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A philosophical and communication shift is needed in river management if we are to meet sustainable development goals and tackle environmental challenges brought about by ongoing anthropogenic and climate change. In some parts of the world, recovery‐enhancement approaches to river management have been adopted, communicated and used for many years. At the heart of these approaches lies an understanding of the biogeomorphic forms, processes and evolutionary trajectories of rivers that differs philosophically from notions of restoration, rewilding or creation of a utopian natural state. Instead, recovery‐enhancement approaches aim to improve the biogeomorphic condition of rivers, recognising that they are dynamic entities and new evolutionary trajectories and novel ecosystems are being created that are now part of the environment. Accepting shifting baselines and moving targets is inherent as boundary conditions (water, sediment and vegetation interactions) continue to be altered under the influence of anthropogenic and climate change, and the impacts of 'unprecedented' wildfires, floods, heatwaves and drought are manifested on the ground. The river management sector has not yet fully adapted to this reality with large amounts of applied science and on‐ground practice still focussed on restoration, re‐engineering and rewilding, words which in themselves produce a false impression of the aims, visions and achievability of river management. Embracing recovery‐enhancement approaches to river management requires a conscious shift in communication strategies and terminology to present more realistic expectations and possibilities for river condition improvement, a responsibility that is incumbent upon us, the scientists and practitioners, who work in the applied science and river management profession. In this Short Communication, I use a case study from eastern Australia to illustrate what biogeomorphic river recovery can look like. I use this to discuss the potential for adoption of a recovery‐enhancement approach to river management more broadly, and call on scientists and practitioners to make a conscious philosophical and communications shift when working in applied science and river management. [ABSTRACT FROM AUTHOR]

Since European colonisation, many coastal rivers of New South Wales (NSW) have been highly modified by channelisation, flow regulation, sediment mining, intensive grazing and agriculture, deforestation, and riparian vegetation and wood removal. Since the late 1980s, nearly 55% of these rivers have undergone a significant 're‐greening' and geomorphic recovery with changes to instream and riparian roughness. However, little research has been undertaken to quantify if there have been any coeval changes in flow hydrology. Approximately 7000 flow hydrographs with one‐hour time‐steps from 117 gauges on 45 study rivers (17 of 20 coastal catchments of NSW) were used to assess changes to in‐channel and overbank hydrology over decadal timeframes. Hydrograph shape and attenuation characteristics for three morphologically defined flow stages were analysed: in‐channel fresh, high flow and overbank flood. Time‐series analysis was used to quantify changes in flow hydrology from the early‐20th century to present and identify trends occurring between known degradation phases (1910s–1940s and 1940s–1980s) and a recovery phase (1990s to present) for these rivers. Our findings indicate that, on average, and for some key examples, changes in flow hydrology are occurring. Flows are slowing and attenuating as indicated by decreases in flood wave celerity and hydrograph kurtosis, skewness and rate of rise and increases in peak‐to‐peak travel time, flood peak attenuation and flood wave attenuation index. The most significant changes have occurred since the 1980s with the most noticeable effects on the behaviour of high flows (around the bankfull stage). However, there is not a consistent direction change in these indicators in all places. We use these findings to categorise the flow mitigation signal of the study regions and catchments and discuss the implication for river and flood management. [ABSTRACT FROM AUTHOR]

Extensive riparian vegetation clearance occurred in many rivers of southeastern Australia throughout the 19th and 20th century, post colonisation. With improvements in river management practices, coincident with a period of minimal flooding, vegetation recovery of riparian corridors has been occurring since the 1980s in all coastal catchments of New South Wales (NSW). However, the catchment‐by‐catchment spatial pattern and temporal trends, trajectories and rates of vegetative recovery remain unknown. We reconstruct a 70‐year time series of change in riparian vegetation coverage for all rivers in coastal catchments of NSW, utilising historical aerial imagery, Landsat and Sentinel data and a manual digitisation and machine learning method. We quantify and statistically analyse decadal trends in woody and non‐woody vegetation coverage along 19 485 km of stream length in 20 catchments. Across the region, there has been, on average, a 40% increase in vegetation coverage along riparian corridors since the 1950s, with some catchments increasing towards a current day coverage of between 60% and 80%. However, the trends vary by subregion and by catchment. An early logarithmic increase occurred up to 2004 on the North coast, and a recent and accelerated exponential increase since 1995 has occurred on the South coast. After a steep initial increase, riparian corridor vegetation coverage has fluctuated on the Central coast since about 1995. We used these linear, exponential and logarithmic regressions to undertake preliminary forecasts of possible future timeframes of riparian vegetation change, based on several climate, management and natural disaster disturbance scenarios. If the current trend continues, riparian vegetation coverage can reach 70% across the region by 2055. However, if management practices change or catastrophic disturbance events such as fire and flood occur, increases in riparian vegetation coverage could be set back by up to 30 to 40 years. [ABSTRACT FROM AUTHOR]

Radiocarbon dates on multiple individual charcoal fragments floating together down the Macdonald River, New South Wales, Australia, have calibrated ages spanning >1700 years. Partial explanations of this range of inherited ages can be attributed to the inbuilt age of living biomass, charcoalisation conditions, hillslope transport and storage and/or valley floor (fluvial) transport and storage, but the contribution of each of these components can be constrained only rarely. These results caution against using radiocarbon dating of charcoal as the sole dating technique to interpret Late-Holocene sedimentary histories. These findings also show that it is unlikely that deposit age has a dependable relationship to charcoal age. [ABSTRACT FROM AUTHOR]

