River-groundwater Interaction Research Articles

Comparison of Aquifer Sustainability Under Groundwater Administrations in Oklahoma and Texas1

Mittelstet, Aaron R., Michael D. Smolen, Garey A. Fox, and Damian C. Adams, 2011. Comparison of Aquifer Sustainability Under Groundwater Administrations in Oklahoma and Texas. Journal of the American Water Resources Association (JAWRA) 1-8. DOI: 10.1111/j.1752-1688.2011.00524.x Abstract: We compared two approaches to administration of groundwater law on a hydrologic model of the North Canadian River, an alluvial aquifer in northwestern Oklahoma. Oklahoma limits pumping rates to retain 50% aquifer saturated thickness after 20 years of groundwater use. The Texas Panhandle Groundwater Conservation District’s (GCD) rules limit pumping to a rate that consumes no more than 50% of saturated thickness in 50 years, with reevaluation and readjustment of permits every 5 years. Using a hydrologic model (MODFLOW), we simulated river-groundwater interaction and aquifer dynamics under increasing levels of “development” (i.e., increasing groundwater withdrawals). Oklahoma’s approach initially would limit groundwater extraction more than the GCD approach, but the GCD approach would be more protective in the long run. Under Oklahoma rules more than half of aquifer storage would be depleted when development reaches 65%. Reevaluation of permits under the Texas Panhandle GCD approach would severely limit pumping as the 50% level is approached. Both Oklahoma and Texas Panhandle GCD approaches would deplete alluvial base flow at approximately 10% development. Results suggest periodic review of permits could protect aquifer storage and river base flow. Modeling total aquifer storage is more sensitive to recharge rate and aquifer hydraulic conductivity than to specific yield, while river leakage is most sensitive to aquifer hydraulic conductivity followed by specific yield.

Development and Application of an Integrated Hydrological Model for Lake Watersheds

Abstract Quantitative estimation of surface and subsurface water flow to lakes is important for lake resources management. The calculation of water volume into lakes is also an essential step for estimation of pollutant loads to lakes. This paper presents a mathematical model for coupled simulation of surface and subsurface water flows for lake watersheds, with emphasis on the modelling of several important aspects including groundwater level-soil water storage-surface runoff relation, river-groundwater interactions and lake-watershed hydrological linkage, which are all fundamental for an integrated simulation of hydrological processes for lake watersheds. Field case studies were also given as examples to test the model's suitability and capability. The model is grid-based spatially distributed to facilitate the discretisation of the high heterogeneity of land use types and soil properties. The model can be used as a useful tool to quantify components of hydrological processes for detailed watershed water balance analysis, and to assess impacts of watershed management strategies on the security of lake water resource

Geological controls and effects of floodplain asymmetry on river–groundwater interactions in the southeastern Coastal Plain, USA

Channel sediment and alluvial aquifer hydraulic properties exert a major control on river–groundwater interactions. Channels and floodplains are often asymmetrical, resulting in differences in sediment hydraulic properties across the river. Floodplain asymmetry is common along Coastal Plain rivers in South Carolina and North Carolina, USA. The Tar River, North Carolina, has an asymmetrical valley. The study objective was to characterize the effects of floodplain asymmetry and geological controls on river–groundwater interactions. Floodplain and river channel sediments adjacent to the river were characterized with split spoon cores and hand auger samples along a 22-km reach. Hydrogeology was characterized with 38 piezometers and water level recorders in and adjacent to the river. Ground penetrating radar was used to define the shallow stratigraphy. Channel sediments were significantly different between the north and south sides of the river. Hydraulic conductivity and groundwater inputs were greater on the side of the river (north) that contained more permeable fluvial deposits. Groundwater chemistry (δ18O, specific conductance) data also suggested greater exchange between surface water and groundwater on the north side of the river channel. A conceptual hydrogeological model illustrates that groundwater movement and contaminant transport to the river differs across the channel due to asymmetrical geology.

