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Oct 27, 2015 · 2010 USGS T&Ms for stage measurements and station levels: Maintain a permanent gage datum so that only one datum for the gage-height record is used for the life of the gaging station. Reference to NAVD88.
The term datum is used when the base gage-height has been surveyed from benchmarks or precision GPS, and the term elevation is used when the base gage-heights has been determined from less accurate means, such as with a map or a barometer.
- °F=(1.8×°C)+32
- U.S. Geological Survey
- Abstract
- Basic Requirements for Collecting Stage Data
- Gage-Component Definitions
- Hydraulically Induced Errors
- Recorder Errors
- Retrieval Errors
- Verification Errors
- Lightning Protection
- Instrumentation
- Nonrecording Gages
- Figure 18. A and B, Type A wire-weight gage.
- Cantilevered Wire-Weight Gages
- Float-Tape Maximum- and Minimum-Stage Indicators
- Water-Level Sensors
- Basic Float System
- Nonsubmersible Pressure Transducers
- Submersible Pressure Transducers
- Radar
- Rapid Deployment Gages
- Figure 44. A and B, Typical USGS rapid deployment streamgage with a DCP and Ott RLS radar stage sensor.
- Optical (Laser)
- Water-Level Recorders
- Electronic Data Loggers
- Figure 47. A, Typical installation of float-tape gage and B, electronic shaft encoder and electronic data logger (EDL).
- Schematic showing flow of hydrological data for a DCP transmission from a gaging station to the Internet.
- Timers
- Power Supplies
- Instrument Shelter, Submersible Pressure Transducer or Noncontact Radar-Stage Sensor and Electronic Data Logger/Data-Collection Platform
- Schematic of a submersible pressure transducer used to measure stage with EDL and (or) DCP.
- Data Retrieval and Conversion
- New Stage-Station Design
- Site Selection
- Sensor Selection
- Recorder Selection
- Operation of Stage-Measurement Station
- Clock, Timer, and Battery Check
- Record Retrieval
- Float-Sensor, Gage-Well, and Intake Inspection
- Bubble-Gage, Gas-System, and Orifice Inspection
- Submersible Pressure Transducers
- Noncontact Radar-Stage Sensors
- Maximum- and Minimum-Stage Determinations
- Final Recheck
Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:
U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey
Stream and reservoir stage are critical parameters in the computation of stream discharge and reservoir volume, respec-tively. In addition, a record of stream stage is useful in the design of structures that may be affected by stream elevation, as well as for the planning for various uses of flood plains. This report describes equipment and methodo...
The collection of stage data, either manually or auto-matically, requires various instrumentation, or components, established at a gaging site. For stage data to be useful for their intended purposes, requirements for maintaining a per-manent gage datum and meeting speciied accuracy limits are important. This section of the report provides definiti...
The reference gage for an automatic recording gaging sta-tion is a nonrecording gage used to set recorders, data loggers, or transmitters from which the primary gage-height record is obtained. The reference gage designated for this purpose is sometimes called the base gage, but this report uses the term “reference gage,” as defined by Rantz (1982)....
High velocity in the stream near the outside end of the intake pipes can cause drawdown, or sometimes buildup, of the water surface inside a stilling well. A similar condi-tion can occur when high velocity occurs near a bubble-gage orifice. For example, where a sensor is located on the downstream or upstream side of a pier, the drawdown or buildup ...
Automatic stage recorders include analog (graphic) recorders, digital (punch tape) recorders, data collection plat-forms (DCPs), and electronic data loggers (EDLs). Analog and digital recorders are mechanical recorders that can have play within the drive chains, gears, and (or) other linkages. Graphic recorders may also experience paper expansion a...
Retrieval errors resulting from DCPs and EDLs occur because downloading the data from the data logger to a field computer is an electronic process that can sometimes result in incorrect stage readings and lost data. An even more seri-ous problem would be the complete loss of stage data. Data errors or loss can also occur when downloading the data f...
Stage readings require frequent and consistent verifica-tion to ensure that errors are reduced or eliminated. Failure to perform proper verification standards can be the source of undetected, and possibly significant, stage errors. Verification procedures include frequent reading of independent auxil-iary gages, comparison of inside- and outside-ga...
A lightning-protection system is needed for gaging structures to ensure uninterrupted data collection and to minimize expensive repairs to instruments and equipment that might otherwise be damaged by lightning. The best and most effective lightning protection for instruments, such as satellite data-collection platforms (DCPs), EDLs, stage sensors, ...
Many instruments are available for observing, sensing, recording, and transmitting stage data. Such instrumenta-tion ranges from the simple nonrecording auxiliary gages to sophisticated water-level sensors, noncontact radar sensors, electronic data loggers, and telemetry systems, such as satel-lite data-collection platforms (DCPs). This section des...
One method of obtaining a record of stage is by the systematic observations of a nonrecording gage. In the early days of the USGS, this was the means generally used to obtain records of stage, and is still used at a few gaging stations, but today water-level sensors and automatic water-stage record-ers are the predominant instruments used at practi...
touches the water. Various methods are used, such as creating slight pendulum motion that will disturb the water surface at the low point of the swing. Another method is to lower the weight into the water a few hundredths of a foot, and raise it a hundredth at a time, each time making a quick upward movement of the weight. If the weight is in the w...
