This document provides guidance on measuring bed load, which is sediment moving along or near the streambed. It discusses bed load measurement frequency, techniques, and common bed load samplers. Specific techniques covered include the single-equal width increment method, multi-equal width increment method, and unequal-width increment method for collecting bed load samples across a cross section. Methods for computing bed load discharge from samples include the total cross-section method, mid-section method, and mean-section method. Common bed load samplers described are pressure difference winch-operated samplers suitable for shallow to medium deep waters, such as the Helley-Smith type sampler.
This document provides instructions and guidelines for conducting sediment transport measurements in rivers, including suspended sediment and bed material sampling. It describes various types of sampling equipment used in India such as bottle samplers, depth-integrating samplers, and point-integrating samplers. Detailed operating procedures and safety precautions are provided for different sampling devices. The document also covers sediment analysis methods in the laboratory and quality control practices for field measurements and equipment calibration.
This document provides guidance on sediment transport measurements and sediment data collection. It discusses the origin and transport of sediments, network design considerations, site selection criteria, measuring frequency, techniques for suspended sediment and bed material measurements, equipment specifications, and station design and installation. Key topics covered include definitions of sediment load types, factors affecting erosion and sediment yield, sediment transport equations, suspended sediment measurement methods, bed material sampling techniques, and specifications for suspended sediment and bed material sampling equipment. The overall aim is to establish standard procedures for collecting sediment data as part of a hydrological information system.
This document discusses stream gauging techniques used to measure stream discharge. It begins by explaining that stream flow represents the runoff phase of the hydrologic cycle and is the most important data for hydrologic studies. It then describes various methods for measuring stream stage including staff gauges, suspended wire gauges, automatic stage recorders, and bubble gauges. Common techniques for directly measuring stream discharge are also summarized, such as area-velocity methods using current meters and floats, as well as moving boat methods. Site selection criteria and types of stage data collected are also briefly outlined.
Real Time Downhole Flow Measurement SensorsSurajit Haldar
1. The document describes using a new coiled tubing real-time flow (CTRF) tool to measure bottom-hole parameters during an acid stimulation treatment of an open-hole horizontal water injector well in the Arab-D formation in Ghawar field, Saudi Arabia.
2. The CTRF tool directly measures fluid velocity and direction using heat transfer sensors, providing real-time data on flow distribution between zones to help optimize stimulation.
3. During the field operation, the CTRF tool was calibrated and used along with distributed temperature surveys (DTS) to identify high-flow zones for diversion and evaluate the treatment effectiveness. The intervention successfully improved well injectivity.
This document is a reference manual on hydrometry that contains information on various topics related to hydrology and hydraulic measurements. It begins with an introduction to hydraulics, covering the classification of flows, properties of water, velocity profiles in laminar and turbulent flow, hydrodynamic equations, and backwater curves. Subsequent sections provide information on measurement structures, instrumentation, errors, and quality assurance plans. The manual contains detailed technical content intended to serve as a reference for professionals performing hydrologic monitoring and discharge measurements.
This document provides guidelines for the routine maintenance of stage and streamflow measurement equipment and installations. It discusses maintenance procedures for staff gauges, autographic water level recorders, digital water level recorders, current meters, and supporting equipment. Key recommendations include regularly cleaning and inspecting equipment for damage, checking instrument readings against references, downloading digital data frequently, and calibrating equipment on a set schedule or when major repairs are done. The document aims to ensure the continued collection of good quality hydrometric data through proper equipment upkeep.
This document discusses techniques for measuring stream flow. There are two main categories of measurement: direct determination using area-velocity methods, dilution techniques, electromagnetic and ultrasonic methods; and indirect determination using hydraulic structures like weirs, flumes and gates or slope-area methods. Velocity is an important aspect measured using current meters, which are the most commonly used instruments. Current meters consist of rotating cups or propellers connected to mechanisms that count revolutions to determine flow velocity. Floating objects can also be used to estimate surface velocities. Accurate stream flow measurement is important for hydrologic studies.
This document provides instructions and guidelines for conducting sediment transport measurements in rivers, including suspended sediment and bed material sampling. It describes various types of sampling equipment used in India such as bottle samplers, depth-integrating samplers, and point-integrating samplers. Detailed operating procedures and safety precautions are provided for different sampling devices. The document also covers sediment analysis methods in the laboratory and quality control practices for field measurements and equipment calibration.
This document provides guidance on sediment transport measurements and sediment data collection. It discusses the origin and transport of sediments, network design considerations, site selection criteria, measuring frequency, techniques for suspended sediment and bed material measurements, equipment specifications, and station design and installation. Key topics covered include definitions of sediment load types, factors affecting erosion and sediment yield, sediment transport equations, suspended sediment measurement methods, bed material sampling techniques, and specifications for suspended sediment and bed material sampling equipment. The overall aim is to establish standard procedures for collecting sediment data as part of a hydrological information system.
This document discusses stream gauging techniques used to measure stream discharge. It begins by explaining that stream flow represents the runoff phase of the hydrologic cycle and is the most important data for hydrologic studies. It then describes various methods for measuring stream stage including staff gauges, suspended wire gauges, automatic stage recorders, and bubble gauges. Common techniques for directly measuring stream discharge are also summarized, such as area-velocity methods using current meters and floats, as well as moving boat methods. Site selection criteria and types of stage data collected are also briefly outlined.
Real Time Downhole Flow Measurement SensorsSurajit Haldar
1. The document describes using a new coiled tubing real-time flow (CTRF) tool to measure bottom-hole parameters during an acid stimulation treatment of an open-hole horizontal water injector well in the Arab-D formation in Ghawar field, Saudi Arabia.
2. The CTRF tool directly measures fluid velocity and direction using heat transfer sensors, providing real-time data on flow distribution between zones to help optimize stimulation.
3. During the field operation, the CTRF tool was calibrated and used along with distributed temperature surveys (DTS) to identify high-flow zones for diversion and evaluate the treatment effectiveness. The intervention successfully improved well injectivity.
This document is a reference manual on hydrometry that contains information on various topics related to hydrology and hydraulic measurements. It begins with an introduction to hydraulics, covering the classification of flows, properties of water, velocity profiles in laminar and turbulent flow, hydrodynamic equations, and backwater curves. Subsequent sections provide information on measurement structures, instrumentation, errors, and quality assurance plans. The manual contains detailed technical content intended to serve as a reference for professionals performing hydrologic monitoring and discharge measurements.
This document provides guidelines for the routine maintenance of stage and streamflow measurement equipment and installations. It discusses maintenance procedures for staff gauges, autographic water level recorders, digital water level recorders, current meters, and supporting equipment. Key recommendations include regularly cleaning and inspecting equipment for damage, checking instrument readings against references, downloading digital data frequently, and calibrating equipment on a set schedule or when major repairs are done. The document aims to ensure the continued collection of good quality hydrometric data through proper equipment upkeep.
This document discusses techniques for measuring stream flow. There are two main categories of measurement: direct determination using area-velocity methods, dilution techniques, electromagnetic and ultrasonic methods; and indirect determination using hydraulic structures like weirs, flumes and gates or slope-area methods. Velocity is an important aspect measured using current meters, which are the most commonly used instruments. Current meters consist of rotating cups or propellers connected to mechanisms that count revolutions to determine flow velocity. Floating objects can also be used to estimate surface velocities. Accurate stream flow measurement is important for hydrologic studies.
This document summarizes the third edition of the Water Measurement Manual published by the U.S. Department of the Interior Bureau of Reclamation. It discusses the need for reliable water measurement to better manage water resources and extend existing supplies. It provides an overview of the benefits of improved water measurement, such as equitable allocation, reduced conflicts, improved decision making, and conservation. The manual contains guidance on selecting and using various devices to measure flow and aims to support accurate water management.
This document provides guidelines for conducting pumping tests to evaluate water sources for public water systems in Washington state. It recommends a step drawdown test followed by a constant rate discharge test for most standard aquifer settings to determine optimal pump size and long-term source reliability. It describes special considerations for complex hydrogeological settings or those with potential water quality or supply issues. The objectives are to obtain data on aquifer properties and establish that a source can safely and reliably meet water demands both now and into the future in accordance with state regulations.
This document summarizes research on parametric analysis of ship squat in shallow water conducted through physical model testing. Ship squat refers to the increase in a ship's draft when moving in shallow water. The research aims to determine squat characteristics for vessels with Series-60 hull forms in various depths. Models with block coefficients of 0.7 and 0.75 were tested in a water tank at different depths and speeds. Test results were analyzed using new dimensionless parameters and showed that squat increases with speed until a crucial speed where the model floor collides with the tank bottom. The results were validated by comparing with other studies and an empirical equation for ship squat as a function of parameters was developed.
1) The document provides guidance on conducting float gauge measurements of river discharge, including selecting cylindrical wooden float types, preparing the measurement reach, taking observational readings, and computing discharge results.
2) Key steps include surveying cross sections at the upstream and downstream ends of the reach, dividing the cross sections into segments of equal width, releasing floats sequentially to measure travel time through the reach, and using travel times and pre-computed segment areas to calculate segment and total discharges.
3) Computation involves determining surface and mean velocities from float travel times, looking up segment areas from pre-surveyed cross sections, calculating segment discharges as the product of area and velocity, and summing segments to determine total discharge.
This document provides guidance on using the area-slope method to estimate stream discharge indirectly when direct measurement is not possible. It describes the principles and steps of the area-slope method, including selecting a study reach, measuring the cross-sectional area and water surface slope, evaluating velocity using Manning's formula, and computing discharge. Guidelines are given for selecting sites, measuring cross-sections and slope, determining roughness coefficients, and performing calculations. The area-slope method provides a rough estimate of discharge but has limitations due to uncertainties in roughness coefficients.
This document discusses hydrographic surveying methods. It describes establishing horizontal and vertical control by traversing and using tide gauges. Soundings are taken along perpendicular range lines using equipment like sounding poles, lead lines, and echo sounders. Depth measurements are referenced to benchmarks and tide gauges. Angle measuring instruments like sextants are used to locate soundings. Soundings are reduced, plotted, and used to produce charts and for engineering projects involving water bodies.
This document provides guidance on river stage observation for staff gauges, autographic chart recorders, and digital water level recorders. It outlines procedures for taking manual staff gauge readings hourly or multiple times per day, checking and maintaining chart recorders daily, and routinely downloading and checking digital recorders against staff gauges. The goal is to ensure uniform and high-quality hydrological data collection through consistent field procedures.
