Hydrological assessment and monitoring of wetlands

The physical and chemical characteristics which favour wetland plant communities, primarily high soil water levels and anaerobic soil chemistry, are related directly to the hydrology/hydrogeology of the wetland and often its surrounding catchment. Appreciation and successful management of a wetland therefore almost always requires an understanding of its hydrological functioning, including the influences on hydrological functioning which often lie beyond the designated boundary of the sit

Diel turbidity cycles in a headwater stream: evidence of nocturnal bioturbation?

Purpose: A small number of recent studies have linked daily cycles in stream turbidity to nocturnal bioturbation by aquatic fauna, principally crayfish, and demonstrated this process can significantly impact upon water quality under baseflow conditions. Adding to this limited body of research, we use high-resolution water quality monitoring data to investigate evidence of diel turbidity cycles in a lowland, headwater stream with a known signal crayfish (Pacifastacus leniusculus) population and explore a range of potential causal mechanisms. Materials and methods: Automatic bankside monitoring stations measured turbidity and other water quality parameters at 30-min resolution at three locations on the River Blackwater, Norfolk, UK during 2013. Specifically, we focused on two 20-day periods of baseflow conditions during January and April 2013 which displayed turbidity trends typical of winter and spring seasons, respectively. The turbidity time-series, which were smoothed with 6.5 hour Savitzky-Golay filters to highlight diel trends, were correlated against temperature, stage, dissolved oxygen and pH to assess the importance of abiotic influences on turbidity. Turbidity was also calibrated against suspended particulate matter (SPM) over a wide range of values via linear regression. Results and discussion: Pronounced diel turbidity cycles were found at two of the three sites under baseflow conditions during April. Spring night-time turbidity values consistently peaked between 21:00 and 04:00 with values increasing by ~10 nephelometric turbidity units (NTU) compared with the lowest recorded daytime values which occurred between 10:00 and 14:00. This translated into statistically significant increases in median midnight SPM concentration of up to 76% compared with midday, with night-time (18:00 – 05:30) SPM loads also up to 30% higher than that recorded during the daytime (06:00 – 17:30). Relating turbidity to other water quality parameters exhibiting diel cycles revealed there to be neither any correlation that might indicate a causal link, nor any obvious mechanistic connections to explain the temporal turbidity trends. Diel turbidity cycles were less prominent at all sites during the winter. Conclusions: Considering the seasonality and timing of elevated turbidity, visual observations of crayfish activity, and an absence of mechanistic connections with other water quality parameters, the results presented here are consistent with the hypothesis that nocturnal bioturbation is responsible for generating diel turbidity cycles under baseflow conditions in headwater streams. However, further research in a variety of fluvial environments is required to better assess the spatial extent, importance and causal mechanisms of this phenomenon

Riverbed sediments buffer phosphorus concentrations downstream of sewage treatment works across the River Wensum catchment, UK

Purpose: Wastewater effluent discharged into rivers from sewage treatment works (STWs) represents one of the most important point sources of soluble reactive phosphorus (SRP) pollution and is a major driver of freshwater eutrophication. In this study, we assess the ability of riverbed sediments to act as a self-regulating buffering system to reduce SRP dissolved in the water column downstream of STW outflows. Materials and methods: River water and riverbed sediment samples were collected from 10 tributary outlets across the River Wensum catchment, Norfolk, UK, at monthly intervals between July and October 2016, such that 40 sediment and 40 water samples were collected in total. Of these locations, five were located downstream of STWs and five were on tributaries without STWs. Dissolved SRP concentrations were analysed and the Equilibrium Phosphorus Concentration (EPC0) of each sediment sample was measured to determine whether riverbed sediments were acting as net sources or sinks of SRP. Results and discussion: The mean SRP concentration downstream of STWs (382 µg P L-1) was double that of sites without a STW (185 µg P L-1), whilst the mean EPC0 for effluent impacted sites (105 µg P L-1) was 70% higher than that recorded at unaffected sites (62 µg P L-1). Regardless of STW influence, riverbed sediments across all 10 sites almost always acted as net sinks for SRP from the overlying water column. This was particularly true at sites downstream of STWs which displayed enhanced potential to buffer the river against increases in SRP released in sewage effluent. Conclusions: Despite EPC0 values revealing riverbed sediments were consistently acting as sinks for SRP, elevated SRP concentrations downstream of STWs clearly demonstrate the sediments have insufficient SRP sorption capacity to completely buffer the river against effluent discharge. Consequently, SRP concentrations across the catchment continue to exceed recommended standards for good chemical status, thus emphasising the need for enhanced mitigation efforts at STWs to minimise riverine phosphorus loading

IntEgrating smoking cessation treAtment into usual online psychological care for people with common mEntal illness: Protocol for an online randomised feasibility and pilot study (ESCAPE digital)

