70 research outputs found
Geological Model of Latvia Developed at Riga Technical University (2010ā2015)
No full textHydrogeological models (HM) are developed in order to gain information that is needed for managing the protection and sustainable consumption of groundwater resources. The researchers of Riga Technical University (RTU) have developed two regional scales of HM of Latvia: in 1993-1996, REMO (Large Riga) and, in 2010-2012, LAMO1 (the first HM version). REMO covered the central part of Latvia and its plane approximation step was 4000 meters. LAMO1 encloses the ground territory of Latvia, the Gulf of Riga, and border areas with neighbouring countries (Estonia, Lithuania, Russian Federation, Belorussia). The HM plane step is 500 metres. Presently, the neighbouring areas of HM are not active. In the case of a transboundary projects the neighbouring country must provide hydrogeological data necessary to activate its neighbouring area. LAMO1 generalizes geological and hydrogeological data that have been accumulated by the Latvian Environment, Geology and Meteorology Centre (LEGMC). LAMO runs into the environment of licensed software Groundwater Vistas that is being used worldwide for modelling groundwater processes. In 2012-2015, LAMO1 was considerably updated, in order to improve the quality of results provided by HM. The LAMO2 version (2013) accounted for deep river valleys cutting the primary strata; the thick Devonian D2ar aquifer was replaced by the two aquifers and the aquitard that separated them; due to this innovation, the number of the HM planes increased from 25 to 27. In 2014, the LAMO3 version was obtained by increasing the density of the HM hydrogeological network (number of rivers and lakes, increased, accordingly, from 199 to 469 and from 67 to 127). For the current LAMO4 version, the plane step was reduced from 500 to 250 meters; the groundwater inflow for rivers was calibrated by accounting for information obtained from measurements of river flows. For LAMO1 and LAMO2, the permeability of primary aquifers (k-maps) was modelled by using a constant permeability value for an aquifer. In LAMO3 and LAMO4, more realistic k-maps were obtained by accounting for pumping data of wells. Presently, the latest LAMO4 version is being used by LEGMC and RTU specialists as the source of information on the geometry and permeability of geological strata, on distributions of groundwater heads and flows, on interaction between groundwater and surface water bodies (sea, lakes, rivers, precipitation). LAMO4 has been used by RTU researchers as a tool for investigating nature processes of the groundwater system of Latvia. The first results were quite unexpected, because it was found that the river watershed basin concept could not be used for the deepest strata of the basin. The research on LAMO3 and LAMO4 is supported by the Latvian state research program EVIDEnT
Latvijas ReÄ£ionÄlo hidroÄ£eoloÄ£isko modeļu Ä«stenoÅ”anas vÄsture RÄ«gas TehniskajÄ universitÄtÄ (metodes un problÄmas)
No full textKopÅ” 1993. gada RÄ«gas TehniskÄ universitÄte (RTU) ir piedalÄ«jusies Latvijas reÄ£ionÄlo hidroÄ£eoloÄ£isko modeļu Ä«stenoÅ”anÄ: ReÄ£ionÄlais Modelis (REMO) āLielÄ RÄ«gaā veidots no 1993. gada lÄ«dz 1996. gadam un 2010. gadÄ uzsÄkts Ä«stenot ERAF projektu āHidroÄ£eoloÄ£iskÄ modeļa izveidoÅ”ana Latvijas pazemes Å«dens krÄjumu apsaimniekoÅ”anai un vides atveseļoÅ”anaiā (vienoÅ”anÄs numurs Nr. 2010/0220/2DP/2.1.1.1.0/10 APIA/VIAA/011).
Modelis REMO izveidots kopÄ ar bijuÅ”o Valsts Ä¢eoloÄ£ijas dienestu un paredzÄts informÄcijas apkopoÅ”anai par Latvijas centrÄlÄs daļas Devona artÄziskajÄm Å«densgÅ«tnÄm (RÄ«ga, JÅ«rmala, Jelgava u.c.). HidroÄ£eoloÄ£iskais modelis (HM) aptver 168kmĆ156km platÄ«bu. Režģa plaknes solis ir 4000m. VertikÄlÄ virzienÄ REMO satur 10 horizontus, kurus atdala sprostslÄÅi. KopÄ«gais mezglu skaits N=43Ć40Ć10=17200. ModelÄÅ”anas rezultÄti apkopoti karÅ”u atlasÄ, kurÅ” publicÄts 1996. g. Modelis tika izmantots RÄ«gas pilsÄtas jauno pazemes Å«dens avotu pÄtÄ«Å”anai (1996.g.), InÄukalna gudrona dÄ«Ä·u areÄla HM veidoÅ”anai (1998.g.) un Å«densgÅ«tnes aprÄÄ·iniem Coca-Cola rÅ«pnÄ«cai (2009.g.)
