Large Catchment Research Articles

Factors affecting the presence of Arctic charr in streams based on a jittered binary genetic programming model

Arctic charr is one of the fish species most sensitive to climate change but studies on their freshwater habitat preferences are limited, especially in the fluvial environment. Machine learning methods offer automatic and objective models for ecohydrological processes based on observed data. However, i) the number of ecological records is often much smaller than hydrological observations, and ii) ecological measurements over the long-term are costly. Consequently, ecohydrological datasets are scarce and imbalanced. To address these problems, we propose jittered binary genetic programming (JBGP) to detect the most dominant ecohydrological parameters affecting the occurrence of Arctic charr across tributaries within the large subarctic Teno River catchment, in northernmost Finland and Norway. We quantitatively assessed the accuracy of the proposed model and compared its performance with that of classic genetic programming (GP), decision tree (DT) and state-of-the-art jittered-DT methods. The JBGP achieves the highest total classification accuracy of 90% and a Heidke skill score of 78%, showing its superiority over its counterparts. Our results showed that the dominant factors contributing to the presence of Arctic charr in Teno River tributaries include i) a higher density of macroinvertebrates, ii) a lower percentage of mires in the catchment and iii) a milder stream channel slope.

The Heavy Mineral Map of Australia: Vision and Pilot Project

We describe a vision for a national-scale heavy mineral (HM) map generated through automated mineralogical identification and quantification of HMs contained in floodplain sediments from large catchments covering most of Australia. The composition of the sediments reflects the dominant rock types in each catchment, with the generally resistant HMs largely preserving the mineralogical fingerprint of their host protoliths through the weathering-transport-deposition cycle. Heavy mineral presence/absence, absolute and relative abundance, and co-occurrence are metrics useful to map, discover and interpret catchment lithotype(s), geodynamic setting, magmatism, metamorphic grade, alteration and/or mineralization. Underpinning this vision is a pilot project, focusing on a subset from the national sediment sample archive, which is used to demonstrate the feasibility of the larger, national-scale project. We preview a bespoke, cloud-based mineral network analysis (MNA) tool to visualize, explore and discover relationships between HMs as well as between them and geological settings or mineral deposits. We envisage that the Heavy Mineral Map of Australia and MNA tool will contribute significantly to mineral prospectivity analysis and modeling, particularly for technology critical elements and their host minerals, which are central to the global economy transitioning to a more sustainable, lower carbon energy model.

Quantitative Attribution Analysis of the Spatial Differentiation of Gully Erosion in the Black Soil Region of Northeast China

Gully erosion is the major soil erosion type in the black soil region of Northeast China. However, studies on multifactor synthesis at a large scale and on the driving mechanism of spatial differentiation are still relatively lacking for gully erosion in this region. In this study, the simulation of gully erosion and its quantitative attribution analysis have been conducted in the Sancha River catchment in Northeast China, based on high-resolution satellite imagery mapping and the geodetector method. A total of 18 indicators in 6 categories, including topography, climate and weather, soil properties, lithology, land use, have been taken into consideration. The influence of each influencing factor and its interactive influence on gully erosion were quantitatively evaluated. The results showed that at the large catchment scale, the submeter images had a strong capacity for the recognition of a permanent gully and obtained satisfactory results. According to the results of the geodetector, lithology and soil type are the main factors that affect the spatial differentiation of gully erosion in the Sancha River basin, because their interpretation power for gully density and gully intensity was close to 10%. The lithology belonged to gray–white matter rhyolite, spherulite rhyolite, and crystal clastic tuff, with the highest gully density and intensity. The interpretation power of the secondary factors, including rainfall erosivity, watershed area, elevation, soil erodibility, land use pattern, slope, and distance from the river, amounted to more than 1%. The interactions among most driving factors showed nonlinear enhancement. The influence of the interaction between lithology and soil type appeared to be the largest. In particular, the lithology of different soil types accounted for 28.7% and 32.5% of the gully density and gully intensity. The interaction of factors had a stronger influence on the spatial differentiation of gully erosion than any single factor.