Using environmental tracers to assess the extent of river–groundwater interaction in a quarried area of the English Chalk

The Swanscombe area of Kent, SE England represents a typical example of a heavily quarried Chalk area currently undergoing re-development. Because the Chalk is also an important aquifer, a good understanding of groundwater movement is required if environmental impacts are to be minimised and the water resource maximised. In particular, the nature of the relationship between the River Darent and groundwater in the Swanscombe Chalk Block requires better characterisation. Here, ‘environmental tracers’ in the form of ambient concentrations of stable isotopes, chlorofluorocarbons (CFCs), sulphur hexafluoride (SF6) and tritium (3H) are used to investigate this and other aspects of groundwater movement in the vicinity of the quarries. Stable isotopic contrasts indicate little evidence for widespread river infiltration to the regional Chalk aquifer, although stable isotope and 3H data suggest that 20–35% of the abstraction by river-valley public water supply boreholes may be derived from the river. The CFCs, while present at above-modern concentrations in almost all groundwaters, can be used as tracers, indicating basically S–N flowpaths in the area south of the quarries, though sub-karstic conduits associated with areas of Palaeogene cover add a level of uncertainty at the local scale. Simple piston flow residence times based on SF6 range from 1 to 17 a, but the data are probably better interpreted in terms of mixing between varying amounts of modern recharge derived from the south and deeper stored groundwater. The information gained from environmental tracers can therefore contribute to effective resource management.

Time-series measurements of stream and sediment temperature for understanding river–groundwater interactions: Border Rivers and Lower Richmond catchments, Australia

Monitoring of temperature in the stream sediment (0.25–1.2 m depth) as well as the stream itself was used to investigate groundwater–surface water interactions in two different Australian catchments (Border Rivers and Lower Richmond). When interpreted with hydrographic and hydraulic conductivity data, the temperature monitoring provided useful insights into the spatial and temporal variability of stream–aquifer connectivity. At one site, sediment temperatures fluctuated with the diurnal temperature variation of the stream, reflecting river leakage (losing conditions). No diurnal signal was detected in the sediment temperatures at other sites, which is a typical indicator of gaining conditions. However, with water-level measurements indicating negative gradients and the stream sediments dominated by clay at these sites, this lack of sediment temperature variability is interpreted to reflect very low rates of downward seepage. At one site, a transition from gaining to losing conditions was observed through time. In the field trials, operational issues such as timing the monitoring to coincide with reasonable diurnal variations of stream temperature, the requirement of understanding the shallow stratigraphy of the stream bed and separating out localised effects (such as weirs) were highlighted. The trials also highlighted that interpretation of the temperature data can be ambiguous when viewed in isolation. Results indicated that time-series measurements of sediment and stream temperatures can be a useful screening tool for identifying gaining and losing reaches and for identifying temporal variations in seepage flux. It is suggested that temperature loggers can be readily and cheaply incorporated into existing hydrographic networks to provide a greater understanding of stream–aquifer connectivity. It is also recommended that existing routine temperature logging (such as with pressure transducers) be upgraded to sufficient accuracy for seepage studies. Temperature monitoring would be particularly useful in estimating seepage from Australian ephemeral streams. These data also have relevance to the investigation and management of aquatic ecosystems, notably in the hyporheic zone.

Investigating groundwater–river interactions using environmental tracers

Groundwater and surface water are hydraulically connected in many landscapes, and a better understanding of their connectivity is critical for effective management of water resources. Environmental tracers are a useful preliminary tool to study the interaction between groundwater and surface water and provide independent means for corroborating or refuting information based on more traditional investigations. This paper discusses the results of using major ions, stable isotopes (deuterium and oxygen-18) and a radioactive isotope (radon-222) as environmental tracers to better understand groundwater–surface water interactions in the Border Rivers catchment, Australia. In the upstream reaches of the catchment, shallow groundwater close to the river has a similar major-ion and stable-isotope chemistry to that of the river water, and is different to the groundwater distant from the river. The near-stream groundwater has an enriched isotopic signature (less negative) whereas groundwater far from the river has a depleted isotopic signature. Overall, the comparison of chloride concentrations with deuterium suggests that three types of groundwater occur in the Border Rivers catchment: (i) the near-stream groundwaters influenced by direct recharge from the river; (ii) the groundwaters marginal to the river that are more influenced by diffuse rainfall recharge; and (iii) saline groundwaters in the downstream part of the catchment which never (or rarely) receive recharge from surface water. River water samples obtained during the high-flow season show a very low variation in radon concentrations (0.11–0.39 Bq/L). The longitudinal transect of radon concentration measurements in river water during the high-flow season indicates that there is no groundwater contribution to stream flow. Radon concentrations are lower in groundwater close to the rivers and increase with distance from the river, in general coincidence with the salinity and chloride concentration. This indicates river water infiltration into nearby alluvial aquifers, rather than groundwater discharge to the river. The results of hydrochemical and environmental isotope sampling indicate that in the upper catchment area (upstream of Keetah) the river is connected to and actively recharges the near-stream shallow alluvial aquifer. Using the environmental isotope data, we have also demonstrated that recharge of the alluvial aquifers by surface water occurs by bank infiltration, with diffuse recharge during high-rainfall events more dominant further away from the river. This information would be useful for a better understanding of the nature and extent of hydrogeological processes at the river–aquifer interface and their links with biogeochemical processes and ultimately water allocation policies.

