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ABSTRACT Natural flood management (NFM), a subset of nature‐based solutions (NBS) in catchment management, attempts to utilize and mimic natural processes in the landscape to reduce flood hazards, and it has been widely applied across Europe and other regions. Despite the wide use of NFM techniques, there is a lack of quantitative evidence for the effectiveness of NFM interventions in flood reduction. This paper examined 454 NFM relevant articles over the past 30 years, and the data they contain. Word frequency and cluster analyses showed changing trends and associations among nature‐based flood mitigation research topics, including shifts from localized flood mitigation to catchment‐wide flood management strategies, and from wood‐related studies to a broader assessment of ecosystem services. Content analysis was conducted on literature directly related to NFM and NBS, revealing that research in large‐scale catchments continues to be dominated by modeling approaches. While past reviews have suggested that increased catchment scale and rainfall intensity may diminish the effectiveness of NFM, we did not find strong empirical evidence (field monitoring and modeling) for this in our systematic review, although research at large catchment scale is still lacking. By assessing the confidence in NFM studies, the paper concludes that integrated understanding of a network of combined NFM interventions at a large catchment scale is necessary for future nature‐based flood mitigation strategies. [ABSTRACT FROM AUTHOR]

This study investigated potential relationships between land-use structure in the catchments of six southern Baltic coastal lakes that differ in the level of hydrological connection with the sea and the lakes' trophic states. Our results indicate that three types of catchments can be distinguished, each of which has a high contribution of agricultural areas, plus: (i) considerable contributions of wetlands and water bodies (C1); (ii) a large contribution of wooded and seminatural habitats (C2); or (iii) a considerable contribution of artificial surfaces (C3). Correlations were analysed between land-use types and single-parameter Carlson's trophic state indices of lakes (TSI Chl , TSI TP , TSI SD , TSI TOC). Type C2 clearly differed from the others and was linked with the lowest trophic state index values. The other two catchment types were similarly related to the fertility of the coastal lakes. The results show that the analysed lakes' levels of connection with the sea do not affect the trophic state of their waters. Catchment structure, analysed using CORINE Land Cover data, is significantly linked with TP and TOC values, but it does not relate to Secchi depth or chlorophyll content of water in the lakes. Wetlands (especially peat bogs) in the catchment area most strongly reduced the phosphorus and organic carbon content of lake water. Furthermore, comparable contributions of natural vs. anthropogenic components (∼1:1) are associated with a lower trophic state of water. The presented results may be important for shaping the proper management of various catchment types in the future, especially when implementing climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

Nature-Based Solutions (NbS) and ecosystem restoration are often conflated, but cannot be assumed to be identical. Understanding and choosing between these different framings is important. It affects our ambitions for reinvigorating natural systems, the range of actors and resources that can be drawn on to achieve them, and every part of how interventions are planned, delivered and appraised.To explore the differences and relationships between NbS and restoration we focus on freshwater catchment management initiatives, but our points are relevant to initiatives in other settings or framed in other terms. We firstly identify the potential differences by analysing accepted definitions of restoration and Nature-Based Solutions; and we then illustrate these with examples of catchment management in UK and Ireland, with which we are familiar from our own work and collaborations.These real-world cases demonstrate that the framings of restoration and NbS can lead to different priorities for how ecosystems and natural processes are managed; and who is involved and how projects develop. The cases also show that interventions may be somewhere on a continuum somewhere in between the two concepts, and potentially shift over time. There is often a lack of clarity over why these terms are used, causing sometimes unacknowledged confusion and potentially missed opportunities to improve catchment management.Different stakeholder groups involved in catchment management could benefit from more opportunity to explicitly reflect on preferred goals, and the implications for how to achieve this. We need more explicit reflection on the purpose of an intervention, and then different actors from site-managers to policy and other enabling groups can plan to achieve that vision. Given the time lags between interventions and outcomes, it is particularly important to use these insights in adaptive approaches to understand the changing drivers shaping current and future action.

An enduring challenge for environmental governance is how to coordinate multiple actors to achieve more collaborative and holistic management of complex socio-ecological systems. Catchment partnerships are often thought able to achieve this, so here we ask: do such partnerships actually help navigate complexity, or merely add to it? We answer this question by analysing the experiences of four voluntary UK catchment partnerships. Our data combined a structured desk-based analysis of partnership documents, with semi-structured interviews with partnership coordinators, chairs and partner representatives. These data were analysed using a qualitative thematic approach informed by the literatures on catchment management and collaborative governance of complexity. We found that partnerships both add to and help navigate the complexity of holistic and inclusive environmental management. Maintaining partnerships entails costs for partners, and partnerships connect messily and multitudinously to other initiatives. However, the partnerships were all judged as worthwhile, and made progress towards goals for water quality, biodiversity and river restoration. They were especially valued for envisioning and initiating complex activities such as Natural Flood Management. Communication and networking by partnership coordinators and partners underpinned these achievements. Aspects of pre-existing governance systems both enabled and constrained the partnerships: in particular, statutory agencies responsible for policy delivery were always important partners, and delivering partnership plans often depended on public-sector grants. This draws attention to the pervasive effect of governmentality in collaborative governance. More attention to analysing—and supporting—such partnerships is worthwhile, complemented by reflection on the limits to environmental governance in the face of complexity. [ABSTRACT FROM AUTHOR]

Representing and measuring the status of land use and land cover (LU and LC) alterations and drivers of alteration are essential for classifying susceptible regions for alteration and planning sustainable environmental services. This study presents the contributing factors of LU and LC and the extent and effects of these changes on sustainable LU in the Diyala River drainage area, north of Iraq. Five major LU and LC types (cultivated and settled land, bare land, water bodies, and palm) from Landsat images of 2013, 2016, 2019, and 2022 were mapped. The images were classified using a classification algorithm and a maximum likelihood classifier. The normalized difference vegetation index (NDVI), vegetation condition index (VCI), and land surface temperature (LST) maps are derived using multi-temporal Landsat 8 and 9 OLI/TIRS satellites. In the past decade, the buildup and barren lands have expanded from 1295.8 km2 (3.9%) to 1677.4 km2 (5.1%) and 5770.3 km2 (17.5%) to 8501.1 km2 (25.8%), whereas the vegetation cover has declined from 25,273.9 km2 (76.6%) to 22,421.8 km2 (68.0%). NDVI saw a significant rise in 2019 and 2022. There were maximum changes in NDVI in the northeast and southeast, where rainfall was higher than before in some parts. The VCI results showed that in 2022, there was a larger class area, with a prolonged extreme drought extent of 5727.1 km2 (47.8%). The findings imply that NDVI and LST are more closely correlated drought indices and are appropriate for use in arid and semi-arid areas to monitor drought with limited data. These studies will advance our knowledge of the connections between drought indices from remote sensing and meteorology. It is suggested that this research methodology be used again in the future, taking into account the impact of changes in climate that affect LU and LC patterns in similar climates. [ABSTRACT FROM AUTHOR]

