• Title/Summary/Keyword: Dry river

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Effect of Irrigation of River Water and Swine Slurry Liquid Fertilizer on Kenaf (Hibiscus cannabinus L.) Growth Cultivated Using Soil Moisture Control System in Reclaimed Land (자동 수분 제어시스템을 이용한 간척지 케나프 재배시 하천수 및 액비 관개 효과)

  • Kang, Chan-Ho;Lee, In-Sok;Lee, Jin-Jae;Kim, Hee-Jun
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.66 no.1
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    • pp.87-96
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    • 2021
  • Information and Communication Technology (ICT) remote soil moisture control system including soil sensing, automatic water supply chain, and remote alarming system was established on reclaimed land and operated stably. The system was operated using river water around the reclaimed land without fertilizer. On applying this system to control soil moisture, the kenaf germination rate was improved up to two times. Kenaf biomass was 4,748 kg/10a and was higher than that of untreated soil moisture management. When the nutritious liquid fertilizer was used, kenaf yield reached 8,390 kg/10a, which was lower than 10,848 kg/10a of the non-reclaimed land treated with standard chemical fertilizers. As the soil moisture was managed stably through the ICT remote soil moisture control system, the quality of the kenaf crop was improved, resulting in a 7% increase in dry weight, and a 11.5% increase in plant hardness. The estimated kenaf yield was 5,039 kg/10a when 800 tonnes of water were supplied by the ICT remote soil moisture control system with the stream water around Saemangeum reclaimed land without chemical fertilizers and organic matter.

Analysis of Functional Traits of Non-woody Native and Naturalized Plant Species Living in a Riparian Park Area near the Hapcheon-Changyeong Weir in Nakdong River (낙동강 합천창녕보 주변 습지공원지역에 서식하는 자생 초본식물과 귀화 초본식물의 기능 형질 분석)

  • Son, Min-Jeong;Nam, Ki-Jung
    • Korean Journal of Ecology and Environment
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    • v.54 no.4
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    • pp.327-333
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    • 2021
  • The two main hypotheses that explain why invasive alien plants successfully colonize new environments are: 1) invasive alien plants are functionally different from native plants in a community, and 2) the plants can adapt well to new environments because they are functionally similar to native plants. The present study investigated the functional traits of naturalized alien herbaceous plants and their native neighbors in a riparian park area near the Hapcheon-Changyeong weir along the Nakdong River to determine which of the two hypotheses applied to the study area. According to the results, leaf functional traits, such as leaf area, specific leaf area, leaf thickness, leaf dry matter content, leaf nitrogen content, and leaf carbon content differed between naturalized alien and native plants, which could be attributed to the higher leaf nitrogen contents in naturalized alien plants than in native plants. The high leaf nitrogen contents are associated with high photosynthetic rates, which lead to effective resource use and rapid growth; therefore, naturalized alien plants growing in the study area were considered to have such functional traits. The results of the present study support the hypothesis that the successful establishment of invasive alien plants is attributed to the functional trait differences between invasive and native plants.

Characteristics of Plants Distribution by Vegetation Community at Janghang Wetland in Han-river Esturary, Korea (한강 하구 장항습지의 식생군락별 식물 분포 특성)

  • Mi-yeo Na;Choong-hyeon Oh
    • Korean Journal of Environment and Ecology
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    • v.37 no.1
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    • pp.59-69
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    • 2023
  • This study was carried for the purpose of using basic data for vegetation management plans by analyzing the current status of herbaceous community and Salix spp. community at Janghang Wetland in Han-river estuary. In order to investigate the vegetation status, the 50 plots were investigated and analyzed using the quadrat and Braun-Branquet method. In the herbaceous community, were found a total of 31 taxa of 11 families, 24 genera, 28 species, and 3 variants. A total of 42 taxa of 16 families, 33 genera, 39 species and 3 variants were appeared in the Salix subfragilis community, and a total of 46 taxa with classification of 19 families, 37 genera, 43 species, and 3 varieties were founded in the Salix koreensis community. As for the analysis of life-form and dominance, the hydatophytes was relatively high in the Salix subfragilis community, the hemicryptothytes was high in herbaceous community and therophytes was high in Salix koreensis community. As a result of correlation analysis of electrical conductivity(EC) and exchangeable sodium(Na+) in the soil, hydatophytes and hemicryptothytes showed a negative correlation, and therophytes showed a positive correlation. Therefore, it was analyzed that Salix koreensis and therophytes have a high rate of appearance in relatively dry and salty soil. Salix subfragilis, hydatophytes, and hemicryptothytes have a high rate of appearance in low salt concentrations and wet areas.