The document discusses various methods for analyzing pumping test data from large diameter wells. It describes the types of large diameter wells commonly used for groundwater extraction. It notes that analyzing pumping test data from such wells is challenging due to factors like well storage effects, partial penetration, and unsteady flow conditions. The document then outlines several methods developed over time to analyze aquifer test and yield test data from large diameter wells, noting the assumptions and limitations of each approach.
This presentation was created to teach community members in the Eola Hills Groundwater Limited Area (northwest of Salem, OR) about groundwater level measurement. Please see this webpage for more information: http://www.wrd.state.or.us/OWRD/GW/NGWN_homepage.shtml.
This document discusses streamflow, factors affecting streamflow quality, and methods of measuring streamflow quantity. It describes the three main mechanisms that generate streamflow: Hortonian overland flow, subsurface flow, and saturation overland flow. It also outlines common issues affecting streamflow quality and provides details on stage-discharge relationships, including guidelines for gauge location and types of gauges used to measure stream stage. Measurement of stream discharge is also briefly discussed.
Editorial - May 2014 - Special Issue jointly coordinated by Mercator Ocean and Coriolis
focusing on Ocean Observations
Greetings all,
Once a year and for the fi fth year in a raw, the Mercator Ocean Forecasting Center in Toulouse and the Coriolis Infrastructure in Brest publish a
common newsletter. Some papers are dedicated to observations only, when others display collaborations between the 2 aspects: Observations and
Modelling/Data assimilation.
The fi rst paper by Cabanes et al. introducing this issue is presenting a new methodology aiming at correcting Argo fl oat salinity measurements in
delayed time when Argo fl oats conductivity sensors are subject to drift and offset due to bio-fouling or other technical problems.
Then, Cravatte et al. are using the Argo arrays in order to compile Argo fl oats’ drifts and show that they are a very valuable tool allowing determining
the absolute velocity. They apply this to study zonal jets at 1000 meters depth in the Tropics.
In the next paper, Maes and O’Kane provide with some results indicating the impact of a sustained ocean observing Argo network on the ability to
resolve the seasonal cycle of salinity stratifi cation by contrasting periods pre- and post-Argo. They take into account the respective thermal and saline
dependencies in the Brunt-Väisälä frequency (N2) in order to isolate the specifi c role of the salinity stratifi cation in the layers above the main pycno-
cline.
Picheral et al. are telling us about the Tara Oceans voyage that took place on the schooner “Tara” from 2009 to 2013 and visited all oceans. The ship
was adapted for modern oceanography. Scientifi c instruments were mounted on a dedicated CTD frame and installed on an underway fl ow-through
system. Data were sent daily to Coriolis. Post cruise calibrations were performed leading to a high quality dataset.
Then, Roquet et al. demonstrate the importance of the contribution of hydrographic and biogeochemical data collected by Antarctic marine mammals,
and in particular elephant seals, equipped with a new generation of oceanographic tags, for the environmental monitoring of the Southern Ocean.
The last paper of the present issue is displaying the collaboration between the Ocean Observations and Ocean Modelling communities: Turpin et
al. perform several Observing System Experiments in order to assess the impact of Argo observations on the Mercator Océan global analysis and
forecasting system at ¼ degree resolution.
We wish you a pleasant reading,
Laurence Crosnier and Sylvie Pouliquen, Editors.
#50
Newsletter
QUARTERLY
The Tara Oceans voyage took place on the schooner “Tara” from 2009 to 2013 and visited all oceans to collect samples and data in order to study the relationships between ecosystem biodiversity and function and the physical-chemical oceanographic environ-
ment (water mass, transport) (cf Picheral et al. this issue).
Credits: Francois Aurat/Tara Expéditions; Marc Picheral/LOV
This document provides guidance on procedures for conducting aquifer pumping tests to estimate aquifer parameters. It outlines the necessary preliminary studies, site preparation, equipment needs, data collection procedures during testing, and methods for analyzing test data either manually or using software. Key steps include conducting step drawdown tests followed by constant discharge tests while monitoring water levels in the pumping well and observation wells over time. Analysis of the water level response curves allows estimation of aquifer transmissivity and storage coefficient. Proper planning and hydrogeological understanding of the site are important for ensuring high quality test results.
This document summarizes research on vortex generation and mass transfer in agitated vessels. Experiments were conducted in 11-inch and 24-inch diameter tanks to measure the mass transfer coefficient (kLa) of an air-water system under varying conditions. A correlation was developed to predict kLa based on impeller type, speed, diameter, and liquid coverage. The correlation showed that kLa increases with scale when the minimum Froude number (FrMIN) and geometry are maintained. This suggests mass transfer is proportional to power input per vortex surface area. Further work is needed to validate the scale up methodology for different impeller types.
This document establishes minimum standards for sedimentation tanks used at construction dewatering sites that discharge wastewater to the King County sanitary sewer system. It summarizes literature on sedimentation tank design principles and reviews two common portable sedimentation tank models. Minimum standards are selected for hydraulic retention time (1.5 hours), overflow rate (800-3,000 gallons per day per square foot), aspect ratio (3:1 to 5:1 length to width), and maximum sediment accumulation (18.75-37.5% of tank height). Tanks meeting these criteria along with proper monitoring of sediment levels are deemed the minimum treatment required for construction dewatering wastewater containing settleable solids.
This document provides job descriptions for various roles within a Hydrological Information System (HIS) for surface water, meteorology, groundwater, water quality, and information technology functions. It describes the key responsibilities, required qualifications and experience, and typical tasks for positions ranging from field helpers to state-level managers. Standard coding is used to identify the different functions, such as S1 to S12 for surface water jobs and G1 to G12 for groundwater roles.
1. Current meters measure the velocity of fluid flow using various mechanical, electrical, or optical methods.
2. The most commonly used current meters for irrigation and watershed measurements are anemometer and propeller types, which measure velocity using rotating cups or propellers.
3. However, electromagnetic current meters that produce voltage proportional to flow velocity are also widely used, especially by water districts, as they provide direct analog readings without moving parts.
This document provides guidance on sediment sampling techniques and analysis. It describes various suspended sediment samplers used in India including bottle-type point samplers, depth-integrating handheld and cable-suspended samplers, and point-integrating cable-suspended samplers. It also discusses bed material sampling techniques like dredges, grabs, and cores. The document gives instructions for operating and maintaining each type of sampler, and outlines standard procedures for sediment analysis including determining coarse, medium, and fine fractions. Field inspection and quality control are emphasized.
This document describes procedures for surface water data processing under the Hydrological Information System (HIS) in India. It discusses various stages of data processing including receipt of data, data entry, validation, completion, compilation, analysis, reporting and transfer. It emphasizes the importance of validation to correct errors and identify data reliability. Validation is done at multiple levels - primary, secondary and hydrological. The document also covers organizing temporary databases, transferring data between databases, and backing up databases.
This document provides an operations manual for water quality analysis. It discusses good laboratory practices and quality assurance protocols that should be followed, including proper handling of chemicals, cleaning of glassware, measurement techniques, and maintenance of laboratory equipment. Standard analytical procedures for over 30 water quality parameters are also described. The manual establishes guidelines for sample receipt, storage, analysis, reporting results, and validating data. Its aim is to help water testing laboratories obtain reliable and comparable water quality information through consistent application of quality control procedures.
This document provides guidance on secondary validation and processing of hydro-meteorological and surface water quantity and quality data for a hydrological information system in India. It describes various procedures for validating rainfall, climatic, water level, discharge, and sediment data through time series analysis, comparison between stations, and relationship curves. It also provides methods for correcting errors and completing missing data through interpolation, rating curves, and areal estimation techniques. The overall goal is to develop a sustainable hydrological information system with standardized, computerized data to support water resources planning and management.
This document provides guidance on using regression analysis for data validation in hydrological data processing. It discusses simple linear regression, multiple linear regression, and stepwise regression. Regression analysis can be used to validate and fill in missing water level, rainfall, and discharge data. It establishes relationships between dependent and independent variables. Both linear and nonlinear regression models are used in hydrological applications. Key applications mentioned include rating curves, spatial interpolation of rainfall, and validating station data against nearby stations.
This document provides guidance on data entry and primary validation procedures for hydro-meteorological and surface water quantity and quality data in India. It describes how to enter master data like data types, administrative boundaries, and office units. It also provides instructions for entering static, semi-static and time series data like rainfall, climate, water levels, flows, sediments, and water quality. Primary validation checks on the data are also outlined to ensure data quality before secondary processing.
This document summarizes the third edition of the Water Measurement Manual published by the U.S. Department of the Interior Bureau of Reclamation. It discusses the need for reliable water measurement to better manage water resources and extend existing supplies. It provides an overview of the benefits of improved water measurement, such as equitable allocation, reduced conflicts, improved decision making, and conservation. The manual contains guidance on selecting and using various devices to measure flow and aims to support accurate water management.
This document provides guidelines for conducting pumping tests to evaluate water sources for public water systems in Washington state. It recommends a step drawdown test followed by a constant rate discharge test for most standard aquifer settings to determine optimal pump size and long-term source reliability. It describes special considerations for complex hydrogeological settings or those with potential water quality or supply issues. The objectives are to obtain data on aquifer properties and establish that a source can safely and reliably meet water demands both now and into the future in accordance with state regulations.
This document summarizes research on parametric analysis of ship squat in shallow water conducted through physical model testing. Ship squat refers to the increase in a ship's draft when moving in shallow water. The research aims to determine squat characteristics for vessels with Series-60 hull forms in various depths. Models with block coefficients of 0.7 and 0.75 were tested in a water tank at different depths and speeds. Test results were analyzed using new dimensionless parameters and showed that squat increases with speed until a crucial speed where the model floor collides with the tank bottom. The results were validated by comparing with other studies and an empirical equation for ship squat as a function of parameters was developed.
1) The document provides guidance on conducting float gauge measurements of river discharge, including selecting cylindrical wooden float types, preparing the measurement reach, taking observational readings, and computing discharge results.
2) Key steps include surveying cross sections at the upstream and downstream ends of the reach, dividing the cross sections into segments of equal width, releasing floats sequentially to measure travel time through the reach, and using travel times and pre-computed segment areas to calculate segment and total discharges.
3) Computation involves determining surface and mean velocities from float travel times, looking up segment areas from pre-surveyed cross sections, calculating segment discharges as the product of area and velocity, and summing segments to determine total discharge.