1996.gadÄ reÄ£ionÄlÄ HM āLielÄ RÄ«gaā izveidoÅ”ana bija ievÄrojams profesionÄls sasniegums. Modeļa Ä«stenoÅ”anai tika radÄ«ti un izmantoti jauni algoritmi un programmatÅ«ras rÄ«ki (galvenÄ modelÄjoÅ”Ä programma, Ä£eoloÄ£isko datu interpolÄcijas programma, kura var izmantot lÄ«nijas kÄ datu nesÄjus, zemes virsmas reljefa karte kÄ robežnoteikums reÄ£ionÄlÄs infiltrÄcijas plÅ«smas automÄtiskai aprÄÄ·inÄÅ”anai u.c.).
MÅ«sdienu vÄrtÄjumÄ HM āLielÄ RÄ«gaā ir Å”Ädi trÅ«kumi:
-modelis aptver tikai centrÄlo Latvijas daļu;
-modeļa realizÄcijas programmatÅ«ra ir oriÄ£inÄls rÄ«ks, kura sekmÄ«gai izmantoÅ”anai lietotÄjam (Valsts Ä£eoloÄ£ijas dienests) bija jÄsaglabÄ cieÅ”a saite ar autoriem. PÄc 1996. gada Å”Äda saite nepastÄvÄja un tÄpÄc HM tika izmantots tikai RTU;
-modeļa plaknes aproksimÄcijas solis 4000m ir pÄrÄk liels;
-modeļa izmantotÄ kvazi-trÄ«sdimensiju galÄ«go starpÄ«bu aproksimÄcijas shÄma nedod precÄ«zu saskaÅojumu ar licenzÄtÄm programmatÅ«rÄm, kuras izmanto Å«dens daļiÅu un piesÄrÅojuma kustÄ«bas modelÄÅ”anai.
Valsts Ä£eoloÄ£ijas dienestam pÄc 1996. gada zuda aktÄ«va vajadzÄ«ba izmantot HM āLielÄ RÄ«gaā Å”Ädu iemeslu dÄļ:
-tika pieÅemts un Ä«stenots lÄmums par Daugavas plaÅ”u izmantoÅ”anu RÄ«gas pilsÄtas Å«dens apgÄdei;
-visÄ LatvijÄ pazemes Å«dens patÄriÅÅ” bÅ«tiski samazinÄjÄs.
Laika posmÄ starp REMO un jauno ERAF projektu RTU Vides modelÄÅ”anas centrs, realizÄjot praktiskos uzdevumus, bÅ«tiski pilnveidoja prasmes, metodes un rÄ«kus HM veidoÅ”anai:
-HM tiek veidoti komecprogrammatÅ«ras Groundwater Vistas (GV) vidÄ; Å Ä« programmatÅ«ra tiek regulÄri modernizÄta (Å”obrÄ«d izmanto GV5 versiju) un tiek plaÅ”i izmantota EiropÄ un pasaulÄ; GV ietver plaÅ”u specializÄto rÄ«ku klÄstu: MODFLOW, MODPATH, MT3D u.c., kurus pilnveido ASV Ä£eoloÄ£ijas dienests;
-vairÄkkÄrt modernizÄts (1999.g., 2007.g.) RTU izstrÄdÄtais Ä£eoloÄ£isko datu interpolÄcijas rÄ«ks;
-pilnveidota metodika, kura paredz zemes virsmas reljefa kartes izmantoÅ”anu infiltrÄcijas plÅ«smas realizÄcijai;
-aprobÄta HM Ä«stenoÅ”anas metode, kura neprasa (vismaz modeļa bÅ«ves sÄkumÄ) izmantot reÄlo Ä£eoloÄ£iskÄs vides Ä£eometriju.
ERAF projektÄ (2 gadi Ä«stenoÅ”anai, finansÄjums 140900Ls) Ä«stenotais HM bÅ«s daļa no Latvijas VienotÄs vides informÄcijas sistÄmas, kuru uztur Latvijas Vides, Ä£eoloÄ£ijas un meteoroloÄ£ijas centrs (LVÄ¢MC). Modeļa esamÄ«ba uzlabos Ŕīs sistÄmas kvalitÄti, jo bÅ«s publiski pieejami dati, kuri nepiecieÅ”ami pazemes Å«dens resursu racionÄlai pÄrvaldÄ«bai un Eiropas SavienÄ«bas direktÄ«vu Ä«stenoÅ”anai pirmajam plÄnoÅ”anas ciklam (2004.g.-2015.g.).
