Large-scale Basin Research Articles

10Be-derived denudation rates from the Burdekin catchment: The largest contributor of sediment to the Great Barrier Reef

Terrestrial cosmogenic nuclides (TCNs) such as Beryllium-10 (10Be) are now routinely used to reconstruct erosional rates over tens of thousands of years at increasingly large basin scales (>100,000km2). In Australia, however, the approach and its assumptions have not been systematically tested within a single, large drainage basin. This study measures 10Be concentrations in river sediments from the Burdekin catchment, one of Australia's largest coastal catchments, to determine long-term (>10,000years), time-integrated rates of sediment generation and denudation. A nested-sampling design was used to test for effects of increasing catchment scale on nuclide concentrations with upstream catchment areas ranging from 4 to 130,000km2. Beryllium-10 concentrations in sediment samples collected from the upstream headwater tributaries and mid-stream locations range from 1.8 to 2.89×105atomsg−1 and data confirm that nuclide concentrations are well and rapidly mixed downstream. Sediment from the same tributaries consistently yielded 10Be concentrations in the range of their upstream samples. Overall, no decrease in 10Be concentrations can be observed at the range of catchment scales measured here. The mean denudation rate for all river sediment samples throughout the Fanning subcatchment (1100km2) is 18.47mMa−1, which compares with the estimate at the end of the Burdekin catchment (130,000km2) of 16.22mMa−1. Nuclide concentrations in the lower gradient western and southern catchments show a higher degree of variability, and several complications emerged as a result of the contrasting geomorphic processes and settings. This study confirms the ability of TCNs to determine long-term denudation rates in Australia and highlights some important considerations in the model assumptions that may affect the accuracy of limited sampling in large, low-gradient catchments with long storage times.

Water Security – science and management challenges

Abstract. This paper briefly reviews the contemporary issues of Water Security, noting that current and prospective pressures represent major challenges for society. It is argued that, given the complex interdependencies and multi-faceted nature of these challenges, new trans-disciplinary science is needed to support the development of science-based policy and management. The effects of human society on land and water are now large and extensive. Hence we conclude that: (a) the management of water involves the management of a complex human-natural system, and (b) potential impacts of the human footprint on land and water systems can influence not only water quantity and quality, but also local and regional climate. We note, however, that research to quantify impacts of human activities is, in many respects, in its infancy. The development of the science base requires a trans-disciplinary place-based focus that must include the natural sciences, social sciences and engineering, and address management challenges at scales that range from local to large river basin scale, and may include trans-boundary issues. Large basin scale studies can provide the focus to address these science and management challenges, including the feedbacks associated with man’s impact from land and water management on regional climate systems.

Surface Water and Energy Budgets for the Mississippi River Basin in Three NCEP Reanalyses

Abstract Surface water and energy budgets from the National Centers for Environmental Prediction–U.S. Department of Energy (NCEP–DOE) Atmospheric Model Intercomparison Project (AMIP-II) Global Reanalysis 2 (GR2), the North American Regional Reanalysis (NARR), and the NCEP Climate Forecast System Reanalysis (CFSR) are compared here with each other and with available observations over the Mississippi River basin. The comparisons in seasonal cycle, interannual variation, and annual mean over a 31-yr period show that there are a number of noticeable differences and similarities in the large-scale basin averages. Warm season precipitation and runoff in the GR2 are too large compared to the observations, and seasonal surface water variation is small. By contrast, the precipitation in both NARR and CFSR is more reasonable and in better agreement with the observation, although the corresponding seasonal runoff is very small. The main causes of the differences in both surface parameterization and approach used in assimilating the observed precipitation datasets and snow analyses are then discussed. Despite the discrepancies in seasonal water budget components, seasonal energy budget terms in the three reanalyses are close to each other and to available observations. The interannual variations in both water and energy budgets are comparable. This study shows that the CFSR achieves a large improvement over the GR2, indicating that the CFSR dataset can be used in climate variability studies. Nonetheless, improved land surface parameterization schemes and data assimilation techniques are needed to depict the surface water and energy climates better, in particular, the variation in seasonal runoff.