This document provides guidance on using the area-slope method to estimate stream discharge indirectly when direct measurement is not possible. It describes the principles and steps of the area-slope method, including selecting a study reach, measuring the cross-sectional area and water surface slope, evaluating velocity using Manning's formula, and computing discharge. Guidelines are given for selecting sites, measuring cross-sections and slope, determining roughness coefficients, and performing calculations. The area-slope method provides a rough estimate of discharge but has limitations due to uncertainties in roughness coefficients.
This document discusses hydrographic surveying methods. It describes establishing horizontal and vertical control by traversing and using tide gauges. Soundings are taken along perpendicular range lines using equipment like sounding poles, lead lines, and echo sounders. Depth measurements are referenced to benchmarks and tide gauges. Angle measuring instruments like sextants are used to locate soundings. Soundings are reduced, plotted, and used to produce charts and for engineering projects involving water bodies.
This document provides guidance on river stage observation for staff gauges, autographic chart recorders, and digital water level recorders. It outlines procedures for taking manual staff gauge readings hourly or multiple times per day, checking and maintaining chart recorders daily, and routinely downloading and checking digital recorders against staff gauges. The goal is to ensure uniform and high-quality hydrological data collection through consistent field procedures.
The document discusses various methods for analyzing pumping test data from large diameter wells. It describes the types of large diameter wells commonly used for groundwater extraction. It notes that analyzing pumping test data from such wells is challenging due to factors like well storage effects, partial penetration, and unsteady flow conditions. The document then outlines several methods developed over time to analyze aquifer test and yield test data from large diameter wells, noting the assumptions and limitations of each approach.
This presentation was created to teach community members in the Eola Hills Groundwater Limited Area (northwest of Salem, OR) about groundwater level measurement. Please see this webpage for more information: http://www.wrd.state.or.us/OWRD/GW/NGWN_homepage.shtml.
This document discusses streamflow, factors affecting streamflow quality, and methods of measuring streamflow quantity. It describes the three main mechanisms that generate streamflow: Hortonian overland flow, subsurface flow, and saturation overland flow. It also outlines common issues affecting streamflow quality and provides details on stage-discharge relationships, including guidelines for gauge location and types of gauges used to measure stream stage. Measurement of stream discharge is also briefly discussed.
Editorial - May 2014 - Special Issue jointly coordinated by Mercator Ocean and Coriolis
focusing on Ocean Observations
Greetings all,
Once a year and for the fi fth year in a raw, the Mercator Ocean Forecasting Center in Toulouse and the Coriolis Infrastructure in Brest publish a
common newsletter. Some papers are dedicated to observations only, when others display collaborations between the 2 aspects: Observations and
Modelling/Data assimilation.
The fi rst paper by Cabanes et al. introducing this issue is presenting a new methodology aiming at correcting Argo fl oat salinity measurements in
delayed time when Argo fl oats conductivity sensors are subject to drift and offset due to bio-fouling or other technical problems.
Then, Cravatte et al. are using the Argo arrays in order to compile Argo fl oats’ drifts and show that they are a very valuable tool allowing determining
the absolute velocity. They apply this to study zonal jets at 1000 meters depth in the Tropics.
In the next paper, Maes and O’Kane provide with some results indicating the impact of a sustained ocean observing Argo network on the ability to
resolve the seasonal cycle of salinity stratifi cation by contrasting periods pre- and post-Argo. They take into account the respective thermal and saline
dependencies in the Brunt-Väisälä frequency (N2) in order to isolate the specifi c role of the salinity stratifi cation in the layers above the main pycno-
cline.
Picheral et al. are telling us about the Tara Oceans voyage that took place on the schooner “Tara” from 2009 to 2013 and visited all oceans. The ship
was adapted for modern oceanography. Scientifi c instruments were mounted on a dedicated CTD frame and installed on an underway fl ow-through
system. Data were sent daily to Coriolis. Post cruise calibrations were performed leading to a high quality dataset.
Then, Roquet et al. demonstrate the importance of the contribution of hydrographic and biogeochemical data collected by Antarctic marine mammals,
and in particular elephant seals, equipped with a new generation of oceanographic tags, for the environmental monitoring of the Southern Ocean.
The last paper of the present issue is displaying the collaboration between the Ocean Observations and Ocean Modelling communities: Turpin et
al. perform several Observing System Experiments in order to assess the impact of Argo observations on the Mercator Océan global analysis and
forecasting system at ¼ degree resolution.
We wish you a pleasant reading,
Laurence Crosnier and Sylvie Pouliquen, Editors.
#50
Newsletter
QUARTERLY
The Tara Oceans voyage took place on the schooner “Tara” from 2009 to 2013 and visited all oceans to collect samples and data in order to study the relationships between ecosystem biodiversity and function and the physical-chemical oceanographic environ-
ment (water mass, transport) (cf Picheral et al. this issue).
Credits: Francois Aurat/Tara Expéditions; Marc Picheral/LOV
This document provides guidance on procedures for conducting aquifer pumping tests to estimate aquifer parameters. It outlines the necessary preliminary studies, site preparation, equipment needs, data collection procedures during testing, and methods for analyzing test data either manually or using software. Key steps include conducting step drawdown tests followed by constant discharge tests while monitoring water levels in the pumping well and observation wells over time. Analysis of the water level response curves allows estimation of aquifer transmissivity and storage coefficient. Proper planning and hydrogeological understanding of the site are important for ensuring high quality test results.
This document summarizes research on vortex generation and mass transfer in agitated vessels. Experiments were conducted in 11-inch and 24-inch diameter tanks to measure the mass transfer coefficient (kLa) of an air-water system under varying conditions. A correlation was developed to predict kLa based on impeller type, speed, diameter, and liquid coverage. The correlation showed that kLa increases with scale when the minimum Froude number (FrMIN) and geometry are maintained. This suggests mass transfer is proportional to power input per vortex surface area. Further work is needed to validate the scale up methodology for different impeller types.
This document establishes minimum standards for sedimentation tanks used at construction dewatering sites that discharge wastewater to the King County sanitary sewer system. It summarizes literature on sedimentation tank design principles and reviews two common portable sedimentation tank models. Minimum standards are selected for hydraulic retention time (1.5 hours), overflow rate (800-3,000 gallons per day per square foot), aspect ratio (3:1 to 5:1 length to width), and maximum sediment accumulation (18.75-37.5% of tank height). Tanks meeting these criteria along with proper monitoring of sediment levels are deemed the minimum treatment required for construction dewatering wastewater containing settleable solids.
This document provides job descriptions for various roles within a Hydrological Information System (HIS) for surface water, meteorology, groundwater, water quality, and information technology functions. It describes the key responsibilities, required qualifications and experience, and typical tasks for positions ranging from field helpers to state-level managers. Standard coding is used to identify the different functions, such as S1 to S12 for surface water jobs and G1 to G12 for groundwater roles.
1. Current meters measure the velocity of fluid flow using various mechanical, electrical, or optical methods.
2. The most commonly used current meters for irrigation and watershed measurements are anemometer and propeller types, which measure velocity using rotating cups or propellers.
3. However, electromagnetic current meters that produce voltage proportional to flow velocity are also widely used, especially by water districts, as they provide direct analog readings without moving parts.
This document provides guidance on sediment sampling techniques and analysis. It describes various suspended sediment samplers used in India including bottle-type point samplers, depth-integrating handheld and cable-suspended samplers, and point-integrating cable-suspended samplers. It also discusses bed material sampling techniques like dredges, grabs, and cores. The document gives instructions for operating and maintaining each type of sampler, and outlines standard procedures for sediment analysis including determining coarse, medium, and fine fractions. Field inspection and quality control are emphasized.
This document describes procedures for surface water data processing under the Hydrological Information System (HIS) in India. It discusses various stages of data processing including receipt of data, data entry, validation, completion, compilation, analysis, reporting and transfer. It emphasizes the importance of validation to correct errors and identify data reliability. Validation is done at multiple levels - primary, secondary and hydrological. The document also covers organizing temporary databases, transferring data between databases, and backing up databases.
This document provides an operations manual for water quality analysis. It discusses good laboratory practices and quality assurance protocols that should be followed, including proper handling of chemicals, cleaning of glassware, measurement techniques, and maintenance of laboratory equipment. Standard analytical procedures for over 30 water quality parameters are also described. The manual establishes guidelines for sample receipt, storage, analysis, reporting results, and validating data. Its aim is to help water testing laboratories obtain reliable and comparable water quality information through consistent application of quality control procedures.
This document provides guidance on secondary validation and processing of hydro-meteorological and surface water quantity and quality data for a hydrological information system in India. It describes various procedures for validating rainfall, climatic, water level, discharge, and sediment data through time series analysis, comparison between stations, and relationship curves. It also provides methods for correcting errors and completing missing data through interpolation, rating curves, and areal estimation techniques. The overall goal is to develop a sustainable hydrological information system with standardized, computerized data to support water resources planning and management.
This document provides guidance on using regression analysis for data validation in hydrological data processing. It discusses simple linear regression, multiple linear regression, and stepwise regression. Regression analysis can be used to validate and fill in missing water level, rainfall, and discharge data. It establishes relationships between dependent and independent variables. Both linear and nonlinear regression models are used in hydrological applications. Key applications mentioned include rating curves, spatial interpolation of rainfall, and validating station data against nearby stations.
This document provides guidance on data entry and primary validation procedures for hydro-meteorological and surface water quantity and quality data in India. It describes how to enter master data like data types, administrative boundaries, and office units. It also provides instructions for entering static, semi-static and time series data like rainfall, climate, water levels, flows, sediments, and water quality. Primary validation checks on the data are also outlined to ensure data quality before secondary processing.
This document contains records of daily rainfall, climatic, stage, and discharge data from multiple hydrological stations in India. It includes tables to record rainfall amounts, minimum and maximum temperatures, stage levels, river water and air temperatures, wind speed and direction, and other meteorological and hydrological parameters. The data is recorded daily and sometimes twice daily or hourly over a month-long period to monitor rainfall, weather, river levels, and discharge at various stations across sub-divisions and divisions for water resource management.
This document provides operation guidelines for a Data Storage Centre (DSC). Key points:
- The DSC stores and disseminates authenticated hydrological data and generates metadata catalogs.
- Staff include a manager, database administrator, IT expert, and secretary. They are responsible for database management, security, backups, metadata, and user support.
- Data processing is done separately at Data Processing Centres to avoid mixing raw and validated data and ensure database integrity. The DSC receives processed data from these centers.
- Standard procedures are described for database administration, metadata handling, reporting, maintenance, and interactions with other organizations in the hydrological information system.