Numerical Experiments on Low Impact Development for Urban Resilience Index

Low impact development (LID) has become one of the strategies that effectively mitigate the impacts of climate change. In addition to the ability to reduce nonpoint source (NPS) pollution caused by flash floods from the surface runoff, LID has also been applied to control water quantity under extreme rainfall events. Due to the fact that studies about LID configuration optimization tended to control water quantity and gradually ignored the main functions of water quality treatment, this study aims to consider water quantity and quality to estimate the benefits and optimal configuration of LID by Non-Dominated Genetic Algorithm (NSGA-II). In addition, regarding to the outlet peak flow, hydrologic footprint residence (HFR) was considered to be the water quantity indicator due to the ability to represent the dynamics of flow changes, and the modified quality indicator (Mass Emission First Flush ratio, MEFF30) was corrected to represent the pollutant transport process in a large catchment area. The results show that the flood and MEFF30 reduction rate of LID are inversely proportional to rainfall duration and intensity. The benefit of pollutant reduction, which can still be maintained by 20% and 15% under a big return period and the long duration was about three times than the quantity control. Taking the cost into account, although the rain barrel had the best effect of reduction per unit area, green roofs and permeable pavements had a higher unit cost reduction rate due to the lower costs. The upper and middle reaches of the open channel and the confluence of rainwater sewers should be the optimal LID configuration to achieve the benefits of both flood and pollution reduction.

<i>Escherichia coli</i> concentration, multiscale monitoring over the decade 2011–2021 in the Mekong River basin, Lao PDR

Abstract. Bacterial pathogens in surface waters may threaten human health, especially in developing countries, where untreated surface water is often used for domestic needs. The objective of the long-term multiscale monitoring of Escherichia coli ([E. coli]) concentration in stream water, and that of associated variables (temperature (T), electrical conductance (EC), dissolved oxygen concentration ([DO]) and saturation (DO%), pH (pH), oxidation-reduction potential (ORP), turbidity (Turb), and total suspended sediment concentration ([TSS])), was to identify the drivers of bacterial dissemination across tropical catchments. This data description paper presents three datasets (see “Data availability” section) collected at 31 sampling stations located within the Mekong River and its tributaries in Lao PDR (0.6–25 946 km2) from 2011 to 2021. The 1602 records have been used to describe the hydrological processes driving in-stream E. coli concentration during flood events, to understand the land-use impact on bacterial dissemination on small and large catchment scales, to relate stream water quality and diarrhea outbreaks, and to build numerical models. The database may be further used, e.g., to interpret new variables measured in the monitored catchments, or to map the health risk posed by fecal pathogens.

Effects of alder- and salmon-derived nutrients on aquatic bacterial community structure and microbial community metabolism in subarctic lakes.

Alder (Alnus spp.) and Pacific salmon (Oncorhynchus spp.) provide key nutrient subsidies to freshwater systems. In southwestern Alaska, alder-derived nutrients (ADNs) are increasing as alder cover expands in response to climate warming, while climate change and habitat degradation are reducing marine-derived nutrients (MDNs) in salmon-spawning habitats. To assess the relative influences of ADN and MDN on aquatic microbial community structure and function, we analyzed lake chemistry, bacterial community structure, and microbial metabolism in 13 lakes with varying alder cover and salmon abundance in southwestern Alaska. We conducted bioassays to determine microbial nutrient limitation and physical factors modulating microbial response to nutrient inputs (+N, +P and +NP treatments). Seasonal shifts in bacterial community structure (F = 7.47, P < 0.01) coincided with changes in lake nitrogen (N) and phosphorus (P) concentrations (r2 = 0.19 and 0.16, both P < 0.05), and putrescine degradation (r2 = 0.13, P = 0.06), suggesting the influx and microbial use of MDN. Higher microbial metabolism occurred in summer than spring, coinciding with salmon runs. Increased microbial metabolism occurred in lakes where more salmon spawned. Microbial metabolic activity was unrelated to alder cover, likely because ADN provides less resource diversity than MDN. When nutrients were added to spring samples, there was greater substrate use by microbial communities from lakes with elevated Chl a concentrations and large relative catchment areas (β estimates for all treatments > 0.56, all P < 0.07). Thus, physical watershed and lake features mediate the effects of nutrient subsidies on aquatic microbial metabolic activity.

