Creek Catchment Research Articles

History of hydrological research in Slovakia and its links to water management

ABSTRACT The article outlines the development of water resources management and research in hydrology in Slovakia in the last century when the centralised water resources planning provided a robust framework for the development of hydrological research. We first present facts about the organisation of research in hydrology from 1948 to 1990, which dealt with various problems of practical relevance. Experimental research and its international outreach in the collaborative programs of the Danube countries or the UNESCO water programmes are described. Then, the main achievements related to experimental hydrological research in two small research catchments with long histories of operation, the Mošteník Brook and the Bystrianka Creek catchments, are presented. Short biographies of researchers who significantly contributed to the overall development of water management or hydrological research in small catchment in Slovakia are provided.

Superiority of artificial neural networks over conventional hydrological models in simulating urban catchment runoff

ABSTRACT The synergistic impacts of climate change and urbanisation have amplified the recurrence and austerity of intense rainfall events, exacerbating persistent flooding risk in urban environments. The intricate topography and inherent non-linearity of urban hydrological processes limit the predictive accuracy of conventional models, leading to significant discrepancies in flow estimation. Recent advancements in artificial neural network (ANNs) have demonstrated remarkable progress in mitigating most limitations, specifically in simulating complex, non-linear relationships, without an intricate comprehension of the underlying physical processes. This paper proposes a deep learning ANN-based flow estimation model for enhanced precision simulation of streamflow in urban catchments, with the research's distinctive contribution involving rigorous comparative evaluation of the developed model against the established Australian hydrological model, RORB. Gardiners Creek catchment, an urban catchment situated in East Melbourne was designated as the study area, with the model being calibrated upon historical storm incidences. The findings reveal that the ANN model substantially outperforms RORB, as evidenced by superior correlation, prediction efficiency, and lower generalisation error. This underscores the ANN's adeptness in accurately replicating non-linear-catchment responses to storm events, marking a substantial advancement over conventional modelling practices and indicating its transformative potential for enhancing flood prediction precision and revolutionising current estimation practices.

Multi-Method Comparative Analysis of Hydroclimatic Trends and Variability in Dry Creek Catchment, South Australia

The trend and variability of hydroclimatic variables over time are apparent in seasonal creeks, especially those located in urbanized areas. Understanding hydro-climatic trends in urban areas is crucial for the sustainable management of water resources and the environment. This study aimed to explore the spatiotemporal variability and trends of hydroclimate variables as well as the potential connection between rainfall and streamflow in Dry Creek catchment, South Australia. The trend-free pre-whitening Mann–Kendall (TFPW-MK) test and Innovative Trend Analysis (ITA) were utilized to examine the monotonic and nonmonotonic trends, respectively, and multiple statistical tests were employed to examine the change points in the hydroclimatic time series. Sen’s slope, Simple Linear Regression (SLR), and ITA were used as alternative approaches to assess the magnitudes of change and overcome the limitations in the underlying assumptions of the various methodologies. The variability in the hydroclimate time series was estimated using several indices, such as the coefficient of variation, seasonality indices, flashiness index, and mean zero flow index. The analyses revealed important findings, notably the high variability of rainfall and streamflow during dry periods. Streamflow displayed greater variability compared to rainfall, with high CV values recorded both seasonally and annually. Furthermore, there was a significant upward trend in seasonal rainfall during winter. Additionally, the maximum and mean temperatures demonstrated a statistically significant increase, which can be attributed to global warming and significant urbanization in the catchment area. Comparative analysis has confirmed that the ITA has superior detection capabilities for nonmonotonic trends, outperforming other methods. It excels at presenting graphical representations that accurately depict trends, effectively differentiating between low, medium, and high values. The strong relationship between rainfall and streamflow demonstrated by the Tanh curve suggests that rainfall is the most reliable predictor of streamflow. The outcomes of this investigation are expected to support local governmental organizations and decision-makers in comprehending the spatial and temporal features of rainfall, as well as its correlation with streamflow. This information will further assist in developing flood and drought mitigation strategies backed by empirical evidence.Graphical

Use of Artificial Intelligence Modelling for the Dynamic Simulation of Urban Catchment Runoff