Natural flood management (NFM), a nature‐based solution to flood mitigation where hydrological and biophysical processes are harnessed to reduce flow velocity, erosive energy and flood risk, is an emerging global theme of water and river management. The catastrophic 2021 and 2022 floods in eastern Australia are used to assess the hydrological properties of discrete events and to start an investigation of whether widespread changes in flood hydrology are occurring. We find that most coastal rivers in New South Wales (NSW) had a noticeable decrease in flood wave celerity (increase in flood travel time) when the 2021 and 2022 floods are contrasted with equivalent floods since the 1970s and that several also exhibit increases in flood peak attenuation. For some rivers, there is a coincident trend between these changing flood properties, riparian vegetation regrowth (regreening) and geomorphic recovery over the last +30 years. These may be the first signals that passive riparian management is counteracting some of the more severe hydrological effects of floods on these rivers and that some degree of NFM is possible. Lessons from this work are that there is an immediate opportunity to implement large‐scale NFM in coastal catchments of NSW, but this will only occur if we re‐examine current flood mitigation and adaption strategies and recognise and prioritise nature‐based solutions that include space‐to‐flood and corridors of river recovery, as essential parts of the modern flood mitigation toolkit. [ABSTRACT FROM AUTHOR]

Despite research into the dynamics of seed transport in fluvial systems, few consider how far seeds will travel, and how far from local or upstream seed sources passive regeneration can occur. We experimentally test the seed floating time of 60 plant species (50 native and 10 exotic) commonly found in riparian corridors of southeastern Australia. Around 50% of species had seeds that floated for 2 days or less, and for most species' (90%) all seeds had sunk within one week. Seeds of native species tended to sink more quickly than exotic, with 64% of native species' seeds floating for less than 2 days. In contrast, most exotic species (80%) floated for longer than 2 days, and 40% had seeds still floating after one week. This suggests that exotic species are good floaters and likely to travel long distances, making them excellent hydrochores. Finally, we applied the findings to a real case study, Wollombi Brook, NSW, Australia. We combined the findings from the seed floating experiment with low flow hydrology calculations to map the potential travel distance of seeds from known extant vegetation sources. We show that maximum seed travel distance per day could be up to 21 km. Thus, species that float for a week could potentially travel almost 150 km downstream before sinking or being deposited. We discuss how local versus upstream seed sources, and hydrochory, could be utilised in passive revegetation and weed management of riparian corridors. [ABSTRACT FROM AUTHOR]

By connecting corridors of river recovery, resilience can be built into river systems to mitigate against future floods and droughts driven by anthropogenic disturbance or climate extremes. However, identifying where these corridors can be built is still lacking in river management practice. The Open Access NSW River Styles database contains comprehensive information on geomorphic river condition and recovery potential. The database can be used to systematically analyse where corridors of river recovery could be created via conservation or rehabilitation. Analysis was undertaken in ArcGIS using the recovery potential layer along 84,342 km of freshwater stream length, across 20 catchments of coastal NSW. We identified 4,905 km of reach connections, defined as an upstream to downstream section of river that is connected end-to-end, and 17,429 km of loci connections defined as more isolated sections of river from which recovery can be seeded and extended into adjacent reaches. There was significant spatial variability in the types and lengths of connections made across the catchments. Some catchments have significant potential to build corridors of recovery along large sections of river, whereas other catchments are more fragmented. These results provide practitioners with a user-friendly distillation of where river conservation and rehabilitation activities could be focussed when working with river recovery in practice. Combined with local on-ground knowledge, this information forms an important input to evidence-based prioritisation and decision making in river management. [ABSTRACT FROM AUTHOR]

Modeling network‐scale sediment (dis)connectivity and its response to anthropic pressures provides a baseline understanding of river processes and sediment dynamics that can be used to forecast future hydro‐morphological changes in river basins. However, this requires a solid understanding of how a system is currently operating, and how it operated in the past. We present the basin‐scale, dynamic sediment connectivity model D‐CASCADE, which combines concepts of network modeling with empirical sediment transport formulas to quantify spatiotemporal sediment (dis)connectivity in river networks. D‐CASCADE accounts for multiple factors affecting sediment transport, such as spatiotemporal variations in hydrological regime, different sediment grain sizes, sediment entrainment and deposition. Add‐ons are included in D‐CASCADE to model local changes in river geomorphology driven by sediment‐induced variations in features such as channel width. We apply D‐CASCADE to the well‐documented Bega River catchment, NSW, Australia, where significant geomorphic changes to rivers have occurred post European colonization (after 1850s), including widespread channel erosion and sediment mobilization. The Bega catchment provides a useful case study to test D‐CASCADE, as original source data on the historical sediment budget are available. By introducing historic drivers of change in the correct chronological sequence, the D‐CASCADE model successfully reproduced the timing and magnitude of major phases of sediment transport and associated channel adjustments over the last two centuries. With this confidence, we then ran the model to test how well it performs at estimating future trajectories of basin‐scale sediment transport and sediment budgets at the river reach scale. Key Points: We present the new dynamic D‐CASCADE model for network‐scale river sediment (dis)connectivity modelingD‐CASCADE successfully reproduced major historic geomorphological changes observed in the Bega river network after European settlementD‐CASCADE is used to test future trajectories of basin‐scale sediment transport and reach‐scale sediment budget in the Bega river system [ABSTRACT FROM AUTHOR]

Freshwater wetlands are a key component of the global carbon cycle. Wet–dry tropics wetlands function as wet-season carbon sinks and dry-season carbon sources with low aquatic metabolism controlled by predictably seasonal, yet magnitude-variable flow regimes and inundation patterns. However, these dynamics have not been adequately quantified in Australia's relatively unmodified wet–dry tropics freshwater wetlands. A baseline understanding is required before analysis of land-use or climate change impacts on these aquatic ecosystems can occur. This study characterises geomorphology and sedimentology within a seasonally connected wet–dry tropics freshwater wetland system at Kings Plains, Queensland, Australia, and quantifies soil carbon stocks and wet- and dry-season aquatic metabolism. Soil carbon stocks derived from loss-on-ignition on samples to 1 m depth were 51.5 ± 7.8 kg C m−2, higher than other wet–dry tropics wetlands globally, with potential for long-term retention at greater depths. Gross primary productivity of phytoplankton (GPP) and planktonic respiration (PR) measured through biological oxygen demand bottle experiments in the water column of sediment inundated under laboratory conditions show overall low GPP and PR in both wet- and dry-season samples (all wetland samples were heterotrophic with GPP/PR < 1). Despite the short-term dominance of aquatic respiration processes leading to net release of carbon in the water column under these conditions, there is appreciable long-term storage of carbon in sediment in the Kings Plains wetlands. This demonstrates the importance of wet–dry-tropics wetland systems as hotspots of carbon sequestration, locally, regionally and globally, and consideration should be given to their conservation and management in this context. [ABSTRACT FROM AUTHOR]