This document provides an overview of water quality monitoring in India. It discusses key water quality issues for rivers, lakes, and reservoirs, including contamination from faecal matter, organic waste, toxic pollutants, eutrophication, salinization, changes in hydrology, agrochemicals, and mining activities. It also describes the monitoring cycle and key elements of designing a water quality monitoring program, including defining information needs, developing a monitoring strategy, network design, sample collection, laboratory analysis, data handling and analysis, reporting, and information utilization.
The document provides guidance on collecting water quality samples for laboratory analysis. It discusses preparing sample containers, reagents, and field equipment in the laboratory. Specific procedures are outlined for collecting grab samples, special samples like dissolved oxygen, and composite samples from surface waters. Quality assurance steps like proper labeling and preservation are also covered.
1. The document outlines various activities and responsibilities for surface water data collection, validation, and analysis in India.
2. Key activities include observation and data collection at stations, data entry and validation at local and district offices, secondary validation and analysis at regional offices, and final validation and reporting at a state level office.
3. Responsible parties, timelines, references, and supervision are defined for each component to ensure an organized workflow and quality control of surface water data.
This document provides information on sediment transport measurements, including definitions, the origin and transport of sediments, network design considerations, site selection, measuring frequency, techniques, equipment specifications, and station design. It contains detailed information on measuring suspended and bed load sediments, including sampling procedures, equipment, and analysis methods. The overall aim is to establish standardized procedures for collecting sediment data within India's Hydrological Information System.
This document describes the design of a hydrological data storage and dissemination system. It discusses the major components of the system including databases to store different types of hydrological data (e.g. field data, processed data, maps), a catalogue to allow users to search and access data, and interfaces to allow external organizations and users to input and retrieve data. It provides specifications for hardware, software, security, and other technical aspects required to build the hydrological information system. The overall aim is to create a centralized, standardized system for permanently storing all types of hydrological data from various agencies and making it accessible to authorized users.
This document discusses the history and development of paper money. It explains that originally paper money was developed as a way to represent gold and silver coins to make large transactions more convenient. Over time, governments began to print paper money that was not backed by precious metals, which led to inflation. The value of paper money now depends solely on the good faith and credit of the government issuing it.
This document provides information on sediment transport measurements, including definitions, the origin and transport of sediments, network design considerations, site selection, measuring frequency, techniques, equipment specifications, and station design. It contains detailed information on measuring suspended and bed load sediments, including sampling procedures, equipment, and analysis methods. The overall aim is to establish standardized procedures for collecting sediment data within India's Hydrological Information System to better understand sediment processes and support water resource planning and design projects.
This document provides procedures for conducting an instantaneous change in head (slug) test to determine the hydraulic conductivity of a water-bearing zone. Key steps include understanding test design and theory, determining well conditions, selecting appropriate equipment for inducing a slug and measuring water level changes, conducting the test, assessing results, and considering special situations like wells containing floating product or testing in karst aquifers. The goal is to obtain a quick measurement of hydraulic conductivity near the well while minimizing disposal of water.
This document discusses various methods for measuring stream flow, which is an important part of the hydrologic cycle that can be accurately quantified. It describes direct methods like the area-velocity method which involves measuring a cross-sectional area and velocities to calculate discharge. Indirect methods involve relating discharge to easier measured variables like stage height. Continuous measurement is challenging, so stagedischarge relationships are often used where stage is routinely monitored and related to estimated discharge.
This document discusses various methods for measuring stream flow. There are direct and indirect methods. Direct methods like area-velocity measure discharge by determining the cross-sectional area and average velocity. Indirect methods relate discharge to easily measured water level/stage using structures or the slope-area method with Manning's equation. Accurate stage measurements are important for estimating discharge from stage-discharge curves developed through direct measurements.
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.
This document provides guidance on conducting accurate draught surveys to measure bulk cargoes. It outlines best practices for reading draught marks, accounting for vessel trim, water density, ballast levels, and other factors. Key steps include taking multiple water samples at various depths, using calibrated equipment, and sounding all tanks to minimize cumulative errors. Following the procedures can achieve an accuracy of +/- 0.5% when measuring cargo quantities. Close cooperation with vessel officers and accounting for weather conditions are also emphasized.
This document discusses sampling procedures and considerations for reservoir fluids. It begins with an overview of why fluid sampling is important for analysis and production design. It then provides guidelines for establishing a sampling program, including selecting sampling sites, determining required measurements, and setting up the sampling plan. Special topics are covered such as sampling crude oil emulsions, waxy/asphaltenic fluids, and on-site measurements. Throughout, it emphasizes the need for representative samples and outlines best practices for fluid sampling.
This document discusses the design and management of packer testing programs for groundwater characterization at mining sites. It describes different types of packer testing methods including single vs double packer configurations, and injection, withdrawal, shut-in and falling head test types. Key considerations for designing a testing program include clearly defining data objectives, assessing data density needs, and planning the type, number and timing of tests based on drilling equipment, hole locations and other site activities. Flexibility is important as real-world constraints may influence testing approach. Overall, the document emphasizes upfront planning but also allowing for adaptive testing strategies to efficiently achieve hydrogeological characterization objectives.
This document provides guidance on analyzing the stability of concrete gravity dams. It discusses the various forces that must be considered in the analysis, including dead loads, water loads, uplift pressures, earth pressures, seismic forces, and more. It describes methods of analysis such as gravity, finite element, and dynamic methods. Criteria for stability are presented along with requirements for safety factors and foundation stability. Guidance is also given on construction materials, site investigations, and properties of concrete and foundations.
This document provides guidance on analyzing the stability of concrete gravity dams. It discusses various forces to consider, including dead loads, water loads, uplift pressures, earth pressures, temperature effects, and earthquakes. It describes recommended methods of analysis and criteria for stability evaluations. Uplift assumptions are presented, including distributions for horizontal planes within the dam and rock foundations. Guidance is given on drain effectiveness and extrapolating measurements to higher reservoir levels. Construction materials and required site investigations are also outlined.
Hydrologic data generally consist of a sequence of observations of some phase of the hydrologic cycle made at a particular site. The data may be a record of the discharge of a stream at a particular place, or it may be a record of the amount of rainfall caught in a particular rain gage.
Although for most hydrologic purposes a long record is preferred to a short one, the user should recognize that the longer the record the greater the chance that there has been a change in the physical conditions of the basin or in the methods of data collection. If these are appreciable, the composite record would represent only a nonexistent condition and not one that existed either before or after the change. Such a record is inconsistent.
1. Stage measurement involves using staff gauges, wire gauges, and automatic recorders like float gauges and bubble gauges to measure the water surface elevation in a river over time.
2. Staff gauges involve a fixed graduated staff while wire gauges lower a weighted wire from above the water surface. Float gauges use a float and pulley system connected to a recorder while bubble gauges measure pressure from gas bled into the river.
3. Automatic recorders provide continuous measurements of stage over time in a stage hydrograph, which is important for estimating design floods and historical flood discharges.
The document provides guidance on using the slope-area method to estimate river discharge. Key points:
1. Water level data is collected from staff gauges or digital sensors at upstream and downstream cross-sections. Ratings relate stage to area.
2. The slope of the water surface is estimated from the elevation difference between the sections. Manning's equation is used in an iterative process to compute discharge.
3. Stable, well-defined cross-sections are essential. Surveys define area and wetted perimeter. At least 10 high water marks define the flood profile.
4. Computations estimate conveyance, velocity head, and the energy slope to iteratively solve for discharge within 1% accuracy
Dr. Shahid Ali discusses sediment transport in rivers. There are 3 main types of sediment transport:
1) Suspended sediment moves through turbulence in the water column. 2) Bedload moves along the river bed through rolling and sliding. 3) Washload is fine sediment that remains suspended through Brownian motion. The size of sediment generally decreases downstream as larger particles are abraded. Sediment transport formulas have been developed but have limitations due to complex field conditions.
Fault seal analysis by seismic velocities ssuser5a6f50
This document discusses fault seal analysis using seismic velocities. It provides background on fault and capillary seals, and how properties like clay content, capillary pressure, and pressure differentials across faults influence their ability to seal or leak. Empirical methods to predict seal capacity from clay ratios are described, but have limitations without robust clay estimates. The pressure differential across a fault provides an indication of fluid communication between fault blocks and potential for an effective seal, though this depends on other factors like reservoir properties and hydrocarbon column heights as well. Well control is often lacking in frontier basins, so seismic velocities may offer a way to help constrain fault seal risk.
Practical wellbore formation test interpretation; #120009 (2009)Tran Dang Sang
The document discusses practical interpretation of wellbore formation test (WFT) pressure data, which is important for defining proved reserves under new SEC regulations. It addresses issues like data quality from different tools, establishing high versus low confidence data, and examples of pressure trends that could indicate reservoir continuity. Topics covered include pretest pressure stability, depth correlation, gradient error, accuracy versus precision, interpreting gradients in low mobility environments, and avoiding compartmentalization. The author argues that integrated analysis of pressure trends with other data like fluid samples, geochemistry, and PVT properties provides a stronger case than pressure gradient analysis alone.
DSD-INT 2019 SPIT - application of a novel sediment pathway visualization met...Deltares
Presentation by Edwin Elias, Deltares USA, at the Delft3D and XBeach User Day: Coastal morphodynamics, during Delft Software Days - Edition 2019. Wednesday, 13 November 2019, Delft.
The time required for the rain falling at the most distant point in the drainage area (i.e., on the fringe of the catchment ) to reach the concentration point is called the concentration time.
This is a very significant variable since only such storms of duration greater than the time of concentration will be able to produce runoff from the entire catchment area and cause high intensity floods.
The characteristics of the drainage net may be physically described by:
The number of streams
The length of streams
Stream density
Drainage density
The country’s annual renewable fresh water resources amount to some 122 BCM/yr in the twelve river basins.
However, only 3% remains in the country.
The rest, 97% is lost in runoff to the lowlands of neighboring countries.
The document specifies requirements for a cup-type current meter used to measure water velocity and discharge in rivers and canals. It must operate reliably under flow conditions, be easy to use, and include accessories for deployment. Key components are a 6-cup sensor measuring velocities from 0.05-3.5 m/s, various suspension methods including wading rods or cables, and fish weights from 25-100kg for suspended use. Accessories like tools, spare parts, and carrying cases must also be provided.
Similar to Download-manuals-surface water-manual-sw-volume5referencemanualsediment (20)
This document provides guidance on working with map layers and network layers in HYMOS, a hydrological modeling software. It describes how to obtain map layers from digitized topographic maps and remotely sensed data. It also explains how to create network layers by manually adding observation stations or importing them from another database. The document outlines how to manage and set properties for map layers and network layers within HYMOS to control visibility, styling, and other display options.
