L. Büngener

Bio: L. Büngener is an academic researcher from University of Oulu. The author has contributed to research in topics: Mire & Groundwater. The author has co-authored 1 publications.

Quantifying groundwater fluxes from an aapa mire to a riverside esker formation

Abstract: Water flows in peatland margins is an under-researched topic. This study examines recharge from a peatland to an esker aquifer in an aapa mire complex of northern Finland. Our objective was to study how the aapa mire margin is hydrogeologically connected to the riverside aquifer and spatial and temporal variations in the recharge of peatland water to groundwater (GW). Following geophysical studies and monitoring of the saturated zone, a GWmodel (MODFLOW) was used in combination with stable isotopes to quantify GW flow volumes and directions. Peatland water recharge to the sandy aquifer indicated a strong connection at the peatland–aquifer boundary. Recharge volumes from peatland to esker were high and rather constant (873 m d ) and dominated esker recharge at the study site. The peat water recharging the esker boundary was rich in dissolved organic carbon (DOC). Stable isotope studies on water (δO, δH, and d-excess) from GW wells verified the recharge of DOC-rich water from peatlands to mineral soil esker. Biogeochemical analysis revealed changes from DOC to dissolved inorganic carbon in the flow pathway from peatland margin to the river Kitinen. This study highlights the importance of careful investigation of aapa mire margin areas and their potential role in regional GW recharge patterns.

Stable Water Isotopes as an Indicator of Surface Water Intrusion in Shallow Aquifer Wells: A Cold Climate Perspective

Abstract: Groundwater in shallow aquifers is commonly used for community water supply in cold climates. Shallow groundwaters are inherently susceptible to contamination from land‐use and surface water intrusion threatening drinking water usage. We used a large‐scale snapshot data set of stable water isotopes from shallow glaciofluvial aquifers used for drinking water supply in Northern Finland to assess surface water intrusion risks and recharge conditions. This data set was supplemented by long‐term stable water isotope precipitation data, Geographic Information System proximity analysis and multivariate statistics. The isotope analysis suggest that a warm season contributes about 60% to the total annual precipitation in the region. This is reflected in the aquifers isotopic composition as it represents an approximately equal mixture of warm and cold season precipitation. Groundwater isotope data normalized to precipitation inputs by line‐conditioned excess (lc‐excess) was used to flag the water supply wells impacted by surface water intrusions. The proximity analysis showed some of the wells may be affected by intrusions from gravel pit ponds, lakes and peatland drainage. On the larger scale, the wells in coastal areas were more likely to have evaporated water (intrusion) compared to inland regions of Northern Finland due to lower water availability and the presence of man‐made structures. This application of stable water isotopes with lc‐excess is a useful approach not only for recharge studies but also within water management for supply well surface water contamination risk assessment.

Stable Water Isotopes as an Indicator of Surface Water Intrusion in Shallow Aquifer Wells: A Cold Climate Perspective

Abstract: Groundwater in shallow aquifers is commonly used for community water supply in cold climates. Shallow groundwaters are inherently susceptible to contamination from land-use and surface water intrusion threatening drinking water usage. We used a large-scale snapshot data set of stable water isotopes from shallow glaciofluvial aquifers used for drinking water supply in Northern Finland to assess surface water intrusion risks and recharge conditions. This data set was supplemented by long-term stable water isotope precipitation data, Geographic Information System proximity analysis and multivariate statistics. The isotope analysis suggest that a warm season contributes about 60% to the total annual precipitation in the region. This is reflected in the aquifers isotopic composition as it represents an approximately equal mixture of warm and cold season precipitation. Groundwater isotope data normalized to precipitation inputs by line-conditioned excess (lc-excess) was used to flag the water supply wells impacted by surface water intrusions. The proximity analysis showed some of the wells may be affected by intrusions from gravel pit ponds, lakes and peatland drainage. On the larger scale, the wells in coastal areas were more likely to have evaporated water (intrusion) compared to inland regions of Northern Finland due to lower water availability and the presence of man-made structures. This application of stable water isotopes with lc-excess is a useful approach not only for recharge studies but also within water management for supply well surface water contamination risk assessment.