The inadequate success of decades-long attempts to restore aquatic biodiversity casts doubt on the effectiveness of common top-down driven approaches that focus on ecological and socio-economic objectives alone. A way forward is engaging with the public with the aim of accounting for cultural values and local knowledge and building community buy-in to restoration and management plans. We demonstrate a values-based framework based on Multi-Criteria Decision Analysis (MCDA) to develop a management plan for the Lake Wānaka catchment, making use of the fact that Aotearoa/New Zealand mandates action plans to consider community values. The MCDA-framework successfully wove together cultural, ecological, and socio-economic values. Clearly translating values into objectives and structuring them hierarchically allowed the identification of current system deficits and management scenarios to address them. Combining the estimated effects of potential actions with the process participants' subjective preferences for high-level objectives led to a clear prioritisation of management scenarios. The elicited preferences highlighted the community's collective perspective on the relative importance of local objectives, which is an optimal basis upon which to agree on a management plan. We recommend values-based approaches such as MCDA as a way forward for inclusive freshwater co-management not only in Aotearoa/New Zealand, but elsewhere as well. Glossary of Māori Terms: Aotearoa: the Māori name for New Zealand; Hui: a meeting; Iwi: the largest tribal unit in Māoridom; Kaitiakitanga: guardianship over the sky, sea, and land; Kākahi: large freshwater mussel species including Echyridella menziezii; Kōaro: an endemic New Zealand fish species (Galaxias brevipinnis); kokopu: a group of endemic New Zealand fish species in the family Galaxiidae; mahinga kai: resources that are customarily used/harvested; mātauranga Māori: Māori knowledge; Mauri: life force or vital essence inherent in all living things; Nohoaka: seasonal occupation site; Pā: a settlement/village; Pākehā: a non-Māori New Zealander; Raupō: wetland plant (bullrush; Typha orientalis); Rūnaka: small or local tribal unit; te ao Māori: the Māori world view acknowledging the interconnectedness and interrelationship of all living and non-living things; te mana o te wai: a Māori concept that refers to the fundamental importance of water and recognises that protecting the health of freshwater protects the health and well-being of the wider environment, including people; tuna: freshwater eels indigenous to New Zealand (Anguilla dieffenbachii and Anguilla australis); important mahinga kai species; waka: canoe [ABSTRACT FROM AUTHOR]

Context. In arid and semi-arid river systems, waterholes are often the only refugia for aquatic organisms during no-flow spells. Sediment accumulation in waterholes reduces their persistence. Aims. To assess this threat, we surveyed the depth of, and dated, waterhole sediments from the Moonie River, a northern tributary of Australia's largest river system, the Murray-Darling Basin. Methods. Fine-sediment depth was determined in three of the deepest waterholes in 2010 and 2011 before, and after, the largest flood in over a century. The rate of sediment build up in two waterholes was also determined. Key results. In the deepest sections (>75th percentile depth), there was between 0.7 and 2 m of fine sediment in 2010. Following flooding, sediment depth reduced by 24-54%, with the largest proportional reductions in sediment occurring in the shallowest waterhole. However, net sediment accumulation is still 1.4-2.0 cm year-1 since the 1950s. Conclusions. Sedimentation has reduced the persistence of the deepest waterholes by over 200 days, representing an up to 30% reduction. During the longest droughts known in the Moonie River, this would dry many otherwise permanent waterholes. Implications. Sedimentation is a marked threat to waterhole persistence even following large floods. [ABSTRACT FROM AUTHOR]

Context: At present, many cities are facing severe water-resources problems caused by urbanisation. With the development of remote sensing and geostatistics, they have been widely used in urban water-resource monitoring. Aims: To review and summarise the application of remote sensing and geostatistics in monitoring urban water resources and prospect for their furtherdevelopment. Methods: First, bibliometrics was used to analyse the existing literature in this field. We then discuss the use of remote sensing and geostatistics to improve urban water-resources monitoring capacity, focusing on the classification of technologies and equipment and their applications in urban surface-water and urban groundwater monitoring. Finally, a look at the future research direction is taken. Conclusions: In the past decade, the relevant research has shown an upward trend. The use of remote sensing and geostatistics can improve the city's water-resource monitoring capacity, thereby promoting better use of water resources in cities. Implications: In the future, with the development and addition of deep learning, remote-sensing and geographic-analysis systems can be used to conduct remote-sensing monitoring and data analysis on urban water resources more accurately, intelligently, and quickly, and improve the status of urban water resources. Urbanisation leads to water-resource problems; monitoring of urban water resources is needed for urban development. This paper systematically introduces the application of geostatistics and remote sensing for monitoring urban water resources. We used bibliometrics to analyse the existing literature, discussed the use of remote sensing and geostatistics to improve urban water-resource monitoring capacity. It is obvious that improving the accuracy of urban water-resource monitoring is needed, so as to promote the city to use water resources better. [ABSTRACT FROM AUTHOR]

