• Title/Summary/Keyword: hydrological environment

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Analysis on Relationships of Migratory Birds Species·Population due to Water-Ecosystem : Shinan-gun Benangkimi wetland (수생태에 따른 철새의 종·개체수 관계 분석 : 신안군 배낭기미습지)

  • Kim, Dong Hyun;Lee, Seung Oh
    • Journal of Korean Society of Disaster and Security
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    • v.11 no.1
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    • pp.7-14
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    • 2018
  • The Benangkimi wetland, which serves as a stopover place for migratory birds in the Dadohae Marine National Park in Wando-gun, Jeollanam-do, is a place where various species and a large number of migratory birds are observed. In order to provide an effective and scientific management plan for the habitat environment of migratory birds, we carried out field survey of Benangkimi wetland. The field survey and survey on habitat use of migratory birds were conducted in parallel to obtain the basic data of hydraulics and hydrology. The hydraulic and hydrological survey of Benangkimi wetland was conducted 1-2 times a year during the period of 2015-2016 (two years). It was classified into 4 sectors according to the topography and geology, rainfall, hydraulic characteristics, and wetland conditions. The 3 sectors same as the migratory birds survey sector and the 1 sector as the inflow of the wetland were analyzed. The survey also focused on small migratory birds arriving at Benangkimi wetland during the spring and autumn season. As a result of investigating the population and species in each section, the habitat environment was different according to the water depth, sediment thickness and salinity. Migratory birds prefer hydraulic and hydrological characteristics. This study will be used for the scientific management of Benangkimi wetland, which serves as a stopping point for migratory birds, and it will contribute to basic data of ecology - hydraulics by examining the relationship between habitat environment and hydrological data.

An Analysis of Groundwater Level Fluctuation Caused by Construction of Groundwater Dam (지하댐 건설에 따른 유역 내 지하수위 변화 특성 해석)

  • Kim, Jong-Tae;Kim, Man-Il;Chung, Il-Moon;Kim, Nam-Won;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.19 no.2
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    • pp.227-233
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    • 2009
  • Most of hydrological processes of groundwater recharge generally are occupied a rainfall, and recharged an aquifer along infiltrate into subsurface. These processes mainly have an influence by hydrological characteristics and topographic gradient of the aquifer. Development of water resources and its management is not good because of temporal and spatial disproportion in local rainfall. In order to deal with insufficiency of water resources from now on, development of groundwater dam requires a plan of a sustainable of new water resources. These are necessary that investigation of construction area of groundwater dam, effective groundwater development interconnected with surface water and groundwater, and assessment of an application of groundwater dam for utilization of water resources. Tn this study we were derived the input data by geological survey, hydraulic and hydrological analysis around Hoengchun-river, located in Hadong-gun, Gyeongsangnam Province where is a plan area for construction of groundwater dam. Based on input data we were carried out the interconnected analysis of surface water and groundwater using the SWAT-MODFLOW, and predicted groundwater fluctuation of its construction before and after.

Simulation of Daily Soil Moisture Content and Reconstruction of Drought Events from the Early 20th Century in Seoul, Korea, using a Hydrological Simulation Model, BROOK

  • Kim, Eun-Shik
    • Journal of Ecology and Environment
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    • v.33 no.1
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    • pp.47-57
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    • 2010
  • To understand day-to-day fluctuations in soil moisture content in Seoul, I simulated daily soil moisture content from 1908 to 2009 using long-term climatic precipitation and temperature data collected at the Surface Synoptic Meteorological Station in Seoul for the last 98 years with a hydrological simulation model, BROOK. The output data set from the BROOK model allowed me to examine day-to-day fluctuations and the severity and duration of droughts in the Seoul area. Although the soil moisture content is highly dependent on the occurrence of precipitation, the pattern of changes in daily soil moisture content was clearly quite different from that of precipitation. Generally, there were several phases in the dynamics of daily soil moisture content. The period from mid-May to late June can be categorized as the initial period of decreasing soil moisture content. With the initiation of the monsoon season in late June, soil moisture content sharply increases until mid-July. From the termination of the rainy season in mid-July, daily soil moisture content decreases again. Highly stochastic events of typhoons from late June to October bring large amount of rain to the Korean peninsula, culminating in late August, and increase the soil moisture content again from late August to early September. From early September until early October, another sharp decrease in soil moisture content was observed. The period from early October to mid-May of the next year can be categorized as a recharging period when soil moisture content shows an increasing trend. It is interesting to note that no statistically significant increase in mean annual soil moisture content in Seoul, Korea was observed over the last 98 years. By simulating daily soil moisture content, I was also able to reconstruct drought phenomena to understand the severity and duration of droughts in Seoul area. During the period from 1908 to 2009, droughts in the years 1913, 1979, 1939, and 2006 were categorized as 'severe' and those in 1988 and 1982 were categorized as 'extreme'. This information provides ecologists with further potential to interpret natural phenomenon, including tree growth and the decline of tree species in Korea.