Regional development and sequence stratigraphy of the Middle to Late Triassic Snadd Formation, Norwegian Barents Sea

The Middle to Late Triassic Snadd Formation represents one of the later stages of Early Mesozoic infilling of the Barents Sea Basin, expressed by a silicilastic wedge prograding from the southeast, where sediments were shed from the Uralide Orogeny. The formation was deposited in a shallow (100–500 m) basin facing the Boreal part of the Panthalassa Ocean, and the progradation reached its peak at the Svalbard Archipelago which has since been uplifted and where outcrops are exposed as the time-equivalent Botneheia and De Geerdalen formations. The Snadd Formation includes depositional environments ranging from offshore shale through shallow marine to fluvial, arranged in discrete stratigraphic sequences.Here we present a refined sequence stratigraphic framework for the Snadd Formation. Two second order sequences have been interpreted within the limits of the study area, divided into six third order sequences. The two second order sequences are split along an Intra Carnian maximum flooding surface. Depositional elements inherent to the sequence stratigraphic framework are also interpreted and extrapolated so as to describe the regional distribution of potential reservoir sandstones and the control exerted on the development of third order sequences.Different depositional environments from various datasets and scales of observation show the progressive development of a prograding delta across more than 700 km from a proximal position on the Finnmark Platform to a distal position on Edgeøya. Regional correlation of well logs and 2D seismic coupled with detailed depositional environment interpretation from 3D seismic and core has resulted in basin-wide palaeogeographic reconstruction of the formation throughout the Norwegian part of the Barents Sea, with implications for understanding the distribution and evolution of depositional systems during this large-scale basin infill.

Multi-model climate impact assessment and intercomparison for three large-scale river basins on three continents

Abstract. Climate change impacts on hydrological processes should be simulated for river basins using validated models and multiple climate scenarios in order to provide reliable results for stakeholders. In the last 10–15 years, climate impact assessment has been performed for many river basins worldwide using different climate scenarios and models. However, their results are hardly comparable, and do not allow one to create a full picture of impacts and uncertainties. Therefore, a systematic intercomparison of impacts is suggested, which should be done for representative regions using state-of-the-art models. Only a few such studies have been available until now with the global-scale hydrological models, and our study is intended as a step in this direction by applying the regional-scale models. The impact assessment presented here was performed for three river basins on three continents: the Rhine in Europe, the Upper Niger in Africa and the Upper Yellow in Asia. For that, climate scenarios from five general circulation models (GCMs) and three hydrological models, HBV, SWIM and VIC, were used. Four representative concentration pathways (RCPs) covering a range of emissions and land-use change projections were included. The objectives were to analyze and compare climate impacts on future river discharge and to evaluate uncertainties from different sources. The results allow one to draw some robust conclusions, but uncertainties are large and shared differently between sources in the studied basins. Robust results in terms of trend direction and slope and changes in seasonal dynamics could be found for the Rhine basin regardless of which hydrological model or forcing GCM is used. For the Niger River, scenarios from climate models are the largest uncertainty source, providing large discrepancies in precipitation, and therefore clear projections are difficult to do. For the Upper Yellow basin, both the hydrological models and climate models contribute to uncertainty in the impacts, though an increase in high flows in the future is a robust outcome ensured by all three hydrological models.

Analysis of the Distribution of Onshore Sedimentary Basins and Hydrocarbon Potential in China

Based on 20 years of onshore exploration in China, we compiled onshore sedimentary basin maps and oil and gas horizontal distributions for the major basins in China and analyzed the characteristics of basin distribution and hydrocarbon potential, which can be summarized in the following four points. (1) More than 400 basins have developed in China’s onshore region. The development of large-scale basins is based on paleo-platforms (plates) or the microplate geological background. (2) The Tianshan-Xingmeng orogen and basin cluster along the North China/eastern Yangtze Platform host the majority of China’s onshore oil reserves (66.64%). (3) The three major craton basins, Tarim, North China and Yangtze, host 70.19% of the total onshore natural gas reserves. (4) China’s onshore oil reserves are concentrated in layers originating from the Cenozoic and Mesozoic, and the natural gas reserves are primarily distributed in layers originating from the Cenozoic, Mesozoic, and Upper Paleozoic.

