Monitoring groundwater temperatures in a shallow urban aquifer before, during and after installation of a Ground Source Heat System in Cardiff, U.K.

Exploitation of shallow urban aquifers, warmed by the Urban Heat Island Effect, is a relatively new concept in the U.K. An extensive groundwater temperature baseline monitoring network has been established for a shallow superficial aquifer in the city of Cardiff, U.K., to characterise groundwater temperatures and monitor the impacts of the first open-loop ground source heat pump (GSHP) installed in the city. In Spring 2014, temperature profiling was carried out at 1m depth intervals at 168 groundwater monitoring boreholes across Cardiff, establishing baseline groundwater temperatures within the shallow (<20m) superficial aquifer during the groundwater’s forecast coldest time of year. Data was contoured to form the first U.K. 2D city heat map. During the warmest time of year, Autumn 2014, a subset of boreholes were re-profiled to ascertain seasonal temperature variation, defining the Zone of Seasonal Fluctuation. Re-profiling was again carried out at these boreholes in Autumn 2015 to confirm these temperatures as normal for that time of year. By comparing Spring and Autumn profiles, the average depth to the base of the Zone of Seasonal Fluctuation was found to be 9.5mbgl. Two >100m boreholes showed the urban warming effect may extend to 80mbgl, before temperatures follow the predicted geothermal gradient. We term this the Zone of Anthropogenic Influence. After initial baseline temperatures were established, a site was selected for the installation of a shallow GSHP. Before installation work began, a monitoring network was set up to establish a temperature baseline for future GSHPs and identify any impacts on the thermal resource caused by removing ~2°C from the abstracted groundwater prior to reinjection into the aquifer. This comprised of 97 temperature loggers in 60 boreholes, including the abstraction and recharge boreholes and boreholes up and down gradient of the site. Some of these boreholes have multiple loggers at different depths, including the near-surface, but the majority of loggers were placed within the boreholes’ slotted sections, below the base of the Zone of Seasonal Fluctuation. In addition, six boreholes, including those used for the GSHP, have been telemetered, providing real-time temperature data. The aim of the monitoring network was to establish a baseline for groundwater temperatures in the shallow aquifer and to monitor local changes in temperatures close to the GSHP system. This study aimed to provide understanding of how GSHPs interact with the groundwater in order to confirm the sustainability of groundwater temperatures as a long-term thermal resource and provide planners with knowledge needed to develop sustainable wide-scale GSHP systems/networks. We present temperature data taken before and after installation

Thiolene-Based Microfluidic Flow Cells for Surface Plasmon Resonance Imaging

Thiolene-based microfluidic devices have been coupled with surface plasmon resonance imaging (SPRI) to provide an integrated platform to study interfacial interactions in both aqueous and organic solutions. In this work, we develop a photolithographic method that interfaces commercially available thiolene resin to gold and glass substrates to generate microfluidic channels with excellent adhesion that leave the underlying sensor surface free from contamination and readily available for surface modification through self-assembly. These devices can sustain high flow rates and have excellent solvent compatibility even with several organic solvents. To demonstrate the versatility of these devices, we have conducted nanomolar detection of streptavidin-biotin interactions using in situ SPRI. (C) 2011 American Institute of Physics. [doi:10.1063/1.3596395

Groundwater modelling with Modflow 6 to support sustainable heat recovery from a shallow urban coastal aquifer

If we are to achieve targets to reduce greenhouse gas emissions then low-enthalpy ground source heating may provide a secure and low carbon form of space heating. The measured shallow groundwater temperatures under the City of Cardiff were found to be 2°C warmer than predicted, attributed to the subsurface urban heat island effect. For geothermal resource mapping and regulation, heat advection and the urban groundwater flow system need to be understood. Here, we develop a groundwater and recharge model of the shallow aquifer in Cardiff. Cardiff is located on a flat coastal plain adjacent to the Bristol Channel. Following the construction of the Cardiff Bay Barrage in 1999, mud flats with a tidal range of ~10 m were turned in to a freshwater lake at a fixed elevation of 4.5 m a.o.D. The city is underlain by Triassic Mercia Mudstone, which is overlain by Quaternary superficial deposits, and consists of the sand and gravel aquifer of gaciofluvial origin, and lower permeability confining units, the tidal flat deposits. From before the construction of the Cardiff Bay Barrage, an extensive groundwater monitoring network was set in place, of which 194 boreholes are still operating. This well instrumented urban environment provides the opportunity to help understanding urban groundwater flow system, with recharge and discharge from urban infrastructure, rivers, docks, the Cardiff Bay barrage and the sea. We have built a distributed recharge model using ZOODRM and a groundwater model using Modflow 6 for the shallow aquifer in Cardiff city. Using a step wise approach of increasing model complexity, we find that the model better represents observed hydraulic heads by including leakage into the sewer network, which we represent as drains in the numerical model and losses from mains water. Model calibration using Monte Carlo thus far has shown the non-uniqueness of fluxes in interaction with the sewer network, docks the sea, and the rivers for a similar goodness of fit with the observed water levels. Consistently however, we find that the groundwater system is strongly influenced by the sewer network. For future work, we aim to better represent the sewer network within the groundwater model, e.g. by considering sewer age across the city. Once a steady state model has been achieved, we will be able to use our model to help environmental regulators to sustainably manage subsurface heat recovery and storage at a city scale