Spring waters as an indicator of nitrate and pesticide pollution of rural watercourses from nonpoint sources: results of repeated monitoring campaigns since the early 2000s in the low mountain landscape of Saarland, Germany

BackgroundSpring waters, which are fed mainly by near-surface groundwater, provide a comprehensive picture of emissions of nitrate and other pollutants caused by the type and intensity of land use in the topographic catchment area. One aim of this study was to develop a model for predicting the contribution of nonpoint-source inputs to the nitrate load of small- and medium-sized watercourses based on the type of agricultural use in the catchment areas.MethodsFifty-five springs in the German Land Saarland and the adjacent Rhineland-Palatinate were monitored for pollutants during three monitoring periods of at least 12 months between 2000 and 2019. The catchment areas are representative of the natural regions in the study area and are outside the influence of settlements and other developments. In addition to nitrate and other physicochemical parameters, 25 agriculturally impacted springs were screened for pesticides and their metabolites.ResultsSince the first measurements were taken in 2000, the vast majority of agriculturally impacted springs have consistently exhibited high nitrate concentrations of between 20 and 40 mg/L NO3−. Springs not influenced by agriculture contained an average of 3.6 mg/L nitrate. The extreme values observed in the early 2000s decreased to the limit value of 50 mg/L, but most of the springs with moderate levels exhibited an increase to approximately 30 mg/L. The number of pesticidal agents detected in the spring waters demonstrated a clear correlation with the watershed’s amount of arable land and the nitrate content detected. Moreover, we found a highly significant correlation between nitrate content and the share of cropland in the catchment area. From this, we derived a regression model that could be used to quantify the share of nitrate pollution attributable to nonpoint-source inputs for larger catchments in the region under investigation.ConclusionNitrate discharged from farmland has not decreased since the European Water Framework Directive (EU WFD) entered into force. At the historically extremely heavily polluted sites, measures have been implemented that have led to compliance with the limit value of the Nitrate Directive. However, below this limit, nitrate levels have increased significantly almost everywhere in the last two decades. We therefore recommend introducing stricter requirements for official water pollution control, such as the marine ecological target value.

Variability and changes in hydrological drought in the Volta Basin, West Africa

Study regionVolta River Basin, West Africa Study focusHydrological droughts have a wide range of impacts on societies and economic sectors such as agriculture and energy production. Analysis of hydrological droughts helps better plan and manage water resources under global change. This study analyses the spatial and temporal variability of hydrological drought occurrence (duration and severity) in the Volta River basin during 1979–2013. We used the Variable Infiltration Capacity and vector-based routing (RAPID) models and high-resolution forcing data to simulate streamflow for 10300 river reaches. New hydrological insights for the regionDrought duration and severity show high spatial variability and large differences between the three decades (1980 s, 1990 s and 2000 s). Droughts are more severe in larger catchments as the flows are generally higher. The trend analysis shows a general decreasing trend (up to 5% per event) in drought duration in the north-eastern and an increasing trend in southern parts of the basin. Drought severity shows an increasing and decreasing trend (up to ± 20%) in south and north part of the basin, respectively. Daily streamflow has a maximum correlation (up to 0.78) with upstream precipitation for the previous 30-days with a clear signal of propagation from meteorological to hydrological drought with an average lag-time of two weeks. The results indicate the need to consider site-specific and adaptive drought management measures to minimize the impacts.