This document contains information about receiving hydrological data at different levels in India, including:
1. Data is transferred from field stations to subdivisional offices, then to divisional offices and state/regional data processing centers in stages. Target dates are set for receipt and transmission at each level to ensure smooth processing.
2. Records of receipt are maintained at each office to track data and identify delays, with feedback provided if data is not received by targets.
3. Original paper records are filed by station for easy retrieval, while digital copies are stored for long-term archiving.
The document describes a training module on understanding different types and forms of data in hydrological information systems (HIS). It was developed with funding from the World Bank and Government of the Netherlands. The module provides an overview of the session plan and covers various types of data in HIS, including space-oriented data like catchment maps, time-oriented data such as meteorological observations, and relation-oriented data like stage-discharge relationships. The goal is for participants to learn about all the different types and forms of data managed in HIS.
The document provides details on a surface water data processing plan for India. It discusses distributing data processing activities across three levels - sub-divisional, divisional, and state data processing centers. It outlines the activities, computing facilities, staffing, and time schedules needed at each level to efficiently manage the large volume of hydrological data. The plan aims to ensure data is properly validated and processed within time limits while not overwhelming staff.
This document outlines the stages of surface water data processing under the Hydrological Information System (HIS) in India. It discusses: 1) Receipt of data from field stations and storage of raw records; 2) Data entry at sub-divisional offices; 3) Validation of data through primary, secondary, and hydrological checks; 4) Completion and correction of missing or erroneous data; 5) Compilation, analysis, and reporting of validated data; 6) Transfer of data between processing levels from sub-division to division to state centers. The overall goal is to process field data in a systematic series of steps to produce quality-controlled hydrological information.
This document provides information on a training module for understanding hydrological information system (HIS) concepts and setup. It includes an introduction to HIS, why they are needed, how they are set up under the Hydrology Project. It also discusses who the key users of hydrological data are and how computers are used in hydrological data processing. The training module contains session plans, presentations, handouts, and text to educate participants on HIS objectives, components, and how they provide reliable hydrological data to various end users.
This document provides guidance on reporting climatic data in India. It discusses the purpose and contents of annual reports on climatic data, including evaporation data. Key points covered include:
- Annual reports summarize evaporation data for the reporting year and compare to long-term statistics.
- Reports include details on the observational network, basic evaporation statistics, data validation processes.
- Network maps and station listings provide details of monitoring locations. Statistics include monthly and annual evaporation amounts for the current year and historical averages.
- Reports aim to inform water resource planning, acknowledge data collection efforts, and provide access to climatic data records.
This document provides information and guidance on analyzing climatic data to estimate evaporation and evapotranspiration rates. It discusses the use of evaporation pans and appropriate pan coefficients to estimate open water evaporation from lakes and reservoirs. It also describes the Penman method for estimating potential evapotranspiration using standard climatological measurements. The Penman method combines the energy budget and mass transfer approaches and provides formulas for calculating evapotranspiration based on climatic variables like temperature, humidity, wind speed, and solar radiation. Substitutions are suggested when some climatic variables are not directly measured.
This document provides guidance on how to carry out secondary validation of climatic data. It describes various methods for validating data spatially using multiple station comparisons, including comparison plots, balance series, regression analysis, and double mass curves. It also describes single station validation tests for homogeneity, including mass curves and tests of differences in means. The document is part of a training module on secondary validation of climatic data funded by the World Bank and Government of the Netherlands. It provides context for the training and outlines the session plan, materials, and main validation methods to be covered.
This document provides guidance on how to carry out primary validation of climatic data. It discusses validating temperature, humidity, wind speed, atmospheric pressure, sunshine duration, and pan evaporation data. For each variable, it describes typical variations and measurement methods, potential errors, and approaches to error detection such as setting maximum/minimum limits. The goal of primary validation is to check for errors by comparing individual observations to physical limits and sequential observations for unacceptable changes.
This document provides guidance on entering climatic data into a hydrological data processing software called SWDES. It describes the various types of climatic data that can be entered, including daily, twice daily, hourly, and sunshine duration data. Instructions are provided on inspecting paper records, setting up data entry screens, entering values, and performing basic data validation checks. The overall aim is to make climatic data available electronically using SWDES in order to facilitate validation, processing, and reporting of the data.
This document provides guidance on how to report rainfall data in yearly and periodic reports. It outlines the typical contents and structure of annual reports including descriptive summaries of rainfall patterns, comparisons to long-term averages, basic statistics, and descriptions of major storms. Periodic reports produced every 10 years would include long-term statistics updated over the previous decade as well as frequency analysis of rainfall data. The reports aim to inform stakeholders of rainfall patterns and data availability as well as validate and improve the quality of data collection.
The document describes a training module on analyzing rainfall data. It includes sessions on checking data homogeneity, computing basic statistics, fitting frequency distributions, and deriving frequency-duration and intensity-duration-frequency curves. Exercises are provided for trainees to practice analyzing monthly and daily rainfall series, fitting distributions, and deriving curves for different durations and return periods. Case studies from India are referenced as examples throughout the training material.
This document provides guidance on compiling rainfall data from various time intervals into longer standardized durations. It discusses aggregating hourly data into daily totals, daily data into weekly, ten-daily, monthly, and yearly totals. Methods are presented for arithmetic averaging and Thiessen polygons to estimate areal rainfall from point measurements. Guidance is also given on transforming non-equidistant time series into equidistant series and compiling extreme rainfall statistics. Examples demonstrate compiling hourly rainfall from an autographic rain gauge into daily totals and further aggregating daily point rainfall into areal averages and statistics for various durations.
This document provides guidance on correcting and completing rainfall data. It discusses using autographic rain gauge (ARG) and standard rain gauge (SRG) data to correct errors. When the SRG is faulty but ARG is available, the SRG can be corrected to match the ARG totals. When the ARG is faulty but SRG is available, hourly distributions from neighboring stations can be used to estimate hourly totals for the station based on its daily SRG total. The document also discusses correcting time shifts, apportioning partial daily accumulations, adjusting for systematic shifts using double mass analysis, and using spatial interpolation methods to estimate missing values. Examples are provided to demonstrate each technique.
This document describes a training module on how to carry out secondary validation of rainfall data. It includes the following key points:
1. Secondary validation involves comparing rainfall data to neighboring stations to identify suspect values, taking into account spatial correlation which depends on duration, distance, precipitation type, and physiography.
2. Validation methods described include screening data against limits, scrutinizing multiple time series graphs and tabulations, checking against data limits for longer durations, spatial homogeneity testing, and double mass analysis.
3. Examples demonstrate how spatial correlation varies with duration and distance, and how physiography affects correlation. Screening listings with basic statistics are used to flag suspect data values.
This document provides guidance on how to carry out primary validation of rainfall data. It discusses comparing daily rainfall measurements from a standard raingauge to those from an autographic or digital raingauge. Differences greater than 5% between the two measurements would be further investigated. Likely sources of error are outlined for each type of raingauge. The validation can be done graphically or tabularly by aggregating hourly rainfall data to daily totals and comparing. Actions are suggested based on the patterns of discrepancies found.
This document provides guidance on entering rainfall data into a dedicated hydrological data processing software (SWDES). It discusses entering daily rainfall data, twice daily rainfall data, and hourly rainfall data from manual records or digital loggers. The key steps are:
1. Manually inspecting field records for completeness and errors before data entry.
2. Entering data into customized SWDES forms that match field observation sheets. This allows direct data transfer with minimal risk of errors.
3. Performing automated checks of the entered data against limits and computed totals to ensure accuracy. Any errors are flagged for further inspection.
4. Graphing the entered time series data during the entry process as an additional validation check.
The document provides guidance on sampling surface waters for water quality analysis. It discusses selecting sampling sites that are representative of the waterbody and safely accessible. It describes three types of samples - grab samples, composite samples, and integrated samples - and when each would be used. It also outlines appropriate sampling devices and containers for different analyses, as well as procedures for sample handling, preservation, and identification. The overall aim is to collect samples that accurately represent water quality without significant changes prior to analysis.
The document describes methods for hydrological observations including rainfall, water level, discharge, and inspection of observation stations. It contains sections on ordinary and recording rainfall observation, ordinary and recording water level observation, observation of discharge using current meters and floats, and inspection of rainfall and water level observation stations. The document was produced by the Ministry of Construction in Japan.
Let's Integrate MuleSoft RPA, COMPOSER, APM with AWS IDP along with Slackshyamraj55
Discover the seamless integration of RPA (Robotic Process Automation), COMPOSER, and APM with AWS IDP enhanced with Slack notifications. Explore how these technologies converge to streamline workflows, optimize performance, and ensure secure access, all while leveraging the power of AWS IDP and real-time communication via Slack notifications.
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
Get an inside look at the latest Neo4j innovations that enable relationship-driven intelligence at scale. Learn more about the newest cloud integrations and product enhancements that make Neo4j an essential choice for developers building apps with interconnected data and generative AI.
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
Join us as we explore breakthrough innovations enabled by interconnected data and AI. Discover firsthand how organizations use relationships in data to uncover contextual insights and solve our most pressing challenges – from optimizing supply chains, detecting fraud, and improving customer experiences to accelerating drug discoveries.
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
A tale of scale & speed: How the US Navy is enabling software delivery from l...sonjaschweigert1
Rapid and secure feature delivery is a goal across every application team and every branch of the DoD. The Navy’s DevSecOps platform, Party Barge, has achieved:
- Reduction in onboarding time from 5 weeks to 1 day
- Improved developer experience and productivity through actionable findings and reduction of false positives
- Maintenance of superior security standards and inherent policy enforcement with Authorization to Operate (ATO)
Development teams can ship efficiently and ensure applications are cyber ready for Navy Authorizing Officials (AOs). In this webinar, Sigma Defense and Anchore will give attendees a look behind the scenes and demo secure pipeline automation and security artifacts that speed up application ATO and time to production.
We will cover:
- How to remove silos in DevSecOps
- How to build efficient development pipeline roles and component templates
- How to deliver security artifacts that matter for ATO’s (SBOMs, vulnerability reports, and policy evidence)
- How to streamline operations with automated policy checks on container images
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
Threats to mobile devices are more prevalent and increasing in scope and complexity. Users of mobile devices desire to take full advantage of the features
available on those devices, but many of the features provide convenience and capability but sacrifice security. This best practices guide outlines steps the users can take to better protect personal devices and information.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Dr. Sean Tan, Head of Data Science, Changi Airport Group
Discover how Changi Airport Group (CAG) leverages graph technologies and generative AI to revolutionize their search capabilities. This session delves into the unique search needs of CAG’s diverse passengers and customers, showcasing how graph data structures enhance the accuracy and relevance of AI-generated search results, mitigating the risk of “hallucinations” and improving the overall customer journey.