Groundwater heat pump feasibility in shallow urban aquifers: experience from Cardiff, UK

Ground source heat pumps have the potential to decarbonise heating and cooling in many urban areas. The impact of using shallow groundwater from unconsolidated sedimentary aquifers for heating in urban areas is often modelled, but rarely validated from field measurements. This study presents findings from the ‘Cardiff Urban Geo-Observatory’ project. This study focuses on an experimental open loop ground source heat pump scheme retrofitted to a school building. Field monitoring for three years between 2015 and 2018 provided data on the environmental impact of the scheme on aquifer conditions. Average aquifer thermal degradation in the first three years was kept below 2 °C, with a maximum change of 4 °C measured during the heating season. The numerically modelled predictions of thermal degradation around the production and injection wells are compared with long-term field monitoring data, providing new insights into both aquifer, and user, behaviour. The Seasonal Performance Factor (SPFH4) of the pilot installation was 4.5 (W13/W50) in the monitoring period. An initial thermal resource estimation of the wider aquifer volume suggests that lowering the temperature of the aquifer by 8 °C could generate equivalent to 26% of the city's 2020 heating demand, but achievable heat extraction would in reality, be less. The study concludes that large parts of the aquifer can sustain shallow open loop ground source heat pump systems, as long as the local ground conditions support the required groundwater abstraction and re-injection rates. Future schemes can be de-risked and better managed by introduction of a registration of all GSHP schemes, with open sharing of investigation, design and performance monitoring data, and by managing thermal interference between systems using spatial planning tools

The contribution of geology and groundwater studies to city-scale ground source heat network strategies: a case study from Cardiff, Wales, UK

The development of integrated heat network strategies involving exploitation of the shallow subsurface requires knowledge of ground conditions at the feasibility stage, and throughout the life of the system. We describe an approach to the assessment of ground constraints and energy opportunities in data-rich urban areas. Geological and hydrogeological investigations have formed a core component of the strategy development for sustainable thermal use of the subsurface in Cardiff, UK. We present findings from a 12 month project titled ‘Ground Heat Network at a City Scale’, which was co-funded by NERC/BGS and the UK Government through the InnovateUK Energy Catalyst grant in 2015-16. The project examined the technical feasibility of extracting low grade waste heat from a shallow gravel aquifer using a cluster of open loop ground source heat pumps. Heat demand mapping was carried out separately. The ground condition assessment approach involved the following steps: (1) city-wide baseline groundwater temperature mapping in 2014 with seasonal monitoring for at least 12 months prior to heat pump installation (Patton et al 2015); (2) desk top and field-based investigation of the aquifer system to determine groundwater levels, likely flow directions, sustainable pumping yields, water chemistry, and boundary conditions; (3) creation of a 3D geological framework model with physical property testing and model attribution; (4) use steps 1-3 to develop conceptual ground models and production of maps and GIS data layers to support scenario planning, and initial heat network concept designs; (5) heat flow modelling in FEFLOW software to analyse sustainability and predict potential thermal breakthrough in higher risk areas; (6) installation of a shallow open loop GSHP research observatory with real-time monitoring of groundwater bodies to provide data for heat flow model validation and feedback for system control. In conclusion, early ground condition modelling and subsurface monitoring have provided an initial indication of ground constraints and opportunities supporting development of aquifer thermal energy systems in Cardiff. Ground models should consider the past and future anthropogenic processes that influence and modify the condition of the ground. These include heat losses from buildings, modification of the groundwater regime by artificial pumping, sewers, and other GSH schemes, and construction hazards such as buried infrastructure, old foundations, land contamination and un-exploded ordnance. This knowledge base forms the foundation for a ‘whole life’ approach for sustainable thermal use of the subsurface. Benefits of the approach include; timely and easy to understand information for land use and financial resource planning, reduced financial risk for developers and investors, clear evidence to help improve public perception of GSHP technology, and provision of independent environmental data to satisfy the needs of the regulator

Groundwater modelling with Modflow 6 to support heat recovery from a shallow urban aquifer

• If we are to achieve targets to reduce greenhouse gas emissions then lowenthalpy ground source heating may provide a secure and low carbon form of space heating. • The measured shallow groundwater temperatures under the City of Cardiff were found to be 2°C warmer than predicted, attributed to the subsurface urban heat island effect. • For geothermal resource mapping and regulation, heat advection and the urban groundwater flow system need to be understood. • Here, we develop a groundwater and recharge model of the shallow aquifer in Cardiff

