate change scenarios.
Follow the path of California's first major water project that stretched from Mono Lake to Southern California, delivering the Owens River to support the growth & population of Los Angeles.
Flood Mapping via HEC-RAS Model and ArcGISLengthong KIM
This research was taken place along the lower Mekong river reach part in Cambodia. The purpose of the study is to evaluate the HEC-RAS performance whether it eligible for Cambodia flood studies or not.
This document discusses hydrograph concepts including:
- Defining a hydrograph as a graph showing variations in stream discharge over time.
- Components of a single peaked hydrograph from an isolated storm.
- Separating surface runoff, interflow, and groundwater flow.
- Estimating the concentration time of a catchment using the Izzard and Kirpich formulas.
- Defining valley storage as water temporarily stored in stream channels.
- Working through an example problem to calculate time of concentration and peak runoff rate.
1. Waves are disturbances that transfer energy through a medium, such as water. They can be regular (single frequency/height) or irregular/random (variable frequency/height).
2. Important wave parameters include wavelength, period, frequency, speed, height, amplitude, and water elevation.
3. Ocean waves are classified based on their period/frequency and include capillary, gravity, and infragravity waves.
4. Wind generates waves by transferring energy and momentum to water. Wave characteristics depend on wind speed, fetch (distance over which wind blows), and duration. Fully developed seas occur when energy input balances dissipation.
This document summarizes a study that used GIS and the Natural Resources Conservation Service Curve Number (NRCS-CN) method to estimate runoff in the Kardeh watershed in Iran. The study aimed to determine runoff depth using the NRCS-CN method with GIS and examine the effect of slope on runoff generation. Land use, soil, and slope maps were generated in GIS and used to assign CN values. Estimated runoff depths were compared to observed data and a positive correlation was found, though some estimated values differed from observed by over 50%. The results supported using the NRCS-CN method with GIS to estimate runoff in ungauged watersheds in the region.
This document provides an overview of reservoir engineering fundamentals including:
- Three types of reservoir fluids based on compressibility: incompressible, slightly compressible, and compressible.
- Three flow regimes in reservoirs: steady-state, unsteady-state, and pseudosteady-state.
- Common reservoir geometries that influence fluid flow including radial, linear, spherical, and hemispherical.
- Darcy's law and its applications to steady-state fluid flow in reservoirs, including for different fluid types and geometries.
Hec ras flood modeling little river newburyportWilliam Mullen
This document describes a HEC-RAS 2D flood modeling case study of the Little River in Newburyport and Newbury, Massachusetts. It summarizes the advantages of 2D modeling, details the HEC-RAS model setup including terrain and hydrologic inputs, and presents calibration results from a historic 2006 rainfall event. Next steps include running additional storm simulations and using the model to evaluate potential flood mitigation measures under future sea level and climate change scenarios.
Follow the path of California's first major water project that stretched from Mono Lake to Southern California, delivering the Owens River to support the growth & population of Los Angeles.
Flood Mapping via HEC-RAS Model and ArcGISLengthong KIM
This research was taken place along the lower Mekong river reach part in Cambodia. The purpose of the study is to evaluate the HEC-RAS performance whether it eligible for Cambodia flood studies or not.
The document discusses Darcy's law, which describes groundwater flow through porous media. It establishes that flow rate is proportional to hydraulic conductivity and hydraulic gradient. Darcy's law allows estimating flow velocity and travel time. The document also covers applications of Darcy's law, including describing saturated groundwater flow using partial differential equations and modeling steady state radial flow to a well.
The document discusses several key aspects of hydrology:
- Precipitation is the main driver of hydrologic processes and is formed as air cools and its ability to hold water decreases.
- Weather patterns result in different biomes and rainfall patterns across geographic regions.
- Water moves across and through soils via processes like infiltration, evaporation, transpiration, surface runoff, subsurface stormflow, and groundwater flow.
- The dominant runoff process depends on factors like rainfall intensity, soil saturation, and watershed characteristics, and can include Horton overland flow, saturation overland flow, or subsurface stormflow.
This document discusses surface runoff and stream gauging. It defines key terms like drainage basin, contour lines, stream ordering, and form factor. It describes how to delineate a basin using a topo map and assign stream orders. Factors that affect runoff include basin characteristics, climate, land use, soil and storage. Stream gauging involves measuring stage using staff gauges or recorders, and discharge using the velocity-area method by dividing the cross-section into vertical subsections.
This document discusses infiltration rate and equations. It defines infiltration rate as the speed at which water enters soil and describes common methods to measure or calculate it over time. These include Horton's equation, Phillips equation, Kostiakov equation, and Holtan's equation. It also introduces the concepts of cumulative infiltration and infiltration capacity curves. Finally, it discusses infiltration indices like the phi index and W index, which provide average infiltration rates for estimating runoff from storms.
This document discusses hydrology and the hydrological cycle. It defines hydrology as the science dealing with the occurrence, distribution, and movement of water on Earth. The hydrological cycle involves the constant circulation of water between the atmosphere and Earth's surface through evaporation, precipitation, and runoff. Factors like precipitation characteristics, catchment shape and size, topography, and geology affect the amount of runoff from a catchment area. Accurate measurement of rainfall and runoff is important for irrigation engineering design and management.
This document discusses hydrologic design storms and methods for developing design precipitation hyetographs. It defines key hydrologic concepts like return period, depth-duration-frequency curves, and SCS design storm methods. The SCS method involves selecting a standard SCS rainfall distribution type curve based on location and scaling it using the design storm depth to develop a hyetograph for the given duration and return period. The document provides an example of applying the SCS method to develop a 25-year, 24-hour hyetograph for Harris County, Texas.
Classification of Deltas. Deltas are a good sink/reservoir for Hydrocarbons; they also important Ecotones for various forms of living organisms. Presented here are the mechanisms responsible for shaping of deltas around the world.
The document discusses channel roughness and efficiency. It states that a river's velocity is not greatest at its start, as large boulders create a rougher channel shape that produces more friction than a smoother channel formed by clays and silt. The roughness coefficient is measured using Manning's 'n', which relates channel roughness to velocity. A river's channel efficiency is measured by finding its hydraulic radius, which is the ratio between the wetted perimeter and cross-sectional area of the channel.
This document discusses various techniques for measuring stream flow, which is the volume of water moving through a designated point over time. It describes common methods like the velocity-area method, using a weir, and the bucket method. It also outlines different types of meters that can directly measure flow properties like velocity, including pygmy meters, vortex meters, and current meters. Accurately measuring stream flow is important for applications like flood prediction, assessing water and sediment levels over time, and monitoring long-term climate changes. A combination of techniques may be needed to account for variability in flow across seasons.
