0000000000264309
AUTHOR
Alise Babre
showing 10 related works from this author
Pleistocene age paleo-groundwater inferred from water-stable isotope values in the central part of the Baltic Artesian Basin.
2016
A new data set of δ(2)H and δ(18)O in the groundwater from the central part of the Baltic Artesian Basin is presented. The hydrogeological section is subdivided into stagnation, slow exchange and active exchange zones. Na-Ca-Cl brine found at the deepest part - the stagnation zone - is characterized by δ(18)O values above -5 ‰ and δ(2)H values approaching -40 ‰ with respect to Vienna Standard Mean Ocean Water. The slow exchange zone where waters of mostly intermediate salinity reside is characterized by δ(18)O values around -11.7 ‰ and δ(2)H values around -85.3 ‰. Mean δ(18)O and δ(2)H values of the fresh groundwater in the active water exchange zone are -11.1 and -79.9 ‰, respectively. Cha…
Gruntsūdens plūsmas modelēšana ūdensgūtņu Baltezers un Baltezers ІІ apkārtnē
2010
Maģistra darba pētījumā veikta hidroģeoloģiskā modeļa izveide Baltezers un Baltezers II ūdensgūtņu apkārtnē. Ūdensgūtņu teritorijā raksturīgi sarežģīti hidroģeoloģiskie apstākļi, kas saistīti ar pazemes ūdens ieguvi no Kvartāra ūdens kompleksa centralizētajai ūdens apgādei un gruntsūdens mākslīgo papildināšanu no virszemes ūdens objektiem. Pētījuma teritorija aptver 20 km2 lielu platību, kurā iekļauta visa aktīvā ūdens apmaiņas zona. Hidroģeoloģiskā modeļa izveidei izmantota PAIC izstrādātā datorprogramma HiFiGeo v3.5. Pētījuma rezultātā tika izveidots kalibrēts hidroģeoloģiskais modelis, kurš izmantots divu situāciju modelēšanai, pie mainīgiem ūdensgūtņu režīmiem. Balstoties uz modelētajie…
Water stable isotope data set in temperate, lowland catchment, two years of monthly observations, River Salaca, Latvia
2020
Highlights • Two years of monthly water stable isotope ratios from temperate lowland catchment. • Hourly water table, temperature and electrical conductivity monitoring. • Distinct isotope ratios for raised bog, groundwater and rivers.
A δ18O isoscape for the shallow groundwater in the Baltic Artesian Basin
2016
The study presents a shallow groundwater isoscape for the Baltic region, which covers the major part of the Baltic Artesian Basin (BAB). BAB is an important palaeogroundwater reservoir, but prior to this study, little has been known about the spatial variability of δD and δ18O values in modern precipitation input across the region. To overcome this limitation, we hypothesized that the isotopic composition of shallow groundwater in the BAB could be used as a proxy for the mean weighted annual isotopic composition of local precipitation. However, the results of the study reveal many clear discrepancies between the isotopic composition of precipitation and shallow groundwater in the area. The …
Geochemical classification of groundwater using multivariate statistical analysis in Latvia
2016
Multivariate statistical methods – principal component analysis (PCA) and hierarchical cluster analysis (HCA) – are applied to identify geochemically distinct groundwater groups in the territory of Latvia. The main processes observed to be responsible for groundwater chemical composition are carbonate and gypsum dissolution, fresh and saltwater mixing and ion exchange. On the basis of major ion concentrations, eight clusters (C1–C8) are identified. C6 is interpreted as recharge water not in equilibrium with most sediment forming minerals. Water table aquifers affected by diffuse agricultural influences are found in C3. Groundwater in C4 reflects brine or seawater admixture and gypsum dissol…
An insight into water stable isotope signatures in temperate catchment
2020
