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Over the past 35 years the Buckman wellfield near Santa Fe, New Mexico, experienced production well drawdowns in excess of 180 m, resulting in ground subsidence and surface cracks. Increased reliance on surface water diversions since 2011 has reduced pumping and yielded water level recovery. To characterize the impact of wellfield management decisions on the aquifer system, we reconstruct the surface deformation history through the European Remote Sensing Satellite, Advanced Land Observing Satellite, and Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) time series analysis during episodes of drawdown (1993–2000), recovery (2007–2010), and modern management (2015–2018) in discontinuous observations over a 25‐year period. The observed deformation generally reflects changes in hydraulic head. However, at times during the wellfield recovery, the deformation signal is complex, with patterns of uplift and subsidence suggesting a compartmentalized aquifer system. Recent records of locally high geothermal gradients and an overall warming of the system (~0.5°C during the water level recovery) obtained from repeat temperature measurements between 2013 and 2018 constrain a conceptual model of convective heat transfer that requires a vertical permeable zone near an observed fault. To reproduce observed temperature patterns at monitoring wells, high basal heat flow and convective cooling associated with downward flow of water from cool shallow aquifers during the drawdown period is necessary. The fault, however, appears to die out southward or may be locally permeable, as conceptual cross‐sectional hydrologic modeling reproduces the surface deformation without such a structure. Our work demonstrates the importance of incorporating well‐constrained stratigraphy and structure when modeling near‐surface deformation induced by, for instance, groundwater production. Interferometric Synthetic Aperture Radar analysis spanning 25 years reveals complex surface deformation dynamics due to groundwater production and suggests permanent storage lossLocally high geothermal gradients and groundwater warming suggest groundwater upflow through a mapped, vertically permeable faultConceptual cross‐sectional hydrologic modeling informed by Interferometric Synthetic Aperture Radar observations suggests a discontinuous or locally permeable fault/stratigraphic discontinuity

The effects of Pleistocene glacial loading on rock failure, permeability increases, pore pressure evolution, and brine migration within two linked sedimentary basins were evaluated using a multiphysics control volume finite element model. We applied this model to an idealized cross section that extends across the continent of North America from the Hudson Bay to the Gulf of Mexico. Our analysis considered lithosphere geomechanical stress changes (σyy> 35 MPa) in response to 10 cycles of ice sheet loading. Hydrologic boundary conditions, lithosphere rheological properties, and aquifer/confining unit configuration were varied in a sensitivity study. We used a Coulomb Failure Stress change metric (ΔCFSp> 0.1 MPa) to increase permeability by a factor of 100 in some simulations. Results suggest that a buildup of anomalous pore pressures up to about 3 MPa occurred in confining units during periods of glaciations, but this had only a second‐order effect on triggering rock failure. In regions prone to failure, permeability increases during glaciations help to explain observations of brine flushing in sedimentary basin aquifers. During the Holocene to present day, deglaciation resulted in underpressure formation in confining units primarily along the northern margin of the northern basin. Holocene‐modern geomechanical stress fields were relatively small (<0.6 MPa). However, pore pressure increases associated with postglacial rebound, especially when a basal sedimentary basin aquifer is present, induced rock failure and seismicity up to 150 km beyond the terminus of the ice sheet. Sedimentary basin salinity patterns did not equilibrate after 10 simulated glacial cycles. Pleistocene glaciations can cause geomechanical failure, permeability increases, and brine flushing within sedimentary basin aquifersTo reconcile computed and observed underpressures within confining units, failure must occur along discrete fracture planes through shalesSimulated Holocene‐Modern overpressure beyond the ice sheet terminus could help to explain failure and seismicity in the basement

Geologic ultrafiltration—slowing of solutes with respect to flowing groundwater—poses a conundrum: it is consistently observed experimentally in clay‐rich lithologies, but has been difficult to identify in subsurface data. Resolving this could be important for clarifying clay and shale transport properties at large scales as well as interpreting solute and isotope patterns for applications ranging from nuclear waste repository siting to understanding fluid transport in tectonically active environments. Simulations of one‐dimensional NaCl transport across ultrafiltering clay membrane strata constrained by emerging data on geologic membrane properties showed different ultrafiltration effects than have often been envisioned. In relatively high‐permeability advection‐dominated regimes, salinity increases occurred mostly within membrane units while their effluent salinity initially fell and then rose to match solute delivery. In relatively low‐permeability diffusion‐dominated regimes, salinity peaked at the membrane upstream boundary and effluent salinity remained low. In both scenarios, however, only modest salinity changes (up to ∼3 g L−1) occurred because of self‐limiting tendencies; membrane efficiency declines as salinity rises, and although sediment compaction increases efficiency, it is also decreases permeability and allows diffusive transport to dominate. It appears difficult for ultrafiltration to generate brines as speculated, but widespread and less extreme ultrafiltration effects in the subsurface could be unrecognized. Conditions needed for ultrafiltration are present in settings that include topographically‐driven flow systems, confined aquifer systems subjected to injection or withdrawal, compacting basins, and accretionary complexes. Ambiguous field data do not rule out large‐scale ultrafiltration by clay‐rich semipermeable formationsUltrafiltration effects can be counterintuitive and difficult to recognizeConfining layers may act as a natural reverse osmosis system for municipal and industrial wells