A fundamental premise of river management is that practitioners understand the resource they are working with. In river management this requires that baseline information is available on the structure, function, health and trajectory of rivers. Such information provides the basis to contextualise, to plan, to be proactive, to prioritise, to set visions, to set goals and to undertake objective, pragmatic, transparent and evidence-based decision making. In this paper we present the State-wide NSW River Styles database, the largest and most comprehensive dataset of geomorphic river type, condition and recovery potential available in Australia. The database is an Open Access product covering over 216,600 km of stream length in an area of 802,000 km2. The availability of the database presents unprecedented opportunities to systematically consider river management issues at local, catchment, regional and state-wide scales, and appropriately contextualise applications in relation to programs at other scales (e.g. internationally)–something that cannot be achieved independent from, or without, such a database. We present summary findings from the database and demonstrate through use of examples how the database has been used in geomorphologically-informed river management. We also provide a cautionary note on the limitations of the database and expert advice on lessons learnt during its development to aid others who are undertaking similar analyses. [ABSTRACT FROM AUTHOR]

Fire in wetlands is poorly understood, yet hazard reduction burns are a common management practice and bushfires are becoming increasingly prevalent because of climate change. Fire may have long-lasting implications for the microbial component of these wetland ecosystems that regulate carbon and nutrient cycling. The extremely fire-prone Blue Mountains World Heritage Area in south-eastern Australia contains hundreds of endangered peat-forming upland swamps that regularly experience both bushfires and hazard reduction burns. In a before–after control–-impact study, we surveyed the sediment microbial community of these swamps to test the impact of a low-intensity hazard reduction burn. Along with sediment pH, moisture and organic content, we measured gene abundances including those relating to carbon cycling (quantitative PCR (qPCR) of pmoA , mcrA , bacterial 16S rRNA and archaeal 16S rRNA), and bacteria community fingerprint (terminal restriction fragment length polymorphism (T-RFLP)). One year after the hazard reduction burn, there were no significant differences in the gene abundances or microbial community fingerprint that could be attributed to the fire, suggesting that the hazard reduction burn did not have a long-term impact on these microbial communities. A hazard reduction burn in an endangered upland peat-forming swamp in eastern Australia did not cause ongoing changes to sediment microbial community or sediment properties 1 year after the fire. [ABSTRACT FROM AUTHOR]

Rivers with discontinuous watercourses are part of the spectrum of river diversity. Chain‐of‐ponds types contain irregularly spaced, steep‐sided ponds that are separated by preferential flow paths on swampy valley fill. They often contain endangered ecological communities and are receiving greater attention for conservation and restoration. Very little is known about how these river types form, how they have evolved and how they function. Here we present the Late‐Quaternary evolution of one of the last remaining large‐scale chain‐of‐ponds systems in Australia, the Mulwaree Ponds. The chain‐of‐ponds was fully formed by 4.5 ka, with the position and alignment of the ponds being related to the position of pools of a palaeo‐river that is up to 100 ka old. Contemporary hydrogeomorphic processes are insufficient to create the ponds, but sufficient to maintain and keep them open. The phases of evolution for this chain‐of‐ponds system are synchronous with Late‐Quaternary changes in fluvial activity documented for other rivers in southeastern Australia. The ponds at Mulwaree have significant preservation potential over thousands of years. In the current landscape they are rare forms, providing significant grounds for conservation and protection of their distinctive geodiversity. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Temperate Highland Peat Swamps on Sandstone of the Sydney Basin occur in the headwaters of Sydney’s drinking water catchments and are listed as endangered ecosystems, yet they have suffered habitat losses and degradation due to human impacts such as urbanisation. Despite ongoing efforts to restore and better protect upland swamps, they remain poorly understood, potentially hindering the effectiveness of management efforts. Essential to overall ecosystem function and the provision of services for human and environmental benefit are the microbial component of wetland ecosystems. In the case of these swamps, the microbes, have not yet been studied. Here, we investigated differences in the microbial community of upland swamps in urbanised catchments compared to swamps from natural catchments in the Blue Mountains. A total of twelve swamps were sampled, six from within urbanised catchments and six with intact vegetation catchments, to compare sediment conditions and microbial community and genes expression and abundances. Catchment impervious area and number of stormwater drains entering a swamp, indicators for urbanisation, positively correlated with the pH and ammonium concentration of swamp sediment. Community analysis of the 16S rRNA gene (T-RFLP, qPCR) revealed the elevated pH of urbanised swamps coincided with changes to the abundance of bacteria and archaea. Furthermore, RT-qPCR revealed genes involved in carbon cycling (mcrA & pmoA) were more likely to be found in urbanised swamps. Taken together, our results indicate that urbanisation of the Blue Mountains is impacting the environmental services provided by the microbial community of upland swamps in the Sydney Basin. [ABSTRACT FROM AUTHOR]

Abstract: Human disturbance induces significant geomorphic changes to river systems. In eastern Australia, land‐use practices such as clearance of forests and riparian vegetation, and removal of wood from channels in the 19th and 20th centuries induced widespread geomorphic impacts. However, since the 1970s, there has been a noticeable shift in the geomorphic condition of many rivers in eastern New South Wales (NSW). This transition to a recovery trajectory reflects a reduction in land‐use pressures and improved farming practices on the one hand and adoption of recovery enhancement approaches to river conservation and rehabilitation by management authorities on the other. Monitoring and tracking changes in condition by state government agencies involves identifying when geomorphic recovery is occurring so that decision‐support frameworks can determine whether river management is required, where, when, and how much to intervene to enhance river recovery and when to opt‐out of management because the system requires little (or no) intervention. Here, we document procedures that are used to manage process‐based, recovery enhancement in NSW. Following a brief review of river change in eastern NSW since European settlement, we outline an approach to identify and measure key geomorphic indicators of river recovery for different river types. We use case studies to demonstrate examples of geomorphic river recovery, prior to showing how state government agencies in NSW are monitoring trajectories and rates of recovery. Broader implications of this ‘good news story’ are discussed. [ABSTRACT FROM AUTHOR]

Flood risk management is an essential responsibility of state governments and local councils to ensure the protection of people residing on floodplains. Globally, floodplains are under increasing pressure from growing populations. Typically, the engineering-type solutions that are used to predict local flood magnitude and frequency based on limited gauging data are inadequate, especially in settings which experience high hydrological variability. This study highlights the importance of incorporating geomorphological understanding into flood risk management in southeast Queensland (SEQ), an area badly affected by extreme flood events in 2011 and 2013. The major aim of this study is to outline the hydrological and sedimentological characteristics of various 'inundation surfaces' that are typical of catchments in the sub-tropics. It identifies four major inundation surfaces; within-channel bench [ Q ~ 2.33 yr average recurrence interval (ARI)]; genetic floodplain ( Q = 20 yr ARI); hydraulic floodplain (20 yr < Q ≤ 200 yr ARI) and terrace ( Q > 1000 yr ARI). These surfaces are considered typical of inundation areas within, and adjacent to, the large macrochannels common to this region and others of similar hydrological variability. An additional area within genetic floodplains was identified where flood surfaces coalesce and produce an abrupt reduction in channel capacity. This is referred to here as a Spill-out Zone (SOZ). The associated vulnerability and risk of these surfaces is reviewed and recommendations made based on incorporating this geomorphological understanding into flood risk assessments. These recommendations recognize the importance to manage for risks associated with flow inundation and sediment erosion, delivery and deposition. The increasing availability of high resolution topographic data opens up the possibility of more rapid and spatially extensive assessments of key geomorphic processes which can readily be used to predict flood risk. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Temperate Highland Peat Swamps on Sandstone (THPSS) are a distinctive feature of low-relief plateaus in eastern Australia and are listed as an endangered ecological community under state and federal policy. A significant proportion of these ‘upland swamps’ occur within the World Heritage Blue Mountains of NSW. Here, long wall mining, coal seam gas extraction and catchment urbanisation are impacting on the conservation and protection status of these systems. Here we undertake a geomorphic condition assessment of these systems and analyse the range of intrinsic and extrinsic controls operating upon them. Of the 458 sites assessed, 120 (26%) were channelised fills and 338 (74%) were intact swamps. For intact swamps, 49% remain in good geomorphic condition compared to only 28% for channelised systems. Incision of these upland swamps cannot be explained by intrinsic controls such as catchment area, swamp slope, swamp size or shape relations alone. A range of interrelated extrinsic impacts associated with urbanisation are key controls on the condition and sensitivity of these systems. The most significant relationships occur between those swamps in good and moderate condition and percent of impervious area in a swamp catchment (< 10% coverage), distance to stormwater pipes and groundwater bores (both < 500 m distant), and the extent of stormwater connectivity (contain no stormwater outlets). In general, once the condition of a swamp deteriorates past good or moderate, it is impacted. In a swamp management context, identifying ‘thresholds of concern’ and treating extrinsic controls associated with human-disturbance (through either conservation or rehabilitation) has the potential to significantly impact swamp type and condition into the future. [ABSTRACT FROM AUTHOR]

Throughout eastern Australia, and much of the New World, river systems have undergone a series of hydro-geomorphic and vegetative changes following colonisation. Recent research has shown that river recovery is occurring, as demonstrated by improved geomorphic and vegetative condition, but there is limited information on the extent of returning riparian vegetation and its effect on roughness and flow hydrology. Using the Allyn River, New South Wales, Australia, as a case study, historical aerial photographs and satellite imagery were used to characterize the structural changes brought about by geomorphic recovery and quantify the amount of riparian vegetation cover that has returned to the system since the 1940s. Along the Allyn River, total riparian vegetation canopy cover has increased from 30% in 1940 to 38% in 1967 and 63% in 2016. Using space-for-time substitution and retrospective analysis, riparian vegetation roughness, calculated using a terrestrial laser scanner (TLS) gap fraction method, showed an increase in average Manning's n from 0.0156 in 1940 to 0.0194 in 1967 to 0.0372 in 2016 for flows that reach a 2 m stage height (approximately 1 in 2 yr flood average recurrence interval). As a result, flood wave travel time has extended by over 8 h (or 220%) for small to moderate within-channel flows, but further river recovery is required to affect major flow hydrology. This study highlights the outcomes of catchment-scale passive river recovery and provides improved methods for quantifying site and stage height specific vegetative roughness. The demonstrated influence of increased vegetation cover on flow hydrology and geomorphic condition holds significant promise for agencies, practitioners and land managers to achieve substantial river recovery outcomes using active and passive vegetation rehabilitation and river management. [Display omitted] • Geomorphic and vegetative recovery are occurring along the Allyn River, Australia. • A terrestrial laser scanner gap fraction method is used to quantify roughness changes. • Flood wave travel time has increased by over 8 h (or 220%) for small to moderate in-channel flows. • Further river recovery is required to affect major flood hydrology. • Passive river management can achieve substantial geomorphic recovery and flood mitigation. [ABSTRACT FROM AUTHOR]