The document discusses water requirements for crops and irrigation concepts. It provides definitions for key terms like gross commanded area, culturable commanded area, crop period, base period, delta, duty of water, and irrigation requirements for various crops. It lists the average delta values for important crops in Pakistan and discusses factors like water depth, number of irrigations, and seed and yield quantities for different kharif and rabi season crops.
This document discusses two methods for synthesizing unit hydrographs for ungauged areas: Snyder's method and the SCS dimensionless unit hydrograph method. Snyder's method uses empirical equations relating basin characteristics like length, slope, and storage to calculate the basin lag, peak discharge, and time base of the unit hydrograph. The SCS method uses a standard dimensionless unit hydrograph curve and the basin's time of concentration to develop a triangular unit hydrograph. The document provides an example of applying Snyder's method and develops a 30-minute triangular unit hydrograph using SCS methods for a given watershed area and time of concentration.
This document provides an overview of groundwater flow concepts including:
- Derivation of the Laplace equation and equations for steady and unsteady confined and unconfined groundwater flow from Darcy's law and the continuity equation.
- Definitions of specific yield, specific storage, and storativity and their relationships.
- Expressions for one-dimensional, two-dimensional, and seepage flow.
- Analytical solutions for steady one-dimensional flow in confined and unconfined aquifers with constant and variable thickness.
This document provides an overview of the field of hydrology. It defines hydrology as the study of the occurrence, circulation, distribution, and properties of water on Earth. The document then discusses the history of hydrology, highlighting early civilizations that developed irrigation systems, and scientists throughout history who contributed to understanding of hydrologic processes. It also outlines the main branches and applications of hydrology, and provides details on key hydrologic concepts like the water cycle, watersheds, and global patterns of water distribution and availability.
This document provides an overview of a presentation on using the HEC-RAS hydraulic modeling software for managers. It discusses the benefits of understanding hydraulic modeling including for planning, risk reduction, and environmental assessments. It also outlines the agenda which will define key hydraulic and modeling concepts, explain what HEC-RAS is and what it can be used for, what is needed to use it, concerns for managers, and where to find help. The presentation will provide managers with a basic understanding of HEC-RAS and its uses.
Sediment is any particulate matter that can be transported by fluid flow and eventually deposited. There are four main categories of sediments based on size: gravel, sand, silt, and clay. Incipient motion, or the initial movement of sediment particles, is important to studying sediment transport and channel design. Two main approaches to modeling incipient motion are the shear stress approach and velocity approach. Shields developed a widely used diagram relating the critical shear stress needed to initiate motion to other dimensionless parameters like particle size, fluid properties, and sediment density. White's analysis also models critical shear stress as proportional to particle size. The velocity approach uses field surveys of permissible flow velocities before sediment starts moving in different channel materials.
Lec-10-Week (7)( Hydraulics of water Distribution System).pdfKkkhanHan
The document discusses the design of water distribution systems. It states that the design must satisfy water needs and minimum residual pressure at all points. It discusses pressures, velocities, and the Hazen-Williams equation for calculating head loss in pipes. Hardy's Cross Method for designing pipe networks is also explained, with the basic principle being that the sum of inflows equals outflows at nodes and the sum of head losses around loops must be zero. Steps of the Hardy's Cross Method procedure are provided.
Hydrological cycle- Meteorological measurements – Requirements, types and forms of Precipitation-Rain Gauges-Spatial analysis of rainfall data using Thiessen and Isohyetal methods Infiltration-Infiltration Index-Interception-Evaporation, Watershed, catchment and basin - Catchment characteristics - factors affecting runoff – Runoff estimation using empirical
This document discusses well hydraulics and advanced hydrogeology concepts. It defines key terms like static water level, pumping water level, drawdown, well yield, and specific capacity. It describes the cone of depression that forms during pumping and how aquifer characteristics like transmissivity and storage coefficient can be estimated from pump tests. It presents the Thiem, Theis and Cooper-Jacob equations that describe confined and unconfined steady-state and non-steady radial groundwater flow. Factors that can cause real aquifers to deviate from the assumptions of these models, like recharge, are also addressed.
Characteristics of sharp weirs and the hydraulic jumpDickens Mimisa
This document summarizes experiments conducted on sharp crested weirs and the hydraulic jump. It includes an experiment on a V-notch weir that measured discharge rates and calculated coefficients. Graphs were plotted showing relationships between head and discharge. The experiment also examined a broad crested weir, measuring effects of width and step height on discharge coefficients. Procedures, results, and conclusions are discussed to analyze weir properties and flow characteristics.
Driver Vehicle (Transportation Engineering Dr.Lina Shbeeb)Hossam Shafiq I
The document discusses several key aspects of the human component in transportation systems. It describes humans as one of the three main components of traffic systems, along with roadways and vehicles. Humans act as drivers, passengers, pedestrians, and cyclists. The document outlines factors that influence perception-reaction times, such as age, environment, visual acuity, and complexity of the situation. It also discusses design considerations for factors like road sign legibility and vehicle characteristics that affect road design.
The document discusses Darcy's law, which describes groundwater flow through porous media. It establishes that flow rate is proportional to hydraulic conductivity and hydraulic gradient. Darcy's law allows estimating flow velocity and travel time. The document also covers applications of Darcy's law, including describing saturated groundwater flow using partial differential equations and modeling steady state radial flow to a well.
The document discusses several key aspects of hydrology:
- Precipitation is the main driver of hydrologic processes and is formed as air cools and its ability to hold water decreases.
- Weather patterns result in different biomes and rainfall patterns across geographic regions.
- Water moves across and through soils via processes like infiltration, evaporation, transpiration, surface runoff, subsurface stormflow, and groundwater flow.
- The dominant runoff process depends on factors like rainfall intensity, soil saturation, and watershed characteristics, and can include Horton overland flow, saturation overland flow, or subsurface stormflow.
This document discusses surface runoff and stream gauging. It defines key terms like drainage basin, contour lines, stream ordering, and form factor. It describes how to delineate a basin using a topo map and assign stream orders. Factors that affect runoff include basin characteristics, climate, land use, soil and storage. Stream gauging involves measuring stage using staff gauges or recorders, and discharge using the velocity-area method by dividing the cross-section into vertical subsections.
This document discusses infiltration rate and equations. It defines infiltration rate as the speed at which water enters soil and describes common methods to measure or calculate it over time. These include Horton's equation, Phillips equation, Kostiakov equation, and Holtan's equation. It also introduces the concepts of cumulative infiltration and infiltration capacity curves. Finally, it discusses infiltration indices like the phi index and W index, which provide average infiltration rates for estimating runoff from storms.
