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The HIF has several labs and field sites that offer unique capabilities for evaluating instrumentation. The Hydraulics Laboratory's tanks and flumes test instruments under a variety of conditions, and the Environmental Test Chamber and Water Quality Labs perform quality assurance tests and evaluations. The HIF also deploys instruments for field testing at stations on the Pearl and Wolf Rivers.

Interior of the USGS HIF Hydraulic Laboratory

Hydraulics Laboratory

The Hydraulics Laboratory is a one-of-a-kind facility within the United States. Meters, flumes, and other flow-measuring devices are evaluated and calibrated at the laboratory before being used by the USGS and other Federal and State agencies. Standards are also developed that affect USGS operations nationwide. The HIF is also used in water-resources investigations and to obtain experimental research data on the mechanics of flow and the transport and dispersion of heat, solutes, and solids in rivers and estuaries.

  • Towing tank:  Sized at 12 x 12 x 450 feet (ft), this tank is used to test and calibrate instruments that measure water velocity by the principle of cup rotation, drag, Doppler effect, acoustic signal, electromagnetic field, deflection, or other means. The tow vehicle is capable of speeds from 0 to 18 feet per second (ft/s) and has a platform size of 12 x 14 ft. The carriage is equipped with a data acquisition system designed to accept distance traveled, elapsed time, and meter pulse count information.

  • Submerged jet tank:  Built as a 12 x 12 ft cross section and is 120 ft long. The tank provides a low turbulence, live-velocity source; that is, the water moves past the stationary meter. The discharge into the tank flows from the constant head tank to the head box of the jet, through the jet, over a weir, and back to the sump from which pumps convey the water back to the constant head tank. The system allows for a discharge stable to less than 0.5 percent. Discharge measurements are made using calibrated volumetric tanks. Velocities of the 2-ft diameter jet have a stable range of 0.25 to 8 ft/s.

  • Large acoustic tank:  The large acoustic meter tow tank is a 4 ft wide, 4 ft deep, 80 ft long tank with a carriage that travels on rails mounted above the tank's side wall. The carriage can travel at velocities ranging from 0.1 to 3 ft/s (0.03 to 0.91 meters per second, or m/s). Constant water velocity is simulated by suspending the meter from the tow carriage into the still water of the tank and moving the carriage at a constant velocity.

  • Small acoustic tank:  The small acoustic meter tow tank is a 3 ft wide, 3 ft deep, 9 ft long tank with a carriage that travels on rails mounted above the tank's side wall. The carriage can travel at velocities ranging from 0.59 to 1.5 ft/s (0.18 to 0.46 m/s). Constant water velocity is simulated by suspending the meter from the tow carriage into the still water of the tank and moving the carriage at a constant velocity. The accuracy limit for any run velocity as computed from the time measured by the tank's data acquisition system to traverse the reference distance is: VLimit = VMeasured * 0.001 VMeasured.

  • Constant head tank:  All flowing water within the Hydraulics Laboratory is supplied by a constant-head tank. This 62,000 gallon tank measures 24 ft high by 21 ft, 6-in in diameter, and has 216 linear feet of weir surface.

  • Tilting flume:  The tilting flume is 6 ft wide, 3 ft deep and 250 ft long and can be tilted to a slope of 1 percent. The discharge capacity is a maximum of 50 cubic feet per second (cfs), partially or wholly supplied by the laboratory's constant head tank. The whole discharge can be recirculated, hence it is adequate for sediment work.


Field Testing Locations

The HIF operates several field facilities to perform tests in a natural environment and to conduct comparisons of various instruments. Since Hurricane Katrina, three Mississippi-based facilities have been restored and are operational: Pearl River at Stennis Space Center, Wolf River near Landon, and the "Corral" site.

The HIF routinely tests instruments and equipment under controlled conditions on the workbench and in environmental chambers to verify vendor stated specifications. Field tests are performed to also evaluate instrument performance in uncontrolled environmental conditions. Sensor performance in comparison to other instruments and tests for durability, longevity, and fouling are some of the things that are effectively evaluated by placing an instrument in the conditions in which it will be used.

HIF - Pearl River testing pier
HIF Pearl River testing pier. USGS-HIF Gaging station with elevated platform, two stilling wells and shelters, and plenty of work area for evaluation instruments. (Credit: Scott Kimball, USGS) 

Pearl River at NSTL Station, MS

Erected and made operational in 1992, the gage site on the left bank of the East Pearl River at Stennis Space Center provides the HIF with a setting to investigate and assess hydrologic instrumentation for the field. The site consists of two shelters and one 4-ft by 40-ft pier. The site has been restructured a few times since its original construction. It is currently used for evaluating new technologies in water quality, stage, and velocity sensors.