This study aimed to determine the extent of geomorphic change resulting from the catastrophic flood of 2011 in the Lockyer Valley in southeast Queensland and to place these impacts within a history of geomorphic adjustment. Aerial photographs dated from 1933 to 2011 and parish maps and historical on-ground photographs dating from 1865 to 1966 were examined for evidence of geomorphic adjustment since European settlement in the first half of the nineteenth century. Eleven forms of geomorphic adjustment were identified in three categories; erosional, depositional, and reorganisational. Only 26% of the Lockyer Creek channel length has been affected by some form of geomorphic adjustment since European settlement. Most of this adjustment was localised and dominated by reorganisation of geomorphic unit assemblages within the macrochannel and sediment deposition on floodplains. No wholesale river change in the form of lateral migration or avulsion has occurred, and the river's morphology has remained relatively characteristic over time (i.e., morphology remains relatively uniform in a reach-averaged sense). Geomorphic responses to extreme flooding have been minor, and the geomorphic effectiveness of floods in this system (including the 2011 flood) has been limited over the last several hundred years. The system is likely still adjusting to past flooding events that ‘set’ the morphology of the current system (i.e., the macrochannel). A form of event resilience has resulted in this system such that it is less prone to geomorphic adjustment during events than would normally be considered geomorphically effective. As a result, antecedent controls on macrochannel presence and capacity are considered to be first-order controls on contemporary forms and processes in this system. Work is required to test whether the resilience of this system will hold in the future, with more extreme episodes of flooding predicted to occur in this region under future climate change. [ABSTRACT FROM AUTHOR]

In response to peatland degradation by human activities worldwide, restoration through gully blocking is now being implemented in an attempt to return valuable ecological and hydrological services to degraded systems. Re-establishing these services requires an understanding of how systems have formed and evolved in order to establish conditions that assist with physical and ecological recovery. However, management of peatlands and swamps continues without prior investigation into the environmental history of these ecosystems. This study investigates stratigraphy, sediment ages and peat forming potential within three Temperate Highland Peat Swamps on Sandstone in the Blue Mountains, NSW. These swamps are listed as Endangered Ecological Communities under the Environment Protection and Biodiversity Conservation Act 1999 ( Cwlth) and the Threatened Species Conservation Act 1995 ( NSW). High discontinuity in sediment structure, peat forming potential and timeframes of swamp initiation were observed across the three swamps. This localised variation reflects the complex geomorphic processes acting within and between these systems. Such data provides scientists and managers with key indicators to assess timeframes over which infilling, vegetation establishment and peat formation occurs. These tools can guide prioritisation, conservation and financial expenditure for the management and rehabilitation of temperate peat swamps. [ABSTRACT FROM AUTHOR]

Temperate Highland Peat Swamps on Sandstone (THPSS) are a form of topogenous mire found on the plateau areas of eastern Australia. They are well recognised for their ecological value, but our understanding of their geomorphic structure, function and evolution remains limited. Across 19 sites, the valley fills of THPSS comprise sequences of mineral-rich sand and loam deposits. Basal sand and gravel sediments have low organic content and low carbon to nitrogen (C:N) ratios (a measure of peat formation) and are dated between 15.3 and 9 kyr cal. BP, with outliers back to 44 kyr cal. BP. These units reflect mineral-sediment trapping and accumulation on the valley floor. The transition to ‘swamp’ conditions through paludification occurred between 15.2 and 10.3 kyr cal. BP in some systems, and between 7.6 and 1.4 kyr cal. BP in other, adjacent valleys. These ‘swamp’ sediments comprise a package of units, progressing upward from fine cohesive sands, through assemblages of alternating organic sands to surface organic fines. These beds vary in texture from loams to sands and have a range of organic matter content (from 7.6% to 79.9%) and C:N ratios (from 15 to 58). The surface organic fines at 0 and 100 cm depth range in age from 13.1 to 0.7 kyr cal. BP. The composition and age structure of the valley fill suggest a mix of allogenic and autogenic controls are responsible for the formation of these swamps, but a regional model of THPSS evolution is emerging. Given these ‘peatlands’ have formed under a climate that experiences significant inter-annual variability in rainfall, conditions for peat formation are localised and not directly equivalent to those documented internationally. [ABSTRACT FROM PUBLISHER]

ABSTRACT Swamps, bogs and fens are diverse wetland ecosystems found worldwide. Within each region, different ecological processes and species dominate them, yet water levels and saturation of sediments appear key to the maintenance of vegetation and the ecosystem as a whole. Consequently, understanding how vegetation responds to water levels in these ecosystems is critical to their future management. This paper describes the floristic patterns observed in an upland swamp on the Budderoo Plateau, Southern Highlands, NSW, and relates the distribution of the vegetation communities to groundwater depth, soil type and site attributes. Three distinct vegetation assemblages were identified associated with (1) the main swamp axis, (2) the swamp margin and (3) the adjacent hillslopes. Elevation above the central swamp axis was the variable most strongly related to vegetation structure. Relative changes in elevation create a drainage gradient that allows higher elevation areas (hillslope and swamp marginal zones) to drain more readily than areas in the main swamp axis. Variation in vegetation was also related to median groundwater depth. Finally, soil organic matter content was a contributing factor with the swamp axis and marginal zones mostly having fibric, highly organic soils in contrast to the sandy, loamy soils on the hillslopes. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Upland swamps are a form of topogenous mire that occur on the plateau areas of eastern Australia. These systems are well recognized for their ecological value, but little is known about their internal hydrological function and how this relates to their geomorphic structure and evolution. In this study, the geomorphic, sedimentological, and hydrological properties of an intact upland swamp on the Budderoo Plateau NSW are investigated. The geomorphic structure of the swamp is simple, and the sedimentology comprises basal layers of coarse sands, overlain by several layers of organic accumulation up to 3.3 m in thickness. Each of these sedimentary units has different hydrological behaviors (rates of water throughflow and discharge) that drive the overall function of the swamp in response to rainfall of various magnitudes and duration. Four hydrological response types have been identified in the functioning of this swamp. These response types (RT) are characterized by different peaks and recession responses to rainfall. The form of the hydrograph produced is controlled by antecedent water table position and the amount, timing and duration of rainfall. Depending on antecedent moisture conditions, the swamp can operate either as a store for water or as a rapid conduit for water throughflow and overland flow. [ABSTRACT FROM AUTHOR]