Temporary storage areas (TSAs) represent a category of soft‐engineered nature‐based solutions that can provide dispersed, small‐scale storage throughout a catchment. TSAs store and attenuate surface runoff, providing new additional storage during flood events. The need for such additional catchment storage will become more urgent as the frequency and magnitude of extreme hydrological events increases due to climate change. Implementation of TSAs in headwater catchments is slowly gaining momentum, but practitioners still require further evidence on how such measures function during flood events. This review focuses on the role of relatively small‐scale (<10,000 m3) TSAs in headwater catchments for flood risk management. It also explores the potential wider benefits for implementing these as part of an integrated catchment management approach. TSA flood mitigation effectiveness is primarily determined by the TSA's available storage prior to the event. At the local scale, this can be represented by the relationship between TSA inputs, outputs and total storage. Factors influencing the local functioning and effectiveness of TSAs are discussed, with potential considerations for optimizing future TSA design and management. Hydrological models have suggested that TSAs could be used to effectively attenuate high magnitude events. However, future considerations should involve addressing the lack of empirical evidence showing TSA catchment scale effectiveness and how local TSA functioning might change in time. Small‐scale headwater TSAs offer a holistic and sustainable approach to catchment management that can deliver both local benefits to landowners and wider flood risk mitigation for society. This article is categorized under:Engineering Water > Sustainable Engineering of WaterScience of Water > Water ExtremesScience of Water > Hydrological Processes [ABSTRACT FROM AUTHOR]

This study evaluated historical land-cover states in order to identify potential land-use transition regimes leading to land degradation. Landsat satellite datasets were used to characterize land-cover states for 1986–2017 period. The multinomial probability distribution was used to establish sample size for training and accuracy assessment. Using a hybrid image classification approach, individual satellite images were initially clustered using the ISODATA technique, and spectral classes later transformed posteriori into respective thematic classes. Maximum Likelihood Function was subsequently used to assign pixels into classes with highest probability. Approximately 12% of mixed forest declined, while cropland increased by 30% between 1995–2008. [ABSTRACT FROM AUTHOR]

The integration of water quality characteristics with habplot‐based habitat quality assessment score (HabQA) has received little attention in ecological quality assessment studies. This study investigated the macroinvertebrate community structure in relation with lake habitat quality and physicochemical water quality variables in Lugo Lake (Ethiopia). Twelve sampling sites (eight agricultural and four recreational) were included. The variation among macroinvertebrates data was significantly explained by HabQA score and soluble reactive phosphorus. The study revealed the greater importance of habitat quality characteristics in comparison with the other conventional physicochemical characteristics on macroinvertebrate community structure. We strongly recommend the use of HabQA system while studying macroinvertebrate community structure for a deeper understanding of the environmental functioning of tropical lakes. The results suggested the need to apply integrated and sustainable protection and management of the lake catchment (including wetlands) to enhance the ecological integrity and hence biodiversity of lakes. [ABSTRACT FROM AUTHOR]

How neighbouring aquatic and terrestrial ecosystems respond to climate change in the same area remains poorly explored, fundamentally constraining our understanding of cross‐ecosystem processes, prediction capabilities and catchment management. This study simultaneously explored how the growth of three fish species at different trophic levels and one riverbank juniper species responds to the climate in the upper Nu‐Salween River. Biochronologies and hierarchical linear mixed‐effects models were used to resolve the contribution of three sources (i.e. random, fixed intrinsic and fixed extrinsic effects) to growth variations. The optimal models explained higher percentages of the annual growth variabilities for fishes (63.1%–90.1%) than for juniper (28.2%). All the growth chronologies showed temporal variations after eliminating the fixed intrinsic effects, and for fishes, extra cohort effects were observed. Age was the major fixed intrinsic factor affecting growth variations for fishes but not for trees. All females showed clearly faster growth than males for all fishes at all ages. Among fixed extrinsic effects, temperature showed a consistent significant correlation with the growth of lower‐trophic level fishes and juniper but not with that of the higher‐trophic level fish. Only one global variable (i.e. El Niño Southern Oscillation) exerted a significant negative effect on the growth of the higher‐trophic level fish. The results suggest that fishes may be more sensitive to climate change than terrestrial trees, and the similarity in the growth response across ecosystems likely depends on trophic levels, which should be highlighted in related predictions and catchment management. [ABSTRACT FROM AUTHOR]

Approaches available for estimating the ecological impacts of climate change on aquatic communities in river networks range from detailed mechanistic models applicable locally to correlative approaches applicable globally. Among them, hydraulic habitat models (HABMs) link hydraulic models of streams with biological models that reflect how organisms select microhabitat hydraulics. Coarser but more general species distribution models (SDMs) predict changes in geographic distributions; they generally involve coarse predictors such as air temperature or distance to source but neglect proximate habitat descriptors such as microhabitat hydraulics. We propose an original application of HABM for predicting the ecological impacts of climate change at large scales, a comparison of their predictions with those of SDM and a linkage of the two modelling approaches. We showcase our approach in a large catchment (Rhône River) where an available distributed hydrological model estimates present and future unregulated daily flows over the whole river network. Despite large local uncertainties, simulations showed that climate change may strongly reduce low flow percentiles (e.g., a median reduction of 38.6% for a pessimistic climate scenario), inducing important alteration of fish hydraulic habitat suitability (e.g., a median loss of 3.9%–18.7% for three modelled fish species with contrasting habitat use: brown trout, barbel and sculpin). The HABM and SDM individually predicted consistent or opposite fish responses to climate change, depending on the species and their habitat requirements. Our results illustrate that accounting for ecological responses to proximate habitat variables such as hydraulics can strongly modify projections related to climate change. [ABSTRACT FROM AUTHOR]

Poor water quality is a widespread issue in urban rivers and streams in London. Localised pollution can have impacts on local communities, from health issues to environmental degradation and restricted recreational use of water. The Salmons and Pymmes Brooks, located in the London Borough of Enfield, flow into the River Lee, and in this paper, the impacts of misconnected sewers, urban runoff and atmospheric pollution have been evaluated. The first step towards finding a sustainable and effective solution to these issues is to identify sources and paths of pollutants and to understand their cycle through catchments and rivers. The INCA water quality model has been applied to the Salmons and Pymmes urban catchments in north-east London, with the aim of providing local communities and community action groups such as Thames21 with a tool they can use to assess the water quality issue. INCA is a process-based, dynamic flow and quality model, and so it can account for daily changes in temperature, flow, water velocity and residence time that all affect reaction kinetics and hence chemical flux. As INCA is process-based, a set of mitigation strategies have been evaluated including constructed wetland across the catchment to assess pollution control. The constructed wetlands can make a significant difference reducing sediment transport and improving nutrient control for nitrogen and phosphorus. The results of this paper show that a substantial reduction in nitrate, ammonium and phosphorus concentrations can be achieved if a proper catchment-scale wetland implementation strategy is put in place. Furthermore, the paper shows how the nutrient reduction efficiency of the wetlands should not be affected by climate change. HIGHLIGHTS Modelling urban flows and water quality in London streams is demonstrated.; Impacts of pollution, deposition and urban runoff are illustrated under future climate change.; The paper uses a dynamic process-based water quality model to assess impacts of wetlands.; Constructed wetlands can make a significant difference improving nutrient control.; Mitigation measures significantly reduce nitrate, ammonium and phosphorus.;