Analysis of interaction between river and groundwaterin Kurobe river fan by a grid-based hydrological model

  • Takeuchi, Masanobu;Murata, Fumito;Katayama, Takeshi;Nakamura, Shigeru;Nakashima, Noriyuki;Yamaguchi, Haruka;Baba, Aki
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.26-26
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    • 2012
  • The Kurobe river, which runs through eastern Toyama Prefecture is one of the most famous rivers for wild water because of its steep slope in the range from 1/5 to 1/120. This river forms an alluvial fan in the range up to 13 kilometers from the sea. In this region, significant seepage flow occurs and thus the stream sometimes been intermitted. Moreover, the amount of seepage flow seems to vary with the groundwater level of the region. To keep the river environment healthy for flora and fauna, especially to conserve good condition for spawning of fishes, an appropriate environmental flow should be maintained in the river. To achieve this target, controlling of the upstream reservoir has to be studied in depth. One of the major problems to decide the amount of water to be released from the reservoir to maintain the environmental flow is to estimate the amount of water leaked into the groundwater from the river. This phenomenon is affected by the river flow rate as well as the groundwater level in the alluvial fan and the conditions vary in space and time. Thus, a grid-based hydrological cycle analysis model NK-GHM has been applied to clarify the hydrological cycle componentsin this area including seepage/discharge from/to the river. The model was tested by comparing with river flow rate, groundwater levels and other observations and found that the model described those observations well. Consequently, the seepage from the Kurobe river was found significant but it was also found that the groundwater in this region has been preserved by the recharge from the irrigation water supply into paddy fields in the alluvial fan.

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Verification of Precipitation Forecast Model and Application of Hydrology Model in Kyoungan-chun Basin (경안천 유역에 대한 강수예보모델의 검증 및 수문모형활용)

  • Choi, Ji-Hye;Kim, Young-Hwa;Nam, Kyung-Yeub;Oh, Sung-Nam
    • Journal of Korea Water Resources Association
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    • v.39 no.3 s.164
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    • pp.215-226
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    • 2006
  • In this study, we performed verification of VSRF (Very Short Range Forecast of precipitation) model and application of NWSPC (National Weather Service PC) rainfall-runoff model in Kyoungan-chun basin. We used two methods for verification of VSRF model. The first method is a meteorological verification that evaluates the special quality feature for rain amount between AWS and VSRF model over Kyoungan-chun basin, while second method is a hydrological verification that compares the calculated Mean Area Precipitation (MAP) between AWS and VSRF Quantitatively. This study examines the usefulness of VSRF precipitation forecasting model data in NWSPC hydrological model. As a result, correlation coefficient is over 0.6 within 3 hour lead time. It represents that the forecast results from VSRF are useful for water resources application.

Intra-event variability of bacterial composition in stormwater runoff from mixed land use and land cover catchment

  • Paule-Mercado, Ma. Cristina A.;Salim, Imran;Lee, Bum-Yeon;Lee, Chang-Hee;Jahng, Deokjin
    • Membrane and Water Treatment
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    • v.10 no.1
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    • pp.29-38
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    • 2019
  • Microbial community and composition in stormwater runoff from mixed land use land cover (LULC) catchment with ongoing land development was diverse across the hydrological stage due different environmental parameters (hydrometeorological and physicochemical) and source of runoff. However, limited studies have been made for bacterial composition in this catchment. Therefore, this study aims to: (1) quantify the concentration of fecal indicator bacteria (FIB), stormwater quality and bacterial composition and structure according to hydrological stage; and (2) determine their correlation to environmental parameters. The 454 pyrosequencing was used to determine the bacterial community and composition; while Pearson's correlation was used to determine the correlation among parameters-FIB, stormwater quality, bacterial composition and structure-to environmental parameters. Results demonstrated that the initial and peak runoff has the highest concentration of FIB, stormwater quality and bacterial composition and structure. Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes were dominant bacteria identified in this catchment. Furthermore, the 20 most abundant genera were correlated with runoff duration, average rainfall intensity, runoff volume, runoff flow, temperature, pH, organic matter, nutrients, TSS and turbidity. An increase of FIB and stormwater quality concentration, diversity and richness of bacterial composition and structure in this study was possibly due to leakage from septic tanks, cesspools and latrines; feces of domestic and wild animals; and runoff from forest, destroyed septic system in land development site and urban LULC. Overall, this study will provide an evidence of hydrological stage impacts on the runoff microbiome environment and public health perspective.

