• Journal of Species Research
• /
• v.5 no.1
• /
• pp.157-165
• /
• 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 the Korean Society of Environmental Restoration Technology
• /
• v.16 no.6
• /
• pp.119-133
• /
• 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 Korea Water Resources Association
• /
• v.55 no.1
• /
• pp.23-32
• /
• 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.

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

• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.94-94
• /
• 2017

지속적인 수질의 모니터링과 관리가 어려운 개발도상국의 경우, 모델링을 통한 병원균의 예측이 중요하다. Soil and Water Assessment Tool (SWAT)은 유역 모델로 병원균의 거동을 모의하는데 널리 활용된다. 하지만 SWAT이 모의하는 in-stream 모듈의 경우, 소멸, 부유, 퇴적의 단계만을 고려하여 정확도가 부족하다. 따라서 본 연구는 기존 모듈에 hyporheic exchange와 생장 단계를 추가하여 모듈의 성능 개선 및 열대 산지 유역에서의 병원균의 거동을 모의하였다. 본 연구는 몬순 기후 및 산지 지형을 가진 라오스의 Houay Pano 유역을 대상으로 대장균 (Escheichia coli, E.coli)의 거동을 2011년부터 2013년까지 일 단위로 모의하였다. 기존의 SWAT 박테리아 모듈의 경우, 소멸 단계만을 가지고 보정하였을 때 모델은 대부분 0의 값을 가졌고, 부유 및 퇴적 단계가 추가 된 후에는 우기시 대부분의 모델값이 관측값의 95% 신뢰 구간에 포함되었으나 건기에는 농도가 여전히 낮게 모의됨을 확인 할 수 있다. 건기 시 낮게 모의된 농도를 증가시키기 위해, 온도에 따른 생장 단계를 추가하였으며, 이때 생장 속도는 설정된 최소-최대 생장 온도 사이에서 최대값을 가진다. 하지만 온도에 따른 생장은 열대 기후의 특성상 전 기간에 걸쳐 동시에 증가하여 건기에만 낮게 모의된 농도를 보완하는 데는 한계가 있었다. Hyporheic exchange는 강바닥에 임시로 저장된 박테리아의 양이 특정 유량에 의해서 수계로 유입되는 현상으로, 본 연구에서는 일정한 양의 hyporheic flow를 가정하여 모의하였다. 결과적으로 Hyporheic exchange를 통해 유입되는 적은 양의 E.coli는 기존에 타당하게 모의된 우기의 농도는 그대로 유지하되, 건기에 낮게 모의된 농도는 증가시켜 기존 SWAT 모듈의 한계점을 잘 보완한 것을 확인 하였다. 결론적으로, 기존의 SWAT 모델은 건기 시 낮은 농도의 E.coli를 모의하기에 한계를 보였으며, 전 기간에 걸쳐 높은 온도를 유지하는 열대 기후에서 생장 단계는 이러한 한계를 보완하기에 적합하지 않은 것으로 판단되었다. 그러나 적은 양이 전 기간에 걸쳐 동일하게 유입되는 hyporheic exchange의 경우, 건기에 낮게 모의된 농도를 증가시켜 기존의 한계를 보완할 수 있었다.

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

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.10a
• /
• pp.240-241
• /
• 2005

• Journal of Wetlands Research
• /
• v.11 no.1
• /
• pp.123-130
• /
• 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
• /
• v.11 no.3
• /
• pp.1-8
• /
• 2009

The groundwater dependent ecosystem associated with a natural stream is the area where mixing and exchange of surface water and groundwater occurs due to large chemical and hydraulic gradients. Surface-groundwater interactions play an important role in biogeochemical processes in groundwater dependent ecosystems and make this area a hydro-ecological hot spot. The objective of this study is to characterize the groundwater dependent ecosystem in a natural stream where nitrate contamination of stream water is observed by means of hydrogeological, chemical, and biological methods. In this study, vertical flow exchange(hyporheic flow) rates between stream and groundwater were estimated based on vertical hydraulic gradients measured at mini-piezometers of various depths. To investigate the biological natural attenuation potential, biological analyses using polymerase chain reaction(PCR)-cloning methods were performed in this study. Results show that the veritical hyporheic water fluxes affect nitrate concentrations and bacterial densities in groundwater dependent ecosystems to some degree. Also, denitrifying bacteria were identified in hyporheic soils, which may support the biodegradation potential of the groundwater dependent ecosystems under certain conditions.

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