In this paper, nature‐based solutions (NBS) include: (1) natural flood management (NFM) interventions with a primary function of flood risk reduction but with additional multiple benefits for water quality improvements through the mitigation of diffuse pollution; and (2) ponds with a primary function of water quality improvement. This study assesses the ability of these NBS to trap pollutants in run‐off within two small (3.4 km2) agricultural catchments (Upper Thames, UK). The masses of sediment, phosphorus, and organic carbon trapped by 14 features (since construction 2–3 years previously) were quantified through sediment surveying and sampling. Streamflow and suspended sediment monitoring downstream of features enabled catchment yields to be calculated. The features trapped a total of 83 t sediment, 122 kg phosphorus, and 4.3 t organic carbon. Although the footprint of the features was <1% of the catchment area, they drained 44% of the total land area and captured the equivalent of 15% of the total suspended sediment yield, 10% of the total phosphorus yield, and 8% of the particulate organic carbon yield as monitored at the catchment outlet over the monitoring period. Results reveal that accumulation rates were influenced by hydrological connectivity, with greater accumulation in features constructed directly on streams (online ponds), and those offline features that filled from overbank flows. The low to moderate accumulation rates observed in offline features suggests that their floodwater storage potential is only likely to significantly reduce in the medium term, necessitating maintenance after ~10 years. Compared with topsoil in each contributing area, trapped sediment was enriched in phosphorus and carbon in the majority of features, having on average 50% higher phosphorus and 17% higher organic carbon concentrations than surrounding arable soils, highlighting its potential value for redistribution on farmland. Monitoring results demonstrate the potential of NBS, including NFM, to mitigate diffuse pollution in lowland catchments. [ABSTRACT FROM AUTHOR]

Context: Increasing water scarcity creates the major challenge of how to achieve environmental outcomes while meeting human water demands. In the Murray–Darling Basin, Australia, this challenge is being addressed by the Murray–Darling Basin Plan and the 'Sustainable Diversion Limit Adjustment Mechanism' (SDLAM), an offsetting program seeking to achieve environmental outcomes using less water. Aims: We provide a critique of the legislated method for evaluation of the SDLAM and the suitability of the process for evaluating whether equivalent environmental outcomes have been achieved. Methods: Four project case studies, project documentation, external reviews and relevant legislation were used to assess the implementation of the SDLAM and the evaluation method. Key results: The SDLAM evaluation method is not scientifically rigorous. It excludes residual risks, Basin-wide impacts and climate change. The evaluation timeline is biased towards measuring infrastructure outputs rather than environmental outcomes and impacts. Conclusions: Flaws in the SDLAM evaluation processes mean that environmental benefits are likely to be overstated, risking further reductions in allocations of water for the environment, contrary to the objectives of the Basin Plan. Implications: Improved evaluation, including empirical data on outputs, outcomes and impacts, is needed to ensure that conservation objectives can be met for wetlands subject to SDLAM projects. In the Murray–Darling Basin, Australia, policy-makers have implemented a program that attempts to use environmental water more effectively, allowing more water to be allocated for human uses. This program must be rigorously evaluated to ensure that the environmental benefits are not overstated. We provide a critique of the legislated method for evaluation, highlighting flaws and recommending improvements. [ABSTRACT FROM AUTHOR]

Channel banks can contribute a significant proportion of fine‐grained (<63 μm) sediment to rivers, thereby also contributing to riverine total particulate phosphorus loads. Improving water quality through better agricultural practices alone can be difficult since the contributions from non‐agricultural sources, including channel banks, can generate a 'spatial mismatch' between the efficacy of best management applied on farms and the likelihood of meeting environmental objectives. Our study undertook a reconnaissance survey (n = 76 sites each with 3 profiles sampled) to determine the total phosphorus (TP) concentrations of channel banks across England and to determine if TP content can be predicted using readily accessible secondary data. TP concentrations in adjacent field topsoils, local soil soil type/texture and geological parent material were examined as potential predictors of bank TP. Carbon and nitrogen content were also analysed to explore the impacts of organic matter content on measured TP concentrations. The results suggest that channel bank TP concentrations are primarily controlled by parent material rather than P additions to adjacent topsoils through fertilizer and organic matter inputs, but significant local variability in concentrations prevents the prediction of bank TP content using mapped soil type or geology. A median TP concentration of 873 mg kg−1 was calculated for the middle section of the sampled channel bank profiles, with a 25th percentile of 675 mg kg−1, and 75th percentile of 1159 mg kg−1. Using these concentrations and, in comparison with previously published estimates, the estimated number of inland WFD waterbodies in England for which channel bank erosion contributes >20% of the riverine total PP load increased from 15 to 25 (corresponding range of 17–35 using the 25th and 75th percentiles of measured TP concentrations). Collectively, these 25 waterbodies account for 0.2% of the total inland WFD waterbody area comprising England. [ABSTRACT FROM AUTHOR]