Evaluating the impact of post-processing medium-range ensemble streamflow forecasts from the European Flood Awareness System

Abstract. Streamflow forecasts provide vital information to aid emergency response preparedness and disaster risk reduction. Medium-range forecasts are created by forcing a hydrological model with output from numerical weather prediction systems. Uncertainties are unavoidably introduced throughout the system and can reduce the skill of the streamflow forecasts. Post-processing is a method used to quantify and reduce the overall uncertainties in order to improve the usefulness of the forecasts. The post-processing method that is used within the operational European Flood Awareness System is based on the model conditional processor and the ensemble model output statistics method. Using 2 years of reforecasts with daily timesteps, this method is evaluated for 522 stations across Europe. Post-processing was found to increase the skill of the forecasts at the majority of stations in terms of both the accuracy of the forecast median and the reliability of the forecast probability distribution. This improvement is seen at all lead times (up to 15 d) but is largest at short lead times. The greatest improvement was seen in low-lying, large catchments with long response times, whereas for catchments at high elevation and with very short response times the forecasts often failed to capture the magnitude of peak flows. Additionally, the quality and length of the observational time series used in the offline calibration of the method were found to be important. This evaluation of the post-processing method, and specifically the new information provided on characteristics that affect the performance of the method, will aid end users in making more informed decisions. It also highlights the potential issues that may be encountered when developing new post-processing methods.

Supraglacial streamflow and meteorological drivers from southwest Greenland

Abstract. Greenland ice sheet surface runoff is drained through supraglacial stream networks. This evacuation influences surface mass balance as well as ice dynamics. However, in situ observations of meltwater discharge through these stream networks are rare. In this study, we present 46 discrete discharge measurements and continuous water level measurements for 62 d spanning the majority of of the melt season (13 June to 13 August) in 2016 for a 0.6 km2 supraglacial stream catchment in southwest Greenland. The result is an unprecedentedly long record of supraglacial discharge that captures both diurnal variability and changes over the melt season. A comparison of surface energy fluxes to stream discharge reveals shortwave radiation as the primary driver of melting. However, during high-melt episodes, the contribution of shortwave radiation to melt energy is reduced by ∼40 % (from 1.13 to 0.73 proportion). Instead, the relative contribution of longwave radiation, sensible heat fluxes, and latent heat fluxes to overall melt increases by ∼24 %, 6 %, and 10 % (proportion increased from −0.32 to −0.08, 0.28 to 0.34, and −0.04 to 0.06) respectively. Our data also identify that the timing of daily maximum discharge during clear-sky days shifts from 16:00 local time (i.e., 2 h 45 min after solar noon) in late June to 14:00 in late July and then rapidly returns to 16:00 in early August. The change in the timing of daily maximum discharge could be attributed to the expansion and contraction of the stream network, caused by skin temperatures that likely fell below freezing at night. The abrupt shift, in early August, in the timing of daily maximum discharge coincides with a drop in air temperature, a drop in the amount of water temporarily stored in weathering crust, and a decreasing covariance between stream velocity and discharge. Further work is needed to investigate if these results can be transferable to larger catchments and uncover if rapid shifts in the timing of peak discharge are widespread across Greenland supraglacial streams and thus have an impact on meltwater delivery to the subglacial system and ice dynamics.

Long-term morpho-structural development of major normal fault zones, Gran Sasso area, Central Apennines (Italy)