Organic Matters Budget and Movement Characteristic in Lake Hoengseong (횡성호의 유기물 수지 및 거동 특성)

  • Joung, Seung-Hyun;Park, Hae-Kyung;Yun, Seok-Hwan
    • Journal of Korean Society on Water Environment
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    • v.28 no.2
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    • pp.238-246
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    • 2012
  • Organic matters budget in Lake Hoengseong were monthly investigated from April 2009 to November 2009. The intense rainfall occurred at between July and August and the hydrological factors were highly varied during the rainfall season. By the concentrated rainfall, the elevation, influx and efflux were sharply increased and the turbid water was also flowed into the middle water column in Lake. The inflow of turbid water increased the nutrient concentrations in water body and this appears to stimulate of phytoplankton regard as the primary productivity of influx of organic matter. Monthly average concentration of dissolved organic carbon (DOC) was generally higher than the particulate organic carbon (POC) concentration in Lake, but Temporal and spatial variation of POC concentration was higher than DOC and the maximum POC concentration was recorded in surface water in August, had the highest phytoplankton biomass. Organic carbon concentration in inflow site was rarely changed during the dry season, but the concentration was rapidly increased by the initial intense rainfall. In organic matters budget, the most of the organic matters was inflowed from the inflow site at rainfall season. Especially, the influx of allochthonous organic matters during the intense rainfall was 72.4% in the total influx organic matters.

Water-Blooms (Green-Tide) Dynamics of Algae Alert System and Rainfall-Hydrological Effects in Daecheong Reservoir, Korea (대청호 조류경보제의 녹조현상 동태와 강우-수문학적 영향)

  • Shin, Jae-Ki;Kang, Bok-Gyoo;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
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    • v.49 no.3
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    • pp.153-175
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    • 2016
  • Daecheong Reservoir has suffered eutrophication and water-blooms by blue-green algae from initial impoundment, and algae alert system (AAS) was introduced in 1997. The purpose of this study was to investigate the effect of rainfall and hydrological factors in increase or decrease variability of green-tide and prolonged AAS, studied and analyzed the current situation of AAS has been operating for 19 years (1997~2015) in Daecheong Reservoir. The total issued number of AAS was 46 times, the most frequent period in August and September were 22 times (752 days) and 16 times (431 days), respectively, it accounted for 82.6%. Many number and frequency during this period were significantly associated with rainfall, various discharge and water level. Rainfall and hydrological events are associated with the rainy season of monsoon-Changma and the typhoon, it was concentrated in June~September, total rainfall in this period accounted for 69.9% of the annual rainfall. An increase in inflows was dependent on the intensity, frequency and the amount of rainfall. Accounted for 68.4% of the total annual inflow, it was a time when the most rapidly changing hydrological variability in the reservoir. The total outflow was closely related to rainfall, and compared the distinctive characteristics of hydropower generation and watergate-spillway discharge. In addition, the upreservoir zone of Daecheong Reservoir could be vulnerable to green-tide by regulating discharge of the upstream dam. The issue of AAS was strongly related to the with and without of watergate-spillway discharge. The watergate-spillway discharge had a total of 25 times, it was maximum 17 days from July to September in the year. And the opening times and each duration of the watergate were 1~4 times and the range of 3~37 days, respectively. When the watergate opened, the issue of AAS was maintained to 13 years and the movement of water bodies and green-tide was great about five times than that of non-open, had a profound effect on prolonged AAS within reservoir. In Daecheong Reservoir, Chusori (CHU) area of the So-ok Stream was still showing serious symptoms green-tide levels in the summer, but Janggye (JAN) waters of the main reservoir was pointed out that more important. AAS will be operated by an absolutely consider the rainfall and hydrological effects around the watergate-spillway discharge. The measures of green-tide will be included in the limnological studies more suited to the characteristics of the watershed and reservoir of the our country. Finally, from now on, we will prepare the systematic management and guidelines for vulnerable zone water-blooms that are the source within the reservoir before the monsoon rather than waiting for the arrival of green-tide on the operating stations of AAS.

The Applicability Assessment of Environmental Flows Method by Hydrological Approach (수문학적 접근법에 의한 환경유량 산정기법의 적용성 평가)

  • Kim, Joo Cheol;Choi, Yong Joon
    • Journal of Korean Society on Water Environment
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    • v.26 no.2
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    • pp.208-214
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    • 2010
  • This study aimed at the introduction of desktop method for assessment of environmental flows developed by International Water Management Institute (IWMI) recently and its application to Geum river basin. This scheme simulated the influence on aquatic ecosystem caused by watershed development and in turn the decrease of water quantity keeping the river's own flow regime. It was found to be as very effective method although it had simple structure. Flow duration curves for different environmental classes at Sutong and Gongjoo sites were estimated according to the natural conditional scenario of Geum river basin and the results were relatively compared well with the previous studies. The behaviors of monthly average runoff time series of both sites showed the level of A class. The results of this study would provide the fundamental data to establish the future plans of monitoring or management for aquatic ecosystem of Geum river basin.