This document discusses hydrology and the hydrological cycle. It defines hydrology as the science dealing with the occurrence, distribution, and movement of water on Earth. The hydrological cycle involves the constant circulation of water between the atmosphere and Earth's surface through evaporation, precipitation, and runoff. Factors like precipitation characteristics, catchment shape and size, topography, and geology affect the amount of runoff from a catchment area. Accurate measurement of rainfall and runoff is important for irrigation engineering design and management.
This document discusses hydrologic design storms and methods for developing design precipitation hyetographs. It defines key hydrologic concepts like return period, depth-duration-frequency curves, and SCS design storm methods. The SCS method involves selecting a standard SCS rainfall distribution type curve based on location and scaling it using the design storm depth to develop a hyetograph for the given duration and return period. The document provides an example of applying the SCS method to develop a 25-year, 24-hour hyetograph for Harris County, Texas.
Classification of Deltas. Deltas are a good sink/reservoir for Hydrocarbons; they also important Ecotones for various forms of living organisms. Presented here are the mechanisms responsible for shaping of deltas around the world.
The document discusses channel roughness and efficiency. It states that a river's velocity is not greatest at its start, as large boulders create a rougher channel shape that produces more friction than a smoother channel formed by clays and silt. The roughness coefficient is measured using Manning's 'n', which relates channel roughness to velocity. A river's channel efficiency is measured by finding its hydraulic radius, which is the ratio between the wetted perimeter and cross-sectional area of the channel.
This document discusses various techniques for measuring stream flow, which is the volume of water moving through a designated point over time. It describes common methods like the velocity-area method, using a weir, and the bucket method. It also outlines different types of meters that can directly measure flow properties like velocity, including pygmy meters, vortex meters, and current meters. Accurately measuring stream flow is important for applications like flood prediction, assessing water and sediment levels over time, and monitoring long-term climate changes. A combination of techniques may be needed to account for variability in flow across seasons.
The document discusses water requirements for crops and irrigation concepts. It provides definitions for key terms like gross commanded area, culturable commanded area, crop period, base period, delta, duty of water, and irrigation requirements for various crops. It lists the average delta values for important crops in Pakistan and discusses factors like water depth, number of irrigations, and seed and yield quantities for different kharif and rabi season crops.
This document discusses two methods for synthesizing unit hydrographs for ungauged areas: Snyder's method and the SCS dimensionless unit hydrograph method. Snyder's method uses empirical equations relating basin characteristics like length, slope, and storage to calculate the basin lag, peak discharge, and time base of the unit hydrograph. The SCS method uses a standard dimensionless unit hydrograph curve and the basin's time of concentration to develop a triangular unit hydrograph. The document provides an example of applying Snyder's method and develops a 30-minute triangular unit hydrograph using SCS methods for a given watershed area and time of concentration.
This document provides an overview of groundwater flow concepts including:
- Derivation of the Laplace equation and equations for steady and unsteady confined and unconfined groundwater flow from Darcy's law and the continuity equation.
- Definitions of specific yield, specific storage, and storativity and their relationships.
- Expressions for one-dimensional, two-dimensional, and seepage flow.
- Analytical solutions for steady one-dimensional flow in confined and unconfined aquifers with constant and variable thickness.
This document provides an overview of the field of hydrology. It defines hydrology as the study of the occurrence, circulation, distribution, and properties of water on Earth. The document then discusses the history of hydrology, highlighting early civilizations that developed irrigation systems, and scientists throughout history who contributed to understanding of hydrologic processes. It also outlines the main branches and applications of hydrology, and provides details on key hydrologic concepts like the water cycle, watersheds, and global patterns of water distribution and availability.
This document provides an overview of a presentation on using the HEC-RAS hydraulic modeling software for managers. It discusses the benefits of understanding hydraulic modeling including for planning, risk reduction, and environmental assessments. It also outlines the agenda which will define key hydraulic and modeling concepts, explain what HEC-RAS is and what it can be used for, what is needed to use it, concerns for managers, and where to find help. The presentation will provide managers with a basic understanding of HEC-RAS and its uses.
Sediment is any particulate matter that can be transported by fluid flow and eventually deposited. There are four main categories of sediments based on size: gravel, sand, silt, and clay. Incipient motion, or the initial movement of sediment particles, is important to studying sediment transport and channel design. Two main approaches to modeling incipient motion are the shear stress approach and velocity approach. Shields developed a widely used diagram relating the critical shear stress needed to initiate motion to other dimensionless parameters like particle size, fluid properties, and sediment density. White's analysis also models critical shear stress as proportional to particle size. The velocity approach uses field surveys of permissible flow velocities before sediment starts moving in different channel materials.
Lec-10-Week (7)( Hydraulics of water Distribution System).pdfKkkhanHan
The document discusses the design of water distribution systems. It states that the design must satisfy water needs and minimum residual pressure at all points. It discusses pressures, velocities, and the Hazen-Williams equation for calculating head loss in pipes. Hardy's Cross Method for designing pipe networks is also explained, with the basic principle being that the sum of inflows equals outflows at nodes and the sum of head losses around loops must be zero. Steps of the Hardy's Cross Method procedure are provided.
Hydrological cycle- Meteorological measurements – Requirements, types and forms of Precipitation-Rain Gauges-Spatial analysis of rainfall data using Thiessen and Isohyetal methods Infiltration-Infiltration Index-Interception-Evaporation, Watershed, catchment and basin - Catchment characteristics - factors affecting runoff – Runoff estimation using empirical
This document discusses well hydraulics and advanced hydrogeology concepts. It defines key terms like static water level, pumping water level, drawdown, well yield, and specific capacity. It describes the cone of depression that forms during pumping and how aquifer characteristics like transmissivity and storage coefficient can be estimated from pump tests. It presents the Thiem, Theis and Cooper-Jacob equations that describe confined and unconfined steady-state and non-steady radial groundwater flow. Factors that can cause real aquifers to deviate from the assumptions of these models, like recharge, are also addressed.
Characteristics of sharp weirs and the hydraulic jumpDickens Mimisa
This document summarizes experiments conducted on sharp crested weirs and the hydraulic jump. It includes an experiment on a V-notch weir that measured discharge rates and calculated coefficients. Graphs were plotted showing relationships between head and discharge. The experiment also examined a broad crested weir, measuring effects of width and step height on discharge coefficients. Procedures, results, and conclusions are discussed to analyze weir properties and flow characteristics.