This study assesses the feasibility of using offshore freshwater for improved oil recovery in passive-margin marine environments. Low-salinity waterflooding (<5%) has recently been shown, on average, to improve oil recovery by 14%. Hydrogeologists estimate that up to 3 × 105 km3 (1.89×1011 bbl) of fresh (<1%) water are sequestered in shallow (<500 m [1640 ft] depth], permeable, poorly lithified sand, sandstone, and carbonate aquifers along passive margins, within 100 km (60 mi] of the presentday coastline in ocean-water depths up to approximately 50 m (164 ft]. The offshore distribution of fresh-brackish water is analyzed for five vertical cross sections from offshore Australia, Suriname, Indonesia, and the United States. The distribution of offshore freshwater is compared with offshore platform locations in three oil-producing marine basins, including the North Sea, the Gulf of Mexico, and the Niger Delta. The continentalshelf cross sections host between 0.8 and 8.6 km3 of freshbrackish water (<5%o] per kilometer of shoreline (8×109 to 8.7×1010 bbl/mi ofshoreline], most within 20to 100 km (12 to 60 mi] from the coast in water depths of 10 to 50 m (33 to 164 ft]. Because the majority of the offshore oil platforms are located less than 100 km (60 mi] from the shore, these resources could be used for low-salinity recovery. Cross sectional aquifer models of offshore fresh-brackish production indicate that a single, 1000-m (3280-ft]-long horizontal well could produce 19,200 m3/day (120,764 bbl/day] from a relatively permeable aquifer (10 11 to 10-12 m2 [10,000 to 1000 md]] overlain by a moderately tight ( ~1015m2 [1 md]], confining unit for the typical life span of a well (30 yr). [ABSTRACT FROM AUTHOR]

Offshore meteoric groundwater (OMG) has long been hypothesized to be a driver of seafloor geomorphic processes in continental margins worldwide. Testing this hypothesis has been challenging because of our limited understanding of the distribution and rate of OMG flow and seepage, and their efficacy as erosive/destabilizing agents. Here we carry out numerical simulations of groundwater flow and slope stability using conceptual models and evolving stratigraphy—for passive siliciclastic and carbonate margin cases—to assess whether OMG and its evolution during a late Quaternary glacial cycle can generate the pore pressures required to trigger mechanical instabilities on the seafloor. Conceptual model results show that mechanical instabilities using OMG flow are most likely to occur in the outer shelf to upper slope, at or shortly before the Last Glacial Maximum sea‐level lowstand. Models with evolving stratigraphy show that OMG flow is a key driver of pore pressure development and instability in the carbonate margin case. In the siliciclastic margin case, OMG flow plays a secondary role in preconditioning the slope to failure. The higher degree of spatial/stratigraphic heterogeneity of carbonate margins, lower shear strengths of their sediments, and limited generation of overpressures by sediment loading may explain the higher susceptibility of carbonate margins, in comparison to siliciclastic margins, to mechanical instability by OMG flow. OMG likely played a more significant role in carbonate margin geomorphology (e.g., Bahamas, Maldives) than currently thought. The flow of fresh to brackish groundwater has been proposed as an important process shaping the seafloor. However, we still have a poor understanding of how groundwater behaves in the sub‐seafloor and whether it can erode seafloor sediments. In this study, we test this hypothesis by using conceptual and realistic numerical models of two common types of seafloor margins—siliciclastic and carbonate—to assess the role of groundwater in making the seafloor susceptible to erosion. We show that the flow of groundwater offshore could have driven seafloor erosion close to the shelf break during the Last Ice Age, when sea level was lower than at present. Carbonate margins are more susceptible to this type of failure than siliciclastic margins. This may be explained by the higher variability in sediment properties across carbonate margins as well as the lower strength of their sediments. Groundwater has likely played an important role in shaping the seafloor in carbonate margins, and it may be responsible for landforms such as canyons, scars, and depressions in the Bahamas and the Maldives. Offshore meteoric groundwater (OMG) flow can drive mechanical instabilities in the outer shelf to upper slopeSuch instabilities occur at, or shortly after, the Last Glacial Maximum sea‐level lowstandCarbonate margins are more susceptible to mechanical instability by OMG than siliciclastic margins Offshore meteoric groundwater (OMG) flow can drive mechanical instabilities in the outer shelf to upper slope Such instabilities occur at, or shortly after, the Last Glacial Maximum sea‐level lowstand Carbonate margins are more susceptible to mechanical instability by OMG than siliciclastic margins

