• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.108-113
• /
• 2000

A field study was performed to investigate the effect of water saving irrigation method on water use efficiency and rice yield. The field plot was 40a (40 ${\times}$ 100m) in size and located at Buryangmyun, Kimjae city, Chonbuk province. Field measurements were made during the growing seasons, May to September of the year 1998 and 1990. Irrigation water volume, drainage water volume, rainfall and ponding depth were measured. Irrigation water management practice employed was such that to keep the ponding depth about 3 to 4cm by intermittent irrigation with drying the soil surface until hair cracks emerge before the next irrigation. The amounts of water volume irrigated and drained were measured by pipe flow meter and ponding depth was observed by using a partly buried 120mm diameter PVC pipe. The results showed that the irrigation water depths, the rainfalls, and the drainage depths were 379mm, 458mm, and 448mm in 1988, and 274mm, 819mm, and 736mm in 1990, respectively. The average yield was 590kg per 10a. The water saving irrigation method saved irrigation water by about 20% with higher yield compared with the traditional method.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.46 no.3
• /
• pp.3-14
• /
• 2004

A two-dimensional numerical model based on a finite volume method was formulated to solve the shallow water equations and applied for evaluating drainage characteristics at large-sized paddy fields. Manning roughness coefficient was calibrated using the observed inundating depths at drainage tests, and used for validating the model with the results from another drainage test. The simulated results were in good agreement with the observed inundating depths. The result of surface drainage showed that the longer width of the outlet was or the more the number of drainage outlet was, the shorter the drainage time was taken, and the larger the size of the field become, the longer the drainage time was taken, and the field shape had little effect on drainage time. To reduce the drainage time to 24 hours, the outlet is located lower than the elevation of the basin and small drainage ditch is constructed at the field. The results showed that the drainage time was taken short as the small drainage ditch was constructed. The comparison of drainage time as to the size of field constructed small drainage ditch showed the field, 100m ${\times}$ 200 m, can be drained in 24 hours.

• Journal of Bio-Environment Control
• /
• v.27 no.1
• /
• pp.1-6
• /
• 2018

Also, t-cincreaseisdecreasein order In hydroponics, the accumulation of inorganic ions in the root zone are closely related to the irrigation volume. Therefore, the effects of irrigation volume on the growth and yield of tomatoes are very signigicant. This study was conducted to investigate the effect of irrigation volume on inorganic ions of root zone in hydroponic culture using coir substrate. The irrigation volume was adjusted to 4 levels depending on the integrated solar radiation for each growth period. The drainage ratio was calculated by daily amount of irrigation and drainage. The higher irrigation volume is, drainage ratio and water absorption tended to increase. But, the water absorption in the treatment of high irrigation volume was decreased in February and March compared to the treatment of medium high irrigation volume. By calculating monthly average irrigation volume and the drainage ratio, 120 to 1$40J/cm^2$ in January, 100 to $120J/cm^2$ in February, 80 to $100J/cm^2$ in March, 70 to $90J/cm^2$ in April and 60 to $75J/cm^2$ in May was detected as appropriate irrigation volume ranges which drainage ratio was 20-30%. The higher irrigation volume, the lower the concentration of ions decrease, which could prevent the accumulation of nutrients in the root zone. However, due to the characteristics of the coir substrate that absorbs ions, concentration of ions was significantly high when the drainage ratio was 20-30%. However, concentrations of P and K were sometimes lower in the drainage than that of irrigation water regardless of the treatment. Mg and S were the most highly accumulated ions even in the treatment of high irrigation volume. In low radiation season, there was no difference in the ion concentration in the drainage depending on the irrigation volume. In high radiation season, the lower irrigation volume, resulted to the higher ion concentration in the drainage. After March, it was difficult to prevent the increase of ions concetration in the drainage by only adjusting irrigation volume. Thus, it is necessary to decrease the EC of irrigation solution to prevent the accumulation of nutrients in the root zone.

