Procedures for running levels at gaging stations-- Training Course SW1683

This training course has been designed to illustrate how methods presented in Techniques and Methods Report 3-A19, "Levels at Gaging Stations", by T. A. Kenney can be implemented. This objective is met using graphics and notes and video clips showing how work is conducted in the field. All class material is linked to the Course Outline on the left side of this page. Links to selected video clips used in the training material are indexed, below. Please see our "Getting Started" presentation if you have questions about how to navigate through the course modules. To get official credit for the course USGS and other Department of Interior (DOI) employees must register for course (SW1683) in DOILearn (

Course Outline
Links to modules are underlined

Selected Video Clips
(Transcripts of all videos in the course are available here)

Why Maintain Datum

  • Stage and Datum
  • Datum changes
  • The T&M reference

Leveling Equipment

  • Types of levels
  • "Secondary" devices
  • Peg test
    • Fixed scale test
    • Testing Frequency
    • Policy on re-running levels when instruments are improperly adjusted
  • The value of "Balanced" shots
  • Care before, during and after use
Level Frequency
  • New gage installations
  • Maintaining an historical summary
  • What must be done if discrepancies are found
  • How is "Stability" defined
  • Decision tree for deciding when to run levels.

Basic Leveling Concepts

  • Backsights
  • Foresights
  • Reading self-reading rod
    • Using Rod Levels
  • Parallax
  • Correcting for temperature of rod-scale material
Preparations to Ensure Successful Field Work
  • In the office
    • Consider site conditions
      • Special equipment
      • Survey origin
      • Safety concerns
  • In the field
    • Plan instrument setups
      • Plan for balanced shots
    • Record gage readings
    • Record rod temperature
Running Levels
  • Side Shots
  • Turning Points
  • Requirements for surveying objective points
  • When more than one "loop" is needed
  • Shooting to gages
    • Staff gages
    • Electric tape gages
    • Wire weight gages
  • Using "Tape Downs"
  • Closure error
    • Office of Surface Water Policy
    • Distributing Closure Error
  • Evaluating error associated with side shots
  • Adjusting gages after surveying
  • Applying corrections to the discharge record
  • Collecting "auxiliary" data
Example Level Run
  • Stilling well site
  • Establishing initial HI
  • Establishing first elevations for RMs and BMs
  • Shooting the ETG index, staff and water surface
  • Reading the gages
  • Shooting ETG weight
  • Establishing second elevations for RMs and BMs
  • Establishing "closure error"
  • Notes

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Image of T&M cover Kenney, T.A., 2010, Levels at gaging stations: U.S. Geological Survey Techniques and Methods 3-A19, 60 p.

To see how guidance in the new T & M differs from previous guidance in TWRI Book 3, Chapter A19 click here

U.S. Geological Survey
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Page Last Modified: March 20, 2013