BACKGROUND: In the UK, smoking prevalence in people with depression (34%) and anxiety (29%) is more than double that of the general population (13%). People who stop smoking improve their mental health with comparable effect sizes found for antidepressants. In England, online psychological therapy is a standard treatment for depression and anxiety. Online therapy is an acceptable setting for smoking cessation support; however, integrated smoking and mental health support is not available. This novel study aims to assess the acceptability and feasibility of an online smoking cessation intervention, and trial procedures, offered alongside online mental health treatment as it offers increased reach to people with common mental health difficulties who smoke. METHODS: A two-armed; Intervention (Integrated SilverCloud smoking cessation support) and control group (SilverCloud usual care), pragmatic, randomised controlled feasibility trial. We aim to recruit 500 adult smokers eligible for online mental health treatment. Follow-up will be conducted at 3-months and 6-months. We will assess the acceptability and feasibility of the trial procedures (i.e., recruitment, data completeness, self-reported acceptability and satisfaction) and the intervention (i.e., self-reported quit attempt, engagement with the smoking cessation and mental health programs, smoking cessation medicine and e-cigarette use, self-reported acceptability and satisfaction) and pilot clinical outcomes (i.e., biologically validated smoking abstinence, anxiety, depression, quality of health). CONCLUSION: If the Trial is successful, a randomised controlled effectiveness trial will follow to examine whether integrated smoking cessation and mental health treatment increases smoking abstinence and improves depression and anxiety compared to usual care. TRIAL REGISTRATION: ISRCTN10612149 (https://doi.org/10.1186/ISRCTN10612149), 02/02/2023

IntEgrating Smoking Cessation treAtment into usual online Psychological care for people with common mEntal illness: Protocol for an online randomised feasibility and pilot study (ESCAPE digital)

Background In the UK, smoking prevalence in people with depression (34%) and anxiety (29%) is more than double that of the general population (13%). People who stop smoking improve their mental health with comparable effect sizes found for antidepressants. In England, online psychological therapy is a standard treatment for depression and anxiety. Online therapy is an acceptable setting for smoking cessation support; however, integrated smoking and mental health support is not available. This novel study aims to assess the acceptability and feasibility of an online smoking cessation intervention, and trial procedures, offered alongside online mental health treatment as it offers increased reach to people with common mental health difficulties who smoke. Methods A two-armed; Intervention (Integrated SilverCloud smoking cessation support) and control group (SilverCloud usual care), pragmatic, randomised controlled feasibility trial. We aim to recruit 500 adult smokers eligible for online mental health treatment. Follow-up will be conducted at 3-months and 6-months. We will assess the acceptability and feasibility of the trial procedures (i.e., recruitment, data completeness, self-reported acceptability and satisfaction) and the intervention (i.e., self-reported quit attempt, engagement with the smoking cessation and mental health programs, smoking cessation medicine and e-cigarette use, self-reported acceptability and satisfaction) and pilot clinical outcomes (i.e., biologically validated smoking abstinence, anxiety, depression, quality of health). Conclusion If the Trial is successful, a randomised controlled effectiveness trial will follow to examine whether integrated smoking cessation and mental health treatment increases smoking abstinence and improves depression and anxiety compared to usual care. Trial registration: ISRCTN10612149 (https://doi.org/10.1186/ISRCTN10612149), 02/02/2023

Lattice Boltzmann method for the fractional advection-diffusion equation

Mass transport, such as movement of phosphorus in soils and solutes in rivers, is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or superdiffusion, and it is well described using a fractional advection-diffusion equation (FADE). The FADE finds a wide range of applications in various areas with great potential for studying complex mass transport in real hydrological systems. However, solution to the FADE is difficult, and the existing numerical methods are complicated and inefficient. In this study, a fresh lattice Boltzmann method is developed for solving the fractional advection-diffusion equation (LabFADE). The FADE is transformed into an equation similar to an advection-diffusion equation and solved using the lattice Boltzmann method. The LabFADE has all the advantages of the conventional lattice Boltzmann method and avoids a complex solution procedure, unlike other existing numerical methods. The method has been validated through simulations of several benchmark tests: a point-source diffusion, a boundary-value problem of steady diffusion, and an initial-boundary-value problem of unsteady diffusion with the coexistence of source and sink terms. In addition, by including the effects of the skewness β , the fractional order α , and the single relaxation time τ , the accuracy and convergence of the method have been assessed. The numerical predictions are compared with the analytical solutions, and they indicate that the method is second-order accurate. The method presented will allow the FADE to be more widely applied to complex mass transport problems in science and engineering

Disentangling the complexity of groundwater dependent social-ecological systems

Groundwater resources are part of larger social-ecological systems. In this chapter, we review the various dimensions of these complex systems in order to uncover the diversity of elements at stake in the evolution of an aquifer and the loci for possible actions to control its dynamics. Two case studies illustrate how the state of an aquifer is embedded in a web of biophysical and sociopolitical processes. We propose here a holistic view through an IGM-scape that describes the various possible pathways of evolution for a groundwater related social-ecological system. Then we describe the elements of this IGM-scape starting with physical entities and processes, including relations with surface water and quality issues. Interactions with society bring an additional layer of considerations, including decisions on groundwater abstraction, land use changes and even energy related choices. Finally we point out the policy levers for groundwater management and their possible consequences for an aquifer, taking into account the complexity of pathways opened by these levers