The complex topography and inherent nonlinearity affiliated with influential hydrological processes of urban catchments, coupled with limited availability of measured data, limits the prediction accuracy of conventional models. Artificial Neural Network models (ANNs) have displayed commendable progress in recognising and simulating highly complex, non-linear associations allied with input-output variables, with limited comprehension of the underlying physical processes. Therefore, this paper investigates the effectiveness and accuracy of ANN models, in estimating the urban catchment runoff, employing minimal and commonly available hydrological data variables – rainfall and upstream catchment flow data, employing two powerful supervised-learning-algorithms, Bayesian-Regularization (BR) and Levenberg-Marquardt (LM). Gardiners Creek catchment, encompassed in Melbourne, Australia, with more than thirty years of quality-checked rainfall and streamflow data was chosen as the study location. Two significant storm events that transpired within the last fifteen years - the 4th of February 2011 and the 6th of November 2018, were nominated for calibration and validation of the ANN model. The study results advocate that the use of the LM-ANN model stipulates accurate estimates of the historical storm events, with a stronger correlation and lower generalisation error, in contrast to the BR-ANN model, while the integration of upstream catchment flow alongside rainfall, vindicate for their collective impact upon the dynamics of the flow being spawned at the downstream catchment locations, significantly enhancing the model performance and providing a more cost-effective and near-realistic modelling approach that can be considered for application in studies of urban catchment responses, with limited data availability.

Distribution of logjams in relation to lateral connectivity in the River Corridor

We examine the redistribution of logjams from the channel to the floodplain during a large flood following a wildfire in a forested montane catchment, conceptualizing redistribution with respect to changes in connectivity within the river corridor during and after the flood. A 2020 wildfire burned much of the 40 km2 Little Beaver Creek catchment at high severity. A flash flood in July 2022 completely inundated the river corridor and moved substantial amounts of large wood from the channel onto the floodplain. Floodplain logjams were largely absent prior to the flood. Forty-two channel-spanning logjams remained in the channel after the July 2022 flood, compared to 91 before the flood, and only 4 of these created backwater at base flow. Most of the large wood present in the river corridor was redistributed into 700 floodplain logjams, most of which were pinned against tree trunks. Multivariate linear models indicate that floodplain jam distribution density (number of logjams/ha surface area) correlates most strongly with floodplain forest basal area and floodplain/channel width ratio. Prior to the July 2022 flood, channel-spanning logjams limited longitudinal connectivity within the active channel but enhanced vertical connectivity via hyporheic exchange and lateral connectivity via formation of secondary channels and obstruction-inducing overbank flows. The enhanced transport capacity of the flood removed or altered most of these logjams, increasing longitudinal connectivity. Complete inundation of the floodplain during the July 2022 flood represented a transient increase in lateral connectivity. The formation of floodplain logjams and secondary channels, along with localized floodplain erosion and deposition, created more persistent alterations in lateral connectivity. Our observations suggest that logjams can increase lateral connectivity within the river corridor by deflecting flow in a manner that creates persistent secondary channels. Although secondary channels might have formed in Little Beaver Creek during the 2022 flood without the presence of logjams, the flow obstructions created by even relatively transient logjams likely increased the formation of a multichannel planform and the associated persistent lateral connectivity.

Trace Element Composition of Placer Gold Across the Okanagan Fault, Kelowna, British Columbia, Canada