Classification of Large Scale River Basins through Hydrological Recurrence

Classification of Large Scale River Basins through Hydrological Recurrence

Status of connected wetlands of the Lake Eyre Basin, Australia

AbstractThe Lake Eyre Basin, one of the world's last unregulated wild river basins, covers almost one sixth of the Australian continent, with large areas of connected wetlands (73 903 km2), including floodplains, lakes, waterholes and river channels. Few data existed and so we used literature and government biotic and abiotic data and anthropogenic impacts to assess the conservation risk of the ecosystem as Least Concern (IUCN Red List criteria for ecosystems, version 2.0). This was based on limited distributional change and low levels of degradation or anthropogenic threatening processes. The approach could be applied to ecosystem assessments of other large river basins around the world, given the Lake Eyre Basin occupies one extreme (unmodified) while the Aral Sea (collapsed), previously assessed, occupies the other extreme (highly modified). River flow analysis with available biotic data is critical for risk assessment as well as identification and tracking of long‐term threats. Assessment was possible at this large basin scale and appropriate, given the critical importance of connectivity but could also occur at finer spatial scale. Increased diversions for irrigation, mining impacts on floodplains and projected increased temperatures threaten the current status (Least Concern) of the connected wetlands of the Lake Eyre Basin ecosystem.

SOLUTE DISPERSION IN THE NEARSHORE DUE TO OBLIQUE WAVES

An experimental study has been conducted in a large scale basin at Danish Hydraulic Institute (DHI). Simultaneous measurements of hydrodynamics using Laser Doppler Anemometry (LDA) and fluorescent tracer studies were undertaken within the surfzone under a regular wave condition with waves approaching the shore at 20. Through a series of hydrodynamic and tracer measurements and their comparison with the existing theoretical values, this study quantifies the physical processes and their integrated effects on a solute tracer in the nearshore zone subject to combined waves and the induced longshore currents. A theoretical dispersion model has been developed, adopting both experimental and theoretical velocimetry approaches. The results of theoretical model have been compared to the tracer data. Using the results from this study together with all known previous studies of dispersion measurements within the surfzone, good agreement exists.

A theoretical analysis of basin-scale groundwater temperature distribution

The theory of regional groundwater flow is critical for explaining heat transport by moving groundwater in basins. Domenico and Palciauskas’s (1973) pioneering study on convective heat transport in a simple basin assumed that convection has a small influence on redistributing groundwater temperature. Moreover, there has been no research focused on the temperature distribution around stagnation zones among flow systems. In this paper, the temperature distribution in the simple basin is reexamined and that in a complex basin with nested flow systems is explored. In both basins, compared to the temperature distribution due to conduction, convection leads to a lower temperature in most parts of the basin except for a small part near the discharge area. There is a high-temperature anomaly around the basin-bottom stagnation point where two flow systems converge due to a low degree of convection and a long travel distance, but there is no anomaly around the basin-bottom stagnation point where two flow systems diverge. In the complex basin, there are also high-temperature anomalies around internal stagnation points. Temperature around internal stagnation points could be very high when they are close to the basin bottom, for example, due to the small permeability anisotropy ratio. The temperature distribution revealed in this study could be valuable when using heat as a tracer to identify the pattern of groundwater flow in large-scale basins. Domenico PA, Palciauskas VV (1973) Theoretical analysis of forced convective heat transfer in regional groundwater flow. Geological Society of America Bulletin 84:3803–3814

Insights on geologic and vegetative controls over hydrologic behavior of a large complex basin – Global Sensitivity Analysis of an integrated parallel hydrologic model