Quantification of large-scale urban mass fluxes of xenobiotics and of the river–groundwater interaction in the city of Halle, Germany

In order to quantify the fluxes of micropollutants like pharmaceuticals including endocrine disruptors, and fragrances in the environment modelling approaches in the area of the city of Halle/Saale, Germany were performed. The investigated micropollutants are Bisphenol A, t-Nonylphenol, Carbamazepine, Galaxolide ® and Tonalide ®. These substances were found ubiquitously in the urban groundwater and surface waters. The assessment of the concentration values of these substances in the urban waters showed no significant changes during the city passage. Therefore, a balance model for the whole city area was set up and the main water-bounded mass fluxes of the substances were estimated. The assessment of the mass fluxes shows increasing values of about 20 up to 400% for nearly all investigated micropollutants during the city passage of the urban waters. An exception is Bisphenol A with a constant mass flux. In order to investigate the surface water–groundwater interaction, a transient hydrodynamic river reach model of the Saale River and a groundwater transport model of the area connected to the reach were created by coupling two well known conventional compartment models for river hydraulic and groundwater transport. The inter-compartmental transport of Carbamazepine initiated through infiltration from the Saale River into the groundwater during a flooding event was simulated . A substance mass flux of 3.29 × 10 5 μg d −1 and a fluid flux of 9.95 × 10 3 m 3 d −1 was calculated.

Some limitations in using 222Rn to assess river–groundwater interactions: the case of Castel di Sangro alluvial plain (central Italy)

222Rn was used to assess river–groundwater interactions within Castel di Sangro alluvial aquifer (Italy). The effectiveness of results obtained through this indicator was verified by also analyzing δ18O, major ions and temperature in both surface and groundwater, and carrying out piezometric head monitoring and discharge measurements. Hydrogeological investigations suggested that the river infiltrates into the aquifer in the south-eastern aquifer portion, while groundwater discharges into the river in the north-eastern portion. The latter phenomenon is supported by 222Rn data. Nevertheless, flow-through conditions cause the modelled discharge along this river reach, estimated by 222Rn data in a degassing-corrected two-component mixing model, to be greater than the measured discharge. Concerning river infiltration into the aquifer, δ18O, major ions and temperature data show that the river contribution is negligible in terms of aquifer recharge. Thus, the observed increase in 222Rn concentration in that portion of the aquifer is due to the enrichment process caused by infiltration of rainwater (222Rn free) which flows from the local divide area. Hence, in the study site, the use of only 222Rn to predict river–groundwater interactions causes some estimation inaccuracies and it must be coupled with other hydrochemical and hydrogeological parameters to gain a thorough understanding of such interactions.