A cantilevered wire-weight gage is sometimes used where outside staff gages are hard to maintain and where a bridge, dock, or other structure over the water is not available for the location of a wire-weight gage. A wire-weight gage can be mounted on a cantilevered arm that extends out over the stream, or which is made in such a way that it can be ...
An advantage of a float-tape gage is that maximum- and minimum-stage indicators can be used on the tape so that the maximum and minimum stage can be determined for the period between station visits. These indicators are wire clips (similar to a paper clip and also referred to as Dahman indicators), or small magnets that are attached to the float ta...
A water-level sensor, or stage sensor, was defined in a previous section of this report as a device that automati-cally determines, or senses, the vertical position of the water surface. In reality, stage sensors are usually not a single device, but a combination of two or more components that work together to sense the water-level position. The tw...
The basic float sensor consists of a float resting on the water surface in a stilling well. The float is attached to a tape or cable passing over a pulley, with a counter weight attached to the other end of the tape or cable. This is identical to the float-tape reference gage described in a previous section of this report, and is shown in figure 20...
Nonsubmersible pressure transducers are generally used as the pressure sensor for bubble-gage systems. These transducers are connected to the gas-purge unit to receive the pressure input from the stream. The transducers are internally programmed to convert the gas pressure to units of water head (feet of water over the orifice), and to then transmi...
A number of submersible pressure transducers are com-mercially available for use, primarily in groundwater wells, although in a growing number of applications, they have been used for streams and reservoirs. Submersible pressure trans-ducers are usually self-contained units having a transducer ele-ment and electronic circuitry. Some also contain a ...
Radar, or radio-frequency transmission, is a distance-measuring method that has been used since before World War II. A radio frequency is the propagation of an electro-magnetic field, and therefore, is performed at the speed of light. The advantages of radar are that the signal is gener-ally immune to weather conditions, such as snow and rain, and ...
In recent years, the USGS has implemented a pro-gram whereby the HIF constructs and stores portable look-in shelters with stage sensors and preconfigured DCPs, batteries, solar panels, and other equipment to use in a rapid deployment during floods. Currently, the stage sensor for most of these gages is a noncontact radar-stage sensor. These portabl...
These gages could also be used for wildfires, major chemical spills, and other natural and anthropogenic disas-ters. The need for rapidly deployable streamgages has grown sequentially over time.
Optical methods of measuring distance are confined mainly to the use of laser, a technology that deserves further investigation for use in measuring water-level stage. Eye safety is a consideration with lasers because direct exposure of the eyes to a laser beam could be dangerous and cause permanent vision loss or other damage to the eyes. Generall...
A water-level recorder is an instrument that automatically records a continuous, or quasicontinuous, record of the water-surface stage with respect to time. Water-level recorders may be paper chart recorders (analog), paper punch-tape analog-digital recorders (ADRs), EDLs, or DCPs. The basic require-ments for a recorder are to systematically and ac...
Electronic data loggers (EDLs) are devices that can be programmed to electronically record stage data (or other variables) on a specific, regular time interval, or on a user-defined schedule that may vary according to stage or other variable. There are a number of manufacturers and vendors of EDLs, which include Sutron, Coastal Environmental System...
memory card. Most EDLs allow for both methods of data stor-age. Data are retrieved either by downloading directly from the EDL to a PDA or other field computer, or by removing the memory card and transferring the data from the card to a PDA or other field computer. The portable memory card can then be carried to the field ofice for downloading. Dat...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
After other work is done at the gaging station, such as making a discharge measurement, painting, differential-level survey, or other maintenance, before leaving that station, return to the gage and make a final check of the DCP, EDL, and other instruments. Make another complete set of gage readings, recording all, including the watch time, on insp...
- 7MB
- Vernon B. Sauer, D. Phil Turnipseed
- 60
- 2010
The term datum is used when the base gage-height has been surveyed in from known benchmarks or with precision GPS. The term elevation is used when the base gage-height has been determined from less accurate means, such as maps, barometer, etc.
- Not Getting Calibration. Let's address the most troublesome mistake first - not getting calibration. It doesn't matter if you have a world class gage management program set up.
- Improper Intervals. Hopefully, you are already getting calibration, but if so, when is the last time you put thought into your calibration intervals?
- Not Using Tracking Software. Once your intervals are under control, the next biggest mistake is not properly tracking these calibrations. Unfortunately, too many people think they can get by with relying on calibration labels, drawers full of calibration certificates, or handwritten spreadsheets for managing this data.
- Manually Updating Data. Simple fact: having a strong calibration program is a huge value add for your company. However, the time you spend on this is not.
Nov 4, 2020 · In a few years the key datum of the last 30 years, the North American Vertical Datum of 1988 — the datum used by federal agencies such as the Federal Emergency Management Agency and the U.S. Army Corps of Engineers — will be replaced by a new, satellite-based system.
People also ask
When should a Gage datum be changed?
What is the meaning of 'datum' and 'elevation'?
Which USGS gages are reported to NGVD or NAVD?
Which datum is used for stream gages?
Key Tips: 3⁄4 Always know your datum, whether on a map sheet, a GPS point, or a GIS layer. 3⁄4 Be sure to use the right ellipsoid for your datum. 3⁄4 Whenever possible, use the WGS 84 datum. 3⁄4 Be aware of datum conversion factors between the commonly used datums in your area. Datum Resources:
