• Applied Biological Chemistry
• /
• v.45 no.2
• /
• pp.84-91
• /
• 2002

If contaminated river water is sprayed over the floodplain, organic matter and nitrogen would be removed by microbial processes in the rhizosphere of vegetation during the filtration through soil. In this study we tested the organic matter and nitrogen removal from contaminated river water by the floodplain filtration. Model system of floodplain was constructed using a PVC pipe (15 cm i.d. ${\times}$ 150 cm L) which was packed with a loamy sand soil collected from a floodplain in Nakdong river. The model system was instrumented with soil solution samplers and gas samplers. A river water collected from Omogcheon in Kyongsan was sprayed from top of the model system at three different rates. The concentration of organic matter, DO, $NO_3^-$, $NO_2^-$, $NH_4^+$, $N_2$ and $N_2O$, and redox potential were measured as a function of soil depth for 24 days after the system reached a steady state. When river water was sprayed at the rates of 40.8 and 68.0 $l/m^2/day$, a significant reductive condition for denitrification was developed at below 5-cm depth of the soil. When the water reached at 90-cm depth of the soil, COD and concentration of inorganic nitrogen were lowered, on an average, from 18.7 to 5 mg/l and from 2.7 to 0.4 mg/l, respectively. $N_2$ comprised most of the N gas evolved from denitrification and $N_2O$ concentrations emitted at the surface of soil were less than 1 {\mu}l/l. The effective removal of organic matter and nitrogen by the filtration in the model system of floodplain demonstrates that the native floodplains, which include rhizosphere of vegetation at the top soil, could be more effective in the treatment of contaminated river waters and other industrial waste waters containing high concentration of organic matter and nitrogen.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
• /
• 2001.06a
• /
• pp.43-48
• /
• 2001

Many applications in the areas of agricultural, hydrological and environmental resource management require data over very large areas and with a high imaging frequency - monitoring crop growth, water stress, seasonal wetland flooding and natural vegetation development. This precludes the use of fine resolution data (Landsat, Spot) on the grounds of cost, accessibility and low imaging frequency. Meteorological satellites have the potential to fill this need, given their very wide spatial coverage, and high repeat imaging. The Remote Sensing Unit (RSU) at the Zambia Meteorological Department routinely receives, processes and archives imagery from both Meteosat and NOAA AVHRR satellites. Here I wish to present some examples of applications of these data sets that arise from the RSU work - relationships between rainfall and vegetation development as assessed by satellite, derived information and seasonal patterns of flooding in the Barotse floodplain and the Kafue flats. I also wish to outline ways in which a more widespread use of this data by the Zambian institutions canbe achieved.

• Journal of Korea Water Resources Association
• /
• v.35 no.2
• /
• pp.203-212
• /
• 2002

The purpose of this study was to examine the effect of vegetation on the flood plain in the Taewha river on the changes of flood level using a hydraulic physical model experiment. To simulate 9.0 km river, 1/300 horizontally and 1/72 vertically distorted model was used. The vegetation areas were divided by three sub -areas and the flood level changes were examined according to the locations of vegetation as well as the transverse Profile. As a result, the flood level changes were not significantly affected by the densely distributed vegetation. It was concluded that additional adjustable vegetation in urban river could make useful hydrophilic space.

• Journal of Korea Water Resources Association
• /
• v.55 no.10
• /
• pp.801-810
• /
• 2022

This study investigates the evolution processes of alternate bars in the channel with bank stability by vegetation by laboratory experiment. Laboratory experiments are conducted to elucidate the behavior of alternate bars by the influence of riparian vegetation on the rivers with erodible banks. To control bank stability of the channel, the actual vegetation, alfalfa, is grown by adjusting the density of alfalfa on the flood plain. As the vegetation density increases in the flood plain, the bank erosion rates and the channel widening rates decrease and the bank stability increases. The alternate bars migrate slow downstream over time. Moreover, the bars in a channel with strong banks migrate rapidly, which is related with the aspect ratio, that is, width to depth ratio. The bar wavelength decrease with vegetation density. Our laboratory experiments show that the behavior of bars differ according to bank strength.

• Korean Journal of Soil Science and Fertilizer
• /
• v.36 no.1
• /
• pp.8-15
• /
• 2003

If contaminated river water is sprayed over a floodplain, the microbial processes can simultaneously remove organic matter and nitrogen during the infiltration through the sediment profile. The effect of rhizosphere on the removal of organic matter and nitrogen from contaminated river water was investigated using floodplain lysimeters. River water was sprayed at a rate of $68.0L\;m^{-2}\;d^{-1}$ on the top of the lysimeters with or without weed vegetation on the surface, Concentrations of $NO_3$, $NH_4$ and dissolved oxygen (DO), and chemical oxygen demand (COD) and Eh in water were measured as functions of depth for 4 weeks after the system reached a steady state water flow and biological reactions. A significant reductive-condition for denitrification developed in the 30-cm surface profile of lysimeters with weeds. At a depth of 30 cm, COD and $NO_3$-N concentration decreased to 5.2 and $0.9mg\;L^{-1}$ from the respective influent concentrations of 18.2 and $9.8mg\;L^{-1}$. The removal of $NO_3$ in lysimeters with weeds was significantly higher than in those without weeds. Vegetation on the top was assumed to remove $NO_3$ directly by absorption and to create more favorable conditions for denitrification by supply of organic matter and rapid $O_2$ consumption, In the lysimeters without weeds, further removal of $NO_3$ was limited by the lack of an electron donor, i.e. organic matter. These results suggest that the filtration through native floodplains, which include rhizospheres of vegetation on the surface, can be effective for the treatment of contaminated river water.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.34 no.3 s.116
• /
• pp.1-11
• /
• 2006

This study analyzed characteristics of natural and human environments in Chuncheon's Gongji stream, and suggested nature-friendly planning strategies for self-purification of water quality, biodiversity improvement and conservative waterfront recreation. The environmental analysis included streambed structures, floodplain soils, water quality, vegetation, wildlife, and human facilities. Natural colonization of vegetation for the middle section of the study stream was obstructed by a straightened concrete revetment of baseflow channel, and vehicle movement and concrete parking lots across the floodplain. These human disturbances also deteriorated the naturalness of the stream landscape and limited habitation of bird species. However, natural sedimented wetlands in half of the channel width for the lower section of the stream contributed to a desirable vegetational landscape and greater bird occurrence. Based on BOD measurements, water quality of the stream fell under class $II{\sim}III$ of the stream water-quality standard, but it was worse around sewage outlets due to incomplete sewage collection especially during the dry season. Dominant fish species included typical inhabitants of good water-quality streams that are tolerant of adverse habitat changes. Nature-friendly planning strategies were established based on analysis of the environmental characteristics. They focused on not merely spatial zoning and layout divided into four zones - preservation, partial preservation, conservation and use -, but close-to-nature channel revetment techniques, natural water-purification facilities, biotope diversification, and water-friendly recreation and circulation. Strategies pursued both renewal of stream naturalness and hydraulic stability of streamflow by minimizing transformation of natural channel micro-topography and biotope, and by reflecting natural traces of streambed structures such as revetment scour and sedimentation.

• Journal of Korea Water Resources Association
• /
• v.53 no.10
• /
• pp.833-843
• /
• 2020

Ecohydraulics is a newly born discipline in the early 1990s by the interdisciplinary approach combined with aquatic ecology in one discipline and geomorphology, hydrology, and fluid hydrodynamics in another. Major areas of ecohydraulics can be delineated as habitat hydraulics (including environmental flow), vegetation hydraulics, eco-corridor hydraulics, eutrophication hydraulics, and ecological restoration hydraulics. Reviews of relevant international journals and literature reveal that ecohydraulics has remained in the limited areas of fish response, hydraulic modeling, and physical habitat response. It has not reached a truly interdisciplinary stage. Literature reviews in Korea reveal that only 3% of the total number of the papers listed in the Journal of KWRA during the last 24 years is related to ecohydraulics. It is about 20% of the total listed in the Journal of Ecology and Resilient Infrastructure. Most of those related to ecohydraulics in Korea concern vegetation hydraulics, habitat hydraulics, and ecological restoration hydraulics. In contrast, dynamic flow modeling areas, including turbulence, fauna motion simulation, and eutrophication hydraulics, are not found. Areas of further research in ecohydraulics in Korea may be specified as follows: 1) environmental flows adapted to the traits of the rivers in Korea, 2) development of the dynamic floodplain vegetation models (DFVM) to assess the changes from the white river to green river, 3) development of the eutrophication hydraulic model to predict the freshwater algal blooms, and 4) development of the models to evaluate the physical, chemical, and biological impacts of the stream restoration, decommissioning and removal of old weirs or small dams.

• Korean Journal of Ecology and Environment
• /
• v.50 no.1
• /
• pp.157-168
• /
• 2017

Backswamp is the section of a floodplain where deposits of fine silts and clays settle after a flood. In general, the wetland is composed of diverse ecosystems, and is characterized by ecotone. The purpose of this study was to analyze vegetation naturalness and to assess vegetation value by syntaxonomy and synecology of Useupje backswamp at Yeongsan river. As a result, the vegetation was divided into four physyiognomy types and 14 vegetation units depending on the species composition and habitats. The vegetation units confirmed in the study were as follow: Spirodela polyrhiza community as floating plant; Trapa bispinosa var. inuma community and Trapa bispinosa var. inumai-Nelumbo nucifera community as floating-leaved plant; Paspalum distichum community, Persicaria thunbergii community and Phalaridetum arundinaceae as lentic vegetation in the eulittoral zone; Scirpo fluviarilis-Zizanietum latifoliae and Typha angustata community in the emerged zone; Scirpetum tabernaemontani and Phragmitetum australis in the littoral zone; Carex dimorpholepis-Salix subfragilis community ecotone region of upland. According to the study, the vegetation distribution was highly affected by water level and artificial interference. Moreover, the development of vegetation units showed a significant relationship between species composition and habitats. Although vegetation value of Useupje resulted by vegetation naturalness was identified as the grade [III], the ecological value is expected to upward evaluation because of unique vegetation and geographical location.

• Journal of Korean Society on Water Environment
• /
• v.33 no.3
• /
• pp.291-301
• /
• 2017

This study was carried out to investigate distribution on the alien plants in the Gyeong-in Ara Waterway. The alien plants were a total of 82 taxa: 17 families, 63 genera, 80 species, and 2 varieties. This number corresponds to 25.5% of alien plants identified in Korea. The proportion of alien plants in every year was increased from upstream to downstream. As the result of the analysis on vegetation stratification, bank of waterside was covered with artificial materials preventing existence of vegetation, and had step-type cross section. Floodplain was composed of waterfront area. An array of vegetation was not typical dispersion, and terrestrial and alien plants were dominated the Gyeong-in Ara Waterway. Evaluation of naturalness based on the vegetation stratification showed grade 3 or 4. In order to solve a problem, method and level of restoration should be decided based on the result of diagnostic assessment. Therefore, we need to restore the step-type cross section as pool type one. From waterside to bank in this waterway, we recommend to introduce natural plants by imitating reference species composition. Since, an invasion of alien plants is expected to be accelerated due to the continuous artificial disturbance, we recommend to quantitative investigation on the invasion of alien plants and monitoring on the change of distribution.

• Journal of Wetlands Research
• /
• v.12 no.3
• /
• pp.1-13
• /
• 2010

Most of investigations about the effects of dam construction on the surrounding environments have focused mainly on the change of climate conditions and crop production. In order to research the effect of dam construction on the surrounding vegetation, we chose the Soyanggang dam whose storage capacity is the largest in Korea, and was built 33 years ago. We surveyed and analyzed the surrounding vegetation by using quadrat method and measured the soil moisture content among floodplain (FP), 5m above the flood plain (AFP) and control group (CG) which is 3km far from the lake through ridge. The largest value of mean importance percentage of the canopy~understory layer at FP was Salix koreensis (87.9%) and those of AFP and CG was Quercus mongolica (38.9% and 40.4% respectively) and the largest important percentage of the herb layer at FP was Artemisia capillaris (34.2%) and those of AFP and CG was Oplismenus undulatifolius var. undulatifolius (9.4% and 24.6% respectively). The Shannon-Wiener diversity index of shrub~canopy layer at FP (0.26) was lower than AFP (2.34) and CG (2.23) and there was not any significant difference in the herb layer among three groups. The S${\o}$rensen similarity index between FP and AFP, FP and CG was 0, and that of AFP and CG was relatively high. The highest density of tree and subtree with the DBH level of FP was S. koreensis of 5~10cm (240/ha), and that of AFP and CG was Quercus spp. of 15~20cm (400/ha and 466/ha respectively). And the highest density of seedlings of FP was Pinus densiflora (7,040/ha), and that of AFP and CG was Quercus spp. (720/ha and 400/ha respectively). The soil water content of FP (6.28%) was relatively lower than AFP and CG (11.13% and 10.14% respectively; p<.01). These results indicated that construction of Soyanggang dam changed the vegetation of the floodplain, without showing a change in its upland areas.