• Current Research on Agriculture and Life Sciences
• /
• v.18
• /
• pp.33-42
• /
• 2000

A field case study was performed to investigate the effect of shallow ponding in paddy field on irrigation water requirement of direct seeded rice. In addition, an economic analysis was made to see the effect of no-till direct seeded rice on cost reduction. A field study was performed at a 2.1ha paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding methods such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Then, cost reductions due to the direct seeding and no-till were calculated. In addition, to investigate the effect of shallow ponding on irrigation water requirement, field measurements such as irrigation water volume, drainage water volume, rainfall depth, and ponding depth, were made at a 40a plot within the same area in 1988 and 1990. The results of the shallow ponding study showed that the irrigation water depth, rainfall, and the drainage depth were 379mm, 458mm, and 448mm in 1988 growing season, and 274mm, 819mm, and 736mm in 1990, respectively. The shallow ponding irrigation method saved irrigation water by about 20% with higher yield compared with the traditional method. The economic analysis showed that won \640,000 per ha can be saved by direct seeding due to no nursery cost, and \1,220,000 per ha due to no-till and no nursery cost. The yields ranged 540 to 640 kg per 10a during the study period with an average of 590kg per 10a. If these cropping techniques with no-till direct seeding and shallow ponding depth for rice cropping prove to be advantageous with further study, they can be adopted for the most of the paddy fields in Korea.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.34 no.5 s.118
• /
• pp.76-83
• /
• 2006

The purpose of this study was to investigate the performance of porous grass block. For the investigation, Festuca arundinacea and Zoysia japonica 'Zenith' were planted, and the volume of evapotranspiration and remains were examined based on different materials in the water tank in the experiment of Festuca arundinacea, the volume of water storage of treatment with perlite ($10.84{\iota}/m^2$) was higher than that with drainage ($7l/m^2$). The difference between the two was $3.84/m^2$. The drainage treatment without water storage capacity showed the higher degree of dryness in turf grass. The volume of evapo-transpiration of treatment with perlite was the highest (21.57mm/week). The volume of evapotranspiration of treatment with sand was 19.57mm/week, and with treatment with drainage was 18.24mm/week. Based on the measured volume of daily evapotranspiration of $2.60{\sim}3.08mm\;d^{-1}$, it was determined that the unit with water storage capacity would store water of one to two days usage compared to unite without such storage capacity. In the experiment of Zoysia japonica 'Zenith', the volume of water storage of treatment with perlite was $10.77l/m^2$ which was similar to the former experiment. The volume of evapotranspiration of treatment with perlite and sand were 21.64mm/week and 20.64mm/week, respectively. In case of airtight water tank, the volume was measured as 22.06mm/week. Each treatment has no notable difference in the volume of evapotranspiration. In conclusion, from the investigation in this study, porous grass block with water tank was found to be effective in plant growth under low irrigation. As the ecological area ratio and vegetated porous pavement have became more emphasized, additional study of rain infiltration and reservoir effect are needed in the future.

• Journal of Korean Society on Water Environment
• /
• v.27 no.1
• /
• pp.9-18
• /
• 2011

In this study the optimal volume for non-point source control retention is estimated considering spatio-temporal variation of land surface. The 3-parameter mixed exponential probability density function is used to represent the statistical properties of rainfall events, and NRCS-CN method is applied as rainfall-runoff transformation. The catchment drainage area is divided into individual $30m{\times}30m$ cells, and runoff curve number is estimated at each cell. Using the derived probability density function theory, the stormwater probability density function at each cell is derived from the rainfall probability density function and NRCS-CN rainfall-runoff transformation. Considering the antecedent soil moisture condition at each cell and the spatial variation of CN value at the whole catchment drainage area, the ensemble stormwater capture curve is established to estimate the optimal volume for an non-point source control retention. The comparison between spatio-temporally varied land surface and constant land surface is presented as a case study for a urban drainage area.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.162-168
• /
• 2000

A two-dimensional numerical model based on a finite volume method was formulated to solve the shallow water equations and applied for evaluating irrigation and drainage characteristics at large-sized paddy fields. Manning roughness coefficient was calibrated using the observed inundating depths at drainage tests and used for validating the model with the results from irrigation and drainage test. The simulated results were in good agreement with the observed inundating depths.

