• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.6
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• pp.119-133
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• 2013

The purpose of this study is to develop riverbed techniques to activating ecological function of hyporheic zone. Hyporheic zone maybe simply defined as an active eco-tone between surface water and groundwater, which facilitates to exchange water, nutrients and aquatic habitat occur in response to variation in discharge and bed geomorphology. The aim of this study is to evaluate the effectiveness of an applied riverbed technique for two years since its installation in the hyporheic zone. The experimental riverbed technique has been implemented on Anyang stream penetrating Anyang city in Gyunggi province. The dimension of the installed structure is 5.0 m in width, 46 m in length. Bottom layer is filled with rip-rap covered with gabion. After the implementation of the technique, the study conducts follow-up monitoring in two years of between 2011 and 2012. The results of follow-up monitoring for two years are as follows:1) In Hydro geomorphic process, the riverbed technique maintains hydraulic stability despite of several flood events in 2011, 2012. 2) After transformation to form pool-and-riffle habitat, for aquatic community composed of freshwater fish, macro invertebrate, and attached algae, the species diversity and population gradually increased. 3) The riverbed technique achieved desired effect on enhancement of ecological function in hyporheic zone.

• Journal of Species Research
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• v.5 no.1
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• pp.157-165
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• 2016

The hyporheic zone is an ecologically important area for investigating habitat biodiversity. However, only few studies have been conducted on this aspect in Korea. This study aimed to investigate the distribution of arthropod communities in the hyporheic zone of Nakdonggang River between 2012 and 2013. The meiobenthic arthropod communities found in the hyporheic zone were identified using a stereomicroscope and classified into 9 taxanomic groups. The abundance of arthropod communities was higher in the hyporheic zones of streams having well-formed sandbanks and gravelly areas. The arthropod communities found along the Nakdonggang River differed depending on the conditions of levees and the regions of the river from where they were collected. The frequency of species of the order Harpacticoida was high in the Nakdonggang main stream and western downstream region. The abundance of species belonging to Cyclopidae was high in the upstream region, midstream region, and eastern downstream region of the river. The frequency of species of the order Bathynellacea was high in the riverside parks or cement levees, but that of species belonging to Cyclopidae was high in the natural levees and gabion levees. Our findings suggested that arthropod communities preferred natural levees.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.265-273
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• 2011

Hyporheic zone, where groundwater-stream water mixing occurs, sensitively responds to heat of groundwater and stream water temperature. Variation of stream water temperature has short time period and time dependent, because stream water temperature is influenced by daily fluctuation and seasonal air temperature. On the other hand, groundwater temperature is insignificant. In this study, we conducted 1-dimensional heat transfer analysis. The results show that there are differences of temperature distribution between gaining stream and losing stream with flux in hyporheic zone. Especially, variations of hyporheic water temperature show a significant difference in adjacent streambed, Also, the results shows that distribution of temperature was more affected by groundwater direction than intensity of flux.

• Journal of Wetlands Research
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• v.11 no.1
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• pp.123-130
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• 2009

Hyporheic zone is an area where hydraulic exchanges occur between surface water and ground water. Such transient area is anticipated to facilitate diverse biogeochemical reactions by providing habitats for various microorganism. However, only a few data are available about microbial properties in hyporheic zone, which would be important in better understanding of biogeochemical reactions in whole streams. The study site is Naesung stream, located in the north Kyoung-Sang Province, of which sediment is sandy with little anthropogenic impacts. Soil samples were collected from a transect placed perpendicular to stream flow. The transect includes upland fringe area dominated by Phragmites japonica, bare soil, and soil adjacent to water. In addition, soil samples were also collected from downwelling and upwelling areas in hyporheic zone within the main channel. Soils were collected from 3 depth in each area, and water content, pH, and DOC were measured. Various microbial properties including extracellular enzyme activities ($\beta$-glucosidase, N-acetylglucosaminidase, phosphatase and arylsulfatase), and microbial community structure using T-RFLP were also determined. The results exhibited a positive correlation between water content and DOC, and between extracellular enzyme activities and DOC. Distinctive patterns were observed in soils adjacent to water and hyporheic zone compared with other soils. Overall results of study provided basic information about microbial properties of hyporheic zone, which appeared to be discernable from other locations in the stream corridor.

• Journal of Wetlands Research
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• v.14 no.1
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• pp.75-87
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• 2012

Hyporheic zone is a region beneath and alongside a stream, river, or lake bed, where there is mixing of shallow groundwater and surfacewater. Hyporheic exchange controls a variety of physical, biogeochemical and thermal processes, and provides unique ecotones in a aquatic ecosystem. Field and experimental observations, and modeling studies indicate that hyporheic exchange is mainly in response to pressure gradients driven by the geomorphological features of stream beds. In the reach scale of a stream, pool-riffle structures dominate the exchange patterns. Flow over a pool-riffle sequence develops recirculation zones and stagnation points, and this flow structures make irregular pressure gradient which is driving force of the hyporheic exchange. In this study, 3 D hydro-dynamic model solves the Reynolds-averaged Navier-Stokes equations for the surface water and Darcy's Law and the continuity equation for ground water. The two sets of equations are coupled via the pressure distribution along the interface. Simulation results show that recirculation zones and stagnation points in the pool-riffle structures dominantly control the upwelling and downwelling patterns. With decrease of recirculation zones, length of donwelling zone formed in front of riffles is reduced and position of maximum downwelling point moves downward. The numerical simulation could successfully predict the behavior of hyporheic exchange and contribute the field study, river management and restoration.