Summary This study demonstrated the first application of a GSA technique to a transient ISSHM–LSM application developed for a large-scale river basin. The Morris method was used to identify the spatially and temporally variable sensitivity amongst a large number of model parameters to provide insights on hydrologic processes dominating behavior in the basin and to identify a small subset of parameters that should be evaluated in subsequent, more computationally intensive quantitative GSA and parameter estimation techniques. Results showed that in the upper region of the basin, evapotranspiration (ET), total streamflow and peak streamflow were less sensitive to surficial aquifer system characteristics, but highly sensitive to the hydraulic conductivity of the confining unit separating the surficial aquifer and the regional aquifer system and leaf area index of near stream vegetation. In the lower region of the basin, hydraulic conductivity of the regional aquifer system was found to have a significant effect on ET, total stream flow, and groundwater contributions to streamflow while surface–groundwater dynamics during storm events was most sensitive to storage properties of the regional aquifer system. Peak streamflow in the lower basin was most sensitive to the hydraulic conductivity of the confining unit in the upper basin, and the Manning’s coefficient of upper basin streams, indicating that all peak storm flows originate in the upper basin. Throughout the basin ET was sensitive to soil/geologic properties and vegetation properties, with unsaturated zone processes and relevant parameters gaining importance in moisture limited conditions existing in the lower regions of the basin.

Performance comparison of Adoptive Neuro Fuzzy Inference System (ANFIS) with Loading Simulation Program C++ (LSPC) model for streamflow simulation in El Niño Southern Oscillation (ENSO)-affected watershed

Suitable selection of hydrological modeling tools and techniques for specific hydrological study is an essential step. Currently, hydrological simulation studies are relied on various physically based, conceptual and data driven models. Though data driven model such as Adoptive Neuro Fuzzy Inference System (ANFIS) has been successfully applied for hydrologic modeling ranging from small watershed scale to large river basin scale, its performance against physically based model has yet to be evaluated to ensure that ANFIS are as capable as any physically based model for simulation study. This study was conducted in Chickasaw Creek watershed, which is located in Mobile County of South Alabama. Since adequate rain gauge stations were not available near the watershed proximity, and also the study area was affected with the El Niño Southern Oscillation (ENSO), the sea surface temperature (SST) and sea level pressure (SLP) were additionally incorporated in the ANFIS model. The research concluded that ANFIS model performance was equally comparable to a physically based watershed model, Loading Simulation Program C++ (LSPC), especially when rain gauge stations were not adequate. Additionally, the research concludes that ANFIS model performance was equally comparable to that of LSPC no matter whether SST and SLP in ANFIS input vector was included or not.

Influence of mean circulation on large-scale decadal basin modes

Influence of mean circulation on large-scale decadal basin modes

The potential of coordinated reservoir operation for flood mitigation in large basins – A case study on the Bavarian Danube using coupled hydrological–hydrodynamic models

Summary The coordinated operation of reservoirs in large-scale river basins has great potential to improve flood mitigation. However, this requires large scale hydrological models to translate the effect of reservoir operation to downstream points of interest, in a quality sufficient for the iterative development of optimized operation strategies. And, of course, it requires reservoirs large enough to make a noticeable impact. In this paper, we present and discuss several methods dealing with these prerequisites for reservoir operation using the example of three major floods in the Bavarian Danube basin (45,000 km2) and nine reservoirs therein: We start by presenting an approach for multi-criteria evaluation of model performance during floods, including aspects of local sensitivity to simulation quality. Then we investigate the potential of joint hydrologic-2d-hydrodynamic modeling to improve model performance. Based on this, we evaluate upper limits of reservoir impact under idealized conditions (perfect knowledge of future rainfall) with two methods: Detailed simulations and statistical analysis of the reservoirs’ specific retention volume. Finally, we investigate to what degree reservoir operation strategies optimized for local (downstream vicinity to the reservoir) and regional (at the Danube) points of interest are compatible. With respect to model evaluation, we found that the consideration of local sensitivities to simulation quality added valuable information not included in the other evaluation criteria (Nash–Sutcliffe efficiency and Peak timing). With respect to the second question, adding hydrodynamic models to the model chain did, contrary to our expectations, not improve simulations, despite the fact that under idealized conditions (using observed instead of simulated lateral inflow) the hydrodynamic models clearly outperformed the routing schemes of the hydrological models. Apparently, the advantages of hydrodynamic models could not be fully exploited when fed by output from hydrological models afflicted with systematic errors in volume and timing. This effect could potentially be reduced by joint calibration of the hydrological–hydrodynamic model chain. Finally, based on the combination of the simulation-based and statistical impact assessment, we identified one reservoir potentially useful for coordinated, regional flood mitigation for the Danube. While this finding is specific to our test basin, the more interesting and generally valid finding is that operation strategies optimized for local and regional flood mitigation are not necessarily mutually exclusive, sometimes they are identical, sometimes they can, due to temporal offsets, be pursued simultaneously.