Krypton‐81 dating provides new insights into the timing, mechanisms, and extent of meteoric flushing versus retention of saline fluids in the subsurface in response to changes in geologic and/or climatic forcings over 50 ka to 1.2 Ma year timescales. Remnant Paleozoic seawater‐derived brines associated with evaporites in the Paradox Basin, Colorado Plateau, are beyond the 81Kr dating range (>1.2 Ma) and have likely been preserved due to negative fluid buoyancy and low permeability. 81Kr dating of formation waters above the evaporites indicates topographically‐driven meteoric recharge and salt dissolution since the Late Pleistocene (0.03–0.8 Ma). Formation waters below the evaporites (up to 3 km depth), in basal aquifers, contain relatively young meteoric water components (0.4–1.1 Ma based on 81Kr) that partially flushed remnant brines and dissolved evaporites. We demonstrate that recent, rapid denudation of the Colorado Plateau (<4–10 Ma) activated deep, basinal‐scale flow systems as recorded in 81Kr groundwater age distributions. Landscape changes over geological time alter hydraulic gradients and the presence or absence of near‐surface confining units, which drive the evolution of subsurface flow systems. However, our understanding of the time required for groundwater flow systems to respond to geological processes, such as shifts in topography, stratigraphy, and permeability structures, is still limited. This study uses krypton‐81 dating to constrain the age of meteoric waters in the Paradox Basin in the Colorado Plateau and constrain the timing of groundwater recharge into basinal aquifers. We discovered that rapid, widespread erosion and incision in the Colorado Plateau in the last 10 Ma activated deep meteoric circulation, partially flushing residual ancient seawater‐derived brines from aquifers above and below thick, evaporite confining units and dissolving salt. Krypton‐81 dating may provide insights into timescales and drivers of subsurface fluid flow and connectivity with the near‐surface in other environments. Meteoric waters up to 3 km in basinal aquifers are <1.1 MaRecent, rapid denudation of the Colorado Plateau enabled deep circulation of meteoric water and flushing of connate brinesKrypton‐81 dating can illuminate the timescales and extent of meteoric circulation in response to geologic and/or climatic forcings Meteoric waters up to 3 km in basinal aquifers are <1.1 Ma Recent, rapid denudation of the Colorado Plateau enabled deep circulation of meteoric water and flushing of connate brines Krypton‐81 dating can illuminate the timescales and extent of meteoric circulation in response to geologic and/or climatic forcings

Localized zones of high‐amplitude, discontinuous seismic reflections 100 km off the coast of Massachusetts, USA, have Pwave velocities up to 190 m/s lower than those of adjacent sediments of equal depth (250 m below the sea floor). To investigate the origin of these low‐velocity zones, we compare the detailed velocity structure across high‐amplitude regions to adjacent, undisturbed regions through full‐waveform inversion. We relate the full‐waveform inversion velocities to effective stress and overpressure with a power law model. This model predicts localized overpressures up to 2.2 MPa associated with the high‐amplitude reflections. To help understand the overpressure source, we model overpressure due to erosion, glacial loading, and sedimentation in one dimension. The modeling results show that ice loading from a late Pleistocene glaciation, ice loading from the Last Glacial Maximum, and rapid sedimentation contributed to the overpressure. Localized overpressure, however, is likely the result of focused fluid flow through a high‐permeability layer below the region characterized by the high‐amplitude reflections. These high overpressures may have also caused localized sediment deformation. Our forward models predict maximum overpressure during the Last Glacial Maximum due to loading by glaciers and rapid sedimentation, but these overpressures are dissipating in the modern, low sedimentation rate environment. This has important implications for our understanding continental shelf morphology, fluid flow, and submarine groundwater discharge off Massachusetts, as we show a mechanism related to Pleistocene ice sheets that may have created regions of anomalously high overpressure. Observe localized zones with high‐amplitude reflections off MassachusettsFull‐waveform inversion and 1D fluid flow modeling to understand overpressureFocused fluid flow from Pleistocene glaciations sources localized overpressure