Introducing Milvus Lite: Easy-to-Install, Easy-to-Use vector database for you...Zilliz
Join us to introduce Milvus Lite, a vector database that can run on notebooks and laptops, share the same API with Milvus, and integrate with every popular GenAI framework. This webinar is perfect for developers seeking easy-to-use, well-integrated vector databases for their GenAI apps.
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Full-RAG: A modern architecture for hyper-personalizationZilliz
Mike Del Balso, CEO & Co-Founder at Tecton, presents "Full RAG," a novel approach to AI recommendation systems, aiming to push beyond the limitations of traditional models through a deep integration of contextual insights and real-time data, leveraging the Retrieval-Augmented Generation architecture. This talk will outline Full RAG's potential to significantly enhance personalization, address engineering challenges such as data management and model training, and introduce data enrichment with reranking as a key solution. Attendees will gain crucial insights into the importance of hyperpersonalization in AI, the capabilities of Full RAG for advanced personalization, and strategies for managing complex data integrations for deploying cutting-edge AI solutions.
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
1. Government of India & Government of The Netherlands
DHV CONSULTANTS &
DELFT HYDRAULICS with
HALCROW, TAHAL, CES,
ORG & JPS
VOLUME 5
SEDIMENT TRANSPORT MEASUREMENTS
REFERENCE MANUAL
2. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page i
Table of Contents
1 INTRODUCTION TO BED LOAD MEASUREMENTS 1-1
2 BED LOAD MEASUREMENT FREQUENCY 2-1
3 MEASURING TECHNIQUES 3-1
3.1 GENERAL 3-1
3.2 BED LOAD AND NEAR-BED MEASURING TECHNIQUES 3-1
3.3 BED LOAD DETERMINATION METHODS 3-3
3.3.1 BED LOAD SAMPLING 3-3
3.3.2 BED LOAD DISCHARGE COMPUTATIONS 3-5
4 BED LOAD SAMPLERS 4-1
4.1 PRESSURE DIFFERENCE - WINCH-OPERATED SAMPLER – FOR
SHALLOW TO MEDIUM DEEP WATER (HELLEY-SMITH TYPE) 4-1
4.1.1 DESCRIPTION 4-1
4.1.2 SPECIFICATIONS 4-1
4.2 PRESSURE DIFFERENCE - WINCH-OPERATED SAMPLER - FOR SHALLOW
TO MEDIUM DEEP WATER (BTMA-TYPE) 4-1
4.2.1 DESCRIPTION 4-1
4.2.2 SPECIFICATIONS 4-2
5 OBSERVATION PRACTICE 5-1
5.1 INTRODUCTION 5-1
5.2 THE BED LOAD TRANSPORT METER ARNHEM (BTMA) 5-1
5.2.1 GENERAL DESCRIPTION 5-1
5.2.2 OPERATION, PRINCIPAL ADVANTAGES AND LIMITATIONS;
ALTERNATIVES OR CORRECTIONS 5-2
5.2.3 ESSENTIAL INSTRUCTIONS AND PRECAUTIONS FOR OPERATION
FOR THE BTMA 5-3
5.3 THE HELLEY-SMITH BED LOAD SAMPLER (HSS) 5-4
5.3.1 GENERAL DESCRIPTION 5-4
5.3.2 OPERATION, PRINCIPAL ADVANTAGES AND LIMITATIONS;
ALTERNATIVES OR CORRECTIONS 5-5
5.3.3 ESSENTIAL INSTRUCTIONS AND PRECAUTIONS FOR OPERATION
FOR THE H-S 5-7
3. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 1-1
1 INTRODUCTION TO BED LOAD MEASUREMENTS
Bed load gauging (also called bed load transport measurement) is often mixed up with bed material
sampling. Bed load gauging is the measurement of the amount of sediment that is moving as “bed
load”, i.e. rolling, sliding and bouncing (in “saltation”) on or over the stream bottom, while bed material
sampling is the collection of the material composing the stream bottom.
Bed load transport measurements are rightly considered as very difficult and complicated. The
reasons for this are:
• the poor understanding of the transport processes: (what are we measuring?)
• the very irregular character of the particle movement in the bed load
• the disturbance of the flow and of the bed load transport processes when a sampling device is
lowered on the stream bottom
As bed load accounts only for a small fraction of the total load and because measurements are
difficult to perform, bed load transport measurements are most often discarded and replaced by
computations. However, the uncertainties on computations with bed load transport formulas are as
bad as those on measurements. Moreover, the economic importance of bed load observations is
usually underestimated, especially in sand bed streams.
Because of the complexity of bed load transport measurements, extensive training is required.
Besides the obvious need for training in a proper operation and maintenance of bed load instruments,
bed load gauging strategies are required to get the most representative samples and measurements.
Bed load measurements should be avoided if a good training and a thorough follow up of the
measurement procedures can not be ensured.
4. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 2-1
2 BED LOAD MEASUREMENT FREQUENCY
Bed load movement is by nature irregular and random. It is not often measured and a consensus
does not seem to exist about how to determine the frequency of bed load gauging. As bed load has
not yet been routinely observed in the Indian Peninsula, only crude rules may be suggested for
determining in advance the minimum required bed load sampling frequency. In this respect, analyses
of pre-existing suspended load observations and bed material sizes may be of some help.
Bed movement occurs above a flow threshold, e.g., a critical level of velocity or of shear stress. For all
flow under this threshold, the bed material will not or barely move; above the threshold, bed material
will be transported.
The geomorphic setting should be established before starting bed load observations. A survey with a
questionnaire about the characteristics of river basin, river course and gauging station would reduce
significantly the investment and cost for operation and maintenance of a bed load measurement
network.
5. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 3-1
3 MEASURING TECHNIQUES
3.1 GENERAL
The total sediment transported by the stream can be classified under various load and transport
modes:
1. according to origin:
• bed material load, which may be moving as:
• bed load
• suspended load
• wash load moving as suspended load
2. according to transport mechanism:
• bed load
• suspended load, including bed material in suspension and wash load.
Sediment transported as bed load can be measured by:
• the direct method, in which the bed load transport rate at a point is measured directly over a
given time lapse with the aid of a single device;
• the indirect method in which the movement of the bed material is assessed by an observation,
e.g. the movement of dunes resulting from the bed load, over a given time period.
The selection of method and/or device should be made cautiously, taking into account the kind of
environment and objectives, e.g. the type of river, the geomorphic setting, the variation of hydraulic
conditions and sediment characteristics with changing stages, the data needs and their users.
Sediment gauging strategies may be set up by adapting the methods, techniques and instruments
depending to the conditions, for one station or for the network in a catchment.
3.2 BED LOAD AND NEAR-BED MEASURING TECHNIQUES
The instruments for bed load measurements are diverse and specific handling rules apply for each.
However, some general rules can be given, some similar to the ones for near-bed sampling:
• hang the sampler so that it is inclined with the front higher than the rear; this will allow a smooth
landing on the bed with little disturbance of the bed sediments;
• lower the instrument quickly over the vertical as to reduce the sampling in transit, but reducing
speed when coming close to the streambed. This is needed as the drag by the flow will reduce
when the instrument comes closer to the bottom, in slower moving flow layers. This makes the
sampler touch the bed even when keeping the same unrolled length of suspension cable (the dry-
and wet-line corrections become smaller). The frame will hit the streambed and scoop the bottom
If the lowering speed is not reduced; the operator will feel with his hand at the cable when the tail
of the frame touches the ground so that he can unroll the suspension cable slowly for 0.50 cm
more, then unrolling some additional length so as to have the frame standing free on the
streambed;
• start the stop-watch as soon as the sampler has reached the bed;
• the operator has to watch carefully the strength of the cable, otherwise the frame could be
dragged over the stream bottom during sampling, due to the possible swinging of the survey
vessel, disturbing the sampling, e.g. by getting the inlet/nozzle wrongly oriented;
6. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 3-2
• when sampling time is over, the operator will wind up the cable in time so as to have enough
strength in the cable before lifting, otherwise sampling time could be exceeded. He then winds up
the cable quickly but not unduly to avoid dragging the frame over the bed;
• pull the sampler quickly to the surface and empty it immediately.
• handle the sample with much care, especially not to loose solids.
Near-bed load measurements with transport-rate trap samplers may be considered as a special case
of suspended load sampling, although the load may be either suspended- or bed load. The Delft
Bottle sampler, as an example, is mounted on a frame (the sleigh, see Figure 3.1), in its near-bed
version. It produces an additional drag, which complicates the handling. The same precautions as for
the bed load measuring devices apply.
Figure 3.1: Delft bottle with bottom frame
7. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 3-3
3.3 BED LOAD DETERMINATION METHODS
The objective is to determine, by sampling or by calculation, that part of the sediment transported near
the bed or in contact with it, most of it being bed material
3.3.1 BED LOAD SAMPLING
Bed load discharge can be extremely variable. Variations in bed load transport rates – both in space
and with time – may be observed during steady-flow conditions, as well as during changing flow
discharges. Moreover, morphological processes affect the bed load more than the suspended load.
Even during conditions of constant flow, the streambed adapts with a certain lag to the changing flow.
In order to collect a sample, which represents the mean bed load discharge, all variations must be
taken into account. Therefore, an in-depth preliminary site inspection and study should be conducted
before starting bed load measurements.
In sandbed rivers, the spatial or cross-channel variation in bed load transport rate is usually
significant. Bed load transport rates often vary from zero or a small value near banks to larger values
toward midstream, but quite often this distribution does not follow the distribution of the flow velocity,
flow discharge, shear stress or streampower.
The mean cross-channel distribution of transport rate may vary uniformly, may be uniformly
consistent, may be erratic with tongues and stringers or may be an unpredictable combination of
varying tendencies
The temporal and spatial variations in transport rates of bed load discharge that occur under steady
flow conditions are amplified when the stage changes rapidly. In most field sampling programs, the
number of samples collected must represent a compromise between accuracy and economic
feasibility.