Natural Flood Management (NFM) and catchment-based solutions for flood risk management and environmental problems are wide-ranging and complex. Management of fluvial flood risk in the UK is undergoing a fundamental shift, with a change in emphasis from solely working with structural defences to considering catchment-based measures which attenuate flood runoff. At the heart of this change are NFM and nature-based solutions. One key type of intervention is the Runoff Attenuation Feature (RAF): a class of features that targets runoff flow pathways and creates new temporary flow storage (such as ponds and leaky barriers). However, there is currently a lack of evidence for the effectiveness of NFM and RAFs at larger catchment scales and for managing extreme flood events. Nevertheless, there is a strong evidence base to suggest that well-designed RAFs deliver a range of ecosystem services if installed in the correct location. This paper reviews and critiques the role of RAFs and NFM as an interventionist and holistic approach to lowering runoff rates. The link between RAF design types and their relationship to land use and scale is made. Recent novel innovations and attempts to scale up RAFs are discussed. The role of antecedent conditions, groundwater and the change in residence time of processes is highlighted. The uncertainty and complexity of proving NFM effectiveness underpin a view that new thinking in catchment flood management is needed. New research is required, and many questions are raised about RAFs and NFM. The direction of travel is that a positive and proactive NFM community can now embrace the problem. Proof that RAFs and NFM can address flood management is not likely to be resolved without a great deal of further research but confidence that RAFs do beneficial work is growing and an argument for greater amounts of runoff attenuation is made. [ABSTRACT FROM AUTHOR]

Freshwater catchments can experience nutrient deficits that result in reduced primary and secondary productivity. The most commonly limiting nutrients are nitrogen and phosphorus, either separately or together. This review considers the impact of increasing nutrient limitation in temperate basin stream and river systems, focusing on upland areas that currently or previously supported wild Atlantic salmon (Salmo salar) populations.Anthropogenic changes to land use and increases in river barriers have altered upland nutrient dynamics, with particular impacts on salmon and other migratory fish species which may be net importers of nutrients to upland streams. Declining salmon populations may further reduce nutrient sources, reducing ecosystem and fisheries productivity below desired levels.Experimental manipulations of nutrient levels have examined the impacts of this cultural oligotrophication. There is evidence that growth and biomass of juvenile salmon can be increased via appropriate additions of nutrients, offering potential as a conservation tool. However, further research is required to understand the long‐term effects of these additions on salmon populations and stream ecosystems, and to assess the vulnerability of downstream habitats to eutrophication as a result.Although purposeful nutrient addition with the aim of enhancing and conserving salmonid populations may be justified in some cases, it should be undertaken in an adaptive management framework. In addition, nutrient addition should be linked to nutrient retention and processing, and integrated into large‐scale habitat restoration and recovery efforts.Both the scientific and the management community should recognize that the ecological costs and benefits associated with adding nutrients to salmon streams may change in a non‐stationary world. [ABSTRACT FROM AUTHOR]

This paper reports soil moisture spatio-temporal variability as influenced by catchment management in the Blue Nile Highlands, Ethiopia. The study was motivated by the need to support the mainstreaming of water security into improved catchment management initiatives. The specific objectives are to (1) determine major environmental factors influencing soil moisture spatio-temporal variability, (2) assess soil moisture spatio-temporal variability under traditional and improved catchment management conditions, and (3) understand the implication of improving catchment management for improving water security. Soil moisture and weather data were monitored intensively between 2017 and 2018 in a pair of agricultural catchments receiving traditional and improved management. A range of factors was found to contribute to soil moisture spatio-temporal variability in the study catchments, including rainfall, air temperature, relative humidity, antecedent soil moisture content, elevation, measurement depth, groundwater table, and catchment management. Soil moisture daily variation was strongly influenced by air temperature, rainfall, relative humidity, and antecedent soil moisture content, whereas soil moisture seasonal fluctuation was controlled by rainfall seasonal pattern. Of all experimental sites, the highest elevation (2032 m) presented the driest soil moisture regime (0.104 m3 m−3) while the lowest elevation (1965 m) displayed the moistest soil moisture regime (0.369 m3 m−3). The results demonstrated that improved catchment management has modified soil moisture response in the treated catchment, reducing soil moisture spatial heterogeneity and temporal variability. We conclude that improved catchment management can play a crucial role for improving agricultural water security in rainfed systems by improving soil moisture availability and storage. [ABSTRACT FROM AUTHOR]

Poor water quality is a widespread issue in urban rivers and streams in London. Localised pollution can have impacts on local communities, from health issues to environmental degradation and restricted recreational use of water. The Salmons and Pymmes Brooks, located in the London Borough of Enfield, flow into the River Lee, and in this paper, the impacts of misconnected sewers, urban runoff and atmospheric pollution have been evaluated. The first step towards finding a sustainable and effective solution to these issues is to identify sources and paths of pollutants and to understand their cycle through catchments and rivers. The INCA water quality model has been applied to the Salmons and Pymmes urban catchments in north-east London, with the aim of providing local communities and community action groups such as Thames21 with a tool they can use to assess the water quality issue. INCA is a process-based, dynamic flow and quality model, and so it can account for daily changes in temperature, flow, water velocity and residence time that all affect reaction kinetics and hence chemical flux. As INCA is process-based, a set of mitigation strategies have been evaluated including constructed wetland across the catchment to assess pollution control. The constructed wetlands can make a significant difference reducing sediment transport and improving nutrient control for nitrogen and phosphorus. The results of this paper show that a substantial reduction in nitrate, ammonium and phosphorus concentrations can be achieved if a proper catchment-scale wetland implementation strategy is put in place. Furthermore, the paper shows how the nutrient reduction efficiency of the wetlands should not be affected by climate change. [ABSTRACT FROM AUTHOR]