The research described in this paper was conducted in part to understand whether different bicycling technology–-in this case, electric-assist bicycles (e-bikes)–-could reduce barriers to bicycling such as trip distance, topography, time, and rider effort. If so, this technology may result in more bike trips and longer bike trips and may increase the diversity of people bicycling, including people with disabilities or chronic injuries. An e-bike typically resembles a standard pedal bicycle with the addition of a rechargeable battery and electric motor to assist with propulsion. To address these aims, an online survey was conducted of existing e-bike users, who were surveyed about their purchase and use decisions. Responses from 553 e-bike users across North America were analyzed. Results suggest that e-bikes enable users to bike more often, to travel longer distances, and to carry more cargo with them. Additionally, e-bikes allow people who otherwise would not be able to bike (because of physical limitations or proximity to locations) the ability to bike with electric assist.

Hydraulic heads from a calibrated, three-dimensional, constant-density, groundwater-flow model were used to compute Hubbert oil potentials and infer secondary petroleum migration directions within the Llanos Basin, Colombia. The oil potentials for the C7 reservoir show evidence of the development of two hydrodynamic stagnation zones. Hydrodynamic effects on secondary oil migration are greatest in the eastern Llanos Basin where structural slopes are lowest and local hydraulic-head gradients drive ground-water flow westward down structural dip. The Rubiales field, a large oil reservoir within the eastern Llanos Basin with no structural closure, is located at the edge of one of these stagnation zones. This oil field hosts heavy oils 12° API) consistent with water washing and biodegradation The best agreement between model results and field conditions occurred in an oil density of 12 API, suggesting that the Rubiales field position is in dynamic equilibrium with modern hydraulic and oil density conditions. Cross sectional ground-water-flow models indicate that the most likely explanation of observed underpressures are caused by hydrodynamic effects associated with a topography-driven flow system. Late Miocene to present-day ground-water flow likely was an important factor in flushing marine connate porewaters from Tertiary reservoirs. Ground-water recharge along the western margin of the basin could help explain the observed low-temperature gradients (20°C/km). However, upward flow rates were not high enough to account for elevated temperature gradients of 50°C/km to the east. [ABSTRACT FROM AUTHOR]

Abstract: A retrospective cohort study was used to determine the extent to which immunisation visits due in the first year of life are split into separate visits. A one–month birth cohort of infants registered in early childhood health centres in the former Eastern Sydney Health Area was followed up when the infants were 8 to 11 months of age. A telephone questionnaire sought documented dates of each dose in the primary series of diphtheria–tetanus–pertussis (DTP), Haemophilus influenzae typeb (Hib) and hepatitis B (HBV) vaccination. Of the 141 subjects, 130 had received all due doses of DTP and Hib vaccines and 63 (45 per cent) had been enrolled in the neonatal hepatitis B program. Infants in the latter group received the first DTP–Hib dose on average one week later than did those not in the hepatitis B program (DTP, P= 0.016; Hib, P= 0.047). The greatest percentage of missed DTP or Hib doses occurred in infants not receiving HBV vaccination (7.1 per cent of doses) or those high–risk infants enrolled in the neonatal hepatitis B program (2.9 per cent). Overall, 12 infants had 28 (6.9 per cent) of the 404 possible scheduled visits fragmented into two separate visits. In all cases, parents reported that this was at the suggestion of the general practitioner. We found no greater likelihood of fragmentation for infants who had also received hepatitis B vaccine. Only 17 infants (29 per cent) had received the third hepatitis B vaccine and DTP doses at the same visit, as recommended. These findings confirm anecdotal reports of fragmentation of scheduled visits and missed doses for infants due to receive multiple injections, and some delay in uptake among those receiving hepatitis B vaccine. Universal infant hepatitis B immunisation should not be considered until combination vaccines (which should also include a Hib component) become available in Australia.

Localized depletion of 18O and 13C in a thin subhorizontal marble layer in the Adamello contact aureole, Southern Alps, Italy, resulted from fluid infiltration focused along a crosscutting dike. Values of δ18O and δ13C in calcite from the 1 m long profile decrease systematically from sedimentary values of δ18O = 22‰(SMOW) and δ13C= 0‰(PDB) to δ18O = 12.5‰ and δ13C ≈ -7‰ near the dike. The presence of clinozoisite and garnet in the 5-15 cm thick marble layers near the granodiorite dike indicates H2O-rich fluid conditions (XCO₂≈ 0.01 ).