Another challenge encountered in bed load sampling is to collect a representative sample. Ideally, the
sampler should trap, during the sampling period, all bed load particles that would normally have
passed through the width occupied by the sampler and reject all particles that normally would not
have passed through the width during the same period. The degree to which this is accomplished is
termed the “sampling efficiency”. It is defined as the ratio of the mass of bed load collected to the
mass of bed load that would have passed through the sampler width in the same time period had the
sampler not been there.
The following general methods that minimise the number of samples required for obtaining a
reasonable estimate of mean cross-sectional bed load discharge, can be used to collect the samples:
1. The single-equal width increment (SEWI, Figure 3.2) method of 20 evenly spaced verticals in the
cross-section. The time the sampler is left on the bottom is equal for all the verticals.
2. The multi-equal width increment (MEWI, Figure 3.3) method: starting at one bank and proceeding
to the other, one sample is collected at 4 to 5 evenly spaced verticals; then, return to the starting
bank and the process is repeated 8 to 10 times until a total of 40 samples has been collected.
Sampling time needs not to be equal at all verticals if the sample collected at each vertical is
bagged separately.
3. The unequal-width increment (UWI, Figure 3.4) method: starting at on bank and proceeding to the
proceeding to the other, one sample is collected from 4 to 10 unevenly spaced verticals, return to
the staring bank, and the process is repeated until a total of 40 samples has been collected.
8. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 3-4
The most suitable method must be derived for each site at which bed load discharge data is to be
collected.
Figure 3.2: Single equal width increment (SEWI) bedload sampling method
Figure 3.3: Multiple equal width increment (MEWI) bedload sampling method
9. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 3-5
Figure 3.4: Unequal width increment (UWI) bedload sampling method
3.3.2 BED LOAD DISCHARGE COMPUTATIONS
The bed load transport rate at a sample vertical may be computed by the equation:
3.1
Where: Ri = bed load transport rate, as measured by bed load sampler at
vertical i, in tons or in m³ per day and unit width (m)
Mi = mass of the sample collected at vertical i , in grams
ti = time the sample was on the bottom at vertical i , in seconds
K = a conversion factor used to convert grams per second per unit
width (meter) into tons or m³ per day per unit width (m).
The simplest method of calculating bed load discharge from a sample collected with a Helley-Smith or
BTMA type bed load sampler is the total cross-section method (Figure 3.5). This is applicable only if
the sample times at each vertical are equal, the verticals were evenly spaced across the cross-section
and the first sample was collected at one half the sample width from the starting bank.
i
i
i
t
M
KR =
10. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 3-6
Figure 3.5: Total cross-section method for computing bed load discharge from samples collected
with a Helley-Smith or BTMA bedload sampler
If these conditions are met then:
3.2
Where: QB = bed load discharge as measured by bed load sampler, in tons or m³
per day
WT = total width of stream from which samples were collected, m
T = total time the sampler was on the bed, in seconds
MT = total mass of the sample collected from all verticals sampled in the
cross-section, in grams
K = conversion factor factor used to convert grams per second per unit
width (meter) into tons or m³ per day per unit width (m).
If the total cross-section method can not be applied, then either the mid section or mean-section
method should be used. The mid-section method (Figure 3.6) is computed using the following
equation:
T
M
WKQ T
TB =
11. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 3-7
3.3
where: Wv1 = width between sampling vertical i and i+1
Si = location of vertical i in the cross-section measured from some
arbitrary starting point, in m.
Figure 3.6: Midsection method for computing bedload discharge from samples collected with a
Helley-Smith or BTMA bedload sampler
The third method, the mean-section method (figure 3.7), is computed using the following equation:
3.4
which is equivalent to:
3.5
( ) ( )
2
WR
2
SS
2
SS
R
2
WR
Q 1n1 vni1i1ii
1n
2i
i
v1
B
−
+
−
+
−
∑+= +−
−
=
( )
2
RR
WQ 1ii
1n
1i
vB i
+
=
=
+
∑=
+∑=
+
+
−
= 1i
1i
i
i
1n
1i
vB
t
M
t
M
W
2
K
Q i
12. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 3-8
Figure 3.7: Mean-section method for computing bedload discharge from samples collected with a
Helley-Smith or BTMA bedload sampler
13. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 4-1
4 BED LOAD SAMPLERS
4.1 PRESSURE DIFFERENCE - WINCH-OPERATED SAMPLER – FOR
SHALLOW TO MEDIUM DEEP WATER (HELLEY-SMITH TYPE)
4.1.1 DESCRIPTION
Winch operated, medium-weight, streamlined sampler for collection of bed load composed of gravel
and sand. The bed material sample is collected in a 0.250 mm-mesh, flexible polyester sample bag
that can be replaced by a spare one. The mechanism to hang the sampler to the suspension cable
must be well designed, making possible a soft landing on the stream bed without scooping of bed
material, with the nozzle well in the direction of the flow.
The sampler efficiency must be provided with the description of the sampler.
4.1.2 SPECIFICATIONS
1 Operating conditions
• Flow velocity : up to 2.5 m/s
• Water depth : up to 15 m
• Sampled zone from the bed : at least 0.05 m
2 Features
• Steel frame, equipped with tail for keeping the sampler aligned in the flow
• Rectangular intake nozzle, with sharp front edges
• Iso-kinetic sampling
• 0.250 mm-mesh, flexible polyester sample bag
• Total weight (empty): 32 Kg
3 Drawings
4.2 PRESSURE DIFFERENCE - WINCH-OPERATED SAMPLER - FOR
SHALLOW TO MEDIUM DEEP WATER (BTMA-TYPE)
4.2.1 DESCRIPTION
Winch operated, medium-weight, streamlined sampler for collection of bed load composed of gravel
and sand. The bed material sample is collected in a 0.3 mm-mesh, rigid metal-wire sample basket.
The basket is to be emptied through a brass tailpiece with emptying plug. The mechanism to hang the
sampler to the suspension cable must be well designed, making possible a soft landing on the
streambed without scooping of bed material, with the nozzle well in the direction of the flow. The
nozzle has a rectangular opening, 0.085 m wide and 0.05 m high.
The sampler efficiency must be provided with the description of the sampler.
14. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 4-2
4.2.2 SPECIFICATIONS
1 Operating conditions
• Flow velocity up to 2.5 m/s
• Water depth up to 15 m
• Sampled zone from the bed at least 0.05 m
2 Features
Sampler:
• Steel frame, equipped with tail for keeping the sampler aligned in the flow
• Rectangular intake nozzle (8.5 cm wide by 5 cm high), with sharp front edges
• Almost iso-kinetic sampling
• 0.300 mm-mesh, rigid metal-wire basket
• Total weight (empty) : 32 Kg
3 Drawings
15. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 5-1
5 OBSERVATION PRACTICE
5.1 INTRODUCTION
This chapter on observation practices contains general instructions for operation and maintenance of
samplers and instruments for bed load measurement.
As a matter of fact, many difficulties and questions may arise during implementation of sediment
measurement methods, techniques and instruments; those may be so specific to the river or site that
they have to be appraised separately for each site by qualified personnel. The routine procedures are
making the operators/observers loosing alertness for basic details. The field checking procedures
would therefore be given due importance.
Though the need to measure bed load was recognised in India, very little experience was gathered in
this field. The CW&PRS can produce the Mulhofer box-basket type sampler, but this is not the most
appropriate instrument available on the market. Both the BTMA and the Helley-Smith might be used in
sand or gravel bed streams.
Quite a lot of devices, instruments and techniques have been developed for bed load measurements.
Very little have passed the experimental stage. In streams where bed load is mainly composed of
gravel and sand/silt, can best be sampled by trapping the transported material during a given time,
with the transport-rate method. When the streambed is covered with bedforms such as dunes, the so-
called “dune-tracking” method can be applied, though the reliability of the method is often disputed.
Considering the present needs in India, only the transport-rate trapping samplers based on the
pressure-difference principle are described hereafter.
5.2 THE BED LOAD TRANSPORT METER ARNHEM (BTMA)
5.2.1 GENERAL DESCRIPTION
The BTMA (see Figure 5.1) was designed for sampling in the Dutch sand bed rivers. The sampling
body is made of brass, with a streamlined shape having a rectangular open mouth directed towards
the flow and a permeable tail through which the entering flow escapes. The shape is designed in such
a way as to have a pressure difference between the front and rear so that it equalises the flow
resistance in the sampler. This feature ensures an almost iso-kinetic sampling.
The mouthpiece is a rectangular tube, connected by an elastic rubber funnel to the “fishing-type”
basket made of fine metal wire meshing (0.3 mm opening). Only the sediment particles having a size
larger than the mesh openings are trapped. The efficiency of the sampler varies obviously with the
rate of filling.
The rectangular mouthpiece may scoop the bed material if it hits the bottom too hard. In order to avoid
this scooping, the sampler body is hanged in a frame equipped with two supporting plates in front and
a tail especially designed to orient the sampler rightly in the flow when landing on the stream bed. The
mouthpiece is attached to a system with lever arm and double leaf spring system, suspended from the
supporting cable together with the tail. The sampler is hanged in such a way that it would land with the
tail first. When the cable is further slackened, the front feet come to rest on the stream bottom, but
with the mouthpiece still away from it. If correctly operated, this mouthpiece will touch smoothly the
riverbed the latest.
16. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 5-2
Figure 5.1: Bed load transport meter Arnhem (BTMA)
Though the device was designed for operating in flow depths and velocities limited respectively to 5 m
and 1 to 1.5 m/s, it was utilised successfully in depths up to 20 metres (even more) and velocities
larger than 2.5 m/s. When operated in high flow depths and strong currents, it is necessary to add
some load on the front and rear supporting plates.
The efficiency of the sampler was studied and correction factors are given with the sampler’s
specifications.
5.2.2 OPERATION, PRINCIPAL ADVANTAGES AND LIMITATIONS; ALTERNATIVES OR
CORRECTIONS
The instrument can be operated from a bridge or from a boat. The sampler must be suspended in
such a way as to have the front plates higher than the tail plate. The water depth must be measured
or assessed as accurately as possible before sampling. The sampler is lowered quickly to a position
close to the stream bed, then much slower as to have a soft landing. The suspension cable must be
sufficiently slackened, so that the sampler remains freely on the stream bottom. This is particularly
true when operating from a boat as its position is never perfectly fixed and the cable can come under
tension when the boat swings around its station. In that case, the sampler may be dragged over the
stream bottom, with the risk to have the mouthpiece scooping in the bed material.