Systematic assessment of the uncertainty in integrated surface water‐groundwater modeling based on the probabilistic collocation method

AbstractSystematic uncertainty analysis (UA) has rarely been conducted for integrated modeling of surface water‐groundwater (SW‐GW) systems, which is subject to significant uncertainty, especially at a large basin scale. The main objective of this study was to explore an innovative framework in which a systematic UA can be effectively and efficiently performed for integrated SW‐GW models of large river basins and to illuminate how process understanding, model calibration, data collection, and management can benefit from such a systematic UA. The framework is based on the computationally efficient Probabilistic Collocation Method (PCM) linked with a complex simulation model. The applicability and advantages of the framework were evaluated and validated through an integrated SW‐GW model for the Zhangye Basin in the middle Heihe River Basin, northwest China. The framework for systematic UA allows for a holistic assessment of the modeling uncertainty, yielding valuable insights into the hydrological processes, model structure, data deficit, and potential effectiveness of management. The study shows that, under the complex SW‐GW interactions, the modeling uncertainty has great spatial and temporal variabilities and is highly output‐dependent. Overall, this study confirms that a systematic UA should play a critical role in integrated SW‐GW modeling of large river basins, and the PCM‐based approach is a promising option to fulfill this role.

Physical and numerical large-scale wave basin modeling of fluid-structure interaction and wave impact phenomena

Physical and numerical large-scale wave basin (LSWB) modeling of fluid-structure interaction (FSI) and wave impact phenomena are examined in this study. In particular, the role of numerical modeling and simulation in designand analysis of physical LSWB FSI andwave impact experiments using a numerical wave basin (NWB) modeling approach is examined. Physical characteristics and testing capabilities of arepresentative LSWBare first described. Selectedphysical FSI and wave impactexperiments pertaining to civil, energy and naval engineering disciplines conducted at the LSWB and the accompanying NWBFSI modeling and simulations of these challenging phenomenaare presented. An effort to further improvetheNWBFSI softwarewith highly nonlinear wave impact modeling capabilities to facilitate physical FSI experiment design and testing,and details of an on-goingNWBdevelopment and validation processesare delineated.It is demonstrated that the NWBFSI software is useful in facilitating the design of complex, highly nonlinear FSI and wave impactexperiments. Conversely, the resulting measured data from the FSI and wave impact experiments can be used to validate and identify further modeling improvement needs of the NWBFSI and wave impactsoftware.

A GIS Based Variable Source Area Model for Large-scale Basin Hydrology

A geographic information system-based rainfall runoff model that simulate variable source area runoff using topographic features of the basin is presented. The model simulate the flow processes on daily time step basis and has four non linear stores viz. Interception store, soil moisture store, channel store and ground water store. Source area fraction is modelled as a function of antecedent soil moisture, net rainfall and pore capacity raised to the power of areal average topographic index (Λ). Source area fraction is used in conjuction with topographic index to develop linear relations for runoff, Infiltration and interflow. An exponential relation is developed for lower zone evapotranspiration and non-linear exponential relations to model macropore flow and base flow are proposed.