Although the Central Apennines of Italy are frequently struck by earthquakes related to normal faulting, so far, no detailed regional study into long-term development and mode of normal faulting exists. In this study, we focus on the Assergi fault zone (AFZ) and the Campo Imperatore fault zone (CIFZ) in the Gran Sasso area.Both fault zones are S-dipping and ~ 20 km in length. Range front faults with ~1 km of footwall topography are associated with basins in the hanging wall. To create footwall relief, long-term throw rates of >0.6 mm/a are required. We compared geologic throw with morphologic markers, such as range and triangular facet height, drainage basin size, spacing between drainage basin outlets, and surface offsets. The morphologic analysis allows to distinguish fault sectors that share morphological characteristics but typically include several mapped fault segments. The history of faulting of the CIFZ indicates that normal fault segments first acquire offset at a constant length until reaching a threshold, and then link with neighbouring fault segments into longer fault zones.Our study of the fault zones suggests the following general concept for long-term development of range-front fault morphology and associated slopes: (1) Surface offset by active faulting is followed, or accompanied, by incision of numerous small alluvial-fan catchments with narrow outlet spacing into the fault footwall. (2) Upon further fault growth, large triangular facets separated by gullies develop. By headward and lateral erosion the small fan catchments merge into fewer and larger catchments with larger outlet spacing. (3) During fault dormance, fault scarps degrade to lower-dipping slopes typically veneered by scree. On these slopes, scarps excavated by differential erosion expose Riedel shears of the main faults.

Prevalence, correlates and treatment needs of dental caries among people on antiretroviral therapy in Uganda: a cross sectional study

BackgroundOral diseases are estimated to affect half of people living with HIV in the western world, and are often marked by pain, discomfort, disfigurement and reduced quality of life. Both HIV-specific and antiretroviral therapy-associated oral diseases have been found in this population. However, the prevalence, correlates and treatment needs of dental caries among people on antiretroviral therapy has not been well studied in rural Africa where majority of people living with HIV reside. Moreover, health behaviors and access to dental care vary significantly from high-income countries in the global north.MethodsA cross-sectional study was conducted among people living with HIV attending a high-volume HIV clinic with an enrollment of 10,000 patients in a regional referral hospital in Southwestern Uganda. The clinic is located in an urban setting with a large rural catchment area. Oral health data was collected using the modified World Health Organization oral health questionnaire for adults. Dental examinations were conducted to identify and classify dental caries using the decayed, missing, filled, teeth (DMFT) index and compute the treatment need. Logistic regression models were employed to identify correlate of dental caries.ResultsA total of 194 participants were included in the study. The majority were female (124/194, 63.9%) with a median age of 42 years (IQR 36–49). The prevalence of dental caries experience among study participants was 67%, (130/194, 95% CI 60–75%). The mean DMFT index score was 4 (IQR 2–6) and treatment need was 96% (192/200). A higher CD4 count was associated with the presence of dental caries (OR 0.403, 95% CI 0.175–0.932) although it was not significant in multivariate analysis.ConclusionThere is a high prevalence of dental caries among people living with HIV on ART in Uganda. Our data demonstrate a high oral treatment need among this population. We recommend inclusion of preventive and therapeutic oral care into HIV care in this region.

Environmental Gradients Shaping the Freshwater Bryophyte Communities of Croatia (Western Balkans)

A comprehensive field survey of 527 sites on 293 watercourses across Croatia revealed 76 sites (14.42%) in which bryophytes were the dominant part of the macrophyte vegetation. Using classification and ordination analyses, we obtained five community types segregated across the gradients of several climatic, physiographic and water chemistry parameters. The Didymodon tophaceus–Apopellia endiviifolia and the Berula erecta-Cratoneuron filicinum communities were mostly confined to the clean and basic karstic rivers of the Dinaric Ecoregion under the influence of the Mediterranean climate, with the Didymodon tophaceus–Apopellia endiviifolia community being a tufa-forming community associated with the seasonally dry watercourses of small catchment areas and cascades along the larger karstic rivers, while the Berula erecta–Cratoneuton filicinum community was mostly associated with rivers with larger catchment areas and permanent flow. On the other hand, the Oxyrrhynchium hians–Chiloscyphus pallescens community and the Fissidens pusillus–Veronica beccabunga community were associated with eutrophic water restricted to small rivers of the Pannonian Ecoregion under the influence of the temperate climate and flowing over silicate bedrock. The most represented and widespread in Croatia was the Cinclidotus community, displaying the widest ecological range in the study. It was mostly associated with the relatively clean karstic rivers of large catchment areas belonging to the Dinaric Ecoregion, with the majority of the sites under the influence of a temperate climate with higher precipitation during the warm period of the year. The geographical patterns of the freshwater bryophyte communities showed that the relatively clean, fast and cold karstic rivers belonging to the Dinaric Ecoregion provide habitats that harbour a greater diversity of bryophyte communities than the watercourses of the Pannonian Ecoregion, where bryophyte-dominated communities are restricted to a small number of small lowland and semi-montane rivers and predominantly occupy periodically flooded microhabitats such as river margins.