Driver Vehicle (Transportation Engineering Dr.Lina Shbeeb)Hossam Shafiq I
The document discusses several key aspects of the human component in transportation systems. It describes humans as one of the three main components of traffic systems, along with roadways and vehicles. Humans act as drivers, passengers, pedestrians, and cyclists. The document outlines factors that influence perception-reaction times, such as age, environment, visual acuity, and complexity of the situation. It also discusses design considerations for factors like road sign legibility and vehicle characteristics that affect road design.
Estimating sewage discharge and peak drainage dischargeAnkit Gola
This document discusses methods for estimating sewage discharge and drainage/runoff. It explains that sewage is estimated based on water supplied plus additions from other sources and minus subtractions. Drainage is estimated using factors like rainfall intensity, duration, soil moisture, and catchment area. The Rational Method and empirical formulas like Dickens are presented to calculate peak runoff rates based on these factors and the imperviousness of surfaces. An example application of the Rational Method to a 36 hectare district with maximum 5 cm/hr rainfall is also provided.
A weir is a structure in an open channel that causes water to pool. As flow rate increases, the depth of water above the weir increases. Weirs are classified based on their crest shape as either sharp-crested or broad-crested. Common types of sharp-crested weirs include rectangular, V-notch, and trapezoidal weirs. Broad-crested weirs are robust structures that span the full channel width and are well-suited for measuring river discharge. Flow rate calculations using weirs can provide useful data for applications like flood control, hydroelectric projects, irrigation, and environmental studies.
Lec 04 Geometric Design (Transportation Engineering) Hossam Shafiq I
This document discusses various aspects of geometric design of highways including static characteristics like lane widths and vertical clearance, and kinematic characteristics like acceleration and dimensions of freeway ramps. It also covers sight distances including stopping sight distance, decision sight distance, and passing sight distance. Finally, it discusses functional classification of highways based on their role in providing mobility versus accessibility and classifications for rural and urban roads.
(1) Drop structures are used in canals to lower the water level along its course. There are several types of drop structures including vertical drops, inclined drops, piped drops, and farm drops.
(2) The main types of vertical drops discussed are the common straight drop, Sarda-type fall, and YMGT-type drop. Inclined drops include common chutes, rapid fall drops, and stepped cascades. Piped drops can be well drops or pipe falls.
(3) Each type has specific design considerations like crest shape and length, basin/stilling pool dimensions, upstream and downstream protections works, and guidelines for selection based on discharge and design head.
This document provides an overview of different seepage theories used in the design of hydraulic structures. It discusses three main theories: 1) Bligh's creep theory, which assumes seepage follows the base contour of the structure; 2) Lane's weighted creep theory, which applies a weighting factor to horizontal seepage; and 3) Khosla's theory, which models seepage using streamlines and flow nets derived from the Laplace equation. The document explains how each theory can be used to calculate hydraulic gradients, uplift pressures, and ensure safety against piping and structural failure. Examples are provided to demonstrate applying the theories to calculate uplift pressures and required floor thickness at different points.
There are various irrigation methods that apply water to crops in different ways. The most common methods are surface irrigation, sprinkler irrigation, and subsurface irrigation. Surface irrigation involves flooding fields and makes up about 90% of irrigated areas. Sprinkler irrigation applies water under pressure and is used on about 5% of irrigated land. When choosing an irrigation method, factors like water supply, topography, climate, soils, crops, economics, and local traditions must be considered. Drip irrigation is the most efficient method, applying water directly to plant roots and minimizing losses, making it suitable for water-scarce areas.
The document discusses various methods of irrigation including surface, subsurface, sprinkler, and trickle irrigation. Surface irrigation methods include uncontrolled flooding, border strip, check, basin, and furrow irrigation. Subsurface irrigation applies water directly below the soil surface. Sprinkler irrigation sprays water into the air to fall on the soil surface. Trickle irrigation uses drippers to supply water directly to the soil at low rates. The choice of irrigation method depends on factors like field size/shape, soil characteristics, water availability, crop type, costs, and farmer experience.
Chapter 6 concrete dam engineering with examplesMohsin Siddique
This document provides an overview of concrete dam engineering. It begins by outlining the key learning outcomes which are to understand dam classification, selection criteria, ancillary works, and forces acting on dams. It then defines what a dam is and discusses the types of dams including gravity, arch, buttress, and embankment dams. It describes the various components of dams such as spillways and outlets. It also covers the forces acting on dams including primary loads from water, self-weight, and seepage, as well as secondary loads from sediment, thermal effects, and seismic loads. It concludes by discussing the analysis of gravity dams and safety criteria for overturning, sliding, crushing, and tension.
This document discusses methods for estimating peak or flood discharge in rivers. It describes 6 main approaches: 1) Using physical conditions from past floods, 2) Flood discharge formulae based on catchment area, 3) Flood frequency studies using probability concepts, 4) The unit hydrograph method, 5) The rational formula, and 6) The modified rational formula which includes a storage coefficient. Examples are provided for each method to illustrate how to estimate peak discharge values.
1) The document discusses groundwater flow to wells and pumping tests. It covers basic well hydraulics, assumptions of groundwater flow, and equations for confined, unconfined, and leaky aquifers.
2) The Theis and Jacob methods are presented for analyzing pumping test data from confined aquifers, while the Hantush and Walton methods are used for leaky aquifers.
3) Pumping tests are important to determine an aquifer's hydraulic properties and long-term well yield.
This document describes an experiment to determine the discharge and coefficient of discharge for a suppressed rectangular weir. The objective is to measure the discharge coefficient 'Cd' for the suppressed rectangular weir model installed in a hydraulic tilting flume. Five different flow rates will be used to measure the water surface elevation above the weir crest. Observations such as flow rate, water surface elevation, and weir dimensions will be recorded. The data will then be used to calculate theoretical discharge and measured discharge to find the coefficient of discharge. Results will be analyzed by plotting flow rate versus water surface elevation on a log-log scale and checking if the average Cd value is within the recommended range.
1) The document outlines a 5-step method for designing a simple stormwater drainage system: analyzing the catchment area, assessing surface type, determining rainfall intensity, calculating stormwater production, and sizing drains.
2) An example calculates the time of concentration, design peak runoff rate, and discharge capacity of a proposed drain for a 12 hectare residential catchment area.
3) The method allows estimating stormwater flows and sizing drains using common terrain data and standard formulas involving runoff coefficients, rainfall intensities, and hydraulic properties.
The document discusses components of runoff including direct runoff and base flow. It describes factors affecting runoff such as precipitation characteristics, land use, topography, and catchment size and storage. Methods for computing runoff are described including the Rational Method, infiltration indices method, SCS Curve Number method, and hydrograph analysis. The Rational Method uses a runoff coefficient and rainfall intensity to estimate peak flow. The SCS Curve Number method relates rainfall to runoff based on soil and land use characteristics. Hydrograph analysis involves plotting stream discharge over time to analyze watershed response to rainfall. Examples are provided to illustrate applying these runoff computation methods.