Abstract Stable isotopes are used to decipher hydrological processes in watershed research. A two-year monthly monitoring of hydrogen and oxygen stable isotope ratios (δ2H and δ18O) in a temperate catchment in Norther Europa, Latvia was undertaken. Isotope ratios in common water types – raised bog, confined groundwater, unconfined groundwater and surface water – were measured. We found characteristic signatures of isotope ratios for each of these four water types. The average isotope ratios of different water types ranged from −80.8 to −68.3‰ for δ2H and −11.46 to −8.76‰ for δ18O, with standard deviations from 18 to 25‰ and 0.10 to 1.59‰, respectively. The isotope ratios of the stream base …
Effects of karst processes on surface water and groundwater hydrology at Skaistkalne Vicinity, Latvia
2012
The Skaistkalne area in Latvia is one of the places where karst processes in gypsum strata occurs. The Iecava and Memele rivers border the area with extensive surface karst features such as sinkholes and karst lakes. Earlier investigations suggested a hydraulic connection between the Iecava and Memele rivers exists via the karst conduits due to the water level (WL) difference in the rivers. A set of methods was performed to study the possible connection: dye tracer was applied in the Iecava river and its occurrence was visually observed at the karst lakes and Memele river; the current velocity was measured and discharge of rivers calculated at several profiles; surface water and groundwater…
Using 81Kr and Noble Gases to Characterize and Date Groundwater and Brines in the Baltic Artesian Basin on the One-Million-Year Timescale
2017
Analyses for $^{81}$Kr and noble gases on groundwater from the deepest aquifer system of the Baltic Artesian Basin (BAB) were performed to determine groundwater ages and uncover the flow dynamics of the system on a timescale of several hundred thousand years. We find that the system is controlled by mixing of three distinct water masses: Interglacial or recent meteoric water $(\delta^{18}\text{O} \approx -10.4\unicode{x2030})$ with a poorly evolved chemical and noble gas signature, glacial meltwater $(\delta^{18}\text{O} \leq -18\unicode{x2030})$ with elevated noble gas concentrations, and an old, high-salinity brine component $(\delta^{18}\text{O} \geq -4.5\unicode{x2030}, \geq 90 \text{g …
Autotransporta radītā trokšņa modelēšana “Rīgas ziemeļu transporta koridoram”
2008
Troksnis ir nozīmīgs miega traucējumu, darbaspēju mazināšanās un stresa izraisītājs. Jo īpaši paaugstinātām trokšņu vērtībām tiek pakļauti lielpilsētu iedzīvotāji. Satiksmes radītais troksnis ir lielākais vides trokšņa avots Eiropas Savienības valstīs. Izmantojot matemātiskās modelēšanas priekšrocības tika veikta trokšņu līmeņa prognozēšana vienam no lielākajiem Rīgas infrastruktūras projektiem. Darba gaitā tika sagatavots kartogrāfiskais materiāls esošās situācijas un iespējamo izmaiņu atainošanai. Iegūtie rezultāti liecina par būtisku trokšņu līmeņa pieaugumu plānotā projekta teritorijā. Lielu ietekmi uz trokšņu nevienmērīgo izplatību noteica valdošo vēju virziens un plānotais ceļa profil…
Pleistocene age paleo-groundwater inferred from water-stable isotope values in the central part of the Baltic Artesian Basin
2016
A new data set of δ2H and δ18O in the groundwater from the central part of the Baltic Artesian Basin is presented. The hydrogeological section is subdivided into stagnation, slow exchange and active exchange zones. Na–Ca–Cl brine found at the deepest part – the stagnation zone – is characterized by δ18O values above −5 ‰ and δ2H values approaching −40 ‰ with respect to Vienna Standard Mean Ocean Water. The slow exchange zone where waters of mostly intermediate salinity reside is characterized by δ18O values around −11.7 ‰ and δ2H values around −85.3 ‰. Mean δ18O and δ2H values of the fresh groundwater in the active water exchange zone are −11.1 and −79.9 ‰, respectively. Characteristically,…