Hyporheic Water Exchange Research Articles

Different intensities and directions of hyporheic water exchange in habitats of aquatic Ranunculus species in rivers-a case study in Poland.

Hyporheic water exchange driven by groundwater-surface water interactions constitutes habitat conditions for aquatic biota. In our study, we conducted a field-research-based analysis of hyporheic water exchange to reveal whether the hyporheic water exchange differentiates particular Ranunculus sp. habitats. We measured the density of the stream of upwelling and hydraulic gradients of water residing in the hyporheic zone in 19 Polish rivers. We revealed that R. peltatus and R. penicillatus persist in habitats of considerably higher hyporheic water exchange upwelling flux (respectively 0.0852 m3∙d-1∙m-2 and 0.0952 m3∙d-1∙m-2) than R. circinatus, R. fluitans, and a hybrid of R. circinatus × R. fluitans (respectively m3∙d-1∙m-2; 0.0222 m3∙d-1∙m-2 and 0.0717 m3∙d-1∙m-2). The presented results can be used to indicate aquatic habitat suitability in the case of protection and management of ecosystems settled by Ranunculus sp.

Water and heat exchange responses to flooding and local storm events in the hyporheic zone driven by a meandering bend

The hyporheic zone, i.e. the groundwater-surface water interface within riverine/riparian ecosystems, plays a key role in water transport, energy flow and biogeochemical cycling at watershed scales. Water and heat exchange are fundamental processes regulating biogeochemical cycles in the hyporheic zones. To improve the understanding of hyporheic flow and heat transport in meandering streams, high-resolution measurements of water level and temperature, combined with a 3-D coupled model of flow and heat transport in the hyporheic zone of a meandering bend, were carried out during a summer flood season. Results show the distinct spatio-temporal variations of hyporheic water and heat exchange. Flooding events (the incoming flood water generated by the upstream rainfall) and local rainstorm events (the storm or rainfall occurring over the local study area) are major drivers for the coupled processes. Incoming flooding from the upper stream increases the hyporheic water and heat exchange in the riverbed and inner bank leading to the longer intra-meander residence times, and warms the riverbed and riverbanks due to the post-rainfall thermal recovery. Local rainstorm event increases hyporheic water and heat exchange flux both laterally and vertically and cools down the riverbed and riverbanks. The water exchange and thermal regimes in the intra-meander seems more driven by the local exchange flows, while the counterparts in the outer bank are dominated by the regional groundwater flow. The temperatures in the inner banks are 1 to 3 °C higher than those in the outer banks, indicating the better hydrological connectivity between river water and groundwater in the intra-meander. The meander apex is a hot spot for hyporheic water and heat exchange. The results highlight the close coupling among river morphology, hyporheic flow, and thermal heterogeneity in a meander system.

Applying Electrical Resistivity Tomography and Biological Methods to Assess the Hyporheic Zone Water Exchanges in Two Mediterranean Stream Reaches

The hyporheic zone (HZ) is a critical area of all river ecosystems. It is the area beneath the stream and adjacent to the stream, where the surface water and groundwater are mixed. The HZ extends both vertically and laterally depending on the sediment configuration, namely their porosity and permeability. This influences the hyporheic communities’ structural pattern and their active dispersal among distinct rivers compartments and alluvial aquifers. It is still difficult to assess the spatial extent of the HZ and the distribution of the mixing zones. This study applies time-lapse images obtained using electrical resistivity tomography (ERT) of 20 m wide and 5 m deep alluvial streams, with regards to the structural pattern of hyporheic communities represented by cyclopoids and ostracods, in order to assess the extent of the HZ in the riverbed and the parafluvial sediment configurations. The ERT images obtained at the hyporheic Site 1 are characterized by alluvial deposits dominated by coarse and very coarse sands with resistivity values ranging from ~20 to 80 Ohm.m, indicating a permeable zone up to ~0.5 m thick and extending laterally for ca. 5 m from the channel and associated with the hyporheic zone. The sediment configurations, texture, and structure indicate an active surface–hyporheic water exchange and low water retention into the sediments. This is also indicated by the hyporheic copepods and ostracods communities’ structure formed by a mixture of non-stygobites (five species) and stygobites (two species). A low-resistivity (<70 Ohm.m) permeable zone located 2.3 m below the streambed and unconnected with the river channel was also detected and associated with the associated alluvial aquifer. In contrast, the resistivity image at Site 2 dominated by coarse, medium, and very fine sands, shows a low-permeability zone in the upper ~0.5 m of the profile, with a resistivity value ranging from ~45 to 80 Ohm.m, indicating a reduced HZ extension in both vertical and lateral dimensions. Here the sediment configurations indicate that the water retention and interaction with the sediment is higher, reflected by more diverse hyporheic communities and with highly abundant stygobite species. The two examples show that non-invasive ERT images and biological assessments provide complementary and valuable information about the characterization of the sub-channel architecture and its potential hydraulic connection to the floodplain aquifer.