Development of an integrated modeling approach for identifying multilevel non-point-source priority management areas at the watershed scale

The identification of priority management areas (PMAs) at the large-basin scale is notably complex because of the random nature of watershed processes, which complicates the application of traditional deterministic PMAs. In this study, a multilevel PMA (ML-PMA) framework is designed as a new tool to pinpoint these sensitive areas, within a basin, that contribute the most to water quality deterioration. The main advantage of the ML-PMA framework is the wide availability of its supplementary tools and its complete framework, which integrates both watershed and river processes in addressing PMAs at the watershed scale. The watershed model, stream model, and a Markov chain approach are integrated to depict the dynamics of watershed processes and various water quality statutes. Based on the results of this study, the river migration process is vital for water quality degradation in the river network and significantly influenced the final PMA map. In addition, the proposed ML-PMA framework considers the impact of climatic conditions and hydrological properties and allows for a more cost-effective allocation of PMAs among different years. In the authors' view, the connectivity of PMAs in terms of flux distribution and propagation downstream on which the ML-PMA is based makes the ML-PMA framework particularly interesting for watershed non-point-source pollution control.

Vegetation Formation in Estuarine Tidal Flats: Influences of Basin Scale and River-Crossing Structures of the Eight Rivers of Ise Bay in Mie and Aichi Prefectures, Japan

In this study, we examined the influences of the differences in basin scale and river-crossing structures of 8 rivers of Ise Bay in Mie and Aichi Prefectures, Japan on the vegetation in the estuarine tidal flats of these rivers. The dominant plant communities of the estuarine tidal flats formed from rivers of large-scale river basins (exceeding 300 km2) were determined. In the Miya River, the dominant plant community was the Suaeda maritima and Artemisia fukudo community. In the Kushida River, the dominant plant community was composed of Phacelurus latifolius, Artemisia fukudo, Phragmites australis, and bamboo. In the Kumozu River, the dominant community was composed of the coastal plants Calystegia soldanella, Lathyrus japonicus, and Carex pumila and the exotic plant of Lolium multiflorum. The plant community of Suzuka River was dominated by the exotic plant of Eragrostis curvula. Among the estuarine tidal flats influenced by a small-scale river basin (50 km2 or less), the plant community of Shinbori River (Fukue tidal flat) was dominated by Suaeda maritima, and the plant communities of the Shio and Harai Rivers were dominated by Phragmites australis. The plant community of Tanaka River was dominated by Phragmites australis and coastal plants. Regarding the relationship between the vegetation and the river environment for each study site, we hypothesised that in a large basin area with few structures crossing the river, the river water catchment in the estuary after heavy rains caused large areas of disturbance and formed bare land, providing suitable habitat for an annual salt marsh plant community. In contrast, in cases with many structures crossing the river, a stable channel, an excavated riverbed and the suppression of runoff and the resulting disturbance of the estuary, flooding did not occur during high tide. Moreover, we hypothesised that in a small basin with many structures crossing the river, disturbance to the estuary was not likely, and the perennial salt marsh plant community of Phragmites australis would be widely distributed, except for a river type such as the Shinbori River, in which tide and river flow were managed by a final closure.

Local and global factors controlling water‐energy balances within the Budyko framework

AbstractQuantifying partitioning of precipitation into evapotranspiration (ET) and runoff is the key to assessing water availability globally. Here we develop a universal model to predict water‐energy partitioning (ϖ parameter for the Fu's equation, one form of the Budyko framework) which spans small to large scale basins globally. A neural network (NN) model was developed using a data set of 224 small U.S. basins (100–10,000 km2) and 32 large, global basins (~230,000–600,000 km2) independently and combined based on both local (slope, normalized difference vegetation index) and global (geolocation) factors. The Budyko framework with NN estimated ϖ reproduced observed mean annual ET well for the combined 256 basins. The predicted mean annual ET for ~36,600 global basins is in good agreement (R2 = 0.72) with an independent global satellite‐based ET product, inversely validating the NN model. The NN model enhances the capability of the Budyko framework for assessing water availability at global scales using readily available data.