Evaluation of effective groundwater recharge of freshwater lens in small islands by the combined modeling of geoelectrical data and water heads

In small islands, a freshwater lens can develop due to the recharge induced by rain. Magnitude and spatial distribution of this recharge control the elevation of freshwater and the depth of its interface with salt water. Therefore, the study of lens morphology gives useful information on both the recharge and water uptake due to evapotranspiration by vegetation. Electrical resistivity tomography was applied on a small coral reef island, giving relevant information on the lens structure. Variable density groundwater flow models were then applied to simulate freshwater behavior. Cross validation of the geoelectrical model and the groundwater model showed that recharge exceeds water uptake in dunes with little vegetation, allowing the lens to develop. Conversely, in the low-lying and densely vegetated sectors, where water uptake exceeds recharge, the lens cannot develop and seawater intrusion occurs. This combined modeling method constitutes an original approach to evaluate effective groundwater recharge in such environments.
[Comte, J.-C., O. Banton, J.-L. Join, and G. Cabioch (2010), Evaluation of effective groundwater recharge of freshwater lens in small islands by the combined modeling of geoelectrical data and water heads, Water Resour. Res., 46, W06601, doi:10.1029/2009WR008058.]

Cross-validation of geo-electrical and hydrogeological models to evaluate seawater intrusion in coastal aquifers

The validation of variable-density flow models simulating seawater intrusion in coastal aquifers requires information about concentration distribution in groundwater. Electrical resistivity tomography (ERT) provides relevant data for this purpose. However, inverse modeling is not accurate because of the non-uniqueness of solutions. Such difficulties in evaluating seawater intrusion can be overcome by coupling geophysical data and groundwater modeling. First, the resistivity distribution obtained by inverse geo-electrical modeling is established. Second, a 3-D variable-density flow hydrogeological model is developed. Third, using Archie's Law, the electrical resistivity model deduced from salt concentration is compared to the formerly interpreted electrical model. Finally, aside from that usual comparison-validation, the theoretical geophysical response of concentrations simulated with the groundwater model can be compared to field-measured resistivity data. This constitutes a cross-validation of both the inverse geo-electrical model and the groundwater model.
[Comte, J.-C., and O. Banton (2007), Cross-validation of geo-electrical and hydrogeological models to evaluate seawater intrusion in coastal aquifers, Geophys. Res. Lett., 34, L10402, doi:10.1029/2007GL029981.]

Assessing spatio-temporal patterns of groundwater salinity in small coral islands in the Western Indian Ocean

We investigated groundwater salinity as a key element in both the short and long-term evolution of the island of Grande Glorieuse. Firstly, we demonstrated that its evolution involved the integration of the whole range of variables forcing climate change. Piezometric surveys designed to sample the salinity of the subsoil waters of Grande Glorieuse could therefore provide an objective indicator of the environment’s evolution. Then, based on information from geoelectrical investigations, we proved that the spatial distribution of salinity is strongly dependent on the geological structure of the island. Structural heterogeneities can influence vulnerability of the island environment to salinization of the freshwater lens. Thus, characterization and monitoring of the freshwater lens will provide a reliable means of observing and managing anticipated climate changes on small islands. [Join J.-L., Banton O., Comte J.-C., Leze J., Massin F., Nicolini E. (2011), Assessing spatio-temporal patterns of groundwater salinity in small coral islands in the Western Indian Ocean, Western Indian Ocean Journal of Marine Science, 10(1), 1-12]

Assessment of groundwater quality recovery strategies using nitrate transport modelling. Application to the Saône alluvial formations (Tournus, Saône-et-Loire)

To assess the efficiency of different agro-environmental strategies used to reduce groundwater pollution by nitrates, transport modelling in soils and groundwater has been carried out on two withdrawal areas in an alluvial plain. In a first time, the agro-environmental model AgriFlux allowed the simulation of water and nitrates fluxes flowing to groundwater. This model was calibrated for each agro-pedological unit of the studied territory. In a second time, the application of the hydrogeological model MODFLOW-MT3D allowed the simulation of nitrate transport in groundwater for the 1980-2004 period. This soil-groundwater coupled modelling has shown that soil nature is the first factor that conditions the vulnerability to nitrates. Thus, nitrate leaching occurs preferentially under sandy soils. Efficiency of different agro-environmental operations for groundwater quality recovery was quantified. The best results are obtained by combination of (1) grassland re-installation on sandy agricultural lots located in near well protection perimeter and (2) fertilization reduction on sandy agricultural lots located in the well alimentation area upstream the near protection perimeter. On other soils, the effect of grassland on groundwater quality improvement is more limited. Nevertheless, the control of nitrate fertilisation remains essential and is justified in both near and far well protection perimeters. Modelling thus allows optimising and priorizing agro-environmental actions in alluvial agricultural zones. [Comte J.-C., Banton O., Kockmann F., Villard A., Creuzot G. (2006), Assessment of groundwater quality recovery strategies using nitrate transport modelling. Application to the Saône alluvial formations (Tournus, Saône-et-Loire), Ingénieries Eau-Agriculture-Territoires, 45, 15-28]