For 100 years, placer gold has been important to the settlement, economic development, and, recently, recreational geology of the Kelowna, British Columbia, area. It is best-known to occur in modern-day, Mission Creek and Lambly Creek sedimentary rocks, as well as a paleoplacer occurrence in Miocene sediments of the historical Winfield mine. The Mission Creek and Winfield localities are east of the west-dipping, low-angle, normal Okanagan Fault, which has been active since the Eocene. Lambly Creek is west of the fault. Late Paleozoic to Eocene igneous and metasedimentary rocks occur in the Lambly Creek catchment but Eocene gneiss units, unroofed by the fault, occur on the Okanagan Valley’s east side. This study tests the hypothesis that native placer gold compositions vary across the Okanagan Fault reflecting different sources and histories for the gold. A modest number of Au and Ag analyses (23 analyses) in usefully representative placer gold samples were determined on a scanning electron microscope with an energy dispersive spectrometer (SEM-EDS). Spots analyzed for Au and Ag were also analyzed for 19 trace elements using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Mercury was semi-quantitatively determined in ‘unknown’ gold grains by first estimating its concentration (~3.69 ppm) in the AuRM2 external standard. Proportions of Au:Ag:Cu in grain cores indicate all the gold came from mesothermal/hypogene or possibly Au porphyry bedrock deposits though primary signatures may have been obscured by metamorphism or weathering. Winfield and Mission Creek grains tend to have higher siderophile Fe, Ni, Pd and Pt and chalcophile elements As, Se, Te, Hg, Pb and Bi but lower Cu and Sb concentrations than Lambly Creek gold. Mercury is distinctly higher in Winfield and Mission Creek gold than in Lambly Creek gold from the west side of the valley; the element appears particularly useful for ‘fingerprinting’ gold. Lambly Creek gold compositions indicate derivation from two orogenic/hypogene sources from greenstone and plutonic/hydrothermal rocks present in the catchment area. Modern day Mission Creek and Miocene paleoplacer Winfield grains have a similar hypogene trace element signature but there are no known local bedrock gold sources. The Mission Creek and Winfield gold grain cores are surrounded by < 10 µm, Au-rich, Ag- and trace element-poor, rims. Lambly Creek grains lack such rims. The Au-rich rims on modern day Mission Creek and Miocene Winfield gold may reflect prolonged near-surface exposure with surficial electrochemical dissolution of hypogene trace elements or the biological precipitation of gold. Low Ag and red colouration on the surface of grains support the biological precipitation hypothesis. The shared trace element signature, together with the Au-rich rims indicate that modern day placer gold in Mission Creek was multiply reworked from Miocene paleoplacers similar to the Winfield occurrence as a result of uplift and erosion of rocks on the east side of Okanagan Fault.

Spatiotemporal trends of urban-induced land use and land cover change and implications on catchment surface imperviousness

Urbanization, changes in land use and land cover (LULC), and an increase in population collectively have significant impacts on urban catchments. However, a vast majority of LULC studies have been conducted using readily available satellite imagery, which often presents limitations due to its coarse spatial resolution. Such imagery fails to accurately depict the surface characteristics and diverse spectrum of LULC classifications contained within a single pixel. This study focused on the highly urbanized Dry Creek catchment in Adelaide, South Australia and aimed to determine the impact of urbanization on spatiotemporal changes in LULC and its implications for the land surface condition of the catchment. Very high spatial resolution imagery was utilized to examine changes in LULC over the past four decades. Support Vector Machine-learning-based image classification was utilized to classify and identify the changes in LULC over the study area. The classification accuracy showed strong agreement, with a kappa value greater than 0.8. The findings of this analysis showed that extensive urban development, which expanded the built-up area by 34 km2, were responsible for the decline in grass cover by 43.1 km2 over the last 40 years (1979–2019). Moreover, built-up areas, plantation, and water features, in contrast to grass cover, have demonstrated an increasing trend during the study period. The overall urban expansion over the study period was 136.6%. Urbanization intensified impervious area coverage, increasing the runoff coefficient, equivalent impervious area, and curve number by 60.6%, 60.6%, and 7.9%, respectively, while decreasing the retention capacity by 38.6%. These modifications suggest a potential variability in catchment surface runoff, prompting the need for further research to understand the surface runoff changes brought by the changes in LULC resulting from urbanization. The findings of this study can be used for land use planning and flood management.

A Framework to Quantify Riverine Dissolved Inorganic Nitrogen Exports under Changing Land-Use Patterns and Hydrologic Regimes

Riverine dissolved inorganic nitrogen (DIN), when elevated by human activities (e.g., land-use change), can accelerate the nitrogen cycle and downstream dispersal. However, estimating DIN export coefficients for individual land-use types can be complex due to mosaic land-use patterns and interactions between fertilizers and hydrological processes. We propose a framework that integrates an empirical model, a moving-window method, and an elasticity method to quantify seasonal DIN export coefficients for each land use in the Shixi Creek catchment, southeast China. Our model showed good agreement with field observations according to root mean square error and a normalized objective function. The export coefficients of farmland and forest were the highest (9.16 mg L−1) and lowest (2.91 mg L−1) ones, resulting in annual DIN exports, respectively, for farmland and forests of 1951 kg km−2 yr−1 and 619 kg km−2 yr−1, respectively. Urbanization was a dominant factor influencing DIN export; the export coefficient of built-up areas showed the highest elasticity and highest uncertainty, with abrupt fluctuations from dry to wet years. Our framework revealed the complex role of built-up areas in nitrogen export. Our results can shed light on how to improve riverine N management in a catchment by considering the interactive effects of climate and land use.