1) The Aswan High Dam was built in Egypt in the 1960s to control flooding of the Nile River and enable irrigation and hydroelectric power generation. It is an embankment dam that is 111m tall and creates Lake Nasser, holding 132 cubic km of water.
2) Sedimentation in the reservoir is a major issue, with the dam trapping between 80-98% of sediments carried by the Nile. This reduces sediments flowing to the Nile delta and causes problems like coastal erosion.
3) To prolong the economic life of the dam, various sediment management techniques can be used such as altering dam operations to sluice sediments through during high flow periods, dredging sediments
1
KNE351 Fluid Mechanics 1
Laboratory Notes
Broad-Crested Weir
This booklet contains instructions and notes for the experiment listed above.
Additional material relating to laboratory work will be delivered during the
course. The expectations regarding lab work and reporting are described in a
separate document,‘KNE351. FLUIDMECHANICS: Laboratory Method and
Reporting’, which will also be circulated at the beginning of the course. It is
expected that all students study these notes and complete the pre-lab component
prior to the laboratory session. An overview of the laboratory equipment will
be provided at the beginning of each session.
A D Henderson
2
1. Learning Objectives
1. Observe and understand the behaviour of a real fluid flowing over a broad-crested weir,
2. Model this behaviour employing the Continuity and Bernoulli (Energy) Principles to
predict the flow rate from depth measurements.
3. Evaluate these predictions by comparing with measured values and use Specific Energy
to explain the changing nature of the flow over the weir.
2. Introduction
The theory of non-uniform flow in channels is covered by the course text, by many other fluid
mechanics texts, and by several web sites.
The specific energy, E, is the energy at a channel cross-section referred to the base of the
channel (in contrast to the Bernoulli equation, which is referred to a fixed horizontal datum).
The expression given for E is actually an approximation valid for small bed slopes. You've
measured the flume slope, and should examine this approximation in your report. A hydrostatic
pressure distribution is assumed, and you should also examine the validity of this assumption. If
the streamlines are not parallel, then the accelerative forces will modify the pressure - depth
relationship.
In general, two conjugate flows depths satisfy the specific energy equation for a given value of
the specific energy. The greater depth is associated with subcritical flow, and the shallower
depth with supercritical flow. At the critical depth the conjugate depths are equal, and the
discharge for the given specific energy is a maximum.
Broad crested weirs are used as a method of flow measurement in open channel flows. If the
weir is sufficiently high and long, the free surface will drop to critical depth. If the height of
the upstream flow is measured, then the flow rate can be determined.
3
3. Apparatus
• Water flume comprising of pump, control valve, venturi and v-notch flow meters,
downstream control gate.
• depth gauges
• 2 vertical water manometers
• 2 total head tubes
4. Preparation
Examine and sketch the layout of the channel and associated flow measuring equipment.
Measure the channel width and note significant geometrical parameters of the nozzle venturi
meter and V-notch weir. Note the directions of readings of all measuring scales.
a. Measure the channel, weir dimensions, a.
This document discusses methods for conducting and analyzing aquifer tests. It begins by listing objectives of aquifer tests such as measuring hydraulic parameters and determining aquifer properties. It then covers considerations for planning a test and equipment requirements. The document explains concepts such as drawdown, transmissivity, and storativity. It presents equations for analyzing confined and unconfined aquifers, including Theis, Cooper-Jacob, and Neuman models. Finally, it lists some common programs that can be used to analyze aquifer test data.
Analytical modelling of groundwater wells and well systems: how to get it r...Anton Nikulenkov
Aquifer tests are probably the most widely used methods to obtain hydrogeological properties that are vital for any mine dewatering or environmental impact assessments. Numerous softwares and methods currently exist that provide quick and easy tests interpretation by fitting theoretical and measured drawdown curves. However, misinterpreting a-priory groundwater concepts and not accounting correctly for such factors as skin-effect, well storage or partial penetration may result in hydraulic conductivity errors by several hundred precents. As illustrated by case studies from WA, both numerical and analytical models generally suffer from non-uniqueness that can be overcome by understanding a-priory groundwater concepts and implementing them appropriately into the interpretation algorithms.
The presentation also discusses an analytical approach for well systems design. The methodology is presently incorporated in ANSDIMAT software package that is developed by the Russian Academy of Sciences. The method uses standard and research analytical solutions and it is based on the principle of superposition. Unlike numerical models, the method allows calculating drawdowns inside a pumping well and regional drawdowns, for example, on an open pit contour. A particle tracking component, incorporated into the methodology, provides a practical alternative to numerical models for simplified environmental impact assessments.
This document provides guidance on deck drainage design for bridges. It discusses analyzing runoff and calculating gutter flow rates. It also examines the capacity of various deck drainage features like grate inlets, sheet flow, gutters, scuppers, and drain pipes. Equations are presented to calculate flow for these drainage elements based on factors like cross slope, depth, and clear opening area. Design recommendations include avoiding sheet flow across decks and ensuring drainage features can accommodate expected flow loads.
This document discusses watersheds and concepts related to watershed hydrology. It begins by defining a watershed as a drainage area that contributes runoff to an outlet point. It then discusses key characteristics of watersheds including size, shape, slope, soils and land use. The document also covers watershed delineation, functions of watersheds, types of watersheds, and hydrologic analysis parameters such as outfall and watershed boundary. Finally, it discusses runoff estimation methods including the Rational Method and provides examples of applying the Rational Method to calculate peak runoff rates.
A pumping test was conducted to determine the permeability of an unconfined aquifer. Observations from the test included a discharge of 240 m3/hour from a well with a diameter of 20 cm. The original water surface level was 240.5 m, and dropped to 235.6 m at the pumping well. An observation well 50 m away recorded a water level of 239.8 m. Using these observations and equations for unconfined radial flow, the permeability was calculated to be 49.13 m/day. Assuming a radius of influence of 300 m instead led to an error of 9.1% in the calculated permeability. The actual radius of influence based on observations was 154 m.
This document provides information about well hydraulic flow and radial flow analysis from pumping tests. It discusses key concepts like unsteady and steady state flow, assumptions of the radial flow model, and analytical solutions for confined and unconfined aquifers. Methods like Theis and Jacob are presented to analyze pumping test data to determine aquifer properties like transmissivity and storativity. Examples are given to demonstrate how these methods are applied. References on groundwater hydrology and related topics are also provided.