NFB-22. Neurofibromatosis Therapeutics Program: Development of a Program

Abstract Neurofibromatosis (NF) therapeutics is a vital field in the care of children with NF. Recent developments in the treatment of plexiform neurofibromas (PN) have increased the numbers of patients seen for therapy. The Neurofibromatosis Therapeutics Program (NTP) provides high quality care to patients receiving therapy for brain tumors and PNs, as well as tumors related to NF2. The program at Children’s Hospital Colorado (CHCO) includes a physician, nurse practitioner, and nurse care coordinator. The team collaborates with other disciplines in the care of the NF patient with plexiform neurofibromas and/or CNS tumors. As the program grew, key players were identified in each subspecialty and educated about the NTP. We have ongoing regular communication with a large number of subspecialists regarding protocols, clinical care pathways, and mutual patients. In addition, an extensive tissue collection study of plexiform neurofibromas and brain tumors enhances NTPs devotion to both clinical and lab research. Weekly clinical care meetings ensure continuity in the care of the nearly 140 patients with NF1 and NF2 under our program. Monthly strategy and vision meetings focus on grant applications, education of primary care providers and subspecialists in our large catchment area, development of new clinical pathways, treatment roadmaps, and growth of our program. Over the last two years of being a formalized program, we have increased research on the epigenetics of plexiform neurofibromas, opened a Phase 2 clinical trial for a Mek inhibitor, and increased our patient volume. The Covid pandemic has increased our ability to manage treatment side effects virtually through telehealth and online patient portals. Future goals of the NTP include completion of a program website, quarterly patient and provider newsletters, educational offerings, collaboration with other centers on Mek inhibitor side effects, adolescent and young adult education on tumor risk, and transition to adult care.

Automatic Extraction of Potential Landslides by Integrating an Optical Remote Sensing Image with an InSAR-Derived Deformation Map

Landslide extraction is one of the most popular topics in remote sensing. Numerous techniques have been proposed to manage the landslide identification problem. However, most aim to extract landslides that have already occurred or delineate the potential landslide manually. It is greatly important to identify and delineate potential landslides automatically, which has not been investigated. In this paper, we propose an automatic identification and delineation method, i.e., object-based image analysis (OBIA) of potential landslides by integrating optical imagery with a deformation map. We applied a deformation map generated by the interferometric synthetic aperture radar (InSAR) technique, rather than the digital elevation model (DEM) for landslide segmentation. Then, we used a classification and regression tree (CART) model with the spectral, spatial, contextual and deformation characteristics for landslide classification. For accuracy assessment, we implemented the evaluation indicators of recall and precision. The proposed method is verified in both specific landslide-prone regions (Jinpingzi and Shuanglongtan landslides) and a large catchment of the Jinsha River, China. By comparing our results with the ones using purely optical imagery, the precision of the Jinpingzi landslide is improved by 14.12%, and the recall and precision of the Shuanglongtan landslide are improved by 3.1% and 3.6%, respectively, and the recall for the large catchment is improved by 9.95%. Our method can improve delineation of potential landslides significantly, which is crucial for landslide early warning and prevention.