Estimation of Water Purification Ability with Applying Porous Concrete to Weir and Riverbed Materials (다공성 콘크리트의 보 및 하상재료 적용에 따른 하천 수질정화 능력 평가)

  • Choi, I-Song;Kim, Jin-Hong;Choi, Gye-Woon;Oh, Jong-Min
    • Journal of Korea Water Resources Association
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    • v.36 no.6
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    • pp.1013-1023
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    • 2003
  • This study was performed to improve water quality of stream by applying hydraulic structures (weir and river bed material) made of porous concrete. The physical and chemical characteristics of porous concrete were measured to estimate application possibility of it in hydraulic structures and it was considered as a proper material for the hydraulic structures. In the results of comparison for the component of matters attached on the hydraulic structures made of porous and ordinary concrete, DW (dry weight) amount attached on porous concrete was 1.6 times higher than that on ordinary concrete under the condition of the same flow rate but influence by flow rate (difference of 10 times) was not shown. Therefore, we could understand that the material of media was more important in DW amount than flow rate. The rate of AFDM (ash free dry mass) to DW also was more at porous concrete than at ordinary concrete. Especially, the high rates of nitrogen and phosphorous in matters attached on porous concrete verify that they were removed by assimilation, adsorption and metabolism of periphyton. The removal percentage of SS, BOD, COD, T-N and T-P by hydraulic structures applying porous concrete compared with ordinary concrete was increased by 34.6%, 36.9%, 33.9%, 18.3% and 21.6%, respectively. Therefore, applying porous concrete to hydraulic structure is expected to contribute to improvement of stream water quality.

A Simulation Model for the Intermittent Hydrologic Process(I) - Alternate Renewal Process (ARP) and Continuous Probability Distribution - (간헐(間歇) 수문과정(水文過程)의 모의발생(模擬發生) 모형(模型)(I) - 교대재생과정(交代再生過程)(ARP)과 연속확률분포(連續確率分布) -)

  • Lee, Jae Joon;Lee, Jung Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.3
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    • pp.509-521
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    • 1994
  • This study is an effort to develop computer simulation model that produce precipitation patterns from stochastic model. A stochastic model is formulated for the process of daily precipitation with considering the sequences of wet and dry days and the precipitation amounts on wet days. This study consists of 2 papers and the process of precipitation occurrence is modelled by an alternate renewal process (ARP) in paper (I). In the ARP model for the precipitation occurrence, four discrete distributions, used to fit the wet and dry spells, were as follows; truncated binomial distribution (TBD), truncated Poisson distribution (TPD), truncated negative binomial distribution (TNBD), logarithmic series distribution (LSD). In companion paper (II) the process of occurrence is developed by Markov chain. The amounts of precipitation, given that precipitation has occurred, are described by a Gamma. Pearson Type-III, Extremal Type-III, and 3 parameter Weibull distribution. Daily precipitation series model consists of two models, A-Wand A-G model, by combining the process of precipitation occurrence and a continuous probability distribution on the precipitation of wet days. To evaluate the performance of the simulation model, output from the model was compared with historical data of 7 stations in the Nakdong and Seomjin river basin. The results of paper (1) show that it is possible to design a model for the synthetic generation of IX)int precipitation patterns.