The Blue Mountains region of New South Wales, including the World Heritage listed Blue Mountains National Park, is arguably one of Australia's most highly valued and iconic wilderness areas. Common to this region are upland swamps (formally 'temperate highland peat swamps on sandstone'), which play a vital hydrological role at the headwaters of the river catchments, as well as providing the habitat for an array of flora and fauna species. This paper involves an interdisciplinary examination into the need and potential for adaptive management in the Blue Mountains. It uses geomorphic (physical) knowledge of swamp condition and social data about the volunteers who rehabilitate them. Research involved using the River Styles river condition framework across 47 swamps and questionnaires and interviews with local rehabilitation volunteers. It is proposed that there is a need and a potential to combine geomorphic understanding with further engagement of community volunteers in order to enable an interdisciplinary approach to adaptive management. Such an approach could result in the effective environmental management of upland swamps in the Blue Mountains. [ABSTRACT FROM AUTHOR]

Restoration of native vegetation often focuses on the canopy layer species, with the assumption that regeneration of the understory elements will occur as a consequence. The goal of this study was to assess the influence of canopy restoration on the composition and abundance of understory plant species assemblages along riparian margins in the Hunter Valley, NSW, Australia. We compared the floristic composition (richness, abundance, and diversity) of understory species between nonrevegetated (open) and canopy revegetated plots across five sites. A number of other factors that may also influence understory vegetation, including soil nutrients, proximity to main channel, and light availability, were also measured. We found that sites where the canopy had been restored had lower exotic species richness and abundance, as well as higher native species cover, but not native species richness, compared with open sites. Multivariate analysis of plots based on plant community composition showed that revegetated sites were associated with lower total species diversity, light availability, and exotic cover. This study has found that the restoration of the canopy layer does result in lower exotic species richness and cover, and higher native species cover and diversity in the understory, a desirable restoration outcome. Our results provide evidence that restoration of native canopy species may facilitate restoration of native understory species; however, other interventions to increase native species richness of the understory should also be considered as part of management practice. [ABSTRACT FROM AUTHOR]

ABSTRACT Applications of ergodic reasoning (or location for time substitution) aid efforts at environmental reconstruction and prediction, providing a useful tool to analyse and communicate stages of landscape evolution. Analysis of the historical range of behaviour and change that a river system has experienced can be used to interpret thresholds that have been breached, and underlying controls and/or triggers for adjustment and change. This information can be used to forecast future trajectories of adjustment and provide target conditions for management activities. This paper uses a case study from upper Wollombi Brook, New South Wales, Australia to demonstrate how ergodic reasoning can be used to assess river behaviour, change and responses to natural and human-disturbances. The 'river evolution diagram' developed by Brierley and Fryirs ( Geomorphology and River Management: Applications of the River Styles Framework. Blackwell Publishing: Oxford, 2005) is presented as a means for depicting the range of behaviour and evolutionary variability of this river. These approaches can be readily applied in other systems. Implications for approaches to analysis of river evolution and management are outlined. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Recognition of the degraded state of rivers across the world has prompted the development of management programmes which promote river repair through rehabilitation practices. Efforts to date have emphasised concerns for biophysical attributes of rivers to the relative exclusion of socio-cultural values. Ultimately, the process of river repair must move beyond this technical focus and incorporate collective societal engagement, participation and ownership. However, the inherent complexities of informing and managing this process limit the prospects that engagement will be translated into an effective and sustained practice. This qualitative case study research analyses the community’s knowledge, views and opinions regarding geomorphic river change and river works projects undertaken in the Upper Hunter catchment, New South Wales, Australia. The responses and views expressed by the participants highlight how ineffective communication and limited understanding of past river work practices has inhibited the connection and ownership between the people and their river. Essentially, historical river management was viewed as a technical process that failed to incorporate social values and aspirations, and which gave inadequate consideration to local knowledge and experience. Participants identified the need to address both diversity and commonality in vision-building and the need for greater confidence and transparency in river science and management. In light of these responses, this paper argues for the adoption of a geo-social, transdisciplinary approach to river rehabilitation. [Copyright &y& Elsevier]

Abstract: A partly confined river is one along which the contemporary channel abuts the valley margin along 10–90% of its length. They occur along sections of longitudinal profiles that are transitional from fully bedrock confined to fully alluvial rivers. At this position in the landscape, there is sufficient accommodation space for discontinuous floodplain pockets to form. Segregation of the river''s load and dissipation of flow energy result in sediments being stored outside the channel. Bedrock- and planform-controlled variants of these rivers, and associated floodplains, are differentiated. Terraces, fans, and piedmont zones act as secondary confining features on channel planform and floodplain formation in these valleys. The influence of these antecedent features on contemporary river character and behaviour in partly confined valleys of the upper Hunter catchment, New South Wales, Australia is appraised. The balance of formative and reworking processes, and associated capacity for geomorphic adjustment, is influenced by the site-specific configuration of antecedent controls at any floodplain pocket. Downstream patterns of these river types are analysed along all major tributaries of the upper Hunter catchment to highlight the extent of antecedent control on contemporary river forms and processes in this landscape setting. [Copyright &y& Elsevier]

Understanding downstream transitions in river character and behavior is a basic concept in fluvial geomorphology. Downstream patterns of depositional processes can be differentiated between channel and floodplain components. In this study a generic set of methods is used to analyze floodplain initiation and continuity in relation to downstream changes in total stream power (slope and discharge) and longitudinal profile form for river courses in the upper Hunter catchment, Australia. Absolute values of these controlling factors are shown to be poor indicators of threshold conditions at which floodplains begin to form along river courses. Catchment-scale patterns of stream power and the form of longitudinal profiles provide better predictors of this transitional zone. The total stream power plot derived along longitudinal profiles represented by a second-order exponential curve has a bimodal pattern. In most cases, floodplains begin to form in a transition zone characterized by a trough area within the bimodal stream power distribution. This bimodal stream power pattern provides a better means to identify this transition in depositional processes along longitudinal profiles than more conventional single peak stream power analyses based on first-order exponential longitudinal profiles. Indirect controls such as basin geology and accommodation space also influence the initiation and pattern of floodplains. [ABSTRACT FROM AUTHOR]