Antecedent Snowpack Cold Content Alters the Hydrologic Response to Extreme Rain-on-Snow Events

Abstract Predicting winter flooding is critical to protecting people and securing water resources in California’s Sierra Nevada. Rain-on-snow (ROS) events are a common cause of widespread flooding and are expected to increase in both frequency and magnitude with anthropogenic climate change in this region. ROS flood severity depends on terrestrial water input (TWI), the sum of rain and snowmelt that reaches the land surface. However, an incomplete understanding of the processes that control the flow and refreezing of liquid water in the snowpack limits flood prediction by operational and research models. We examine how antecedent snowpack conditions alter TWI during 71 ROS events between water years 1981 and 2019. Observations across a 500-m elevation gradient from the Independence Creek catchment were input into SNOWPACK, a one-dimensional, physically based snow model, initiated with the Richards equation and calibrated with collocated snow pillow observations. We compare observed “historical” and “scenario” ROS events, where we hold meteorologic conditions constant but vary snowpack conditions. Snowpack variables include cold content, snow density, liquid water content, and snow water equivalent. Results indicate that historical events with TWI > rain are associated with the largest observed streamflows. A multiple linear regression analysis of scenario events suggests that TWI is sensitive to interactions between snow density and cold content, with denser (>0.30 g cm−3) and colder (<−0.3 MJ of cold content) snowpacks retaining >50 mm of TWI. These results highlight the importance of hydraulic limitations in dense snowpacks and energy limitations in warm snowpacks for retaining liquid water that would otherwise be available as TWI for flooding. Significance Statement The purpose of this study is to understand how the snowpack modulates quantities of water that reach the land surface during rain-on-snow (ROS) events. While the amount of near-term storm rainfall is reasonably predicted by meteorologists, major floods associated with ROS are more difficult to predict and are expected to increase in frequency. Our key findings are that liquid water inputs to the land surface vary with snowpack characteristics, and although many hydrologic models incorporate snowpack cold content and density to some degree, the complexity of ROS events justifies the need for additional observations to improve operational forecasting model results. Our findings suggest additional comparisons between existing forecasting models and those that physically represent the snowpack, as well as field-based observations of cold content and density and liquid water content, would be useful follow-up investigations.

RECONSTRUCTION OF SEDIMENT RUNOFF FORMATION FEATURES IN THE LAKE KHORLAKEL (NORTH CAUCASUS) CATCHMENT FOR THE LAST 8 THOUSAND YEARS (ACCORDING TO GEOMORPHOLOGICAL AND LITHOSTRATIGRAPHIC DATA)<a href="#FN2"><sup>2</sup></a>

The change in sediment yield is an important indicator of the natural environment dynamics, depending on the combination of landscape, tectonic and climatic conditions. Assessment of sediment yield often based on the results of studying the bottom sediments of mountain lakes with relatively compact catchments. However, for correct reconstructions, in addition to analyzing lake sediments, it is necessary to study the causes and mechanizm of sediment redistribution in their catchments, to identify sediment delivery pathways to the reservoir and their possible changes over different time windows. The drainless Lake Khorlakel, located at the altitude of 2045.0 m above sea level on the northern macroslope of the Greater Caucasus. It is a suitable testing ground for complex research: on the one hand, the relict reservoir is an ideal sedimentation trap, and on the other, it is located with in an area of intensive exogenous processes and tectonic activity. The two boreholes were drilled in 2017 in the deepest (≈8 m) part of the lake and 17 samples collected taken from the cores for radiocarbon dating, which made it possible to build an age model for the range from 8000 to 500 yr. BP. Complex geological and geomorphological studies were carried out in 2021 to interpret the obtained data. It was found that sedimentation in the lake is associated with runoff and sediment redistribution in the Elbashi creek catchment. A number of episodes of proluvial activation with the formation of an outflow cone, followed by lake accumulation, have been traced for the last 8 kyr. The connection between lake and catchment ceased only in the last 1 kyr. BP. Two main stages of lake sedimentation with a boundary of 3 kyr. BP and 10 episodes, that are characterized by different proportions of mineral and organic components in bottom sediments were established. Some of the lithostratigraphic boundaries correlate with strong earthquakes that occurred in the Elbrus region, and some – with climatic events.