Drivers of multi-decadal nitrate regime shifts in a large European catchment

Long-term monitoring shows evidence of persistent changes in the magnitude and timing of the seasonal pattern of nitrate concentrations in streams, with possibly grave effects on aquatic ecosystems. Seasonal patterns of stream nutrient concentrations are determined by a complex interplay of inputs, transport, and turnover. Over multi-decadal periods, each of these factors may change due to socio-economic factors such as consumption patterns, governance regimes, or technological control measures. Here we test the hypothesis that observed multi-decadal changes in stream nitrate seasonality could be explained by changes in the relative importance of catchment nutrient sources over time. We analyze 66 years of shifting nitrate seasonality in a large, central-European river (Elbe) during a period of significant socio-political changes (1954–2019), with correspondingly significant changes in the sources of anthropogenic nitrate emissions. We develop a mixed-source succession model to test how the multi-decadal evolution of the composition of nitrate sources (point and diffuse) influences in-stream seasonality. We show that the in-stream nitrate seasonality of the River Elbe changed significantly from a weak seasonal pattern with peak concentrations during summer in the 1950s to a strong seasonal pattern with peak concentrations during winter in the 1990s. We link these shifts to a succession of technical and political developments which influence the contribution of point and diffuse sources over time. Such shifts in seasonal concentration patterns can significantly impact the macronutrient (carbon, nitrogen, phosphorus) ratios in rivers, which in turn highly affect the health of aquatic ecosystems.

Event and Catchment Controls of Heavy Tail Behavior of Floods

AbstractIn some catchments, the distribution of annual maximum streamflow shows heavy tail behavior, meaning the occurrence probability of extreme events is higher than if the upper tail decayed exponentially. Neglecting heavy tail behavior can lead to an underestimation of the likelihood of extreme floods and the associated risk. Partly contradictory results regarding the controls of heavy tail behavior exist in the literature and the knowledge is still very dispersed and limited. To better understand the drivers, we analyze the upper tail behavior and its controls for 480 catchments in Germany and Austria over a period of more than 50 years. The catchments span from quickly reacting mountain catchments to large lowland catchments, allowing for general conclusions. We compile a wide range of event and catchment characteristics and investigate their association with an indicator of the tail heaviness of flood distributions, namely the shape parameter of the GEV distribution. Following univariate analyses of these characteristics, along with an evaluation of different aggregations of event characteristics, multiple linear regression models, as well as random forests, are constructed. A novel slope indicator, which represents the relation between the return period of flood peaks and event characteristics, captures the controls of heavy tails best. Variables describing the catchment response are found to dominate the heavy tail behavior, followed by event precipitation, flood seasonality, and catchment size. The pre‐event moisture state in a catchment has no relevant impact on the tail heaviness even though it does influence flood magnitudes.

Telehealth cognitive-behavioral therapy for cancer-related cognitive impairment: A model for remote clinical trial participation.

TPS12143 Background: Cancer-related cognitive impairment (CRCI) can include persistent memory symptoms, and affects many cancer survivors. Memory and Attention Adaptation Training (MAAT) is an evidence-based cognitive behavioral therapy (CBT) that improves CRCI with demonstrated efficacy in telehealth delivery. MAAT consists of 8 weekly (45-minute) video visits. The aims of this study are to confirm MAAT telehealth efficacy in a phase III RCT (MAAT versus Supportive Therapy; ST) across large catchment areas of two comprehensive cancer centers. A secondary aim is to evaluate treatment-induced brain activation as assessed by functional MRI (fMRI) in a subset of participants. We present remote treatment and data capture methods of this open NCI-sponsored (R01CA244673) randomized clinical trial (NCT 04586530). These methods have high success in participant accrual despite COVID-19 pandemic conditions, and can be readily adopted to other clinical trials to enhance rural/underserved enrollment. Methods: We are enrolling 200 adult, stage I-III breast cancer survivors 1-5 years post-chemotherapy with cognitive complaints. Individuals with CNS disease, previous brain injury, dementia or psychiatric disorder are excluded. All study procedures are completed from the participant’s home (except fMRI). Eligibility screening is a semi-structured phone interview followed by detailed informed consent online (Research Electronic Data Capture: REDCap) with staff phone guidance. Consented participants complete baseline brief phone-based neurocognitive assessment and validated patient-reported outcome measures (PROs) of cognition and quality of life via REDCap. Participants are randomized to MAAT or ST and assigned treating clinicians at respective cancer centers. All 8 visits are completed through secure telehealth platforms, followed by repeat phone/online assessment post-treatment and again at 6 months. Enrollment began in 3/2021. As of 1/2022 (9 months), 56 participants are enrolled (28% of the planned sample), 47 randomized (MAAT 24; ST 23), with 24 completing post-treatment assessments. If all assessments and treatment visits were in person, travel burden per participant is 968 miles/20.5 hours driven, and $542 (US 2021 Federal rate). Thus, study travel savings to date are $30,352. Participant feedback indicates telehealth makes participation possible, similar to previous MAAT research. The current RCT demonstrates utility, efficiency and cost-savings of telehealth and remote data capture technology in the conduct of cancer control research. Elements of methods described can also be adopted for cancer therapeutic trials. Comprehensive cancer centers, where most clinical trials are based, can enhance participation of remote and/or underserved populations that have higher rates of cancer, more disease burden and less opportunity for trial participation. Clinical trial information: NCT04586530.

