• 한국농공학회논문집
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• 제55권3호
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• pp.91-104
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• 2013

The objectives of this study were to monitor and assess the environmental impacts of indirect wastewater reuse on water quality and soil in paddy fields. Yongin monitoring site (YI) irrigated from agricultural reservoir and Osan monitoring site (OS) irrigated with treated wastewater diluted with stream water were selected as control and treatment, respectively. Monitoring results for irrigation water quality showed a significant statistical difference in salinity, exchangeable cation and nutrients. Pond water quality showed a similar tendency with irrigation water except for the decreased difference in nutrients due to the fertilization impact. Soil chemical properties mainly influenced by fertilization activity such as T-N, T-P, and $P_2O_5$ were changed similarly in soil profiles of both monitoring sites, while the properties, EC, Ca, Mg, and Na, mainly effected by irrigation water quality showed a considerable change with time and soil depth in treatment plots. Heavy metal contents in paddy soil of both control and treatment did not exceed the soil contamination warning standards. This study could contribute to suggest the irrigation water quality standards and proper agricultural practices including fertilization for indirect wastewater reuse, although long-term monitoring is needed to get more scientific results.

• 한국관개배수논문집
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• 제18권1호
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• pp.94-102
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• 2011

The aim of this study was to evaluate the load of non-point sources pollutant at a paddy plot located at the valley watershed during irrigation period. Irrigation, runoff and water quality data in the paddy plot were analyzed periodically from June 1 to October 31 in 2005. The observed amount of precipitation, irrigation, runoff for the experimental paddy plot during the irrigation period was 1,297.8, 223.2, and 825.4mm, respectively. Total-N concentrations ranged from 3.73 to 18.10mg/L, which was generally higher than the quality standard of agricultural water (1.0mg/L). Total-P concentrations ranged from 0.111 to 0.243mg/L and the average was 0.139mg/L. The observed runoff pollutants loadings from the paddy plot were measured as 34.4 kg/ha for T-N, 1.0 kg/ha for T-P and 213.8 kg/ha for SS. The non-point sources pollutant load in drainage water depends on rainfall and surface drainage water amount from the paddy plot. We are considering that these results were affected by rainfall as well as hydrological condition, soil management, whether or not fertilizer application, cropping, rice straw and plowing.

• 한국농공학회논문집
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• 제55권6호
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• pp.167-175
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• 2013

The objective of this study was to investigate the nutrient load balance in the reservoir irrigated paddy block during growing seasons. Idong reservoir irrigation paddy block of 10.3 ha in size was selected to collect hydrologic and water quality data. Irrigation, canal flows, and paddy field drainage were measured using a water level gauge, while water samples were collected and analysed for water quality. The water balance analysis showed that 81 % and 75 % of total outflow were through paddy and irrigation canal drainage during 2011 and 2012, respectively. The water quality of paddy field drainage varied greatly depending on rice cultivation stage ranging from 0.05 to 24.55 mg/L and from 0.01 to 0.76 mg/L for T-N and T-P, correspondently. Paddy field drainage loads during May through June account for 64 % and 76 % in 2012 and 2013, while 82 % and 81 % for T-P in 2011 and 2012, respectively. The Pearson correlation analysis showed that rainfall was significantly correlated with nutrient loads during July through August due to runoff, and irrigation was related with nutrient loads of drainage during some period of July through September due to irrigation return flow. This study results showed characteristics of inflow and outflow nutrient loads from plentiful irrigated paddy block.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.105-110
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• 1999

Unused irrigation water due to delievery losses and management losses. and ground water releases from infiltration in the paddy irrigation system are eventually returned to the stream. They are called as irrigation return flow. It affects the discharge of drought flow in the down strenamflow. And it may contain chemicals, and threaten streamflow quality . Thus, the accurage estimation of irrigation return flow is important to the streamflow modeling and water resources planning , and also to the control of agriculutral nonpoint source pollution . The irrigation return flow of pumped water was investigated in the Keum river watershed.

• 물과 미래
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• 제35권5호
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• pp.51-59
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• 2002

In recent years the human impact on the environment becomes increasing lift threatening, calls for the better management of resources. In field of water quality of river flow, the best way to conserve water quality is specific efforts to control the pollutant loadings and treat the loadings in the basin to reduce the discharge of pollutant loadings to river. But in general the water quality influenced by the dam discharge. Especially in dry season, it is more dominant way to improve the water quality which contaminated with the pollutant loadings from the basin. The dam discharge amounts of the 2 dams in the Keum River that maintain the down stream water quality were estimated for the year of 1999, 2001, 2006, 2011, in case of irrigation and non-irrigation seasons. The pollutant loadings for the basin are estimated with the planning of treatment plants construction schedule for every sub-basins. The river flow rates were considered low flow as 2.33 year low flow and 10 year low flow. The QUAL2E model was used as a tool of simulation.