Application of multi-criteria decision-making methods to identification of soil moisture monitoring sites in an urban catchment in South Australia

When choosing sites for monitoring of soil moisture for hydrological purposes, a suitable process that considers the factors influencing soil moisture level should be followed. In this study, two multi-criteria decision-making (MCDM) methods, the multi-influencing factor (MIF) method and the analytical hierarchy process (AHP) method, were used to identify the optimal soil moisture monitoring (SMM) sites in the Dry Creek Catchment in South Australia. The most representative areas for nine SMM sites were obtained using the MIF method, considering the factors of rainfall, soil type, land use, catchment slope, elevation, and upslope accumulated area (UAA). The AHP method was used to select the optimal sites using the site-specific criteria. 30.3% of the catchment area in the Australian Water Resources Assessment Landscape (AWRA-L) Grid_DC2 can be considered acceptable as representative area with the MIF method. Four potential sites were evaluated for each AWRA-L grid using the relative weights of the site-specific criteria with the AHP method. The Grid_DC2 required two sites that had the highest overall weight chosen with the AHP analysis. The procedure was repeated for the remaining four AWRA-L grids within the study area to select the required SMM sites.

Integrated approach for landslide hazard assessment in the High City of Antananarivo, Madagascar (UNESCO tentative site)

The High City of Antananarivo is one of the most important cultural heritage sites of Madagascar, on the UNESCO Tentative List since 2016. Built on the hilltop of the Analamanga Hill, a granite ridge overlooking the Ikopa River valley, it is renowned for its baroque-style palaces, such as the Rova royal complex, and neo-Gothic cathedrals dating back to the nineteenth century. During the winter of 2015, the twin cyclones Bansi and Chedza hit the urban area of Antananarivo, triggering floods and shallow landslides, as well as causing thousands of evacuees and many casualties. Between 2018 and 2019 several rockfalls occurred from the rock cliffs of the Analamanga hills, destroying housings and killing over 30 people. Both events showed that landslides can pose a high risk to the safety of the inhabitants, the infrastructure, and the cultural heritage of the High City. To assess the landslide hazard in the Analamanga Hill area, an integrated approach was adopted by means of the following actions: (i) creation of a multitemporal detailed scale landslide map; (ii) geotechnical characterization of the involved materials; (iii) analysis of landslide susceptibility in soils/loose deposits; (iv) runout analysis of debris flows channeling within large creek gullies; (v) landslide kinematic analysis of the rockmass; (vi) simulation of rockfall trajectories; (vii) analysis of rainfall data. The results show that the main factors affecting landslides are slope, lithology, creek-gully erosion, and anthropization, while most of the landslide events are clearly triggered by heavy rainfall. The landslide-prone areas (the phenomena include shallow landslides, rock falls, and debris flows) are located primarily along the cliff bounding the western hill slope, the southeastern sector (where abandoned quarries form large slope cuts), and subordinately in the steep creek catchment just east of the Rova. The thematic maps produced represent fundamental land use management tools to be used in Geo Disaster Risk Reduction (GDRR) by scientists, practitioners and the decision-makers involved in the High City protection and conservation. The study conducted represents an important contribution for improving the knowledge on landslide processes in an area with limited data such as Madagascar, and may be reproduced in cultural heritage sites characterized by similar geomorphological and urban scenarios.