  • STORAGE SHELTER: The shelter is an insulated, 12-ft by 8-ft metal building on a concrete pad 350 feet up the bank. It is equipped with electric power, air conditioning, and interior lighting. This shelter provides AC power to the instruments on the pier and stores extra parts and equipment used for site visits.
  • PIER: The pier has a large 12 ft x 12 ft elevated platform, two 18-inch diameter stilling wells, separate shelters, and 12-volt power supplied by batteries and solar panels. It has AC power that operates an automated pumping system for water quality sensors. Data is collected in each shelter by independent data collection platforms utilizing GOES and cellular telemetry. The HIF uses this facility to test and evaluate new commercially available equipment and interfaces built for older equipment.
Wolf River instrument shelter
Wolf River instrument shelter. USGS-HIF instrument shelter located on the left bank on the upstream side of the bridge with Iridium and GOES antennas. (Credit: Scott Kimball, USGS) 

Wolf River near Landon, MS

The HIF Wolf River test site is located at the USGS gaging station (Wolf River near Landon, MS 02481510) on the downstream side of the bridge on Cable Bridge Road, operated by the Mississippi Water Science Center in Pearl, MS.

The HIF test site is located on the upstream side of the bridge. The equipment in the test site shelter consists of a pressure sensor on a continuous bubbler and a data collection platform utilizing GOES and Iridium telemetry. It runs on 12-volt power provided by solar panels and batteries. The gage can test several water level sensors against the pressure sensor that serves as the reference sensor. The water level sensor accuracy is checked by an outside reference gage.

The Wolf River is a good test site for water level sensors due to its significant changes in water level in response to precipitation events. Changes of five to twenty feet are not uncommon at this site. It is a relatively small drainage, so the changes can be sudden at times depending on the intensity of the rainfall triggering the rise.



HIF "Corral" testing site
HIF "Corral" testing site. USGS-HIF rain gauge and meteorological instrument testing site, “the Corral,” with multiple instruments currently under test. (Credit: Scott Kimball, USGS) 

USGS Climate Station at Stennis Space Center, MS

The climate station is fenced on the northwest lawn outside the HIF building. It is a facility dedicated to the testing of meteorological sensors. Rainfall sensors are compared to a U.S. National Weather Service 8-inch rain gage located in the center of the facility. The site can test up to four tipping bucket rain gages. A stand with wind and rainfall sensors is continuously monitored by a data collection platform utilizing iridium telemetry. It is powered by 12 volts of solar panels and a battery.


Environmental Chambers

The HIF’s Testing Section uses environmental chambers to subject instruments and equipment to the temperature extremes they will encounter when they are deployed at USGS field sites. The environmental test chambers can be used in concert with pressure controllers to subject pressure-sensing devices (pressure transducers used to measure water levels) to a range of pressures and temperatures. Temperatures within the environmental chambers and pressures provided by the pressure controllers are calibrated with standards that are National Institute of Standards and Technology (NIST) traceable.

The HIF’s Testing Section operates three reach-in environmental chambers to evaluate and quality-assure submersible and non-submersible pressure transducers, data loggers, and satellite telemetry radios. A walk-in chamber is used primarily to evaluate non-contact, radar stage-sensing equipment.


Water Quality Laboratory

The water quality laboratory supports three main functions; QA/QC (quality assurance/quality control) of newly purchased water quality instruments, maintenance and calibration of all WQ monitors currently in the HIF rental program and the test and evaluation of other commercially available monitors. This area is approximately 1,000 square feet of work space consisting of eight work stations equipped with computer and internet access. NIST certified standard solutions and use of an on-site Contractor calibration lab keeps reference equipment calibration current. Fume hoods, ovens, water baths, deionized water system, heated glassware washer and the availability of a field test location, helps to validate the proper operation of nearly 1,000 monitors processed per year.


USGS staff member examines inventory in bins while holding a barcode scanner and tablet.
The HIF Warehouse. (Credit: Joanne Jones, USGS)


The HIF warehouse occupies over 10,000 square feet of space and maintains over 1000 active stock items needed for the support of USGS field hydrologic data collection activities. The HIF warehouse is responsible for the shipping and receiving of all products, arranging for transportation, maintaining inventory control of stock, analyzing stock levels and determining needs for re-supply and maintaining warehouse facilities and equipment.

All equipment purchased for the HIF warehouse is subjected to quality-assurance inspection to ensure the equipment functions properly, meets the manufacturer's specifications, and meets any additional USGS requirements. The scope of quality assurance varies with complexity of the products, a manufacturer’s past performance, and quantity procured. Some items, such as off-the-shelf connectors, screws, nuts, bolts, etc only require a level low level inspection of a small sample of the total number procurred. Other items, such as pressure transducers, require extensive testing of every item at multiple temperatures and pressures. Approximately ten percent of all shipments do not pass QA inspection, and are returned to the manufacturer.