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Actual Vegetation and Vegetation Structure at the Coastal Sand Bars in the Nakdong Estuary, South Korea (낙동강 하구 연안사주섬의 현존식생 및 식생구조 연구)

  • Lee, Youl-Kyong;Ahn, Kyung-Hwan
    • Korean Journal of Environment and Ecology
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    • v.26 no.6
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    • pp.911-922
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    • 2012
  • This study aim that definite the relationship between coastal environment and different sand bar communities, as well as to analyze their spatial distribution of barrier island in the Nakdong river estuary. Survey method follow by Braun-Blanquet(1965) and there a total of 118 relev$\acute{e}$'s were undertaken. Definition of the relationships between species and environmental variables with Canonical Correlation Analysis(CCoA) and that to applied these relev$\acute{e}$'s with the RIM(Kim and Kim, 2006) program and that to classification used the SYN-TAX 2000 program(Podani 1979). On the basis of about 118 phytosociological releve's, the vegetation of xeric and hydric type was arranged in twelve plant communities: Xeric type-Pinus thunbergii community,Vitex rotundifolia community, Carex pumila community, Imperata cylindrica var. koenigii community, Miscanthus sacchariflorus community and Calystegia soldanella community, Hydric type-Salix dependens-Calamagrostis epigeios community, Calamagrostis epigeios-Phragmites communis community, Phragmites communis-Ischaemum aristatum community, Phragmites communis community, Scirpus planiculmis community and Suaeda glauca-S. japonica community.These plant communities represents sand dune vegetation and salt marsh vegetation. Widely distributing types in the actual vegetation map were sea club-rush community, reed community in salt marsh, and dry grassland. The edge in the coastal sand bars has zonation that almost distribution by the reed community in salt marsh. But outside of it were distributed sea club-rush community. Dry grassland type distributes higher zone of the center in coastal sand bars. Respectively, the coastal sand dune and salt marsh vegetation types were distributed ocean and inland on the frontier of it.

Development of Backfill Materials for Underground Power Cables Considering Thermal Effect (열특성 효과를 고려한 지중송전관로용 되메움재 개발)

  • Lee Dae-Soo;Kim Dae-Hong;Hong Sung-Yun
    • Journal of the Korean Geotechnical Society
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    • v.21 no.6
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    • pp.41-52
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    • 2005
  • Because the allowable current loading of buried electrical transmission cables is frequently limited by the maximum permissible temperature of the cable or of the surrounding ground, there is a need fur cable backfill materials that can maintain a low thermal resistivity even while subjected to high temperatures for prolonged periods. Temperatures greater than $50^{\circ}C\;to\;60^{\circ}C$ may lead to breakdown of cable insulation and thermal runaway if the surrounding backfill material is unable to dissipate the heat as rapidly as it is generated. This paper describes the results of studies aimed at the development of backfill material to reduce the thermal resistivity. A large number of different additive materials were tested to determine their applicability as a substitute material. Tests were carried out for Dongrim river sand, a relatively uniform sand of very high thermal resistivity, $50^{\circ}C-cm/watt\;at\;10\%$ water content, $260^{\circ}C-cnuwatt$ when dry, and Jinsan granite screenings, and D-2 (sand and granite screenings mixture), E-1 (rubble and granite screenings mixture), a well-graded materials with low thermal resistivity, about $35^{\circ}C-cm/watt$ when at 10 percent water content, $100^{\circ}C-cm/watt$ when dry. Based on this research, 3 types of backfill materials were suggested for improved materials with low thermal resistivity and the applicability was assessed through field tests.

Distribution characteristics of hexabromocyclododecanes in crucian carp and sediment from the major rivers (우리나라 하천에 서식하는 붕어와 주변 퇴적토에 축적된 HBCDs의 분포 특성)