The earthquake that occurred on 6 September 2018, in the eastern part of the Iburi region of Hokkaido, Japan (the Hokkaido Eastern Iburi Earthquake) caused thousands of shallow landslides in mountain areas. In areas where many landslides occurred, the trees on the slope became large woody debris (LWD) and were supplied to the catchment. Understanding the properties of LWD during the earthquake and its subsequent movement after the earthquake are important to manage the produced LWD and implement disaster prevention measures. This study evaluates the risk of future LWD disasters based on the sequence of LWD generation, its spatial distribution, and LWD relocation linked to temporal fluctuations in rainfall events. The study site is the upper Habiu River catchment (0.37 km2), where multiple shallow earthquake-related landslides occurred. Orthophotos and elevation data acquired before and after the earthquake were used to detect the properties of LWD. To evaluate the risk of an LWD disaster, we examined the correspondence between the hydraulic quantities, including the precipitation for 2 years after the earthquake and the water depth. It was estimated that approximately 7,000 LWD pieces (9,119 m3 km−2) were produced during the earthquake. Orthophoto interpretations indicate that over 80% of the LWD produced at the time of the landslide moved from the slope to the channel accompanied by the landslide debris; some of that then flowed down, accumulated, and formed logjams. In the river channel approximately two years after the earthquake, the destruction of logjams and the clear and drastic movement of LWD could not be confirmed. In this catchment, the uneven LWD distribution and the formation of logjams were fixed almost immediately after the landslide at the time of the earthquake; these characteristics are important when considering future actions. The water depth evaluation based on the difference in the excess return period indicate that the degree of risk differs depending on the deposition location in the channel. This suggests that not all LWD in the catchment are dangerous and that a risk assessment focusing on the LWD location can be effective. This study also makes it possible to determine high priority areas for LWD treatment.

Flow–ecology relationships within river systems are an important area of ongoing investigation, because of potential applications such as understanding the ecological impact of flow alteration at modified sites. This study analyses relationships between flow characteristics and benthic macroinvertebrates from 18 streams of similar size and typology within Northern England, to develop quantitative flow–ecology relationships applicable at regional scale. High and low flow event frequencies displayed statistically significant relationships with the ecological metrics of LIFE Score, Shannon's Diversity and a velocity flow affinity trait score. Results suggest that flow event frequencies have a significant role in influencing ecology within the river network system. Hence, this indicates that future flow regime design in the region may be enhanced if this variable is considered. [ABSTRACT FROM AUTHOR]

Using ecosystem services provided by stream buffers has the potential to complement conventional engineering solutions, such as water treatment, and reduce public health risks to consumers. These buffers interrupt the movement of contaminants and sediments from non-point sources such as agricultural land to surface waters. This study uses System Theoretic Process Analysis (STPA) and Early Warning Signal Analysis based on STPA (EWaSAP) methodologies to systematically examine the sociotechnical structures involved in managing vegetated buffers in surface water catchments using a theoretical scenario representative of typical surface water supplies.

Novel data-intelligence models developed through hybridization of an adaptive neuro-fuzzy inference system (ANFIS) with different metaheuristic algorithms, namely grey wolf optimizer (GWO), particle swarm optimizer (PSO) and whale optimization algorithm (WOA), are proposed for daily river flow prediction of the Taleghan River, which is the major source of potable water for Tehran, the capital of Iran. Gamma test (GT) was used for the determination of input variables for the models. The ANFIS-WOA model was found to exhibit the best performance in prediction of river flow according to root mean square error (RMSE ≈ 3.75 m3.s−1) and Nash-Sutcliffe efficiency (NSE ≈ 0.93). It improved the prediction performance of the classical ANFIS model by 6.5%. The convergence speed of ANFIS-WOA was also found to be higher compared to other hybrid models. The success of the ANFIS-WOA model indicates its potential for use in the simulation of highly nonlinear daily rainfall–runoff relationships. [ABSTRACT FROM AUTHOR]

Dam construction threatens global aquatic biodiversity by fragmenting stream networks and altering flow regimes. The negative effects of dams are exacerbated by increased drought periods and associated water withdrawals, especially in semi‐arid regions. Stream fishes are particularly threatened owing to their mobile nature and requirement for multiple habitats to complete their life cycles. An understanding of relationships with fragmentation and flow regimes, particularly as coarse‐scale (e.g. catchment) constraints on species distributions, is essential for stream fish conservation strategies.Prairie chub (Macrhybopsis australis) is a small‐bodied minnow (Cyprinidae) with poorly understood ecology endemic to the North American Great Plains. Suspected declines in abundance and extirpations have resulted in conservation interest for prairie chub at state and federal levels. Prairie chub is thought to share its reproductive strategy with pelagic‐broadcast spawning minnows (pelagophils). Freshwater pelagic‐broadcast spawning fishes have been disproportionately affected by fragmentation and streamflow alteration globally.Relationships of prairie chub occurrence with coarse‐scale fragmentation and streamflow metrics were examined in the upper Red River catchment. Occurrence probability was modelled using existing survey data, while accounting for variable detection. The modelled relationships were used to project the distribution of prairie chub in both a wet and dry climatic period.The probability of prairie chub occurrence was essentially zero at sites with higher densities of upstream dams, but increased sharply with increases in flow magnitude, downstream open mainstem, and flood duration. The projected distribution of prairie chub was broader than indicated by naïve occurrence, but similar in both climatic periods. The occurrence relationships are consistent with the hypotheses of pelagic broadcast spawning and represent coarse‐scale constraints that are useful for identifying areas of the stream network with higher potential for finer‐scale prairie chub conservation and recovery efforts. In addition to informing pelagophil conservation, the relationships are also applicable to pelagic‐broadcast spawning fishes in marine environments. [ABSTRACT FROM AUTHOR]

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• Mining results in reduced surface water flows and losses from peatland storage. • Observed impacts may be irreversible, with severe ecological implications. • Water management policy should implement guidelines to limit water loss from peatlands. Peatlands cover about 3% of the Earth's land surface, but are the largest terrestrial carbon store and are important for freshwater storage. In Australia, nationally protected peatlands (called upland swamps) exist in the catchment headwaters for Sydney's drinking water supply. In this region, longwall mining of underground coal seams can result in subsurface fracturing, land subsidence, and, potentially, peatland drainage. This study presents the water balance modelling results for an upland peat swamp before and after it was undermined in 2020. Following a detailed field campaign, a conceptual lumped hydrology model was developed to estimate the local water balance, with a Nash Sutcliffe Efficiency of 0.85 for the modelled storage of the intact swamp. After undermining, the water balance of the swamp changed, with higher deep seepage rates and reduced surface water discharge rates. For the first time, these findings detail the hydrologic effects of longwall mining on peatland environments. Based on these findings, broader catchment management initiatives are recommended to prevent or limit further water extraction from upland swamps, including incidental water losses associated with subsidence. [ABSTRACT FROM AUTHOR]