Revealing the influence of hyporheic water exchange on the composition and abundance of bottom-dwelling macroinvertebrates in a temperate lowland river

We studied distributions and abundances of macroinvertebrates in relation to hyporheic water exchange (HWE) patterns of the upper Biebrza − a small, lowland, low dynamic European river located in Northeast Poland. On a 6-km stretch of the river; we determined the variability of water exchange in the hyporheic zone by using direct field measurements of the pressure gradient to determine groundwater–surface water interactions. We identified locations with upwelling and downwelling fluxes of HWE as well as ambiguous hydraulic contact between groundwater and surface water along the river. In these locations, we sampled bottom-dwelling macroinvertebrates. In total, 627 individuals of benthic macroinvertebrates of 34 taxa were identified. We revealed that bottom-dwelling macroinvertebrate fauna is more abundant and diverse in river stretches where water from the river infiltrates the hyporheic zone. Results also show higher taxonomic richness and abundances of benthic macroinvertebrates in stretches with diagnosed infiltrating conditions (downwelling flux in a hyporheic zone) compared to in stretches where the river drained groundwater (upwelling flux in a hyporheic zone), but the recorded differences were not statistically significant.

The Effect of Tubificid Bioturbation on Vertical Water Exchange across the Sediment–Water Interface

The bioturbation activity of macroinvertebrates can affect the level of water exchange across the sediment–water interface. The impact of tubificid worm with different densities on the vertical water exchange at the sediment–water interface was investigated based on laboratory flume experiments. Vertical water fluxes, as well as physiochemical parameters, were measured at seven-day intervals, and the maximum penetration depths were obtained by dye injection before and after the tubificid bioturbation experiment, respectively. The bioturbation effects can be summarized in two aspects: (1) when the density was less than (or equal to) 20 individual/10 cm2, the volume of vertical water exchange positively correlated with the tubificid bioturbation. Once the density exceeded (or equaled) 25 individual/10 cm2, the vertical water flux decreased with increasing tubificid bioturbation. After 14 to 21 days, a negative correlation was identified between the bioturbation and the vertical water flux under all biological densities. (2) The maximum depth that the surface water can penetrate the sediment increased with increasing tubificid density. These results revealed that the vertical water was closely related to the biological density. The study has certain reference significance to understanding the spatiotemporal heterogeneity of hyporheic water exchange on a local scale.

Influences of riverbed morphology on patterns and magnitudes of hyporheic water exchange within a natural river confluence

River confluences are pivotal junctions that have vital influences on hydraulic characteristics and sediment particle distributions as well as on hyporheic water exchange. However, hyporheic water exchange is poorly understood because of the complicated river morphology within a river confluence. Therefore, the river confluence between the Juehe River and Haohe River located in arid and semi-arid areas of northwestern China was selected to evaluate the hyporheic water exchange processes, and the temperatures of different depth sediment were measured on July 11th and 12th, 2016 by an instrument equipped with five temperature sensors. The patterns and magnitudes of hyporheic water exchange were estimated using a one-dimensional heat transport model coupled with temperature data. Meanwhile, terrain points elevations and sediment particle distributions in this river confluence were collected to determine the confluence riverbed morphology. Furthermore, the river confluence morphology effects on hyporheic water exchange were investigated in this study. The different riverbed morphology and hydrodynamic zone locations were observed, which were controlled by the planform geometry with low river confluence flux momentum during the test period. Meanwhile, the upwelling flow dominated in the test area, and the downwelling occurred at three of the 23 total test points, which was induced by the complicated riverbed morphology and hydraulic characteristics. Additionally, the magnitudes of the upwelling flow were significantly influenced by the sediment heterogeneity subjected to the erosional and depositional processes. Hyporheic water exchange is a vital hydrological process in arid and semi-arid areas, where it significantly impacts the ecological environment of rivers. This study provides a valuable guideline for water quality and quantity management in arid and semi-arid areas.

