Assessing the magnitude and timing of anthropogenic warming of a shallow aquifer: example from Virginia Beach, USA

Eggleston, Jack; McCoy, Kurt J.

doi:10.1007/s10040-014-1189-y

Cited by 20 publications

(12 citation statements)

References 33 publications

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“…Cold water ecosystems have evolved around the physical hydrogeologic template, where groundwater discharge zones contribute to refugia points of thermal buffering against highly variable atmospheric conditions (Isaak, Young, Nagel, Horan, & Groce, ). Human development in watershed contributing areas and warming air temperatures are expected to alter groundwater temperature (Eggleston & McCoy, ) and impair groundwater‐dependent ecosystems (Kløve et al, ). As a spatially distributed characterization of preferential groundwater discharges and their source flowpath dynamics is developed, predictions of future cold water habitat dynamics can more reliably be developed (Burns, ; Hare et al, ).…”

Section: Realized Benefits and Future Targetsmentioning

confidence: 99%

Explicit consideration of preferential groundwater discharges as surface water ecosystem control points

Briggs

Hare

2018

Hydrological Processes

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| BACKGROUNDHeterogeneities in sediment and rock permeability induce preferential groundwater flow from the scale of pore networks to large basins. In the unsaturated zone, preferential flow is frequently conceptualized as an infiltration process dominated by macropores, resulting in stronger delivery of surface-derived solute than would be predicted via diffuse percolation alone (Beven & Germann, 2013). In the saturated zone, preferential flow occurs in bedrock fractures and karst, along geologic contacts and fault zones, and through unconsolidated materials of relatively high connectivity (Winter, Harvey, Franke, & Alley, 1998). Focused flow paths emanate on the land surface as preferential groundwater discharges, observed throughout stream, lake, wetland, and estuary systems. The prevalence, and perhaps dominance, of spatially focused discharges to surface water contrasts with the spatially diffuse flow often assumed in various conceptual and predictive process-based models. This simplification is not made out of an unawareness of preferential groundwater discharge; rather, the ability to reliably measure focused flow across a range of scales is hampered by a reliance on (relatively) sparse point measurements. Additionally, realistic distributions of <1-to 100-m-scale preferential groundwater discharges are computationally expensive to simulate at scales relevant to decision making. If we accept that preferential discharge of groundwater to surface water is an ubiquitous process, fundamental questions facing contemporary hydrogeology include (a) When does spatially focused groundwater discharge matter to the process we would like to predict? Followed by (b) If we determine when preferential discharge "matters" and should not be simplified to diffuse inflows, how do we measure it at the spatial and temporal scales needed to inform process-based models?A lopsided emphasis on hyporheic exchange processes has dominated groundwater/surface water exchange research for the past 15 years, as reviewed thoroughly by Boano et al. (2014) and Cardenas (2015). Within this body of research, there is growing recognition of the need to characterize surface water "ecosystem control points" that exert strong influence on the physical exchange and reaction of elements throughout river networks (Bernhardt et al., 2017). However, the process of preferential groundwater discharge is often not explicit in these discussions. The more universal definitions of hyporheic flow involve bidirectional exchange of surface water with near-stream saturated sediments. This definition is distinct from unidirectional preferential groundwater discharge to the land surface. The streambed is often incorrectly characterized as a zone of substantial mixing of groundwater and surface water; however, multiple studies indicate that groundwater and surface water mixing is limited to relatively narrow subsurface convergence zones (e.g., Hester, Young, & Widdowson, 2013). Popular stream-based transient storage models conceptually reduce groundwater discharge...

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Section: Realized Benefits and Future Targetsmentioning

confidence: 99%

Explicit consideration of preferential groundwater discharges as surface water ecosystem control points

Briggs

Hare

2018

Hydrological Processes

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“…Therefore, it is unlikely that observed SGW temperature differences can be attributed to increased radiative heating of the Ag site ground surface. This conclusion contrasts with those of previous studies (Hewlett and Fortson, ; Henriksen and Kirkhusmo, ; Beltrami and Kellman, ; Ferguson and Beltrami, ; Eggleston and McCoy, ; Guenther et al ., ). However, the majority of such studies investigated the impact of recent forest clearing on groundwater temperatures.…”

Section: Discussionmentioning

confidence: 99%

“…basements and sewers) between 1977 (median: 759 mW/m 2 ; standard deviation: 89 mW/m 2 ) and 2011 (median: 828 mW/m 2 ; standard deviation: 143 mW/m 2 ). Eggleston and McCoy (), studying the impact of urbanization on coastal aquifer thermal regimes, reported a negative correlation between canopy cover and groundwater temperatures at 30 m depth. Kurylyk et al .…”