A global assessment of change in flood volume with surface air temperature

Climate change is expected to have a significant impact on water security, with higher temperatures causing both enhanced droughts and flood extremes. Here, using global flow data from non-urban catchments, we investigate the sensitivity of flood volume to changes in concurrent surface air temperature. We find most of the world shows decreases in flood volumes with increasing temperature. To understand why this correlation exists, we assess the sensitivity of the above result to mean daily temperatures (climate region), catchment size, and severity of the flood event. Our results indicate that most of the world shows decreases in flood volume with rising temperature for frequent events (50th percentile in this study) and a lesser decrease for rarer events. Changes in the flood volume in tropical regions show the greatest sensitivity to flood percentiles and catchment size. Large catchments in the tropics (≥ 1000 km2) have considerable sensitivities of flood volume with temperature at rates of -10 to -5%/ °C for frequent events (< 90th percentile) whereas small catchments (1000 km2) have sensitivities that only -5%/ °C or greater (i.e., less magnitude). On the other hand, when temperature increases, smaller catchments in the regions are likely to be exposed to more severe flooding at rates up to 15%/ °C for the most severe floods (99.99 percentile in this study) while the rate for large catchments approach zero. Although this study does not seek to find a causality between air temperature and flood runoff, the results suggest a possible decrease in water security with climate change, particularly in large tropical catchments.

Habitat-based biodiversity assessment for ecosystem accounting in the Murray-Darling Basin.

Understanding how biodiversity is changing over space and time is crucial for well-informed decisions that help retain Earth's biological heritage over the long term. Tracking changes in biodiversity through ecosystem accounting provides this important information in a systematic way and readily enables linking to other relevant environmental and economic data to provide an integrated perspective. We derived biodiversity accounts for the Murray-Darling Basin, Australia's largest catchment. We assessed biodiversity change from 2010 to 2015 for all vascular plants, all waterbirds, and 10 focal species. We applied a scalable habitat-based assessment approach that combined expected patterns in the distribution of biodiversity from spatial biodiversity models with a time series of spatially complete data on habitat condition derived from remote sensing. Changes in biodiversity from 2010 to 2015 varied across regions and biodiversity features. For the entire Murray-Darling Basin, the expected persistence of vascular plants increased slightly from 2010 to 2015 (from 86.8% to 87.1%), mean species richness of waterbirds decreased slightly (from 12.5 to 12.3 species), whereas for the focal species the estimated area of habitat increased for 8 species and decreased for 1 species. Regions in the north of the Murray-Darling Basin generally had decreases in biodiversity from 2010 to 2015, whereas in the south biodiversity was stable or increased. Our results demonstrate the benefits of habitat-based biodiversity assessments in providing fully scalable biodiversity accounts across different biodiversity features, consistent with the United Nations System of Environmental Economic Accounting - Ecosystem Accounting (SEEA EA) framework.