Potential of X-band polarimetric synthetic aperture radar co-polar phase difference for arctic snow depth estimation

Abstract. Changes in snowpack associated with climatic warming has drastic impacts on surface energy balance in the cryosphere. Yet, traditional monitoring techniques, such as punctual measurements in the field, do not cover the full snowpack spatial and temporal variability, which hampers efforts to upscale measurements to the global scale. This variability is one of the primary constraints in model development. In terms of spatial resolution, active microwaves (synthetic aperture radar – SAR) can address the issue and outperform methods based on passive microwaves. Thus, high-spatial-resolution monitoring of snow depth (SD) would allow for better parameterization of local processes that drive the spatial variability of snow. The overall objective of this study is to evaluate the potential of the TerraSAR-X (TSX) SAR sensor and the wave co-polar phase difference (CPD) method for characterizing snow cover at high spatial resolution. Consequently, we first (1) investigate SD and depth hoar fraction (DHF) variability between different vegetation classes in the Ice Creek catchment (Qikiqtaruk/Herschel Island, Yukon, Canada) using in situ measurements collected over the course of a field campaign in 2019; (2) evaluate linkages between snow characteristics and CPD distribution over the 2019 dataset; and (3) determine CPD seasonality considering meteorological data over the 2015–2019 period. SD could be extracted using the CPD when certain conditions are met. A high incidence angle (>30∘) with a high topographic wetness index (TWI) (>7.0) showed correlation between SD and CPD (R2 up to 0.72). Further, future work should address a threshold of sensitivity to TWI and incidence angle to map snow depth in such environments and assess the potential of using interpolation tools to fill in gaps in SD information on drier vegetation types.

Challenges in Quantifying Losses in a Partly Urbanised Catchment: A South Australian Case Study

Quantifying hydrological losses in a catchment is crucial for developing an effective flood forecasting system and estimating design floods. This can be a complicated and challenging task when the catchment is urbanised as the interaction of pervious and impervious (both directly connected and indirectly connected) areas makes responses to rainfall hard to predict. This paper presents the challenges faced in estimating initial losses (IL) and proportional losses (PL) of the partly urbanised Brownhill Creek catchment in South Australia. The loss components were calculated for 57 runoff generating rainfall events using the non-parametric IL-PL method and parametric method based on two runoff routing models, Runoff Routing Burroughs (RORB) and Rainfall-Runoff Routing (RRR). The analysis showed that the RORB model provided the most representative median IL and PL for the rural portion of the study area as 9 mm and 0.81, respectively. However, none of the methods can provide a reliable loss value for the urban portion because there is no runoff contribution from unconnected areas for each event. However, the estimated non-parametric IL of 1.37 mm can be considered as IL of EIA of the urban portion. Several challenges were identified in the loss estimation process, mainly when selecting appropriate storm events, collecting data with the available temporal resolution, extracting baseflow, and determining the main-stream transmission losses, which reduced the urban flow by 5.7%. The effect of hydrograph shape in non-parametric loss estimation and how combined runoff from the effective impervious area and unconnected (combined indirectly connected impervious and pervious) areas affects the loss estimation process using the RORB and RRR models are further discussed. We also demonstrate the importance of identifying the catchment specific conditions appropriately when quantifying baseflow and runoff of selected events for loss estimation.

Controls on Stream Water Age in a Saturation Overland Flow‐Dominated Catchment

AbstractWater age and flow pathways should be related; however, it is still generally unclear how integrated catchment runoff generation mechanisms result in streamflow age distributions at the outlet. Here, we combine field observations of runoff generation at the Dry Creek catchment with StorAge Selection (SAS) age models to explore the relationship between stream water age and runoff pathways. Dry Creek is a 3.5 km2catchment in the Northern California Coast Ranges with a Mediterranean climate, and, despite an average rainfall of ≈1,800 mm/yr, is an oak savannah due to the limited hillslope water storage capacity. Runoff lag to peak—after initial seasonal wet‐up—is rapid (∼1–2 hr), and total annual streamflow consists predominantly of saturation overland flow, based on field mapping of saturated extents and an inferred runoff threshold for the expansion of saturation extent beyond the geomorphic channel. SAS modeling based on daily isotope sampling reveals that streamflow is typically older than 1 day. Since streamflow primarily consists of overland flow, a significant portion of overland flow must not be event‐rain but instead derive from older, nonevent groundwater returning to the surface, consistent with field observations of exfiltrating head gradients, return flow through macropores, and extensive saturation days after storm events. We conclude that even in a watershed fed primarily by overland flow, runoff is primarily not composed of event water. Our findings have implications for the interpretation of stream chemistry and the assumptions built into widely used hydrograph separation inferences, namely, the assumption that overland flow consists of new (event) water.