• Journal of Korean Society on Water Environment
• /
• v.24 no.3
• /
• pp.333-339
• /
• 2008

This study was carried out to assay the relationships between empirical factors and water quality in 23 agricultural reservoirs. Based on the trophic state index (TSI) deviation analysis, phosphorus in type II and III was the primary limiting factor on algal growth. BOD, COD, TP and chl.a concentration in type III reservoirs showed higher concentration than those of other types, while SS and TN concentration was no noticeable difference among three types. Characteristics of type III reservoirs showed large reservoir surface and drainage area, large surface area to volume (SAV) ratio, small drainage area to reservoir area (DA/RA) ratio, relatively old age, large paddy field and upland field to drainage area ratio (Mean 17.4%) and high generation and discharge loads compared to other types of reservoirs. In type I and II reservoirs, trends of BOD, TN, TP concentration in water column, were similar to those of the discharge load of pollutants. Although type II reservoirs generally showed low phosphorus discharge loads compared to type I reservoirs, TP and chl.a concentration in water column was greater than that of type I. Characteristics of type II reservoirs showed relatively large SAV ratio and old age compared to type I reservoirs and was similar to those of type III including eutrophic reservoirs.

• Environmental Engineering Research
• /
• v.18 no.3
• /
• pp.117-121
• /
• 2013

For underpasses in Yeongjong Sky City business district, the guided drainage system, as a buoyancy prevention system has been designed, and is under construction. This paper investigates the safety of the guided drainage system for underpass structures being constructed in Yeongjong Sky City business district. This paper also calculates the amount of outflowing groundwater generated by the guided drainage system, and proposes alternative usages of the water. In order to investigate safety and field applicability of the guided drainage system for underpasses, characteristics of the surface flow for the area of interest have been analyzed, and the flow change of groundwater following the underpass structure construction has been evaluated using the 3-dimensional groundwater program MODFLOW. The influence of ground water on safety of the underpass structures has been calculated by FLAC2D analysis. For alternative usages for the outflowing groundwater generated by the guided drainage system, utilization methods of the outflowing groundwater in national and international resources have been researched. The amount of an outflowing groundwater to be generated in the area of interest has been analyzed, and efficient potential usages of this groundwater have been researched. When guided drainage technique is applied, the change in flow of groundwater must be evaluated and considered as safety factor relating to the buoyancy of the structure. As a result, safety factor demonstrated more than 1.2, meaning that the underpass structure is safe. The amount of subsoil drain generated by the guided drainage system was also analyzed. The quality and amount of water satisfied the standards and volume requirements, so as to make it applicable for a number of uses, such as X, Y, and Z, and should prove to be a valuable resource as the circumstances of the neighboring area change over time. These resources can be used as basic data for future urban water circulation studies, as well as generating research of alternative water usages.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2001.10a
• /
• pp.99-105
• /
• 2001

The purpose of this study is to investigate the effects of pending depth treatment on water balance in paddy fields. The pending depth treatments were very shallow, shallow and deep. The experimental plots were three $80m{\times}25m$ rectangular plots. Daily values of rainfall amount, pending depth, irrigation water, drainage water, evapotranspiration, infiltration, and piezometeric head were measured in the field. The pending depth was continuously observered by water level logger during the growing season. The ET was measured in 1m diameter PVC lysimeters. Irrigation water volume was measured by 75m pipe flow meter and the drainage water volume was measured by 25mm and 75mm pipe flow meters and a recording Parshall fulume. PVC pipe piezometers with 12mm diameter were used. The results of the water balance showed that irrigation water of 881.1mm, 735.4mm, and 532.6mm in very shallow, shallow, and deep pending, respectively. The effective rainfall was 182.6mm(44.6%), 254.7mm(62.2%), and 188.6mm(46.0%) in very shallow, shallow, and deep pending, respectively. The results show that the shallow pending depth looks the best of the three treatments.