A retrospective cohort study was used to determine the extent to which immunisation visits due in the first year of life are split into separate visits. A one-month birth cohort of infants registered in early childhood health centres in the former Eastern Sydney Health Area was followed up when the infants were 8 to 11 months of age. A telephone questionnaire sought documented dates of each dose in the primary series of diphtheria-tetanus-pertussis (DTP), Haemophilus influenzae typeb (Hib) and hepatitis B (HBV) vaccination. Of the 141 subjects, 130 had received all due doses of DTP and Hib vaccines and 63 (45 per cent) had been enrolled in the neonatal hepatitis B program. Infants in the latter group received the first DTP-Hib dose on average one week later than did those not in the hepatitis B program (DTP, P= 0.016; Hib, P= 0.047). The greatest percentage of missed DTP or Hib doses occurred in infants not receiving HBV vaccination (7.1 per cent of doses) or those high-risk infants enrolled in the neonatal hepatitis B program (2.9 per cent). Overall, 12 infants had 28 (6.9 per cent) of the 404 possible scheduled visits fragmented into two separate visits. In all cases, parents reported that this was at the suggestion of the general practitioner. We found no greater likelihood of fragmentation for infants who had also received hepatitis B vaccine. Only 17 infants (29 per cent) had received the third hepatitis B vaccine and DTP doses at the same visit, as recommended. These findings confirm anecdotal reports of fragmentation of scheduled visits and missed doses for infants due to receive multiple injections, and some delay in uptake among those receiving hepatitis B vaccine. Universal infant hepatitis B immunisation should not be considered until combination vaccines (which should also include a Hib component) become available in Australia.

First reported in the 1960s, offshore freshened groundwater (OFG) has now been documented in most continental margins around the world. In this review we compile a database documenting OFG occurrences and analyze it to establish the general characteristics and controlling factors. We also assess methods used to map and characterize OFG, identify major knowledge gaps, and propose strategies to address them. OFG has a global volume of 1 × 106km3; it predominantly occurs within 55 km of the coast and down to a water depth of 100 m. OFG is mainly hosted within siliciclastic aquifers on passive margins and recharged by meteoric water during Pleistocene sea level lowstands. Key factors influencing OFG distribution are topography‐driven flow, salinization via haline convection, permeability contrasts, and the continuity/connectivity of permeable and confining strata. Geochemical and stable isotope measurements of pore waters from boreholes have provided insights into OFG emplacement mechanisms, while recent advances in seismic reflection profiling, electromagnetic surveying, and numerical models have improved our understanding of OFG geometry and controls. Key knowledge gaps, such as the extent and function of OFG, and the timing of their emplacement, can be addressed by the application of isotopic age tracers, joint inversion of electromagnetic and seismic reflection data, and development of three‐dimensional hydrological models. We show that such advances, combined with site‐specific modeling, are necessary to assess the potential use of OFG as an unconventional source of water and its role in sub‐seafloor geomicrobiology. This review paper considers offshore freshened groundwater (OFG), which is water hosted in sediments and rocks below the seafloor, with a total dissolved solid concentration lower than seawater. We have compiled >300 records to demonstrate that freshened groundwater occurs offshore on most continents around the world and has a global volume of 1 × 106km3. The majority of OFG was deposited when sea level was lower than today and is hosted in sandy sub‐seafloor layers that are located within 55 km of coasts in water depths less than 100 m. We present a range of geochemical, geophysical, and modeling approaches that have successfully been used to investigate OFG systems. We also propose approaches to address key scientific questions related to OFG, including whether it may be used as an unconventional source of potable water in coastal areas. Most known OFG is located at water depths of <100 m within 55 km of the coast, hosted in siliciclastic aquifers in passive marginsKey gaps in knowledge include the extent and function of OFG systems, as well as the mechanism and timing of emplacementIsotopic tracers, jointly inverted geophysical data and 3‐D hydrological models can help address these knowledge gaps

Since 1996, south‐eastern Australia has been experiencing a pertussis epidemic which has resulted in the deaths of several infants, including four from NSW in the 12 months to July 1997. All were less than six weeks of age and died from overwhelming cardiovascular compromise despite intensive care support. This excessive infant mortality from a preventable disease demonstrates the need for better pertussis immunity in the community and for erythromycin treatment of all suspected cases and family contacts, especially infants.

Reports on the development of the Coupled Land Atmosphere Simulation Program (CLASP II) to evaluate aquifer-land-surface-atmosphere interactions at the watershed scale by University of Minnesota and Iowa State University. Evaluation of past, present and future surface water-aquifer-atmosphere by model; Simulation by ATMOS, Vegetation, Overland flow, Soil (VOS), and Modular groundwater Flow models.