• 한국농공학회논문집
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• 제55권6호
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• pp.177-186
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• 2013

The purpose of this study was to analyze the temporal and spatial characteristics of the stream flow of small rural streams for investigating the status of stream depletion located downstream of irrigation reservoir. Bonghyun and Hai reservoirs and each downstream were selected for this study. Streamflow was measured for 8 stations downstream from two reservoirs from 2010 to 2012. The water quality samples were collected monthly from the 8 stream stations and 2 reservoir stations from 2011 to 2012. The stream depletion was found in most of the downstream of reservoirs for the non-irrigation period and even in the irrigation period when there were a lot of antecedent precipitation. We found that the stream segments where there were few streamflow, vegetation covers the stream and block the streamflow which makes the stream lost its original function as a stream. Water quality monitoring results of Bonghyun stream indicated that the concentration of SS, Turbidity, TOC, COD were decreased as the stream flows from the reservoir to downstream while the TN and TP were increased. The correlation analysis for water quality data indicated that the correlation between T-N and T-P was high for Bonghyeon and Sukji streams, respectively. Continuous monitoring for rural streams located in downstream of reservoirs are required to quantify the status of stream flow depletion and determine the amount of environmental flows.

• 한국관개배수논문집
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• 제10권1호
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• pp.112-120
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• 2003

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.515-520
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• 2005

The objective of the study is to assess the water quality improvement resulted from the rearrangement of the irrigation water supply systems at Mankyeong River and Ansung Chun basin. There is a mixed type of watershed composed of urban and rural areas in the region. From the water quality analysis, showed high T-N, T-P concentration in Ansung chun and Mankyeong river caused by paddies separated widely around Ansung chun and Mankyeong river and by runoff of the pollution from the Ansung and Jeonju city. but the upstream of the river showed clean water quality, so if we use the upstream water as river maintenance water for water quality improvement, it is expected to be positive effect for rural environmental aspect.

• 한국농공학회논문집
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• 제53권3호
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• pp.13-17
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• 2011

There was a transition from participatory irrigation management (PIM) to public irrigation management (PubIM) in Korea when Korea Rural corporation and Community (KRC) merged with Farm Land Improvement Associations (FLIAs), which had managed 60 % of irrigation areas. While making a number of achievements, some problems occurred in the public irrigation management, such as lack of farmers' participation, increased amount of water usage, and elevating operating costs. Accordingly, this paper suggested ways to increase efficiency in water usage and reduce operating costs under the public management through the motive power of farmers participation. First, WUGs replaced the discarded water management committee should be reorganized to revive the concept of PIM in the form of autonomously reinforced one and the roles and functions of WUGs and the board of representatives should be strengthened. The member of new type of WUGs should participate in the national and regional water management committees as a stakeholder of irrigation water user. And also new type of WUGs initiates not only the management of irrigation water but also the management of irrigation water quality and non-point source pollution in the watersheds. Those additional activities of WUGs should be properly compensated. Second, subsidies (direct payments) should be provided to faithful farmers as an incentive for their labor supply. Third, water fees could be charged to large scale agriculture companies. Fourth, professional managers could be hired, management targets would be adjusted, and incentives should be offered. These efforts are expected to improve the irrigation management by encouraging farmers' participation under public system.

• 한국농공학회논문집
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• 제47권4호
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• pp.75-85
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• 2005

A study was performed to examine the effects of reclaimed-water irrigation on microorganism con-centration in ponded-water of paddy rice plots. Several treatments were used and each one was triplicated to evaluate the change of indicator microorganisms (total coliforms (TC), fecal coliforms FC), and E. coli) concentrations in 2003 and 2004 growing seasons. Their concentrations increased significantly right after irrigation, but decreased about $45\%$ in 24 hours. It implies that agricultural activities such as plowing and fertilizing should be practiced one or two days after irrigation considering health-risks. Treatments with UV-disinfected water irrigation demonstrated significantly lower concentrations than others including control plots where natural surface water was irrigated. The monitoring results from actual paddy rice fields and experimental paddy plots showed that concentrations of indicator microorganisms ranged from $10^2\;to\;10^5$ MPN/100mL. A comprehensive assessment of existing agricultural practices and a thorough monitoring in the field as well as treatment-plots are recommended to make more realistic national guidelines more applicable. UV-disinfected water irrigation reduced microorganism concentrations in paddy fields down to below the concentration of conventional paddy rice culture, and is thought to be an effective and feasible measure fur agricultural reuse of secondary effluent.