Calibration of a continuous hydrologic simulation model in the urban Gowrie Creek catchment in Toowoomba, Australia

Study regionToowoomba, Queensland, Australia Study focusIn this study we derive loss model parameters suitable for use in the dynamic loss Australian Representative Basin Model (ARBM) through the calibration of a continuous simulation hydrologic model. We compare the derived parameters to those published in the literature, and our results highlight the need to develop a database of calibrated loss parameters for urban catchments. New hydrological insightsThe development of design storms for flood modelling commonly uses the initial loss/continuous loss model to estimate the conversion of rainfall to runoff. This loss model, when applied to pervious areas, uses parameters that have been calibrated for gauged rural catchments. These same parameters are often applied to the pervious component of ungauged urban catchments with minimal understanding of the resulting impact on runoff. This research uses a continuous simulation modelling approach to calibrate parameters suitable for use in the ARBM loss model built into the hydrological modelling software XPRAFTS. Through a two-stage calibration approach, the model offered a satisfactory fit (Nash Sutcliffe Efficiency > 0.5) for 9 of the 11 selected storm events, with seven events exceeding a Nash Sutcliffe Efficiency of 0.75. Events used in the calibration/validation included peak flows as low as 9 m3/s and as high as 600 m3/s. Developing these loss model parameters offers new insights into the suitability of a dynamic loss model approach in an urban catchment in regional Australia and provides an alternative to the parameters already available in the literature which were found to overestimate the peak flow in frequent events.

Crayfish connections: Linking ecology and hydrogeology in Alabama’s Black Prairie using crayfish distribution patterns

Abstract Floodplain ecosystems host diverse surface‐water habitats (e.g., lotic, lentic, ephemeral) and groundwater features that support high levels of species diversity. Our understanding of species–habitat relationships within these complex ecosystems, however, remains incomplete, potentially hindering conservation efforts. Understanding associations between burrowing crayfish and habitat features of floodplains is particularly valuable because crayfish, through burrowing, play an important role in establishing aquatic‐terrestrial connections which enhance local biodiversity. Species of crayfish that persist in floodplains must burrow deep enough to access shallow groundwater. Consequently, burrow presence may indicate a preference for specific surface and subsurface habitat characteristics. The primary goal of our study was to evaluate specific habitat attributes as predictors of burrowing crayfish presence/absence, and our secondary goal was to evaluate species‐specific habitat associations with respect to the same environmental variables. We evaluated burrowing crayfish presence/absence and crayfish species composition with respect to groundwater depth, flood frequency (standing surface water), soil characteristics, and tree size in the Bogue Chitto Creek catchment, Dallas County, Alabama, U.S.A. Active burrows were expected at sites with access to water (a shallow water table) and at sites with environmental variables more conducive to burrow stability (fine‐grained soils and mature trees). Species composition was predicted to vary with groundwater depth and flood frequency. Groundwater depth was the primary driver of burrowing crayfish presence/absence in our system; active burrows were more likely to be present in areas with relatively shallow groundwater depths. Within occupied sites, differences in crayfish species composition were significantly associated with the degree of flooding during the 1‐year study period. Species associated with a high dependence on surface waters were collected alongside species dependent on burrowing to access groundwater, suggesting that the environmental features of floodplains satisfy a diverse set of requirements. In particular, sites offering a mosaic of accessible groundwater depths and floodplain pools may provide critical habitat for diverse assemblages of burrowing crayfish species. Our study revealed a strong association between the presence/absence of active crayfish burrows and the depth to groundwater, a result that supports using burrowing crayfish as indicators of accessible groundwater. This will be increasingly important in the context of how climate change might influence water availability and local species diversity.

Stream Suspended Mud as an Indicator of Post-Mining Landform Stability in Tropical Northern Australia