Estimating spatial pattern of hyporheic water exchange in slack water pool

Hyporheic zone (HZ) influences hydraulic and biogeochemical processes in and alongside streams, therefore, investigating the controlling geographic factors is beneficial for understanding the hydrological processes in HZ. Slack water pool (SWP) is an essential micro-topographic structure that has an impact on surface water and groundwater interactions in the HZ during and after high flows. However, only a few studies investigate HZ surface water and groundwater exchange in the SWP. This study used the thermal method to estimate the HZ water exchange in the SWP in a segment of the Weihe River in China during the winter season. The findings show that on the flow-direction parallel to the stream, river recharge dominates the HZ water exchange, while on the opposing flow-direction bank groundwater discharge dominates the water exchange. The water exchange in the opposing flow-direction bank is about 1.6 times of that in the flow-direction bank. The HZ water exchange is not only controlled by flow velocity but also the location and shape of the SWP. Great water exchange amount corresponds to the shape with more deformation. The maximum water exchange within the SWP is close to the river bank where the edge is relatively high. This study provides some guidelines for water resources management during flooding events.

The Influence of Hyporheic Exchange on Water Temperatures in a Headwater Stream

A headwater stream in coastal California was used to evaluate the temperature response of effective shade reduction. Spatial distribution of stream water temperatures for summer low-flow conditions (<0.006 m3 s−1) were highly correlated with net radiation and advective heat transfers from hyporheic exchange and subsequent streambed conduction. Using a heat budget model, mean maximum stream water temperatures were predicted to increase by 1.7 to 2.2 °C for 50% and 0% effective shade scenarios, respectively, at the downstream end of a 300 m treatment reach. Effects on mean maximum stream water temperature changes, as water flowed downstream through a 500 m shaded reach below the treatment reach, were reduced by 52 to 30% from the expected maximum temperature increases under the 50% and 0% effective shade scenarios, respectively. Maximum stream water temperature change predicted by net radiation heating alone was greater than measured and heat-budget-estimated temperatures. When the influence of hyporheic water exchange was combined with net radiation predictions, predicted temperatures were similar to measured and heat-budget-predicted temperatures. Results indicate that advective heat transfers associated with hyporheic exchange can promote downstream cooling following stream water temperature increases from shade reduction in a headwater stream with cascade, step-pool, and large woody debris forced-pool morphology.

The influence of hyporheic upwelling fluxes on inorganic nitrogen concentrations in the pore water of the Weihe River

Hyporheic zone is an important region of nitrogen removal in river systems. Hyporheic exchange generally leads to heterogeneous redox environments, which are conducive to nitrogen transformation. This study seeks to determine the influence of hyporheic upwelling fluxes on inorganic nitrogen (NH4+, NO3−, and NO2−) concentrations in the sediment pore water of the Weihe River, China. The patterns and magnitudes of hyporheic water exchange on 12 August 2016 were derived by a one-dimensional heat transport model, and inorganic nitrogen concentrations in the pore water, surface water, and groundwater were obtained. The results indicated that hyporheic water exchange was characterized by upwelling at each point during the test period. Moreover, NH4+ dominated the hyporheic zone from 0 to 45 cm, likely due to organic nitrogen mineralization. Additionally, a non-linear relationship was observed between NH4+ concentrations and upwelling fluxes. This relationship was derived by analyzing the effect of upwelling on biogeochemical activity and nitrogen transformation. Notably, increasing upwelling fluxes less than 400 mm/d resulted in high NH4+ concentrations, whereas fluxes exceeding 400 mm/d led to low NH4+ concentrations. Overall, the variations in inorganic nitrogen associated with hyporheic water exchange are of great importance for controlling nitrogen pollution and maintaining sustainable health in river systems.