Regional Differences in Climate Change Impacts on Groundwater and Stream Discharge in Denmark

Regional impact studies of the effects of future climate change are necessary because projected changes in meteorological variables vary regionally, and different hydrological systems can react in various ways to the same changes. In this study the effects of climate change on groundwater recharge, storage, and discharge to streams are compared in two geologically and climatologically different regions in Denmark. Outputs are used for the periods 1961 to 1990 and 2071 to 2100 from a regional climate model representing the Intergovernmental Panel on Climate Change (IPCC) scenarios A2 and B2. A physically based, distributed hydrological model simulates changes in groundwater head, recharge, and discharge. Precipitation, temperature, and reference evapotranspiration increased for both the A2 and B2 scenarios. This results in a significant increase in mean annual net precipitation, but with decreased values in the summer months. The magnitude of the hydrological response to the simulated climate change is highly dependent on the geological setting of the model area. In the Jylland area, characterized by sandy top soils and large interconnected aquifers, groundwater recharge increased significantly, resulting in higher groundwater levels and increasing groundwater–river interaction. On Sjaelland, where the topsoil is dominated by low‐permeability soils and the aquifers are protected by thick clay layers of regional extent, only minor changes in groundwater levels are predicted. The primary effect in this area is the change in stream discharge, caused by changes in drain flow and overland flow, with up to 50% increase in winter and 50% decrease in summer. This study shows the added value of studying different climate scenarios and hydrological systems, so that the simulated effects can be compared both qualitatively and quantitatively.

Spatial distribution of groundwater pollution in the Porsuk River Basin (PRB), Turkey

The groundwater in the alluvium aquifer of the Eskisehir Plain (EP) is polluted by wastewaters transported through Porsuk River, agricultural-industrial activities, river-groundwater interactions and unsanitary landfill. Porsuk River flows throughout the alluvium aquifer in the EP. In this study, the effects of anthropogenic activities on groundwater quality in the EP were investigated. Since the sewage system has been operated from 1998, the ammonia content of the groundwater has decreased, but the groundwater and Porsuk River water have high contents of nitrite, ammonium, phenol, phosphorus, AOX, sulphide, and heavy metals. Thus, groundwater in the EP is in a poor quality both for drinking and domestic purposes.

Numerical modeling of wastewater transport and degradation in soil aquifer

Modeling of wastewater transport and degradation in soil aquifer is a problem of concern with regard to the optimization of design and operation of the wastewater soil treatment system. To solve this problem, three-dimensional groundwater flow and wastewater transport and degradation model was developed using MODFLOW and MT3DMS modeling. The developed model was calibrated using the Soil Infiltration Treatment System (SITS) in the Chongming island of China after considering the river—groundwater interaction and the regional geological and hydrological conditions. Using the calibrated model, the following problems with regard to the design and operation of SITS were discussed: (1) Allowable hydraulic load. The hydraulic load increases with the drop in the water level of the adjoining river, the increase in the actual soil area under operation, and the increase in the distance among the individual operation units of SITS. (2) Optimized layout of the groundwater monitoring wells. The concentration contour of the simulated contaminants is very useful to depict the typical areas that are most severely polluted and very sensitive to the peripheral environment, thus lesser number of monitoring wells can be set up based on the model, and the goal of the accurate assessment of the influence of soil-infiltrated wastewater on groundwater can be achieved.

River-groundwater interaction: a practical management approach

In much of Australia, groundwater and surface water are interconnected and interchangeable resources. This physical reality is however not reflected in our water management systems whereby groundwater and surface water are managed as separate resources. This paper proposes a methodology for managing groundwater - surface water interaction. It is proposed that all groundwater bores be classified into four zones to reflect the relative significance of their impact on surface waters. The proposed zones would be dependent upon the level of groundwater and stream interaction and may range from an area covering bores which should be managed under surface water extraction rules, through to areas where groundwater extraction has no discernible impact on surface water. It is proposed that the zonal classification be adopted when considering new licences/trades/restrictions/cancellations, as follows: Zone 1- this applies close to streams where groundwater extraction has an almost immediate impact upon stream flow. All existing groundwater licences in Zone 1 would be managed under surface water extraction rules. Zone 2- this zone would deal with all groundwater usage that would impact on stream flow over the critical low flow period of the stream. It would be expected to cover groundwater extraction where impacts would be typically felt within 6 months. Zone 3- this zone would deal with long term (100 year) impacts of groundwater use on stream flow. This would often cover all other groundwater users in a surface water catchment with licences generally managed to annual allocations. Zone 4- this zone is where there is no discernible impact of groundwater use on the stream. The zone would not necessarily be a certain distance from a stream, but would apply to certain hydrogeological situations, for example, deep confined aquifers or disconnected streams. Various analytical methods which are available to calculate the impacts of groundwater extraction on stream flows are discussed. In many catchments, any groundwater use, regardless of the distance of the bore from the river, will result in a reduction in stream flow. The time lag between commencement of pumping and the impact on streamflow is considered particularly with respect to Zone 2 where the impacts of groundwater use on streams is recognised as occurring within the short term planning period, but no tools have been available for conjunctive management. As the distance between a pumping bore and stream increases so does the lag or delay between the commencement of pumping and the impact on streamflow (ie reduced discharge and/or induced recharge). This lag between pumping groundwater and the impact on streamflow means decisions on how to manage streamflow impacts due to groundwater pumping need to be taken well in advance of the commencement of groundwater pumping. Criteria that could be used to develop operational rules (ie restrictions) that could be applied to groundwater users in order to manage streamflow impacts are proposed.

