Direct Load Cell-Based Weighing Lysimeter System
A low-cost weighing lysimeter system is described which is capable of measuring evapotranspiration with an accuracy of 0.05-0.10 mm. A two-lysimeter system with electronic data logger...

Field Experience with Hydraulic Weighing Lysimeters
Hydraulic weighing lysimeters can be a reliable and relatively inexpensive source of actual crop evapotranspiration (ET) data for field water use studies and crop coefficient development....

Australian Lysimeter Studies of Field Evaporation
Evaporation data are summarised from separate lysimeter installations involving forest, crops and pastures along the 35?S parallel in south-eastern Australia. In each study, lysimeter...

Relationship Between Lysimeter Area and Evapotranspiration (ET)
The lysimeter is an important instrument for measuring evapotranspiration (ET) of crops. It is widely used in the irrigation and drainage experimental stations in China. However, the areas...

Overview and Objectives of the Macrodispersion Experiment
TVA is conducting large-scale field experiments to better define movement and dispersion of contaminants in groundwater. This will support groundwater protection by making possible more...

Second Natural-Gradient Tracer Experiment
The Tennessee Valley Authority (TVA) has begun a second large-scale groundwater field experiment at the Columbus Groundwater Research test site in Mississippi. This research is a continuation...

Practical Technology Resulting from MADE Research
As is often the case, when theoretical research is performed, practical technology is developed in the process. This has occurred with the Macrodispersion Experiment (MADE) conducted at...

Prematurely Terminated Slug Tests?A Field Application
Slug tests suffer problems of non-uniqueness to a greater extent than other well tests. Alternatively, a prematurely terminated slug test (PTST) or a systematized drillstem test is proposed,...

Type Curves for a Slug Test in an Infinitely or Semi-infinitely Thick Aquifer
Type curves are provided for a slug test in an infinitely or semi-infinitely thick aquifer, the latter with the single confining layer immediately above or immediately below the well....

Aquifer Measurements at Different Scales
Multilevel slug test data from five wells in a confined, sandy aquifer were analyzed to obtain an estimate of the vertical variation of the horizontal hydraulic conductivity, K(z). Hydraulic...

Application of Tracer Tests in Groundwater Remediation Design
Recent advances in the area of field testing for the quantification of hydraulic conductivity have resulted in improved site characterization of aquifer hydraulics and greater reliability...

Operational Procedures for Estimating Bottom Exchange Rates
After briefly reviewing the terminology of the various bottom and water column exchange fluxes, the body of this paper summarizes five possible procedures for establishing operational...

Stepped Spillway Design for Flow Over Embankments
Many embankment dams have been identified as unable to pass their design flows without failure due to overtopping. The U.S. Bureau of Reclamation (Reclamation) is currently at the forefront...

Modeling and Field Experiments for Tracer Gas Tests
Numerical modeling and field experiments were used to extend the tracer gas technique for determining surface gas transfer rates to shallow bays. Two-dimensional modeling was used to investigate...

Bridge Scour Vulnerability Assessment
Although the failure of the New York Throughway bridge over Schoharie Creek in 1987 has focused national attention on scour related failures, other failures reinforce the need for implementing...

Modeling of Wetland Hydrodynamics and Transport in Coastal Louisiana
Modeling of hydraulics and transport of large wetland systems poses critical decisions between resolution of the complex geometry of a wetland and the testing required to meet study goals....

Scour Measuring and Monitoring Equipment for Bridges
The National Cooperative Highway Research program (NCHRP), through the Transportation Research Board (TRB) of the National Academy of Sciences, is currently sponsoring a research effort...

Set-Down in a Tidal Embayment
A mean water level in tidal bays and estuaries that is higher than the ocean mean water level (set-up) is a fairly common occurrence. Set-down of the mean water level can be shown to be...

Experimental Model Study of Over and Under Baffles
A hydraulic model study of a chlorine mixing channel was conducted at the Hydraulic Research Laboratory of the City of Los Angeles. An arrangement of over-under baffles was used to facilitate...

Ultrasonic Velocity Meter Used in Stream Gaging
Many streams and canals in Florida are affected by tides or control structures and experience very low flow velocities at times. For example, the St. Johns River in northeastern Florida...

 

 

 

 

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