3D-Simulation of the Twin Lake Tracer Test
The 1983 Twin Lake tracer test was simulated using a three-dimensional finite element model. The model was calibrated comparing calculated and measured piezometric heads as well as vertical...
A Semi Passive Nutrient Injection System for In Situ Bioremediation
A permeable cutoff wall is installed across the path of a contaminant plume. The water in the wall can be amended with the desired nutrient solution using pumping and injecting wells within...
Strategies to Preserve Endangered Salmon in the Columbia River
The recent listing of some Snake River salmon stocks as threatened and endangered has forcefully brought Pacific Northwest resource interests together to seek solutions to preserve the...
Electro-Osmotic Removal of Nitrates from Soils
Nitrate migration to ground and surface waters is a serious U.S. contamination threat. Electro-osmosis may be a more effective means for soil reclamation than leaching or chemical treatment....
Nitrogen Leaching from Young Florida Citrus
Sixteen buried drainage lysimeters were constructed from 2300 L polyethylene containment basins for the study. The lysimeters were 2.1 m in diameter by 0.8 m deep and were filled with...
Managing Irrigation in the Presence of Groundwater
A method was developed to use lysimeter data for groundwater contribution to crop water use in the irrigation scheduling procedure for a subsurface drip irrigated field underlain by shallow...
AZSCHED?Software for Real-time Irrigation Scheduling
A user-friendly computer based scheduling program was developed to minimize the amount of data which needs to be input by the user by utilizing a network of twenty automated weather stations...
Evapotranspiration by Soil Water Balance Using TDR and Neutron Scattering
The soil water balance method of estimating evapotranspiration (ET) has been widely used since it is considerably cheaper than alternative methods such as the use of weighing lysimeters....
Estimating ET Using Turbulent Coherent Structures
Two methods for estimating sensible heat flux to use in energy balance equations for computing crop evapotranspiration are discussed. The methods use high frequency temperature measurements...
Atmospheric Radiation Balance Over Alfalfa
An experiment was carried out in an alfalfa field in Logan, Utah, U.S.A., during 8-12 September 1992, to evaluate methods and expected accuracy of continuous radiation balance component...
Density Fluctuations and Use of the Krypton Hygrometer in Surface Flux Measurements
The magnitude of the of the Webb et al. (1980) density corrections on water vapor fluxes due to the flux of sensible heat is examined in terms of the Bowen ratio. The correction due to...
Evaluation of Electronic Temperature/Relative Humidity Sensors
Temperature and relative humidity measurements are routine parameters required for most agricultural meteorological applications. Reliable measurements of relative humidity, especially...
Nongrowing Season ET from Irrigated Fields
The evaporative loss of water from agricultural fields during the nongrowing season is an important component of the annual water balance of irrigated lands. This study was conducted to...
Streamflow Depletions Resulting from Ground Water Transfers
An application to move the point of diversion of a quasi-municipal ground water right from about 4.8 km to a second well about 0.3 km from a river channel was made in the Reno/Sparks,...
The ASCE Neutron Probe Calibration Study: Overview
A workshop was held at Logan, Utah to gather field information on neutron probe calibration and operation. Several techniques and instruments were compared. This paper serves to establish...
Measuring Soil Bulk Density Profiles with a Single Probe Gamma Density Gauge
Calibrating neutron depth gauges for measuring soil water content profiles requires soil bulk density data. In this study, the feasibility of using a single probe gamma density gauge to...
Error Analysis of Bulk Density Measurements for Neutron Moisture Gauge Calibration
Six bulk density sampling methods were evaluated for use in neutron gauge calibration. All six methods provided estimates of bulk density which were generally within 5% of bulk density...
Performance Factors of Neutron Moisture Probes Related to Position of Source on Detector
The performances of two commercially available neutron moisture probes with different source-detector placement were evaluated. The probes were the Troxler with the neutron source placed...
Soil Moisture Monitoring Using a Portable Capacitance Probe
Accurate monitoring of soil moisture has long been in integral part of a successful agricultural management system. Water has increasingly become a valuable and much sought after natural...
Effect of Choptank Watershed Drainage Project on Stream Temperatures
Between 1974 and 1982, the Soil Conservation Service, U.S.D.A conducted a stream study on the Choptank Watershed in Caroline County, Maryland to monitor the effects of channel construction...
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