Patchiness of River–Groundwater Interactions within Two Floodplain Landscapes and Diversity of Aquatic Invertebrate Communities

In fluvial systems, the interactions between rivers and groundwater significantly affect various ecological structures (for example, riparian vegetation) and functions. To examine the effects of hydrological exchange between groundwater and surface water on the distribution of aquatic invertebrates within a riverine landscape, we investigated the main stem, tributaries, and various surface and subsurface waters of two floodplains of a southern Alpine river (Brenno, Switzerland) in terms of their physicochemical, hydraulic, substratum, and faunal characteristics. The origins of the water were investigated by analyzing geomorphic settings and physicochemical variables. The two floodplains had different hydrological regimes. The middle floodplain was dominated by lateral inputs and exfiltration of hillslope groundwater from two different subcatchments. Bank filtration of river water sustained subsurface water only close to the channel. The aquatic habitats of the middle floodplain formed a rather homogeneous group with high taxon richness and intrahabitat diversities. These aquatic habitats resembled mountain springbrooks in their physicochemical characteristics and faunal compositions. In the lower floodplain, the exchange between river water and groundwater was more extensive. The aquatic floodplain habitats of the lower floodplain were fed mainly by deep and shallow alluvial groundwater, hyporheic exfiltration, and partly by surface water. In contrast to aquatic habitats of the middle floodplain, habitats of the lower floodplain showed a low intrahabitat and a high interhabitat diversity in terms of both substrate characteristics and faunal compositions. For both floodplains, ordination analyses showed a high concordance between the structure of the invertebrate community and the characteristics of the environmental habitat, including chemical, geomorphic, and hydraulic variables. Ordinations grouped aquatic habitats according to the origins of the waters. Taxon richness was related to local structural diversity, but species turnover was related to differential vertical and lateral connectivity. Exfiltration of groundwaters provided aquatic floodplain habitats for several specialized species. The results of this study show the significance of the river–groundwater connectivity for the creation of the habitat mosaic that sustains biodiversity in floodplains and thus have important implications for managing the ecological integrity of floodplains.

River–groundwater interactions in the Brazilian Pantanal. The case of the Cuiabá River

The Pantanal is a vast evaporation plain and sediment accumulation surface that floods annually. It is located in the Upper Paraguay River Basin, a major source of floodwaters to the Pantanal. The recent construction of a large dam in the upper reach of the Cuiabá River raises questions: What will be the dam influence on the flood area and duration? What will be the consequence for groundwater replenishment and permanence of flow in the floodplain channels during the dry period? This study of the Cuiabá River, within the Pantanal, describes water flow between the river channel and its adjacent floodplain, as well as relations between the surface water and groundwater near the river. Flooding of the plain adjacent to the Cuiabá River critically depends on the river stage and proceeds through a complex hydrographic network. No free water table was encountered; groundwater was confined below clay–silt layers. Two groundwater bodies were distinguished based on their piezometric behavior. In both cases the river stage variations appeared to control the piezometric heads and the flood was the main recharge source. The groundwater moved from the river towards the floodplain where it appeared to sustain channel flow and to maintain soil humidity in depressed areas during the dry period.