The typology of Irish hard rock aquifers based on an integrated hydrogeological and geophysical approach

Groundwater flow in hard-rock aquifers is strongly controlled by the characteristics and distribution of structural heterogeneity. A methodology for catchment-scale characterisation is presented, based on the integration of complementary, multi-scale hydrogeological, geophysical and geological approaches. This was applied to three contrasting catchments underlain by metamorphic rocks in the northern parts of Ireland (Republic of Ireland and Northern Ireland, UK). Cross-validated surface and borehole geophysical investigations confirm the discontinuous overburden, lithological compartmentalisation of the bedrock and important spatial variations of the weathered bedrock profiles at macro-scale. Fracture analysis suggests that the recent (Alpine) tectonic fabric exerts strong control on the internal aquifer structure at meso-scale, which is likely to impact on the anisotropy of aquifer properties. The combination of the interpretation of depth-specific hydraulic-test data with the structural information provided by geophysical tests allows characterisation of the hydrodynamic properties of the identified aquifer units. Regionally, the distribution of hydraulic conductivities can be described by inverse power laws specific to the aquifer litho-type. Observed groundwater flow directions reflect this multi-scale structure. The proposed integrated approach applies widely available investigative tools to identify key dominant structures controlling groundwater flow, characterising the aquifer type for each catchment and resolving the spatial distribution of relevant aquifer units and associated hydrodynamic parameters.

Coelum non animum muto? Milton's Neo-Latin Poetry and Catholic Italy

Milton’s Elegiarum Liber, the first half of his Poemata published in Poems of Mr John Milton Both English and Latin (1645), concludes with a series of eight Latin epigrams: five bitterly anti-Catholic pieces on the failed Gunpowder Plot of 1605, followed by three encomiastic poems hymning the praises of an Italian soprano, Leonora Baroni, singing in Catholic Rome. The disparity in terms of subject matter and tone is self-evident yet surprising in an epigrammatic series that runs sequentially. Whereas the gunpowder epigrams denigrate Rome, the Leonora epigrams present the city as a cultured hub of inclusivity, the welcome host of a Neapolitan soprano. In providing the setting for a human song that both enthrals its audience and attests to the presence of a divine power, Rome now epitomizes something other than brute idolatry, clerical habit or doctrine. And for the poet this facilitates an interrogation of theological (especially Catholic) doctrines. Coelum non animum muto, dum trans mare curro wrote the homeward-bound Milton in the autograph book of Camillo Cardoini at Geneva on 10 June 1639. But that this was an animus that could indeed acclimatize to religious and cultural difference is suggested by the Latin poems which Milton “patch [ed] up” in the course of his Italian journey. Central to that acclimatisation, as this chapter argues, is Milton’s quasi-Catholic self-fashioning. Thus Mansus offers a poetic autobiography of sorts, a self-inscribed vita coloured by intertextually kaleidoscopic links with two Catholic poets of Renaissance Italy and their patron; Ad Leonoram 1 both invokes and interrogates Catholic doctrine before a Catholic audience only to view the whole through the lens of a neo-Platonic hermeticism that may refreshingly transcend religious difference. Finally, Epitaphium Damonis, composed upon Milton’s return home, seems to highlight the potential interconnectedness of Protestant England and Catholic Italy, through the Anglo-Italian identity of its deceased subject, and through a pseudo-monasticism suggested by the poem’s possible engagement with the hagiography of a Catholic Saint. Perhaps continental travel and the physical encounter with the symbols, personages and institutions of the other have engendered in the Milton of the Italian journey a tolerance or, more accurately, the manipulation of a seeming tolerance to serve poetic and cultural ends.


First reviewer:
Haan: a fine piece by the senior neo-Latinist in Milton studies.

Second reviewer:
Chapter 7 is ... a high-spot of the collection. Its argument that in his Latin poetry Milton’s is a ‘quasi-Catholic self-fashioning’ stressing ‘the potential interconnectedness of Protestant England and Catholic Italy’ is striking and is advanced with learning, clarity and insight. Its sensitive exploration of the paradox of Milton’s coupling of humanistically complimentary and tolerant address to Roman Catholic friends with fiercely Protestant partisanship demonstrates that there is much greater complexity to his poetic persona than the self-construction and self-presentation of the later works would suggest. The essay is always adroit and sure-footed, often critically acute and illuminating (as, for example, in its discussion of the adjective and adverb mollis and molliter in Mansus, or in the identification in n. 99 of hitherto unnoticed Virgilian echoes). It has the added merits of being very well written, precise and apt in its citation of evidence, and absolutely central to the concerns of the volume.