The risk for bed scooping is larger in strong currents, as described earlier. Because of the drag
created by shape of the instrument, it will have the tendency to drift away during the lowering to the
stream bottom. However, when approaching the bed, the drag reduces in the near-bed zone where
the flow velocities are smaller, so that the sampler will move in upstream direction. With a length of
the cable equal to the water depth measured vertically from the suspension point, the sampler could
hit the bed if the unrolled cable length is higher than the water depth.
Overestimation of bed load transport is therefore quite common, as it is quite difficult to reject peak
values for a transport process in which these peaks can be explained by the irregularity of the
sediment movement on the bed.
17. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 5-3
Bed load movement is very irregular and unpredictable, especially for sand bed rivers for which the
BTMA is well suited. Consecutive catch volumes may thus vary in a strong and erratic way, requiring
repetitive sampling to get a representative average. It is obviously never possible to assess how much
the variability in the catch size is due to the variation in time of the transport rate in comparison with
the sampling errors due to the operation of the sampler (such as those due scooping effect, or due to
dragging of the sampler over the river bed, besides others).
The bed load transport rates can display a strong spatial variation, mainly in relation with bedforms.
This presence of bed forms may contribute to this variability. When sampling from a boat, this would
always be positioning in the upper part of the upstream side of the bed form, never on the lee side or
in the trough between two bed forms. In presence of bed forms, the sampling procedure becomes
quite complicated, because the operators have first to survey by echo-sounder a longitudinal profile
passing along the predetermined sampling position. Based on the presence of bed forms, the best
possible sampling position is selected, usually not in the gauge line, mostly up- or downstream of it.
5.2.3 ESSENTIAL INSTRUCTIONS AND PRECAUTIONS FOR OPERATION FOR THE BTMA
Before sampling
• Verify the sampler for possible damage, among other mouthpiece, suspension of the basket,
mesh wiring
• Verify the inclination of the sampler when hanging free from the davit : front support plates higher
than the back one (by at least 20 cm)
• Check regularly the landing of the instrument on a flat surface, such as the boat deck
• Measure or assess the water depth at the sampling position
While sampling
• Lower the sampler as quickly as possible to about one meter above the stream bed, then slower
in the last meter
• Control the tension in the cable to detect the landing of the sampler on the stream bottom,
moment of the start of the sampling
• Some 20 seconds before the end of the sampling, start to wind up the cable, without bringing it
under too high tension
• At the end of the sampling period, wind up quickly the suspension cable, but without any sudden
movement
• Avoid dragging the sampler on the stream bottom; try to detect such dragging, if any
• Repeat the sampling to assess how much the catch varies with time
From a boat
• Keep the boat as much as possible in a stable position, eventually with the help of the engines if
the boat is anchored
• Slacken more cable if this comes in tension when the boat swings around its anchor
• Wind up the cable sufficiently in advance – at least 30 seconds – to reduce the slack, without
bringing it too much under tension
• Start hoisting the sampler at the predetermined time, taking the right end-time for sampling when
the cable is fully under tension
From a bridge
• If the dry line is very long and the flow velocity strong, it might be difficult to assess when the
sampler reaches the bed and a first “blank” measurement may be required to evaluate the length
of cable needed for the sampler to reach the stream bottom dry- and wet-line corrections
18. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 5-4
• Cable must be given enough slack, but not too much
• Stop the measurement if the cable had enough slack at the start but comes into tension during
sampling, as this would indicate that the device is drifting under too much drag
• If the sampler is dragged over the stream bottom by too strong currents, this may be corrected by:
• Adding some weight on the supporting plates (or “feet”)
• Fixing a heavy fish-weight on the cable just above the sampler, at the end of the suspension line
• Start hoisting the sampler at the predetermined time, taking the right end-time for sampling when
the cable is fully under tension
After sampling
• Except for those samples for which the sampler was evidently not behaving correctly (e.g.
scooping at landing, dragging over bed), no samples may be rejected before analysis
• Large variation in catch size and in particle size may be normal
• Empty the basket in the special tray and wash it out with clean water
• Drain the excess water
• Open the tray stop to fill the measuring glass while washing with clean water and let the
suspension settle for 100 seconds
• Measure the sample volume and collect it in a polyethylene bag, to be stored in a cloth bag,
properly sealed and labelled
• Record all circumstances of the sampling
5.3 THE HELLEY-SMITH BED LOAD SAMPLER (HSS)
5.3.1 GENERAL DESCRIPTION
The Helley-Smith sampler (Figure 5.2) was designed in the US, based on the experience with the
BTMA. The concept is much more elementary. The quite large supporting frame of the BTMA has
been replaced by a simple steel frame without front playing the role of sample support, and on which
the nozzle (mouth-piece) is fixed rigidly. The brass mesh wire basket was replaced by a 0.250 mm-
mesh, flexible polyester sample bag.
Several versions of the sampler have been used for various field conditions. Larger nozzles are
needed for larger particle sizes and heavier samplers for deeper and faster rivers. The Helley-Smith is
widely used and has been calibrated with a large number of experiments, in the field and in the
laboratory.
19. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 5-5
Figure 5.2:
Helley Smith bed-load sampler
5.3.2 OPERATION, PRINCIPAL ADVANTAGES AND LIMITATIONS; ALTERNATIVES OR
CORRECTIONS
The advantage of the sampler is its simplicity. It is well suited for gravel bed rivers, with particle sizes
above the silt fraction (mainly the “coarse” fraction). The design is elementary, without moving parts
and there is little risk of malfunctioning of the device itself. The flexible polyester basket is easy to
handle and to replace if damaged.
The sampler is quite popular, but it is not always utilised in an optimum way. The rather limited frame
is appropriate for coarse bed material, but in very mobile sand bed rivers, the frame may become
buried in the sand. As the nozzle is rigidly fixed to the frame, it will also be buried and take more
material than carried by the actual bed load transport. The landing of the instrument on the stream
bottom in fast flowing rivers can also be problematic when lowered too quickly, scooping the bed (see
Figure 5.3).
20. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 5-6
The efficiency of the Helley-Smith was assessed in field and laboratory conditions. The efficiency is
said to be related to the difference between intake velocity and the local flow velocity. However,
during some laboratory tests, the sampler was taking more sample than the actual bed load transport
rate. Video observations showed gravel particles travelling aside of the nozzle suddenly “sucked” into
it; the corresponding sampling efficiency for that experiment appeared to be of the order of 140%.
Figure 5.3: Scooping when lowering too fast
Most important is to select the appropriate version of the Helley-Smith sampler for the conditions
prevailing in the river to be gauged. In case the discharges, flow velocities and water depths vary
widely, different versions of the sampler may be needed.
The instrument can be operated from a bridge or from a boat. The sampler must be suspended in
such a way as to have the nozzle basis higher than the tail plate. The water depth must be measured
or assessed as accurately as possible before sampling. It is lowered quickly to a position close to the
stream bed, then much slower as to have a soft landing. The suspension cable must be sufficiently
slackened, so that the sampler remains freely on the stream bottom. This is particularly true when
operating from a boat as its position is never perfectly fixed and the cable can become under tension
when the boat moves around its station. In that case, the sampler may be dragged over the stream
bottom, with the risk to have the nozzle scooping in the bed material.
21. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 5-7
The risk for bed scooping is larger in strong currents. In fine-sand bed rivers, for which the Helley-
Smith is not so well suited, the bed load movement is very irregular and unpredictable. For gravel bed
rivers (bed load particles coarser than fine sand), the instrument is well suited, but the bed load
transport can still be quite irregular.
The bed load transport rates can display a strong spatial variation. This presence of bed forms may
contribute to this variability. When sampling from a boat, this would always be positioning in the upper
part of the upstream side of the bed form, never on the lee side or in the trough between two bed
forms. In presence of bed forms, the sampling procedure becomes quite complicated, because the
operators have first to survey by echo-sounder a longitudinal profile passing along the predetermined
sampling position. Based on the presence of bed forms, the best possible sampling position is
selected, usually not in the gauge line, mostly up- or downstream of it.
5.3.3 ESSENTIAL INSTRUCTIONS AND PRECAUTIONS FOR OPERATION FOR THE H-S
Before sampling
• Verify the sampler for possible damage: frame, nozzle and basket
• Verify the inclination of the sampler when hanging from the davit : nozzle higher at least 20 cm
higher than tail bottom plate
• Check regularly the landing of the instrument on a flat surface, such as the boat deck
• Measure or assess the water depth at the sampling position
While sampling
• Lower the sampler as quickly as possible to about one meter above the stream bed, then slower
in the last meter
• Control the tension in the cable to detect the landing of the sampler on the stream bottom,
moment of the start of the sampling
• Some 20 seconds before the end of the sampling, start to wind up the cable, without bringing it
under tension
• At the end of the sampling period, wind up quickly the suspension cable, but without any sudden
movement
• Avoid dragging the sampler on the stream bottom; try to detect such dragging
• Repeat the sampling to assess how much the catch varies with time
From a boat
• Keep the boat as much as possible in a stable position, eventually with the help of the engines if
the boat is anchored
• Slacken more cable if this comes in tension when the boat swings around its anchor
• Wind up the cable sufficiently in advance – at least 30 seconds – to reduce the slack, without
bringing it under tension
• Start hoisting the sampler at the predetermined time, taking the right end-time for sampling when
the cable is fully under tension
From a bridge
• If the dry line is very long and the flow velocity strong, it might be difficult to assess when the
sampler reaches the bed and a first “blank” measurement may be needed to evaluate the length
of cable needed for the sampler to reach the stream bottom dry- and wet-line corrections
• Cable must be given enough slack, but not too much
22. Reference Manual – Sediment (SW) Volume 5
Sediment Transport Measurements January 2003 Page 5-8
• Stop the measurement if the cable had enough slack at the start but comes into tension during
sampling, as this would indicate that the device is drifting under too much drag
• If the sampler is dragged over the stream bottom by too strong currents, this may be corrected by
fixing a heavy fish-weight on the cable just above the sampler, at the end of the suspension line
• Start hoisting the sampler at the predetermined time, taking the right end-time for sampling when
the cable is fully under tension
After Sampling
• Except for those samples for which the sampler was evidently not behaving correctly (e.g.
scooping at landing, dragging over bed), no samples may be rejected before analysis
• Large variation in catch size and in particle size may be normal
• Empty the bag in a tray and wash it out with clean water
• Drain the excess water
• Open the tray stop to fill the measuring glass while washing with clean water and let the
suspension settle for 100 seconds
• Measure the sample volume and collect it in a polyethylene bag, to be stored in a cloth bag,
properly sealed and labelled
• Record all circumstances of the sampling