Abstract The Montseny brook newt (Calotriton arnoldi) is a critically endangered amphibian species which inhabits a small 20 km2 holm oak and beech forest area in NE Spain. Calotriton arnoldi strictly lives in running waters and might be highly vulnerable to hydrological perturbations expected to occur under climate and vegetation cover changes. Knowledge about the potential response of the species habitat to environmental changes can help assessing the actions needed for its conservation. Based on knowledge of the species and supported by observations, we proposed daily low and high streamflow event thresholds for the viability of C. arnoldi. We used the rainfall–runoff model PERSiST to simulate changes in the frequency and duration of these events, which were predicted under two climate and four vegetation cover scenarios for near‐future (2031–2050) and far‐future (2081–2100) periods in a reference catchment. All future scenarios projected a significant decrease in annual streamflow (from 21% to as much as 67%) with respect to the reference period. The frequency and length of low streamflow events will dramatically increase. In contrast, the risk of catastrophic drift linked to high streamflow events was predicted to decrease. The potential change in vegetation toward an expansion of holm oak forests will be more important than climate changes in determining threshold low flow conditions. We thus demonstrated that consideration of potential changes in vegetation and not only changes in climate variables is essential in simulating future streamflows. This study shows that future low streamflow conditions will pose a severe threat for the survival of C. arnoldi and may help taking management actions, including limiting the expansion of holm oak forest, for ameliorating the species habitat and help its conservation.

Effective implementation of drinking water source protection (DWSP) programmes relies on a range of factors working successfully for the effective protection of water quality. The objective of this research is to develop a weighted scoring framework for assessing the controls applied to risk management in DWSP programmes. The proposed scoring framework for DWSP programmes robustness is based on statistical analysis and pairwise comparisons of the perceptions of DWSP experts and professionals in Taiwan, Australia, and Greece on the importance of the control measures for the hazards involved in managing DWSP programmes. The scores show that although there is consistent opinion on factors for robustness of DWSP programmes, respondents' background such as country significantly influences how effectively the factors are achieved. The systems in place for DWSP can be complex, and this approach provides a way of assessing the robustness of the programmes for protecting water quality under differing jurisdictional arrangements. [ABSTRACT FROM AUTHOR]

Constructed farms wetlands (CFWs) are increasingly being used to treat faecally contaminated 'dirty waters' from yard areas on livestock farms. The findings of the present study, undertaken at the Pwllpeiran experimental CFW, West Wales, provide empirical data on the effectiveness of CFWs in attenuating faecal indicator organism (FIO) concentrations and fluxes to the receiving waters to which they discharge; and insight into the extent to which attenuation rates are affected by retention times within the CFW and seasonal factors. Based on the maximum flows that a CFW is being designed to treat, an equation is developed to enable estimates to be made of the size of wetland required to achieve a desired level of FIO attenuation. Other aspects of CFW design to optimise FIO attenuation are considered, including the construction of frequent baffles (transverse ridges), leaving parts of cells unvegetated and incorporating an initial settling pond. [ABSTRACT FROM AUTHOR]

In this study, the Hydrological Simulation Programme‐FORTRAN (HSPF) and the Water Quality Analysis Simulation Programme (WASP), were adopted as a combined tool. The long Feitsui impounding reservoir located in Taiwan was used as a case study. The combined model helped illustrate the total phosphorus (TP) mass balance. Approximately 51.4% of the TP flowed out from the reservoir, while 16.2% of the TP remained in the waterbody and 32.2% of the TP was deposited. The reservoir was divided into five sections along its length for a quality analysis. The exceedance probability (the probability of exceeding the eutrophic level, i.e., TP = 24 μg/L) was 9.7% in the upstream section. If the TP load increased by 20%, the eutrophication exceedance probability could increase to 25.5%. This study demonstrated the usage of the combined model tool and the exceedance probability method in the data analysis, which could guide effective catchment management and eutrophication risk prevention. [ABSTRACT FROM AUTHOR]

Few conservation studies have examined fish communities in entire drainage basins, especially in developing regions such as Southeast Asia, one of the most diverse biomes globally. The aim of this study was to establish conservation projections for the whole of the Irrawaddy River system, based on fish diversity patterns, human impact, and environmental change.The Irrawaddy River is one of the five largest rivers in Southeast Asia. Although it has very high diversity of fish species and species endemism, our understanding of resident fish status remains poor.Based on 1,726 field survey and 1,056 database records, 470 fish species and their distribution patterns (i.e. alpha, beta, threatened species, and endemic species diversities) in sub‐basins of the Irrawaddy drainage were identified. Canonical correspondence analysis of diversity and environmental patterns indicated that climatic factors had the largest effect on diversity, compatible with the species–energy theory.Fish conservation priorities of sub‐basins were evaluated based on diversity patterns and human impact. The delta and Manipur basin regions were highlighted as areas of focus for future fish diversity conservation, and the importance of connectivity in the Irrawaddy main stem was demonstrated.The results of this study will be valuable for future management of the Irrawaddy basin and as a reference for other river basins when implementing protection strategies for fish diversity. This study also advocates the need for systematic investigations across entire drainage basins and further detailed studies on the ecological conditions of poorly studied river systems. [ABSTRACT FROM AUTHOR]

Embayments and the biota they support are highly susceptible to disturbance within adjacent catchments. Examining the timing and magnitude of impacts arising from human-induced disturbance in these systems is often limited due to the absence of long-term monitoring. Moreton Bay in south-eastern Queensland is a shallow embayment that receives inflows from a 21 220-km2 catchment. In this study, diatom abundances, pigment (chlorophyll-a, phaeopigments) and biogenic silica concentrations were evaluated in a composite sediment from central Moreton Bay to explore temporal trends in the photosynthetic community. The record extends from 1200 to 2011, incorporating the period of European settlement (c. 1840s) and rapid population growth and urbanisation of the catchment. The record shows that in central Moreton Bay bloom-forming marine diatoms (Thalassiosira, Thalassiothrix, Thalassionema) have increased in relative abundance since the mid-20th century, whereas the dominant benthic diatom (Paralia fenestrata) has declined. This transition most likely occurred in response to the compounding effects of increased delivery of nitrogen, fine sediments and pollutants to Moreton Bay as a consequence of changes in land use. The inferred historical decline in relative contributions of benthic microalgae to total primary production in central Moreton Bay has likely had wide-ranging ecological effects. [ABSTRACT FROM AUTHOR]