Hydrologic Design of a Percolation TankC. P. Kumar
The document discusses the design of percolation tanks for artificial groundwater recharge. It provides details on:
1. The basic requirements for an effective percolation tank design, including the availability of surface water runoff and suitable hydrogeological conditions.
2. The steps involved in hydrologic design of a percolation tank, which include calculating the tank capacity based on catchment area and rainfall, designing the embankment dimensions, and checking for stability.
3. Design considerations like embankment slopes, spillway sizing, and locating the saturation line for stability. An example design calculation is also provided.
This document discusses floods and methods for estimating peak flood discharge. It begins by defining a flood and design flood. It then describes various methods for estimating peak flood discharge, including using physical indicators, empirical formulas, unit hydrographs, the rational method, and flood frequency studies. As an example of applying the rational method, it calculates the peak discharge for a culvert project in Alberta, Canada with a 50-year return period. It also provides an example of using Gumbel's extreme value distribution to estimate flood discharges with 100-year and 150-year return periods based on annual maximum flood data from 1951-1977.
The document discusses various methods for analyzing rainfall and runoff data in hydrology. It describes hyetographs and mass curves as ways to present rainfall intensity over time. Point rainfall data represents daily/weekly rainfall values in bar diagrams. Intensity-duration-frequency curves relate rainfall intensity, duration and probability. Depth-area-duration curves show the relationship between rainfall depth, area and duration. Infiltration and factors affecting it are also discussed. Common methods for measuring infiltration include single tube and double tube infiltrometers. Empirical equations, tables and regression models are presented for estimating runoff from rainfall-runoff data.
The document describes a physical model facility constructed to study coastal inlets. The facility includes a 46-m by 99-m concrete basin with adjustable bathymetry. Sensors measure waves, currents and water levels. Studies examine how changes to channel alignment or structures impact flows. The facility can model specific inlets or perform generic studies, and has been used to examine issues like bank erosion or spit development. It aims to efficiently study inlet hydraulics and sedimentation.
Non equilibrium equation for unsteady radial flowAbhishek Gupta
This document discusses unsteady radial flow in aquifers and methods for analyzing pumping test data. It describes equations for confined, unconfined, and leaky aquifers. The Theis and Cooper-Jacob methods are presented for analyzing confined aquifer data using type curves. For unconfined aquifers, Neuman's equation and the Penman method are described. The Hantush-Jacob solution and Walton graphical method are provided for analyzing pumping tests in leaky aquifers.
Irrigation water measurement is essential for determining how much water to apply to crops and for field experiments. Water can be measured by volume per unit of time for flowing water, or by total volume for stationary water. Common units include cubic meters per second. Accurate measurement requires choosing an appropriate technique depending on the volume of water, desired accuracy, and financial resources. Methods include the direct volumetric method, velocity-area method using floats or current meters, water meters, venturi meters, and tracer techniques.
This document provides an overview of groundwater hydrology and aquifer systems. It discusses key topics such as:
- Aquifer parameters like porosity, hydraulic conductivity, and storage coefficients.
- Governing equations for groundwater flow including Darcy's Law and the Dupuit equation for unconfined flow.
- Vertical zones of subsurface water and soil moisture relationships.
- Characteristics of confined and unconfined aquifers.
- Flow nets as a graphical tool for analyzing groundwater flow patterns.
The document serves as an introduction to analyzing groundwater resources and flow using fundamental hydrogeological principles.
[Peter fritz, xiong_zheng]_a_finite_element_framew(book_fi)Zagazig University
This document describes a finite element framework called IMAGINE developed using object-oriented programming. It was created by Peter Fritz and Xiong Zheng at the Swiss Federal Institute of Technology. The framework includes modules for documentation, an object database, a development environment, finite element kernel, geometric modeling, postprocessing, project management, and a user interface. It was designed using object-oriented principles to create a flexible and reusable system for finite element analysis applications.
This document describes a procedure for developing a conceptual model of a river system for flood control purposes using a case study of the Demer River in Belgium. Key points:
- A conceptual model was developed based on simulations from a detailed full hydrodynamic model to reduce computation time for real-time flood control applications.
- The conceptual model was developed through identifying representative discharges, storage points, and hydraulic structures from the river network and calibrating it using a limited number of full model simulations.
- The performance of the conceptual model was evaluated against historical flood events and showed close agreement with the full model, enabling its use for real-time flood control applications requiring many model iterations.
Structures placed in channels can control or measure water flow. Common structures include weirs and orifices. Weirs have a crest over which water flows. As head increases, flow increases dramatically for weirs. Sharp-crested weirs come in triangular, rectangular, and trapezoidal shapes. Broad-crested weirs support flow longitudinally. Orifices are openings where flow occurs. At low heads, orifices can act as weirs. Pipes also control flow as head loss from entrance, bends, and friction must be considered. Multiple flow regimes like weir, orifice, and full pipe flow apply for drop inlet spillways depending on head. Rockfill outlets provide energy dissipation
This document discusses key hydrologic concepts and quantities important for flood forecasting. It explains the hydrologic cycle and its components like infiltration, evaporation and transpiration. It also discusses watershed characteristics that influence runoff like area, slope and land use. Finally, it describes the combination of precipitation and antecedent moisture conditions that can lead to flooding, and how forecasts must consider both short-term weather and long-term hydrologic patterns.
This document discusses calibration and data preparation for hydrological modeling. It describes the calibration process, including estimating parameter values to minimize differences between observed and simulated streamflows. It also outlines generating time series data for mean areal precipitation, temperature, and potential evaporation using various algorithms and checking for consistency. The goal of calibration is to match historical data and improve accuracy versus precision of hydrological simulations.
Channel routing methods simulate the movement of flood waves through channels using equations like the continuity equation. There are two main types: hydrologic routing which uses empirical relationships between inflow, outflow, and storage, and hydraulic routing which uses the momentum equation to model actual water movement physics more accurately. Common routing methods include Modified Puls, Kinematic Wave, Muskingum, and Muskingum-Cunge, which apply combinations of the continuity, momentum, and other equations to calculate outflow hydrographs from inflow hydrographs.
Information and Communication Technology in EducationMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 2)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐈𝐂𝐓 𝐢𝐧 𝐞𝐝𝐮𝐜𝐚𝐭𝐢𝐨𝐧:
Students will be able to explain the role and impact of Information and Communication Technology (ICT) in education. They will understand how ICT tools, such as computers, the internet, and educational software, enhance learning and teaching processes. By exploring various ICT applications, students will recognize how these technologies facilitate access to information, improve communication, support collaboration, and enable personalized learning experiences.
