Min-Kyeong Kim

Transferability of SWAT Models between SWAT2009 and SWAT2012

In recent years, the Soil and Water Assessment Tool (SWAT) has experienced upgrades with enhanced functionalities and modeling capacities as it gets to the current version, SWAT2012. Changes in the SWAT code on a specific process may result in propagating influences in the output of other related processes. In this study, the characteristic significance of the enhancements in SWAT code was investigated using the two recent versions, SWAT2009 and SWAT2012. Using a global optimization technique, each model was calibrated for flow, sediment, and nutrient and then tested for transferability of parameters between the models. Results indicate that flow and water quality output were well calibrated with both models. However, the calibrated parameters determined by SWAT2009 and SWAT2012 were noticeably different, due mostly to the enhancements made in SWAT2012. Our results indicate that only the stream flow result was reliable when the models were upgraded or downgraded between the two versions after calibration. Sediment prediction was marginally reliable. SWAT parameters were nontransferrable if nutrient was the main output. The differences are due to various reasons, such as disparities in algorithms at the process level and propagation of the resulting uncertainty into higher-order processes.

ON-LINE MEASUREMENT OF GRAIN MOISTURE CONTENT USING RF IMPEDANCE

The dielectric properties of Korean short– and medium–grain rough rice, brown rice, barley, and wheat with moisture ranges of 11% to 27%, 11% to 18%, 11% to 21%, and 11% to 22%, wet basis, respectively, were characterized at 1 to 10 MHz for use in developing a prototype on–line moisture meter using RF impedance and moisture density (moisture content . bulk density). Moisture density was a materially significant parameter for moisture measurement. A linear regression model including oscillation frequency of the LC oscillator, moisture density, and grain temperature indicated coefficients of determination of 0.985 for rough rice, 0.934 for brown rice, 0.996 for barley, and 0.991 for wheat. The root mean square error of an on–line moisture meter was .0.40% moisture content, wet basis, compared with the oven method for moisture determination.

Simple instrument for moisture measurement in grain by free-space microwave transmission

A simple microwave moisture meter for grain was introduced with reduction of the size and volume of the instrument by means of 2×2 microstrip patch array antennas. The attenuation and phase shift produced by Korean short-grain rough rice, brown rice, and barley were analyzed to estimate the relationships between moisture density in the grain and the attenuation and phase shift. Second- and third-order polynomial attenuation models were a better measure of moisture density than were phase shift models. A grain moisture meter using microwave attenuation in free-space was constructed. A prototype grain moisture meter consisting of a 10.5 GHz oscillator, patch array antennas, isolator, detector, and digital voltmeter provided a coefficient of determination, standard error of prediction (SEP), and bias of 0.975, 0.62% moisture content, and -0.05% moisture content, respectively.

Wastewater retreatment and reuse system for agricultural irrigation in rural villages.

Climate changes and continuous population growth increase water demands that will not be met by traditional water resources, like surface and ground water. To handle increased water demand, treated municipal wastewater is offered to farmers for agricultural irrigation. This study aimed to enhance the effluent quality from worn-out sewage treatment facilities in rural villages, retreat effluent to meet water quality criteria for irrigation, and assess any health-related and environmental impacts from using retreated wastewater irrigation on crops and in soil. We developed the compact wastewater retreatment and reuse system (WRRS), equipped with filters, ultraviolet light, and bubble elements. A pilot greenhouse experiment was conducted to evaluate lettuce growth patterns and quantify the heavy metal concentration and pathogenic microorganisms on lettuce and in soil after irrigating with tap water, treated wastewater, and WRRS retreated wastewater. The purification performance of each WRRS component was also assessed. The study findings revealed that existing worn-out sewage treatment facilities in rural villages could meet the water quality criteria for treated effluent and also reuse retreated wastewater for crop growth and other miscellaneous agricultural purposes.

Design of Vegetative Filter Strip Using Web-Based System with Groundwater Table and Pesticide Degradation Analysis Modules

AbstractVegetative filter strips (VFS) are an effective approach to reducing edge-of-field discharge of sediment and pesticide. The web-based Vegetative Filter Strip MODel (VFSMOD) system, develope...