Section: Introductionmentioning

confidence: 99%

“…basements and sewers) between 1977 (median: 759 mW/m 2 ; standard deviation: 89 mW/m 2 ) and 2011 (median: 828 mW/m 2 ; standard deviation: 143 mW/m 2 ). Eggleston and McCoy (2014), studying the impact of urbanization on coastal aquifer thermal regimes, reported a negative correlation between canopy cover and groundwater temperatures at 30 m depth. Kurylyk et al (2015), in a comparative modelling study using several analytical solutions to the one-dimensional equation for subsurface heat transport, found that land cover disturbances (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Agricultural and forested land use impacts on floodplain shallow groundwater temperature regime

Kellner

Hubbart

2015

Hydrological Processes

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Given the importance of groundwater temperature to the biogeochemical health of aquatic ecosystems, a floodplain study was implemented to improve understanding of rural land use impacts on shallow groundwater (SGW) temperature. Study sites included a historic agricultural field (Ag) and bottomland hardwood forest (BHF), each with nine piezometers in an 80 × 80 m grid. Piezometers were equipped with pressure transducers to monitor SGW temperature and level at 30 min intervals during the 2011, 2012, 2013, and 2014 water years. The study is one of the first to utilize long‐term, continuous, automated, in situ monitoring to investigate rural land use impacts on shallow groundwater temperatures. Average SGW temperature during the study period was 11.1 and 11.2 °C at the Ag and BHF sites, respectively. However, temperature range at the Ag site was 72% greater than at the BHF site. Results indicate a greater responsiveness to seasonal climate fluctuations in Ag site SGW temperature related to absence of forest canopy. Patterns of intra‐site groundwater temperature differences at both study sites illustrate the influence of stream–aquifer thermal conduction and occasional baseflow reversals. Considering similar surface soil temperature amplitudes and low average groundwater flow values at both sites, results suggest that contrasting rates of plant water use, groundwater recharge, and subsurface hydraulic conductivity are likely mechanistic causes for the observed SGW temperature differences. Results highlight the long‐term impact of forest removal on subsurface hydrology and groundwater temperature regime. Copyright © 2015 John Wiley & Sons, Ltd.

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“…Natural in situ temperatures usually do not substantially vary at a depth of more than 10-20 m. Here, ground and groundwater temperatures are close to the annual mean values in the atmosphere, and commonly only a marginal attenuated influence of the coupled seasonal temperature variation in the atmosphere can be detected [1]. During recent years, attention has been growing to the thermal conditions beneath cities, which were revealed to be completely different when compared to the undisturbed rural surrounding [2][3][4][5][6][7][8][9]. However, the knowledge of the spatial and temporal variability of temperature in urban ground is crucial for proper planning of geothermal energy use.…”

Section: Introductionmentioning

confidence: 95%

Estimation of Groundwater Temperatures in Paris, France

et al. 2019

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Subsurface temperature data is usually only accessible as point information with a very limited number of observations. To spatialize these isolated insights underground, we usually rely on interpolation methods. Unfortunately, these conventional tools are in many cases not suitable to be applied to areas with high local variability, like densely populated areas, and in addition are very vulnerable to uneven distributions of wells. Since thermal conditions of the surface and shallow subsurface are coupled, we can utilize this relationship to estimate shallow groundwater temperatures from satellite-derived land surface temperatures. Here, we propose an estimation approach that provides spatial groundwater temperature data and can be applied to natural, urban, and mixed environments. To achieve this, we combine land surface temperatures with anthropogenic and natural processes, such as downward heat transfer from buildings, insulation through snow coverage, and latent heat flux in the form of evapotranspiration. This is demonstrated for the city of Paris, where measurements from as early as 1977 reveal the existence of a substantial subsurface urban heat island (SUHI) with a maximum groundwater temperature anomaly of around 7 K. It is demonstrated that groundwater temperatures in Paris can be well predicted with a root mean squared error of below 1 K by means of satellite-derived land surface images. This combined approach is shown to improve existing estimation procedures that are focused either on rural or on urban conditions. While they do not detect local hotspots caused by small-scaled heat sources located underground (e.g., sewage systems and tunnels), the findings for the city of Paris for the estimation of large-scale thermal anomalies in the subsurface are promising. Thus, the new estimation procedure may also be suitable for other cities to obtain a more reliable insight into the spatial distribution of urban ground and groundwater temperatures.

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Assessing the magnitude and timing of anthropogenic warming of a shallow aquifer: example from Virginia Beach, USA

Cited by 20 publications

References 33 publications

Explicit consideration of preferential groundwater discharges as surface water ecosystem control points

Explicit consideration of preferential groundwater discharges as surface water ecosystem control points

Agricultural and forested land use impacts on floodplain shallow groundwater temperature regime

Estimation of Groundwater Temperatures in Paris, France

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