The Amazon River basin contains a vast diversity of lotic habitats and accompanying hydrological regimes. Further understanding the spatial distribution of flow regimes across the Amazon can be useful for recognizing riverine ecohydrological processes and informing river management and conservation, especially in areas with limited or inconsistent streamflow monitoring.This study compares four inductive approaches for classifying streamflow regimes across the Amazon using an unprecedented compilation of streamflow records from Bolivia, Brazil, Colombia, Ecuador, and Peru.Inductive classification schemes use attributes of streamflow data to categorize river reaches into similar classes, which then may be generalized to understand streamflow behaviour at the basin scale. In this study, classification was accomplished through hierarchical clustering of 67 flow metrics calculated using indicators of hydrologic alteration (IHA) and daily streamflow data from median annual hydrographs (MAHs) for 404 stations (representing >7,000 station‐years) across five Amazonian countries.Classification was performed using both flow magnitude‐inclusive and flow magnitude‐independent datasets. For flow magnitude‐independent methods, optimal solutions included six or seven primary hydrological classes for IHA and MAH datasets; for approaches that retained magnitude, variance was sufficiently large to prevent convergence to a specific number of classes.Across methods, class membership was strongly associated with the timing, frequency, and rate of change of flow, and spatially coherent clusters were associated with seasonal, elevational, and stream‐order gradients. These results highlight the diversity of flow regimes across the Amazon and provide a framework for studying relationships between hydrological regimes and ecological responses in the context of changing climate, land use, and human‐induced hydrological alteration.The methodology applied provides a data‐driven approach for classifying flow regimes based on observed data. When coupled with ecological knowledge and expertise, these classifications can be used to develop ecohydrologically informed and management‐relevant conservation practices. [ABSTRACT FROM AUTHOR]

The use of socioeconomic and cultural parameters in the assessment and biomonitoring of ecological health of aquatic ecosystems is still in its nascent stages. Yet, degradation of aquatic ecosystems has elicited concerns because of its bearing on social and economic development of communities consisting of marginalized and vulnerable groups, as well as the expenses and technical knowhow involved in biomonitoring approaches. In this study we developed a Citizen-based Index of Ecological Integrity (CIEI) for assessing and monitoring the ecological status of vulnerable African riverine ecosystems in Lake Victoria Basin, Kenya. The hypothesis is that the citizen-led socioeconomic and cultural metrics provides a more cost-effective broad view of ecosystems than other biomonitoring methods in the assessment of water resources in the developing countries. Selected rivers in the southern part of Lake Victoria (Rivers Kuja and Sondu-Mirui) recorded the highest CIEI than their northern counterparts (Rivers Yala and Nzoia) that had moderate to poor ecosystem integrities. The study demonstrates the usefulness of this approach to elucidate the source of impairment, the extent of impacts and provide a justifiable rationale to advice policy makers on developing guidelines for conservation and management of aquatic ecosystems. We recommend for adoption and promotion of the CIEI perspective in areas where such approaches appear defensible for the assessment of catchment-wide practices in areas with robust indigenous knowledge to provide a broad-view of the ecological health of the aquatic ecosystem.

As its name would suggest, landscape architecture has, by definition, a relationship to land. This relationship varies between the prosaic – as a “steward” of the land – and the pragmatic – as a designer of it. However, while it often views land broadly in landscape planning and landscape ecological terms, its real agency is limited by a factor that it rarely considers: land tenure. The contradiction between large-scale ecological functioning and the limitations of the building lot is the basis for this paper. Reflecting broader societal conceptions of land, inflected by the way the discipline operates, in this paper I work through a series of conceptions of “land” for landscape architecture: Land AS Boundary; Land AS Pattern; Land AS Surface, and Land AS Depth. In doing so, I seek to demonstrate how each of these geometric descriptors sits within the frame of land tenure and larger land-management practices, generally in ways that contradict the values of the discipline. Ultimately, I conclude by proposing changes in both practice and future areas of theorization about the relationship between landscape architecture and land tenure specifically, toward which I aim to contribute.

Abstract Background There is a substantial interest in the values that consumers place on drinking water quality and supply. Financial resources are crucial to improving the urban potable water supply in developing countries that are characterized by low-cost recovery rates and a high and rapidly growing demand for more reliable services. This study examined households’ willingness to pay (WTP) for the improvement of water services by identifying their water choice decisions and the mode of water supply that they prefer the water supply authority to use among several alternative water supply options. Stated-preference data were collected from 322 randomly selected households in Addis Ababa, who were presented with three sets of choices (three alternative bundle choices, including the reference scenario). The data were analyzed using the mixed logit WTP space model. Three approaches to modeling the distribution of WTP (fixed, uncorrelated, and correlated) using mixed logit WTP space models were compared. Results Three-quarters of the households agreed to contribute money toward ecosystem-based water supply management (EBWSM) intervention programs on a monthly basis. The average contribution that the respondents were willing to pay was 150.5 Ethiopian Birr (ETB) as a one-off lump sum to kick off the EBWSM activities. Most of the respondents chose a bundle of water supply options that provides risk-free and high-quality water with no months of shortages than moderate water quality that is safe to drink and palatable with 1 month shortages annually. This implies that households would need to be supplied with risk-free, high-quality water without interruption at an appropriate flow pressure. The model with correlations fitted the data well with the highest simulated log-likelihoods at convergence and gave the best estimate of the households’ WTP for water improvement. Nearly 46% of the sampled households were willing to pay more than 33 ETB per month, and 49% of the households were willing to pay between 21 ETB and 33 ETB per month for the monthly water bill. Overall, approximately 95% of the sampled households were willing to pay more than 21 ETB. Conclusion Customers are willing to pay to avoid most types of water supply restrictions. Moreover, WTP is sensitive to the scope of service improvement, income, affixed price, and elicitation method. In summary, mixed logit WTP-space models can help accurately predict household-level WTP, which can be used to select improvements in drinking water access and services in the Legedadie-Dire catchments.