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐫𝐞𝐥𝐢𝐚𝐛𝐥𝐞 𝐬𝐨𝐮𝐫𝐜𝐞𝐬 𝐨𝐧 𝐭𝐡𝐞 𝐢𝐧𝐭𝐞𝐫𝐧𝐞𝐭:
-Students will be able to discuss what constitutes reliable sources on the internet. They will learn to identify key characteristics of trustworthy information, such as credibility, accuracy, and authority. By examining different types of online sources, students will develop skills to evaluate the reliability of websites and content, ensuring they can distinguish between reputable information and misinformation.
Environmental science 1.What is environmental science and components of envir...Deepika
Environmental science for Degree ,Engineering and pharmacy background.you can learn about multidisciplinary of nature and Natural resources with notes, examples and studies.
1.What is environmental science and components of environmental science
2. Explain about multidisciplinary of nature.
3. Explain about natural resources and its types
Brand Guideline of Bashundhara A4 Paper - 2024khabri85
It outlines the basic identity elements such as symbol, logotype, colors, and typefaces. It provides examples of applying the identity to materials like letterhead, business cards, reports, folders, and websites.
Get Success with the Latest UiPath UIPATH-ADPV1 Exam Dumps (V11.02) 2024yarusun
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Cross-Cultural Leadership and CommunicationMattVassar1
Business is done in many different ways across the world. How you connect with colleagues and communicate feedback constructively differs tremendously depending on where a person comes from. Drawing on the culture map from the cultural anthropologist, Erin Meyer, this class discusses how best to manage effectively across the invisible lines of culture.
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 3)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
Lesson Outcomes:
- students will be able to identify and name various types of ornamental plants commonly used in landscaping and decoration, classifying them based on their characteristics such as foliage, flowering, and growth habits. They will understand the ecological, aesthetic, and economic benefits of ornamental plants, including their roles in improving air quality, providing habitats for wildlife, and enhancing the visual appeal of environments. Additionally, students will demonstrate knowledge of the basic requirements for growing ornamental plants, ensuring they can effectively cultivate and maintain these plants in various settings.
pol sci Election and Representation Class 11 Notes.pdf
2012 pe review__hyd_
1. 2012 PE Review:
IV-A: Hydrology and Hydraulics
Michael C. Hirschi, PhD, PE, D.WRE
Senior Engineer
Waterborne Environmental, Inc.
hirschim@waterborne-env.com
also Professor Emeritus
University of Illinois
2. Acknowledgements:
Daniel Yoder, I-A, PE Review 2006
Rafael (Rafa) Muñoz-Carpena, I-A, PE Review 2007-09
Rod Huffman, PE Review coordinator
3. Session Topics
• Hydrology
• Hydraulics of Structures
• Open Channel Flow
4. Hydrology
• Hydrologic Cycle
• Precipitation
– Average over Area
– Return Period
• Abstractions from Rainfall
• Runoff
– Hydrographs
– Determination methods
7. A few comments
• Material outlined is about 3 weeks or more in a
3-semester hour class. I’m compressing at least
6 hours of lecture and 3 laboratories into 2
hours, so I will:
– Review highlights and critical points
– Do example problems
• You need to:
– Review and tab references
– Do additional example problems, or at least
thoroughly review examples in references
12. Example 1
How do different calculation methods of rainfall average compare?
Consider:
13. Raingage data
• Gages (clockwise from upper left): 1.9”,
2.1”, 1.8”, 1.9”, 2.1”, 2.2”
Arithmetic average: 2.0”
14. Theissen Polygons
• Areas closest to each raingage
determined by perpendicular bisectors of
each line between raingages.
• Areas for each raingage, again clockwise
from upper left: 65ac, 150ac, 55ac, 140ac,
215 ac, 270ac
• Figure is repeated with Theissen polygon
construction added.
15. Why bisectors?
• When perpendicular bisectors are
constructed, they are, by definition, lines
that are equidistant from the points at the
ends of the lines they bisect.
• So, the combination of the constructions
delineate areas that are closest to a given
point (raingage in this case)
16. Is the watershed average
rainfall using the Theissen
Polygon method most nearly:
A. 2.0”
B. 2.1”
C. 2.2”
D. 1.9”
17. Theissen calculation
• Uses areal weighted average, so the sum of the
products of area x depth divided by total area
• Hint: If you measure the areas yourself, the
denominator should be the sum of the areas, not
the known watershed area
• So, average Theissen rain: Answer B, 2.1”
(65*1.9+150*2.1+55*1.8+140*1.9+215*2.1+270*2.
2)/(65+150+55+140+215+270)=2.07”, which is
best represented as 2.1” given most data is 2
significant digits.
19. Return Period (two descriptions)
• A 10 year-24 hour rainfall volume is that
depth of rainfall over a 24 hour period that
is met or exceeded, on the long-term
average, once every 10 years.
• Another way to describe it is the 24 hour
rainfall depth that has a 1 in 10 (10%)
chance to be met or exceeded each year,
on the long term average.
20. US 100yr-24hr Rainfall
100yr-24hr data from TP-40 (Hershfield (1961)
as referenced by Fangmeier et al. (2006)
21. Return Period Data
• Constructed from historical rainfall data
• Available in tabular form via website or
state USDA-NRCS reports.
• Available as national maps (similar to
previous slide) in several references such
as Haan, Barfield & Hayes (1994).
22. Example
A reservoir is to be designed to contain the
runoff from a 10yr-24hr rainfall event in
Northeastern Illinois. What rainfall
volume is to be considered?
A. 4.5”
B. 3.9”
C. 4.1”
D. Cannot estimate from available maps
26. Abstractions from Rainfall
• Abstractions from rainfall are “losses” from
rainfall that do not show up as storm water
runoff:
– Interception
– Evapotranspiration
– Storage
• In bank
• On surface
– Infiltration
27. Runoff by other names…
• “Effective” rainfall
• Rainfall “excess”
28. Runoff
If rainfall rate exceeds the soil infiltration
capacity, ponding begins, and any soil
surface roughness creates storage on the
surface. After at least some of those
depressions are filled with water, runoff
begins. Additional rain continues to fill
depressional storage and runoff rate
increases as more of the hill slope and
subsequently the watershed contributes
runoff.
30. Time of Concentration, tc
The time from the beginning of runoff to the
time at which the entire watershed is
contributing runoff that reaches the
watershed outlet is called the Time of
Concentration. It is also described as the
“travel time from the hydraulically most
remote point in a watershed to the outlet”.
36. Runoff Example
In a previous problem, a design rain event in NE
Illinois was determined to be 4.1”. Assuming the
watershed in question was a completed 300 ac
residential area with an average lot size of ½ ac,
all on Hydrologic Group C soils, what is the
needed pond volume, if all runoff is to be
retained?