Mining can cause environmental disturbances and thus mined lands must be managed properly to avoid detrimental impacts in the future. They should be rehabilitated in such a way that post mining landforms behave similarly as the surrounding stable undisturbed areas. A challenge for government regulators and mine operators is setting closure criteria for assessment of the stability of the elevated post-mining landforms. Stability of a landform is often measured by the number and incision depth of gullies. This can assess mass stability and bulk movement of coarse material. However, there is a need for a more sensitive approach to assess catchment disturbances using the concept of waves of fine suspended sediment and thus determine the dynamics of recovery of a post mining landform. A more environmentally meaningful approach would be to assess the fine suspended sediment (FSS, silt + clay (0.45 µm < diameter < 63 µm)) leaving the system and entering downstream waterways. We propose assessing stability through relationships between rainfall event loads of FSS and event discharge (Q) in receiving streams. This study used an innovative approach where, instead of using instantaneous FSS concentration, it used total FSS load in waves of sediment driven through the system by rainfall runoff events. High resolution stream monitoring data from 2004 to 2015 in Gulungul and Magela Creeks, Northern Territory, Australia, were used to develop a relationship between sediment wave and event discharge, ∑FSS α f(Q). These creeks are adjacent to and receive runoff from Ranger Mine. In 2008, a 10 ha elevated waste rock landform was constructed and instrumented in the Gulungul Creek catchment. The earthworks required to build the landform created a considerable disturbance in the catchment, making a large volume of disturbed soil and substrate material available for erosion. Between 2008 and 2010, in the first two wet seasons immediately after construction, the downstream monitoring site on Gulungul Creek showed elevated FSS wave loads relative to discharge, compared with the upstream site. From 2010 onwards, the FSS loads relative to Q were no longer elevated. This was due to the establishment of vegetation on the site and loose fine sediment being trapped by vegetation. Large scale disturbance associated with mining and rehabilitation of elevated landforms causes elevated FSS loads in receiving streams. The predicted FSS loads for the stream as per the relationships between FSS and event discharge may not show a 1:1 relation with the observed loads for respective gauging stations. When downstream monitoring shows that FSS wave loads relative to rainfall runoff event discharge reduce back to pre-construction catchment levels, it will indicate that the landform is approaching equilibrium. This approach to assess landform stability will increase the sensitivity of assessing post-mining landform recovery and assist rehabilitation engineers to heal the land and benefit owners of the land to whom it is bestowed after rehabilitation.

Assessing sediment yield and streamflow with SWAT model in a small sub-basin of the Cantareira System

Hydro-sedimentological models might be useful tools for investigating the effectiveness of soil and water conservation practices. However, evaluating the usefulness of such models requires that predictions are tested against observational data and that uncertainty from model parameterization is addressed. Here we aimed to evaluate the capacity of the SWAT model to simulate monthly streamflow and sediment load in the Posses creek catchment (12 km2), Southeast Brazil. The SUFI-2 algorithm from SWAT-CUP was applied for calibration, testing, uncertainty, and sensitivity [...]

Hydroclimatic variability and riparian wetland restoration control the hydrology and nutrient fluxes in a lowland agricultural catchment

Climate change and riparian management are major drivers of hydrological change, with important implications for nutrient fluxes in lowland streams. However, the coupling of hydrological and nutrient dynamics is complex due to time-variant flow paths, interacting biogeochemical processes and variation in land use, fertilization levels and management measures. Here, we assessed the long-term (30 year) changes in climate, discharge, groundwater levels and stream water quality in a mixed land use catchment (Demnitzer Mill Creek catchment, DMC) in northern Germany. The catchment was subject to wetland restoration and subsequent beaver (Castor fiber) recolonization over the last 15 years. Climatic variability is the primary driver of the hydrological regime, with discharge and groundwater variations closely coupled to increases in annual air temperature and fluctuations of annual rainfall. Over the past 8 years, stream flows have been greatly reduced during a prolonged drought period. Meanwhile, beaver dams have also moderated flow regimes and facilitated groundwater recharge. In terms of water quality regimes, the concentration-discharge (C-Q) relationship for nitrate (NO3-N) and soluble reactive phosphate (SRP) showed positive and negative chemodynamic behavior respectively, whilst dissolved organic carbon (DOC) exhibited chemostatic behavior. These differences were dictated by the intrinsic properties of each solute in terms of contrasting catchment storage and immobilization processes. Moreover, the changing hydrological conditions regulated such patterns and strengthened the C-Q relationships for nutrients during the drought. As an integrated result of drought and wetland restoration, nutrient concentrations and fluxes in stream water have been reduced in recent years. Headwater catchments like DMC, where much of the hydrochemical signature of larger, downstream river networks are generated, are critical observatories for integrating understanding of the linkages between water quality and land management in an era of climate change.