A post-rehabilitation audit of the derelict Conrad base metal mine, eastern Australia, indicates ongoing environmental hazard regarding acid mine drainage and concentrations of arsenic and lead to 3 wt% in the soil and sediment. In order to rehabilitate remote contaminated sites effectively, on-site analyses should be carried out to ensure that the materials used to rehabilitate the site are not contaminant-bearing. Understanding the geomorphic setting of the rehabilitated areas is also important in understanding where, and for what period, contaminated materials might be stored in fluvial systems downstream of mine workings. Chemical and geomorphic audits should form a fundamental part of all rehabilitation works to ensure favourable environmental outcomes. [Copyright &y& Elsevier]

Australia and New Zealand have been at the forefront of many advances in river management through policy and legislative initiatives and the introduction of participatory frameworks. In part this leadership role is a response to the pervasive extent and impact of post-colonial societies on Australasian environments. Core geographical concepts have contributed significantly to the increased recognition of a ‘sense of place’ in management practice. Grounded and authentic applications recognise explicitly the complexity of interactions across an array of biophysical and social scales. The contribution of geography to river management is particularly significant in the implementation of catchment-framed programmes, the development of generic scientific tools that can be used on a catchment-by-catchment basis, and the application of adaptive management principles that are operationalised within participatory frameworks. Failing to acknowledge geographical concepts can lead to a placeless universalism in river management that is unsustainable and unacceptable in biophysical and social terms. [ABSTRACT FROM AUTHOR]

1. The River Styles® framework is a geomorphic approach to the classification of river types, assessment of the physical condition of rivers, and planning of physical rehabilitation. However, the linkages between River Styles and aquatic biodiversity conservation are still only weakly developed. 2. In this study, 41 sites in the Bega River basin in New South Wales, Australia, were classified according to River Style and geomorphic condition, and surveyed for four biological assemblages: diatoms, aquatic and semi-aquatic macrophytes, aquatic macroinvertebrates and fish. 3. Each assemblage differed significantly among River Styles. However, in the case of diatoms and fish, these differences could be accounted for by geographic clustering of sites in the same River Style, and a tendency for River Styles to occupy particular altitudinal zones and sizes of streams. This result was attributed to the overriding influences of water quality on diatoms and of altitude-related variation in water temperature and distance from the ocean on fish. For macrophytes and macroinvertebrates, geomorphic river type appeared to exert a direct influence, probably via variation in physical habitat characteristics. 4. Geomorphic condition, judged as good, moderate or poor by reference to the inferred natural condition of each River Style, was also significantly associated with differences in biological assemblages other than fish. Twice as many taxa appeared to favour sites in good geomorphic condition as favoured sites in poor condition. Many of the taxa associated with sites in poor condition are alien taxa introduced to Australia since European settlement. 5. These findings imply that protection of reaches that are in good geomorphic condition is likely to be critical for the maintenance of indigenous biodiversity, and that rehabilitation of geomorphic condition can assist in the rehabilitation of native riverine biota. [ABSTRACT FROM AUTHOR]

Clearance of riparian vegetation and removal of woody debris are perhaps the most pervasive of all forms of human disturbance to river courses. Geomorphic consequences of these impacts have varied markedly from river system to river system, a result of variations in catchment setting, climate, geology, sediment supply and evolutionary history. In this paper, geomorphic responses of rivers to rapid, systematic clearance of riparian vegetation in New World (colonial) societies are contrasted with changes associated with gradual, piecemeal, yet progressive clearance of riparian forests in northern Europe (the Old World). It is postulated that the dramatic nature of river metamorphosis experienced in landscapes such as southeastern Australia records the breaching of fundamental geomorphic thresholds in a different manner to that experienced in Old World landscapes. [ABSTRACT FROM AUTHOR]

Based on principles from the ecological literature, a semi-quantitative framework to assess geomorphic river condition is outlined. Guiding principles that underlie the framework include the need to compare like-with-like, selection of appropriate ‘natural’ reference conditions for differing types of river, framed in terms of their natural range of variability, and measurement of parameters that are relevant for each type of river. Solid understanding of river character and behaviour along with assessment of capacity for adjustment, and appraisal of river evolution, including responses to human disturbance, are core components of the framework. Reference conditions are defined for each type of river using ergodic reasoning.The procedure for assessing geomorphic river condition has three steps: (1) identify the type of river, termed River Style, and its capacity for adjustment within its valley setting; (2) assess river evolution as a basis for identifying irreversible geomorphic change and a ‘natural’ reference condition; (3) determine and explain the geomorphic condition of each reach in a catchment. Application of the procedure is demonstrated for reaches of an alluvial and a confined River Style in Bega catchment on the South Coast of New South Wales, Australia. [Copyright &y& Elsevier]

ABSTRACT / Geomorphologically derived river styles provide an integrative framework for examining the interactions of biophysical processes in rivers throughout a drainage basin. Nine styles of river character and behavior are identified in Bega catchment, on the south coast of New South Wales, Australia. Headwater streams above the escarpment drain into gorges in the escarpment zone. In different subcatchments at the base of the escarpment, there are three different river styles, namely cut-and-fill, vertically accreted floodplains, and fans. Downstream of these river styles, in the rounded foothills of the catchment, throughput and transfer river styles convey sediments to the lowland plain. In one mid-catchment setting, a floodout traps sediment. Finally, along the lowland plain of Bega River, there is a floodplain accumulation river style. Downstream patterns of river styles in differing subcatchments of the Bega River basin are differentiated into three types, reflecting river adjustments to valley width, slope, and responses to human disturbance. Analysis of the character and condition of each river style in Bega catchment, and their downstream patterns, are used to provide a biophysical basis to prioritorize river management strategies. These reach-scale strategies are prioritorized within an integrative catchment framework. Conserving near-intact sections of the catchment is the first priority. Second, those parts of the catchment that have natural recovery potential are targeted. Finally, rehabilitation priorities are considered for highly degraded reaches. At these sites, erosion and sedimentation problems may reflect irreversible changes to river structure. [ABSTRACT FROM AUTHOR]

Examines the extensive valley fills that have formed at the base of the escarpment in granitic catchments along the Upper Wolumla Creek, South Coast, New South Wales. Effect of downstream transfer of deposits in the bedrock confinement in downstream reaches; Effect of the fluvial sediments in the geomorphic transformation of the lower Bega River.