• Ecology and Resilient Infrastructure
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• v.11 no.2
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• pp.23-34
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• 2024

Sediment, aquifer materials, surface water, and groundwater from brackish Songji lake affected by salinity of seawater, were collected and a pilot scale column experiment was conducted to simulate the nitrogen transport through the hyporheic zone. Upstream experiments of groundwater displayed that groundwater containing a small amount of salt percolated into aquifers and sediments, maintaining low dissolved oxygen concentrations. In addition, partial denitrification occurred in the aquifer due to salinity and low dissolved oxygen, resulting in the accumulation of NO₂^-. In sediments,nitrogenous compounds were reduced due to adsorption by long residence times or microbial-mediated oxidation/reduction reactions. Downstream experiments of surface water displayed that surface water from the brackish lake, containing high concentrations of dissolved oxygen and salts, infiltrated into the sediments and aquifer, supplying high dissolved oxygen concentrations. This resulted in biological nitrification in the sediments and aquifer, which reduced nitrogen-based pollutants despite the high salt concentration in the surface water. Whereas partial denitrification at low dissolved oxygen concentrations in the upwelling mixing zone was observed by salinity and accumulated NO₂^-, nitrification at high dissolved oxygen concentrations in the downwelling mixing zone was not significantly affected by salinity. These results confirm that salinity in the brackish water lake has some influence on the nitrogen behavior of the hyporheic mixing zone, although nitrogen behavior is a complex combination of factors such as DO, pH, substrate concentration, and organic matter concentration.

• Journal of Korea Water Resources Association
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• v.55 no.1
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• pp.23-32
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• 2022

This paper performs two-dimensional numerical simulation of surface water-groundwater coupled flow and solute transport to investigate the effect of the hyporheic exchange at the sediment-water interface (SWI) on surface solute transport. For the impermeable bed case in the absence of hyporheic flow, the trapping effect of flow recirculation associated with the ripple bed controls the shape of breakthrough curves (BTCs). However, the permeable bed case with hyporheic flow stimulates the extended tailing of the BTCs more significantly due to the elevated concentration of the BTC tailing resulting from slow hyporheic velocity. Also, the increased bottom pressure at the SWI with an increase in surface velocity shortens the BTC tailing because of increasing hyporheic velocity. These results infer that hyporhiec flow is critically important in predicting solute residence times in surface water.

• Animal Systematics, Evolution and Diversity
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• v.37 no.3
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• pp.242-248
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• 2021

Lobohalacarus weberi (Romijn and Viets, 1924) is added to the halacarid fauna of Korea as the third member of freshwater halacarid species. Both the genus and species are newly recorded from Korea. Halacarid mites were collected from two hillside wells and a streamside hyporheic zone in the southeastern region of South Korea. Lobohalacarus weberi is characterized by a well-developed frontal spine-like process, seven dorsal setae, the fourth segment of palp with a short distal and three long proximal setae, and tibiae of legs II to IV with two, one, two pectinate setae, respectively. A few minor individual variabilities were observed in the number of perigenital seta and genital acetabula, the setal armature on genua of legs, and the shape of spinule row on lateral claws.

• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.525-535
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• 2006

A study on stream-groundwater exchange was performed using head and temperature data of stream water, streambed, and groundwater. Groundwater level and temperature were obtained from multi-depth monitoring wells in small-scale watershed. During the summer and winter season, time series of temperature data at streambed and groundwater were monitored for six months. In the winter time, we measured the temperature gradient between stream water and streambed. The observed data showed three typical types of temperature characteristics. First, the temperature of streambed was lower than that of stream water; second, the temperature of streambed and stream water was similar; and the last, the temperature of streambed was higher than that of stream water. The interconnections between the stream and the streambed were not homogeneously distributed due to weakly developed sediments and heterogeneous bedrock exposed as bed of the stream. The temperature data may be used in formal solutions of the inverse problems to estimate groundwater flow and hydraulic conductivity.

• Journal of Species Research
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• v.5 no.1
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• pp.49-156
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• 2016

Fourteen new species and A. coreana Morimoto, 1970 of Allobathynella Morimoto and Miura, 1957 are (re-)described and illustrated from the Korean Penninsula. Comparison of the external morphology of these species and two previously known species, A. japonica Morimoto and Miura, 1957 and A. shinjongieei Park and Cho, 2008 enables us to amend the generic diagnosis. A 7-segmented antennule turns out to be inconsistent character due to A. wonjuensis sp. nov., which has a 6-segmented antennule. On the other hand, the exopodal distal segment of thoracopods I-VII with a tiny terminal knob and with outer seta covered by long and strong barbs is proved to be a autapomorphic character of the genus. The 14 new species belong to the mirabilis-group and display more or less similar morphology. However, they differ from A. coreana, A. japonica and A. shinjongieei and from each other not only in quantitative but also in qualitative characters. These differences are summarized in tables. The species inhabit hyporheic zones of rivers and each appears to be highly endemic to a given tributary, having a range limit less than 100 km.