The Ploemeur-Guidel observatory (Britanny, France) is focusing on surface-depth relationships in a fractured crystalline geological context and oceanic climate. It is built on 2 sub-sites, one highly anthropized, the other in natural state. In Ploemeur, groundwater has been pumped since 1991, supplying more than 1 million m3 of clean drinking water annual at a sustainable rate. Such high productivity is explained the specific fractured network in granite and micaschists, draining deep geological layers (~400 m). Extracted water quality is very good, with limited nitrate concentration, in a region that has been strongly affected by widespread pollution. Guidel site is in a similar, but natural context. Deep iron-rich groundwater is upflowing, creating surface and deep groundwater-dependent ecosystems, and feeding a classified coastal wetland. Both sites have a very dense equipment to study rapid to long-term surface-depth exchanges: a flux tower, unsaturated zone monitoring, a network of ~50 shallow (<10m) and deep boreholes (>80m), hydrochemical, temperature and deformation. An well-characterized fractured experimental site offers the possibility to conduct experiments to test innovative instruments and develop new methodologies

This data set contains the temperature values at the position of 557 Pardosa saltans spiders, measured each minute during 90 minutes in a laboratory thermal gradient. Additionnal information on sex, development stage and morphology is provided for each individual. For details see Cabon et al 2023 in Journal of Thermal Biology: https://www-sciencedirect-com.passerelle.univ-rennes1.fr/science/article/pii/S0306456523002474 https://doi.org/10.1016/j.jtherbio.2023.103706 Link to the dataset: https://doi.org/10.48579/PRO/AF5COX

Fractured aquifers are known to be very heterogeneous with complex flow path geometries. Their characterization and monitoring remain challenging despite the importance to better understand their behavior at all spatial and temporal scales. Heat and correspondingly temperature data have gained much interest in recent years and are often used as a tracer for characterizing groundwater flows. In the current work,a fast computer code is developed using Ramey and Hassan and Kabir analytical solutions which converts the temperature profile to the flow rate profile along the borehole. The method developed is validated through numerical simulations. A global sensitivity study recognizes the media thermal properties as the most influential parameters. For testing the method in the field,fiber-optic distributed temperature sensing (FO-DTS) data were used to monitor the dynamic behavior of fractured aquifers at the borehole scale at the Ploemeur-Guidel field site in Brittany,France. DTS data are used to infer the flow rates in the different sections of a fractured wellbore (flow profile) and calculate the contribution of each fracture to the total flow. DTS data were acquired for about three days in three different hydraulic conditions corresponding to two different ambient flow conditions and one pumping condition. Flow profiling using distributed temperature data matches satisfactorily with results from heat-pulse flow metering performed in parallel for cross-checking. Moreover,flow profiling reveals the daily variations of ambient flow in this fractured borehole. Furthermore,it shows that during ambient flowing conditions,shallow and deep fractures contribute roughly equally to the total flow while during the pumping condition,the deepest fractures contribute more to the total flow,suggesting a possible reorganization of flow and hydraulic heads depending on the hydraulic conditions. Thus,although the proposed method (DTS data and proposed framework) may be costlier and is based on indirect characterization through temperature measurements,it provides real-time monitoring of complex fracture interactions and recharge processes in fractured media. Thus,this method allows for a full analysis of the temporal behavior of the system with a simple and fast analytical model. Furthermore,thanks to its narrow width,DTS can be used and installed in boreholes for long-term monitoring while heat-pulse flow metering may lead to head losses in the borehole and may not be always possible depending on some borehole conditions. One of the limitations of the approach proposed is the proper knowledge of the thermal properties of media required to infer the flow rate from the temperature. Nevertheless,surface rate measurement can be useful to constrain these properties and reduce the flow profiling uncertainty. Thus,the method proposed appears to be an interesting and complementary method for characterizing borehole flows and groundwater dynamics in fractured media such as for instance,monitoring the recharge dynamic

This borehole hydrogeophysical logging data include optical imaging,acoustic logging,induction and electrical resistivity,natural and spectral gamma radioactivity,fiber optic measurements an d multiparameter probe logs.

Available data include monitoring data (weather parameters,piezometric levels and pumping flow rates). Note that soil and flux tower parameters are available in the dataset Soil-atmosphere exchange.