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Indirect Measurement Field Techniques Video Index

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General Field Procedures for Indirect Measurements

Overview of Indirect Measurements—Survey Requirements
This video provides an overview of the different indirect measurement methods used by the USGS, as well as a brief description of what you'll need to survey for each.

 

Site Selection for Indirect Discharge Measurements
This video demonstrates how to select an appropriate location for an indirect measurement. Theory and initial reconnaissance are discussed.

 

A USGS Guide for Finding and Interpreting High-Water Marks 
High-water marks provide valuable data for understanding recent and historical flood events. The proper collection and recording of high-water mark data from perishable and preserved evidence informs flood assessments, research, and water resource management. This video provides guidance for skilled high-water mark identification, including marks left behind in natural and man-made environments by tranquil and rapid flowing water. Additionally, this video also presents pitfalls and challenges associated with various types of flood evidence that help hydrographers identify the best high-water marks and assess the uncertainty associated with a given mark. Proficient high-water mark data collection contributes to better understanding of the flooding process and reduces risk through greater ability to estimate flood probability. For a more detailed explanation of these methods be sure to read the Techniques and Methods Manual: Identifying and preserving high-water mark data.

 

Surveying High-Water Marks and Cross-Sections for Indirects
This video describes how to survey high-water marks and cross-sections for indirect measurements. Included are tips and tricks for getting across non-wadeable sections of the stream. 

 

Plotting High-Water Marks in the Field Using SAC-GUI
This video describes how to use SAC-GUI in the field to plot high-water mark profiles. Plotting high-water marks in the field is required for most indirect measurement techniques.

 

Indirect Measurement Field Notes and Metadata
This video describes the notes and other metadata that need to be recorded during indirect measurement surveys.

 

Selection of Roughness Coefficients
This video describes the field selection of roughness coefficients, or Manning's "n" values. Both the comparative (photos) and analytical (Cowan's) methods are discussed. Roughness Coefficients PDF.

 

 

Slope-Area Method

Theory of the Slope-Area Method
This video covers the theory behind a slope-area indirect measurement, the most common type of indirect measurement used in the USGS.

 

Surveying Slope-Area Measurements
This video goes into detail about where to flag high-water marks and how to survey a slope-area measurement. A simple one-setup Total Station survey is demonstrated.

 

 

Culverts

Survey Requirements for Culvert Indirect Measurements - Overview
This video describes the survey requirements for culvert indirect measurements, including high-water mark and cross-section locations.

 

Survey Requirements for Culvert Indirect Measurements – Culvert Survey
This video describes the survey requirements for culvert indirect measurements, specifically how to measure various aspects of the culvert itself. This video provides a general overview of how to survey culvert attributes, such as the invert and length.

 

Survey Requirements for Box Culverts
This video details how to measure various aspects of a box culvert for a culvert indirect measurement. The video includes tips and tricks for measuring the geometry, wingwall angles, and entrance types including rounded or beveled entrances.

 

Survey Requirements for Pipe Culverts
This video demonstrates how to measure various aspects of pipe and pipe-arch culverts for culvert indirect measurements. The video includes tips and tricks for measuring the geometry, corrugations, and entrance types including rounded or beveled entrances.

 

Survey Requirements for Non-Standard Culverts
This video discusses how to measure various aspects of non-standard culverts, such as mitered culverts. Using the slope-area method inside a culvert is also discussed.

 

 

Width Contractions

Requirements for the Contracted-Opening Method
This video discusses the general requirements that will be needed to accomplish a contracted-opening indirect discharge measurement. Approach section, contracted section, and necessary high-water mark locations are described along with scenarios where the method will not be successful.

 

Surveying Contracted-Opening Indirect Measurements
This video goes into detail about surveying high-water marks, various aspects of bridges, and cross sections for the contracted-opening method.  

 

 

Dams, Road Overflows, and Broad-Crested Weirs

Survey Requirements - Road Overflow/Broad-Crested Weir
This video describes how and where to flag high water marks for a road overflow or broad-crested weir indirect measurement of peak discharge.

 

Survey Requirements for Road Overflow Indirect Measurements
In this video, you will learn what and where to survey for a road overflow or broad-crested weir indirect measurement.

 

 

Combined Methods

Survey Requirements for Multiple Component Indirect Measurements
This video describes the survey requirements for indirect measurements with multiple components, like flow going through a culvert and over a road on top of the culvert at the same time.

 

 

Critical Depth Method

Survey Requirements for Critical Depth Indirect Measurements
This video describes the high-water marks needed along with cross-section locations for critical depth indirect measurements. Critical depth computations are those performed when flow goes through a critical flow regime at a drop, such as at a waterfall. 

 

 

Slope-Conveyance Method

Introduction to the Slope-Conveyance Method
This video provides an introduction to the slope-conveyance method of indirect measurement. Theory and background are described as well as high-water mark and cross-section placement.

 

Surveying Slope-Conveyance Indirect Measurements
This video shows how to survey a slope-conveyance indirect measurement using a conventional optical or digital level.

 

 

Surveying Methods

Surveying with Conventional Level
In order to present the most up‐to‐date information possible for this series, this video will be released when the new trigonometric leveling Techniques and Methods Report has been published. In the meantime, you can view the video called Surveying Slope‐Conveyance Indirect Measurements to understand the mechanics of how to use a conventional level to survey distances and angles for an indirect measurement.

 

Conventional Level Data Management
This video describes how to use the SAC conversion spreadsheet to convert data from a conventional level in angles and distances (polar coordinates) to Cartesian coordinates (northings and eastings).

 

Surveying with Total Station
In order to present the most up‐to‐date information possible for this series, this video will be released when the new trigonometric leveling Techniques and Methods Report has been published. In the meantime, you can view the video called Surveying Slope‐Area Measurements to understand the mechanics of how to use a Total Station to survey northings and eastings for an indirect measurement.

 

Surveying Indirect Measurements with GNSS
This video details how to survey indirect measurements with GNSS. Both RTN and RTK setups are discussed, along with tips and tricks and troubleshooting.

 

 

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