Variability in the vertical hyporheic water exchange affected by hydraulic conductivity and river morphology at a natural confluent meander bend

AbstractRiver confluences and their associated tributaries are key morphodynamic nodes that play important roles in controlling hydraulic geometry and hyporheic water exchange in fluvial networks. However, the existing knowledge regarding hyporheic water exchange associated with river confluence morphology is relatively scarce. On January 14 and 15, 2016, the general hydraulic and morphological characteristics of the confluent meander bend (CMB) between the Juehe River and the Haohe River in the southern region of Xi'an City, Shaanxi Province, China, were investigated. The patterns and magnitudes of vertical hyporheic water exchange (VHWE) were estimated based on a one‐dimensional heat steady‐state model, whereas the sediment vertical hydraulic conductivity (Kv) was calculated via in situ permeameter tests. The results demonstrated that 6 hydrodynamic zones and their extensions were observed at the CMB during the test period. These zones were likely controlled by the obtuse junction angle and low momentum flux ratio, influencing the sediment grain size distribution of the CMB. The VHWE patterns at the test site during the test period mostly showed upwelling flow dominated by regional groundwater discharging into the river. The occurrence of longitudinal downwelling and upwelling patterns along the meander bend at the CMB was likely subjected to the comprehensive influences of the local sinuosity of the meander bend and regional groundwater discharge and finally formed regional and local flow paths. Additionally, in dominated upwelling areas, the change in VHWE magnitudes was nearly consistent with that in Kv values, and higher values of both variables generally occurred in erosional zones near the thalweg paths of the CMB, which were mostly made up of sand and gravel. This was potentially caused by the erosional and depositional processes subjected to confluence morphology. Furthermore, lower Kv values observed in downwelling areas at the CMB were attributed to sediment clogging caused by local downwelling flow. The confluence morphology and sediment Kv are thus likely the driving factors that cause local variations in the VHWE of fluvial systems.

Seasonal variability of hyporheic water exchange of the Weihe River in Shaanxi Province, China

Interactions between surface water and groundwater play a major role in hydrological processes. Understanding the seasonal variations of the water exchange is important to clear drivers of water transferring in a catchment. However, the seasonal variations of water exchange have been limited by the resolution of methods and the experimental problems. In this paper, the Weihe River, in Shaanxi Province, China was chosen, as a case study area to access the seasonal variability of water exchange in the hyporheic zone (HZ). Five testing sites were in the main channel of the river, and seasonal field data were collected from fall 2012 to summer 2014. The temperature profiles and heat convection-diffusion equation were applied to analyze the hyporheic water exchange pattern (the type of movement) and its magnitude, as well as characterizing the seasonal variability of the water exchange features. The results indicate that the patterns and magnitudes of water exchange in the hyporheic zone vary significantly in seasons and test sites. The water exchange general in the fall season (71.5mm/d) is larger than in other seasons (i.e., spring 54.14mm/d, summer 56.19mm/d and winter 23.26mm/d). This study provides the guidelines for the water resources management in different seasons.

Quantifying the Spatial Variations of Hyporheic Water Exchange at Catchment Scale Using the Thermal Method: A Case Study in the Weihe River, China

Understanding the dynamics of hyporheic water exchange (HWE) has been limited by the hydrological heterogeneity at large catchment scale. The thermal method has been widely used to understand water exchange patterns in a hyporheic zone. This study was conducted in the Weihe River catchment in Shaanxi Province, China. A conceptual model was developed to determine water transfer patterns, and a one-dimensional heat diffusion-advection equation was employed to estimate vertical fluxes of ten different segments in the hyporheic zone in various ten segments of the catchment. The amount of water exchange varied from 78.47 mm/d to 23.66 mm/d and a decreasing trend from the upstream to downstream of catchment was observed. The spatial correlation of variability between the water exchange and distance is 0.62. The results indicate that mountain’s topography trend is the primary driver influencing the distribution of river tributaries, and the water exchange amount has a decreasing trend from upstream to downstream of the main river channel.