1. Within a few decades of European disturbance in the mid-nineteenth century, river character and behaviour were transformed in Bega catchment on the south coast of New South Wales, Australia. Ecological impacts of geomorphic changes to river structure and function throughout the catchment are assessed. 2. At the time of European settlement, many water courses in Bega catchment were discontinuous, with extensive swamps along middle and upper courses. Following a series of direct and indirect human impacts, channels became continuous in the middle and upper parts of the catchment, as extensive valley fills at the base of the escarpment were incised. Along the lowland plain, the channel widened by over 300%, fundamentally altering the relationship between the channel and its adjacent floodplain. 3. Geomorphic changes to river structure have modified habitat availability throughout Bega catchment. The impacts have been least pronounced in headwater streams, but have been dramatic along virtually all river courses beyond the base of the escarpment. 4. Changes in river structure have been directly related to altered riparian vegetation cover, and vice versa. As a consequence of changes to river structure, bed substrate calibre (and supply volume/rate) has been modified along most streams. 5. A series of indirect, secondary impacts have modified habitat viability along river courses. Lateral, longitudinal and vertical linkages within the river system have been altered, affecting the transfer of water, sediment, organic matter, nutrients and other biotic interactions. 6. These direct and indirect consequences of geomorphic changes in river structure suggest that ecologists need to adopt a longer-term, catchment-framed view of human disturbance to river ecosystems. 7. Effective, sustainable ecological rehabilitation of river courses is dependent on an understanding of geomorphic processes and determination of appropriate river structure at differing positions in catchments. [ABSTRACT FROM AUTHOR]

Abstract: Monitoring and assessment are integral components in adaptive management programmes that strive to improve the condition of river systems. Unfortunately, these procedures are generally applied with an emphasis upon biotic attributes and water quality, with limited regard for the geomorphic structure, function and evolutionary trajectory of a river system. Geomorphic principles convey an understanding of the landscape context within which ecohydrologic processes interact. Collectively, geo-eco-hydrologic understanding presents a coherent biophysical template that can be used to frame spatially and temporally rigorous approaches to monitoring that respect the inherent diversity, variability and complexity of any given river system. This understanding aids the development of management programmes that ‘work with nature.’ Unless an integrative perspective is used to monitor river condition, conservation and rehabilitation plans are unlikely to reach their true potential. [Copyright &y& Elsevier]

Abstract This study derives a new function describing the relationship of channel bankfull discharge (Q bf) to channel width in modern rivers of the Murray-Darling Basin (MDB) of southeastern Australia and applies this to dated palaeochannels of seven rivers to quantify late Quaternary discharge history in this important basin. All rivers show high MIS3 and MIS2 Q bf , declining in the Holocene. The Q bf of modern MDB rivers is correlated with total catchment precipitation but comparison with palaeochannel Q bf estimates shows that while enhanced runoff efficiency is necessary to account for much larger late Pleistocene palaeochannels, either lower or higher precipitation rates could have prevailed. A strong association between relative palaeo- Q bf enhancement and temperature suggests a temperature-mediated mechanism controlling river discharge, such as the fraction of precipitation stored as snow and thawing in spring, the enhancement of orographic rainfall, or CO 2 feedbacks with vegetation cover. Significantly enhanced MIS3 Q bf requires an additional mechanism, such as increased rainfall. These findings are consistent with others that increased moisture availability was associated with past colder climates, although this was not necessarily the result of enhanced precipitation. Highlights • Dated palaeochannels of the Murray-Darling basin, Australia, reveal late Quaternary hydrological history. • A regime equation based on modern rivers is used to predict palaeo-discharge. • Discharge of MIS2 and MIS3 palaeochannels was 3–270 times equivalent modern rivers. • MDB palaeochannel discharge follows Antarctic temperature, which determines catchment runoff. • Relatively larger MIS3 MDB palaeochannels require additional moisture sources. [ABSTRACT FROM AUTHOR]

Eastern Australia has a climate characterised by extreme variability and the occurrence of multiple years of drought conditions. Arguably one of the severest droughts on record - the Big Dry ended in many areas with the La Niña of 2009/2010. A succession of subsequent dry years brought a return to drought conditions across much of eastern Australia in 2018 and 2019, ending with the catastrophic fires of 2019/2020. An analysis of river gauges in eastern Australia demonstrates that unregulated rivers have been subject to reduced monthly and total annual flow for far longer than the recent multi-year droughts. A breakpoint regression model on the annual streamflow data shows statistically significant declines in total annual flow (by up to a factor of three) since 1992/93 on the far South coast of New South Wales (NSW). In the monthly data, fifteen of the nineteen gauges analysed exhibit modelled breakpoints, but with statistically significant differences in monthly mean discharge between consecutive periods only occurring in three of these gauges (occurring between 1972 and 1993 in both the North and South coast). The trend toward reduced flow over the last few decades has, for many rivers, coincided with land use and river management changes resulting in increases in woody riparian vegetation. To show this we use a remote sensing technique and estimate the magnitude of vegetation change along all major rivers and their tributaries on the eastern seaboard of NSW (28 catchments with total river length assessed of 19,750 km) using a normalized difference vegetation index (NDVI) analysis of woody vs non-woody riparian vegetation extent. Predicted vegetation change between 1987 and 2020 is spatially variable across catchments but the mean increase in woody riparian vegetation across all catchments is 9-51% (0.2 and 0.1 NDVI increases). Such increases are perhaps the largest biogeomorphic change the SE Australian drainage network has experienced since the initial clearance of vegetation associated with European colonisation in the late 18th and early 19th centuries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)