  • Lee, Sumin;Kim, Seongwook;Jeong, Gi Ho
    • Analytical Science and Technology
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    • v.27 no.6
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    • pp.321-332
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    • 2014
  • The accumulation levels of hexabromocyclododecanes (HBCDs) were measured in samples of muscle tissue from crucian carp (Carassius auratus) and also in samples of associated sediments. Samples were collected from 15 sites along the courses of four major rivers. Widespread contamination by HBCDs in this area was identified from the results of this investigation. HBCDs were found above the detection limit from all of the sampling sites. The ${\Sigma}HBCDs$ (sum of ${\alpha}$-, ${\beta}$-, and ${\gamma}$-HBCDs) levels ranged from 1.3 to 19 ng/g (lipid wt) in the crucian carp musscle tissue samples, and from 0.17 to 30 ng/g (dry wt) in the associated sediment samples. The predominance of ${\alpha}$-diastereomer in the muscle tissue of the carp and ${\gamma}$-diastereomer in the sediments was identified, accounting for 88% and 60% of the ${\Sigma}HBCDs$, respectively. The ${\Sigma}HBCDs$ levels in the muscle tissue samples of carp collected from the upstream sections of each river were much lower than those in the samples from carp in the downstream sections. In addition, the ${\Sigma}HBCDs$ levels in carp tissue samples from an isolated site were much lower than those in carp collected from the sites along the major rivers. This suggests that HBCD contamination in the rivers is likely to be sourced from the environment adjacent to them.

Evaluation of Compaction and Thermal Characteristics of Recycled Aggregates for Backfilling Power Transmission Pipeline (송배전관로 되메움재로 활용하기 위한 국내 순환골재의 다짐 및 열적 특성 평가)

  • Wi, Ji-Hae;Hong, Sung-Yun;Lee, Dae-Soo;Park, Sang-Woo;Choi, Hang-Seok
    • Journal of the Korean Geotechnical Society
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    • v.27 no.7
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    • pp.17-33
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    • 2011
  • Recently, the utilization of recycled aggregates for backfilling a power transmission pipeline trench has been considered due to the issues of eco-friendly construction and a lack of natural aggregate resource. It is important to identify the physical and thermal properties of domestic recycled aggregates that can be used as a backfill material. This paper evaluated thermal properties of concrete-based recycled aggregates with various particle size distributions. The thermal properties of the recycled aggregates and river sand provided by local vendors were measured using the transient hot wire method and the transient needle probe method after performing the standard compaction test. The needle probe method considerably overestimated the thermal resistivity of recycled aggregates especially at the dry of optimum water content because of experiencing disturbance while the needle probe is being inserted into the specimen. Similar to silica sand, the thermal resistivity of recycled aggregates decreased when the water content increased at a given dry density. Also, this paper evaluated some of the existing prediction models for the thermal resistivity of recycled aggregates with the experimental data, and developed a new prediction model for recycled aggregates. This study shows that recycled aggregates can be a promising backfill material substituting for natural aggregates when backfilling the power transmission pipeline trench.

Thermal Resistivity of Backfill Materials for Underground Power Cables (지중송전관로 되메움재의 열저항 특성)

  • 김대홍;이대수
    • Journal of the Korean Geotechnical Society
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    • v.18 no.5
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    • pp.209-220
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    • 2002
  • Because the allowable current loading of buried electrical transmission cables is frequently limited by the maximum permissible temperature of the cable or of the surrounding ground, there is a need for cable backfill materials that can maintain a low thermal resistivity (less than 5$0^{\circ}C$-cm/watt) even while they are subjected to high temperatures for prolonged periods. Temperatures greater than 5$0^{\circ}C$ to 6$0^{\circ}C$ may lead to breakdown of cable insulation and thermal nlnaway if the surrounding backfill material is unable to dissipate the heat as rapidly as it is generated. This paper describes the results of studies aiming at the development of backfill material to reduce the thermal resistivity. A large number of different additive materials were tested to determine their applicability as a substitute material. Tests were called out for DonUing river sand, a relatively uniffrm sand of very high thermal resistivity (5$0^{\circ}C$ -cnuwatt at 10% water content, 26$0^{\circ}C$-cm/watt when dry), and Jinsan granite screenings, and A-2(sand and gravel mixture), E-1 (rubble and granite screenings mixture), a well-graded materials with low thermal resistivity (about 35$^{\circ}C$ -cm/watt when at 10 percent water content, 10$0^{\circ}C$-cm/watt when dry). Based on this research, 3 types of backfill materials were suggested for improved materials with low thermal resistivity.