Results from the GeoERA MUSE shallow geothermal project – UK Cardiff pilot area

Shallow geothermal energy systems deployment will play an important part in decarbonisation of heating and cooling of buildings. This trend will stimulate research into ground physical, thermal and hydraulic properties and impacts on urban aquifers and infrastructures. Moreover, subsurface heat extraction must be perceived as reliable, sustainable and equitable to create an environment for social acceptance and uptake of geothermal technologies. The EU H2020-funded GeoERA ‘MUSE’ project (2018-2021), involved 16 Geological Surveys, who shared methods and developed harmonised workflows for the evaluation of shallow geothermal resources in European urban areas (Götzl et al., EGC 2022). The project deployed and tested ground characterisation and geophysical monitoring techniques, monitored GSHP schemes, analysed the local market situation, produced fact sheets, made policy recommendations, and developed adaptive management strategies. The research included in-field monitoring studies in 14 urban pilot areas across Europe, including three UK urban pilot areas; Cardiff in south Wales, Glasgow in west Scotland and Colchester in east England. This paper summarises the result with a focus on the Cardiff area

"Just Going Through the Motions.…": A Qualitative Exploration of Athlete Perceptions of Social Loafing in Training and Competition Contexts - Implications for Team Sport Coaches

Semi-structured interviews were conducted with twenty team sport athletes representing a range of different sports with the aim of investigating their views relating to social loafing in training and competition. General themes investigated and subsequent content analysis highlighted factors that promote or reduce the extent of social loafing. Determinants of self-loafing were grouped according to three distinct categories: Group processes; Task characteristics and Individual perceptions. Social loafing among others was perceived to be prevalent in both the training and competition scenarios with more examples of social loafing provided in the training situation. The signs of social loafing were grouped according to the following themes: Cognitive & Emotional, Behavioural, Communication and Player Intuition. Consequences of social loafing were found to be detrimental to the effort and performance of both the individual and the team. Athletes were also able to differentiate between perceived social loafing and the perceived use of ‘strategic rest’ in team sports. Implications for the coaching process are far reaching with the need to develop an effective team culture and to provide training sessions that are interesting, engaging and relevant

Fish from Head to Tail:The 9th European Zebrafish Meeting in Oslo

International audienceThe 9th European Zebrafish Meeting took place recently in Oslo (June 28-July 2, 2015). A total of 650 participants came to hear the latest research news focused on the zebrafish, Danio rerio, and to its distant evolutionary relative medaka, Oryzias latipes. The packed program included keynote and plenary talks, short oral presentations and poster sessions, workshops, and strategic discussions. The meeting was a great success and revealed dramatically how important the zebrafish in particular has become as a model system for topics, such as developmental biology, functional genomics, biomedicine, toxicology, and drug development. A new emphasis was given to its potential as a model for aquaculture, a topic of great economic interest to the host country Norway and for the future global food supply in general. Zebrafish husbandry as well as its use in teaching were also covered in separate workshops. As has become a tradition in these meetings, there was a well-attended Wellcome Trust Sanger Institute and ZFIN workshop focused on Zebrafish Genome Resources on the first day. The full EZM 2015 program with abstracts can be read and downloaded from the EZM 2015 Web site zebrafish2015.org

Using AMF inoculum to improve the nutritional status of Prunella vulgaris plants in green roof substrate during establishment

Arbuscular mycorrhizal fungi (AMF) have been shown to improve the growth, health, nutrient uptake, flowering and drought tolerance of many terrestrial plant species. Green roofs are generally deficient in nutrients, organic matter and water, and therefore AMF could be extremely beneficial in improving green roof plant performance. Despite this there is a lack of empirical research into artificially introducing AMF into green roof substrates. In this study, a commercial AMF inoculum was applied to Prunella vulgaris green roof plugs grown in small modules on a flat roof in Sheffield, UK. The modules were filled with commercial green roof substrate (80% small particle sized crushed brick, 20% green waste compost) to a depth of 100 mm. AMF inoculum was applied as four treatments: (i) directly with plug, (ii) mixed evenly into surrounding substrate, (iii) split between plug and substrate, (iv) control treatment with no inoculum added. Significantly greater levels of AMF colonisation of P. vulgaris roots was detected in all AMF treatments compared to the control. Low levels of AMF colonisation of P. vulgaris roots were also observed in the control treatment, confirming that low levels of AMF inoculum were present in this commercial substrate. Shoot phosphorous (P) concentration was improved in all AMF treatments, however there was no significant effect of any AMF treatment on P. vulgaris growth rate or biomass production. The highest AMF colonisation of P. vulgaris roots was observed when AMF inoculum was directly added to just the plug. Promisingly, P. vulgaris flowering time at the end of the first growing season was also extended in the plug AMF treatment only. This study has confirmed that commercial AMF inoculum can be used to successfully colonise plants and introduce AMF networks into green roof substrate. Although AMF inoculum was naturally present in the substrate used in this study, levels were extremely low, and unlikely to have any significant effect on plants. This study indicates that care should be taken in the use of AMF inoculum on green roofs, as the growth and health benefits of AMF are not always immediately apparent for green roof plants. In addition much more research is required in order to fully assess the extent of the benefits of AMF on green roof plants and to determine if their use can be financially viable