Effect of bank curvatures on hyporheic water exchange at meter scale

The micro-topography feature of a riverine system is a controlling attribute to induce the change of patterns and magnitudes of hyporheic water exchange. The study aims to determine how hyporheic water exchange is affected by the bank curvatures of test points at meter scale. A one-dimensional heat steady-state transport model was applied to determine patterns and magnitudes of vertical hyporheic water exchange in January and July 2015. The bank curvatures were calculated based on the curvature formula. The results demonstrate that vertical water exchange patterns of all test points were upwards during the two test periods, and the higher vertical fluxes mostly occurred in January 2015. Large curvatures for either sides of convex banks in the two periods resulted in higher vertical water exchange fluxes, and the significantly higher vertical fluxes occurred near the apex of bends. Additionally, a flow pattern from river bank discharging into stream was derived during the campaign in July 2015, and significantly higher fluxes were obtained along the straight bank where more riparian vegetation was adjacent to the bank/water interface. It can be suggested that the bank curvatures and riparian vegetation are considered the crucial attributes influencing hyporheic water exchange.

Glacial and periglacial floodplain sediments regulate hydrologic transfer of reactive iron to a high arctic fjord

AbstractThe transport of reactive iron (i.e. colloidal and dissolved) by a glacier‐fed stream system draining a high relief periglacial landscape in the high Arctic archipelago of Svalbard is described. A negative, non‐linear relationship between discharge and iron concentration is found, indicative of increased iron acquisition along baseflow pathways. Because the glaciers are cold‐based and there are no intra‐ or sub‐permafrost groundwater springs, baseflow is principally supplied by the active layer and the colluvial and alluvial sediments in the lower valley. Collectively, these environments increase the flux of iron in the stream by 40% over a floodplain length of just 8 km, resulting in 6 kg Fe km−2a−1 of reactive iron export for a 20% glacierized watershed. We show that pyrite oxidation in shallow‐groundwater flowpaths of the floodplain is the most important source of reactive iron, although it is far less influential in the upper parts of the catchment where other sources are significant (including ironstone and secondary oxide coatings). Microbial catalysis of the pyrite oxidation occurs in the floodplain, enabling rapid, hyporheic water exchange to enhance the iron fluxes at high discharge and cause the non‐linear relationship between discharge and reactive iron concentrations. Furthermore, because the pyrite oxidation is tightly coupled to carbonate and silicate mineral weathering, other nutrients such as base cations and silica are also released to the stream system. Our work therefore shows that high Arctic floodplains should be regarded as critically important regulators of terrestrial nutrient fluxes to coastal ecosystems from glacial and periglacial sources. Copyright © 2015 John Wiley & Sons, Ltd.

Hyporheic water exchange in a large hydropower-regulated boreal river – directions and rates

Widespread river regulation is known to modify river-aquifer interactions, influencing entire watersheds, but knowledge of the hyporheic flowpath along regulated rivers is limited. This study measured the hydraulic conductivity of the river bed and the aquifer, water levels and seepage fluxes in the heavily regulated Lule River in Northern Sweden, with the aim of characterising water exchange across the river-aquifer interface. While pristine rivers in the area are gaining, the Lule River was recharging the aquifer during 10% of the time. Daily river level fluctuations (typically ±0.25 m) directed ~3% of the total orthogonal flux across the river bed towards the aquifer, while during ~2% of the time the orthogonal fluxes were negligible (≤10–4 m d–1). A clogging layer on the river bed, most likely formed due to the modified river discharge, restricted river-aquifer exchange. The hyporheic zone had higher electrical conductivity than the river and the aquifer and electrical conductivity occasionally decreased following rising river water levels, with 3–5 hours' delay. Overall, hydropower regulation has severely altered the hydrological regime of the hyporheic zone in the Lule River.

Temporal variation of hydrological exchange and hyporheic biogeochemistry in a headwater stream during autumn

AbstractThe hyporheic zone is of great interest for stream ecologists because of its role in stream biogeochemical processing. Our study addresses the effects of leaf-litter inputs and varying discharge on surface–hyporheic water exchange and their possible consequences for the hyporheic zone biogeochemistry. Our study was conducted during autumn in Riera de Santa Fe (northeastern Iberian Peninsula), a stream with a well developed deciduous riparian canopy. We placed 15 wells spaced at 5-m intervals longitudinally down the study reach and measured surface and hyporheic nutrient and dissolved O2 (DO) concentrations on 23 sampling dates (15 during the leaffall period and 8 after a flood that washed out 65% of the accumulated leaf biomass). We assessed changes in surface-water exchange and in hyporheic NH4-N and soluble reactive P (SRP) uptake via coinjection of a conservative tracer and nutrients. Compared to surface water, hyporheic water had lower DO, higher SRP and NO3-N concentrations, and similar NH4-N...