A: 2.5 runoff-inches
B: 53 acre-inches
C: 630 acre-ft
D: 53 acre-ft
39. Answer to Runoff Example
The answer is D, 53 acre-ft. From the table,
the CN for Hyd group C soil with ½-ac lot
is 80. Using the graph with a 4.1” rainfall,
runoff depth is 2.1”. Volume is then
300ac*2.1in = 630 ac-in, divided by 12 is
53 ac-ft.
40. Additional example
You discover that the subdivision is actually 100
acres of ½ ac lots on C soils, 100 acres of ½ ac
lots on D soils, 50 acres of ¼ ac lots on B soils
and 50 acres of townhouses on A soils. What
CN value would you use?
A: 79
B: 85
C: 80
D: 75
42. Answer
The correct answer is C, 80. Use an area-weighted
average, similar to Theissen
method. The respective CN values for ½
ac on C, ½ ac on D, ¼ ac on B and
townhouses on A are 80, 85, 75 & 77.
The area-weighted CN is then
(80*100+85*100+75*50+77*50)/300 =
80.33, which is more appropriately 80.
43. Peak Discharge
The CN method also provides for Peak
Discharge estimation, using graphs or
tables. Required information includes
average watershed slope, watershed flow
path length, CN, and rainfall depth. The
graphical method from the EFM is:
45. Peak Discharge Example
Same residential watershed that produced
2.1” of runoff from a 4.1” rainfall. Flow
length is 2500’, slope is 2%. CN is 80, so
S is 2.5”. Ia = 0.2*S = 0.5”. Ia/P =
0.5/4.1=0.122.
Tc = 2500^0.8*(1000/80-9)^0.7/1140/2^0.5
=0.8hr
47. Example solution
From graph, with Ia/P of 0.122 and Tc of
0.8hr, unit peak discharge is 0.57 cfs/ac/in
or qp = 0.57*300*2.1 = 360 cfs
48. Rational Method
The Rational Equation is:
Qp = CiA
where:
C is a coefficient
i is rainfall intensity of duration tc
A is area in acres
C is approximately 0.4, A is 300ac, i is 2” in 30min, so 4iph,
peak rate is then 0.4*300*4 = 480 cfs
50. Hydraulics of Structures
Flow through structures is important given
that such structures control the rate of
flow. Sizing of such structures is then
important to allow flow to pass while
protecting downstream areas from the
effects of too high a flow rate. Structures
may also be used for measurement of
water flow. Each type of structure will
produce different types of flow depending
upon size and flow rate passing through it.
55. Example
• You are measuring flow using a 90° V-notch
weir. H is measured as 0.53’ at
2.5’ upstream of the weir. What is the
flow rate?
A. 230 gpm
B. 0.51 cfs
C. 0.51 gpm
D. A & B
56. Answer
• The answer is D. The equation from Haan
et al (1994) is:
57. Answer, continued
• Q = 2.5*H^2.5, where Q is in cfs and H is
in feet
• Q=2.5*(0.53)^2.5=0.511 cfs or 0.51 cfs
• Q=0.51 cfs*60sec/min*7.48gal/cf=230
gpm
• Note: Both answers contain 2 significant
figures
58. Orifice Flow
• Submerged vs Free Outlet
• Shapes affecting C
62. Example
• Markers Mark distillery just moved a 3’ diameter
barrel of their bourbon over their charcoal filter
bed to drain the bourbon into the system to be
bottled. The bung plug is removed
instantaneously, allowing barrel strength
bourbon to flow freely from the 2” diameter
bung, which can be considered a sharp-edged
orifice. What is the initial flow rate (assuming
same specific gravity as water, which is an
incorrect assumption)?
65. Pipe flow
When considering pipe flow in a structure,
Bernoulli’s equation is used:
Frictional losses are multiples of the velocity head (V2/2g)
and are additive.
66. Head loss under pipe flow
• Entrance loss (Ke)
• Bend loss (Kb)
• Pipe friction loss (Kc)
• Each coefficient is documented in references
Considering the Bernoulli equation for a spillway,
the pressure at entrance and exit is atmospheric,
the elevation difference is the water surface elevation
difference between upstream and downstream,
and the remaining term is the velocity head plus losses
69. Spillway considerations
A given spillway may have several
discharge relationships (weir, orifice, pipe)
depending upon the head (stage). The
stage discharge curve then becomes a
combination curve, with the type of
relationship allowing the highest flow at a
given head in control.
Consider a drop inlet control structure:
72. Example
An 18” CMP with an 18” vertical riser is used
as the principal spillway for a pond. The
pipe is 50’ long with one 90° bend. The
top of the inlet is 10’ above the bottom of
the outlet. Develop the stage-discharge
relationship assuming a free outfall.
73. Weir flow
Basic equation:
Given 18” riser, length of weir is 2πr, or 4.7’, so
74. Orifice flow
Basic orifice equation:
Given 18” riser and assuming C’ of 0.6,
75. Pipe flow
Basic pipe flow equation:
After looking up each parameter:
78. Open Channel Flow
Flow through open channels is another
important area to consider and review.
Velocity and flow rate are usually
calculated using Manning’s equation,
which considers flow geometry, channel
roughness and slope.
79. Manning’s Equation
Where:
V= flow velocity in fps
Rh = Hydraulic Radius in ft
S = Energy gradeline slope in ft/ft (=bed slope for normal flow)
n = Manning coefficient
1.49 = conversion from SI to English units
Hydraulic radius is the flow area divided by the wetted perimeter.
82. Example
What is the flow rate for a rectangular
finished (clean) concrete channel with a
base width of 8’, channel slope of 0.5%,
with a “normal” water depth of 2’?
A: 140 cfs
B: 8.5 cfs
C: 100 cfs
D: 200 cfs
83. Solution
n is 0.015, Rh is 8*2 sq.ft./(2+8+2) ft, S is 0.005 ft/ft, so
V = 8.5 ft/sec
Q = V*A= 8.5 ft/sec*16 sq.ft. = 140 cfs
84. Vegetated Waterway Design
The design of a vegetated waterway is an
iterative process, considering both
capacity when the grass is unmowed and
hence higher resistance to flow and
stability when recently mowed and more
susceptible to bed scour at high flow
velocities. Fortunately, the EFM has tables
of suitable channel dimensions.
86. Example
A subdivision produces a peak runoff rate of
60 cfs from a 10yr-24hr rainfall. A
vegetated waterway with an average slope
of 3% is to be planted with Kentucky
bluegrass. The soil at the waterway site is
easily eroded. The waterway will be
constructed with a parabolic shape. What
top width and depth are required (ignoring
freeboard)?