Latvijas HM aptvers 475kmļ“300km areÄlu aktÄ«vajai pazemes Å«dens zonai (lÄ«dz PÄrnavas horizontam), kuru LatvijÄ izmanto dzeramÄ Å«dens apgÄdei. Modelis tiks realizÄts GV vidÄ, plaknes aproksimÄcijas solis 500m, izmantojot pilno trÄ«sdimensiju galÄ«go starpÄ«bu aproksimÄcijas shÄmu. Galvenie HM Ä«stenoÅ”anas pasÄkumi ir Å”Ädi:
-prasÄ«bu saskaÅoÅ”ana ar LVÄ¢MC par HM kÄ VienotÄs vides informÄcijas sistÄmas moduli; modeļa
Limits and Presuppositions on Creating and Use of the Regional Hydrogeological Model of Latvia
No full textTe main limits regarding the regional hydrogeological model (HM) of Latvia (see Fig. 1) are, as follows:
-HM will be used for management of drinking groundwater resources of Latvia;
-HM is created by the Environment Modelling Centre team of the Riga Technical University (RTU) ; the project is co financed by the European Fund of Regional Development;
-the project duration is 24 months; in 2013, HM must be established;
-geological and hydrogeological information, needed for establishing HM, is provided by the Latvian Environment, Geology and Meteorology Centre (LEGMC);
-principal parameters of HM must be agreed between RTU and LEGMC;
-data carried by HM must be publicly available as a part of Latvia environment information system; the system is supported by LEGMC;
-during five years (till 2017), RTU and LEGMC cannot use HM commercially.
Fig. 1: Location of Latvia HM
HM of Latvia will generalize geological and hydrogeological information accumulated by LEGMC. HM will also serve as the base for creating more detailed local HM.
It is not possible to incorporate into regional HM all data that can be provided by LEGMC. Reasonable reduction of HM complexity can be achieved by implementing the following presuppositions:
-complexity and dimensions of HM must not exceed feasibility of a modern personal computer used to run HM; HM simulates the steady state average regimes of the groundwater flow; the HM area size is 475kmļ“300km; the HM volume is approximated by the finite difference method; its plane approximation step is 500 meters; the spatial HM grid contains 25 planes; therefore, the grid consists of 951ļ“601ļ“25=14.86ļ“106 nodes; the HM volume represents the active groundwater zone that is bedded by the regional Narva aquitard;
-to ensure compatibility with models and software tools of other countries, the commercial program āGroundwater Vistasā (GV) is used for running of HM; the program is being regularly updated (GV- 6 version is available); it contains software tools MODFLOW, MODPATH, MT3D applied for groundwater modelling worldwide;
-at the present, HM consists of its active and passive parts; the active part includes the land territory of Latvia and the Gulf of Riga; the passive part represents border areas of neighboring countries. However, HM is open for trans boundary modelling projects; then a neighboring country provides data for activating the HM area involved;
-although, buried valleys may be of considerable importance, they are not accounted for by the current HM version; it is difficult to create them geometrically, a filling material of valleys may be unknown;
-in HM, only the Narva aquitard is continuous; the other geological layers are discontinuous, because they include areas with a zero thickness; for the model, these areas have the thickness 0.02 meters, their permeability is 1.0m/day;
-three elevation surfaces of HM are especially important:
-the hydrogeological relief relh that represents the ground surface where the hydrographical network is incorporated;
-the geological relief relg that gives land surface elevations;
-the sub Quaternary surface subQ that covers the system of basic geological layers.
The difference mw=relh-relg is the thickness of surface water bodies. (in HM, mw >0 for the sea area and for the Daugava river with its three lakes of hydroelectric power stations); for other water bodies (lakes, rivers), mw =0.
The difference ā=relg-subQ is used for obtaining the Quarternary system thickness mQ: mQ=ā if ā>1.0; mQ=1.0 if āļ£1.0 and relg=subQ+1; by correcting relg, along the river valleys where ā<0, the subQ surface remains unchanged (no deep valleys are cut into it); otherwise, the grid nodes will be lost where river long lines elevations must be connected (option River of GV):
-the relh map serves as the piezometric boundary condition, on the HM top; due to this condition, HM automatically creates a feasible infiltration flow distribution;
-no re
Latvijas hidroÄ£eoloÄ£iskais modelis pazemes dzeramÄ Å«dens krÄjumu pÄrvaldÄ«Å”anai un atveseļoÅ”anai
No full textRÄ«gas TehniskÄ universitÄte (RTU) ir piedalÄ«jusies Latvijas reÄ£ionÄlo hidroÄ£eoloÄ£isko modeļu (HM) izveidoÅ”anÄ pazemes Å«dens krÄjumu racionÄlai apsaimniekoÅ”anai. ReÄ£ionÄlais modelis (REMO) āLielÄ RÄ«gaā veidots no 1993. gada lÄ«dz 1996. gadam kopÄ ar bijuÅ”o Valsts Ä£eoloÄ£ijas dienestu. Modelis REMO aptvÄra Latvijas centrÄlo daļu. HM izveidoÅ”anu visai Latvijas teritorijai RTU uzsÄka 2010. gadÄ. RakstÄ aplÅ«kota Å«dens krÄjumu apsaimniekoÅ”ana LatvijÄ, dots Latvijas HM apraksts un izklÄstÄ«ti tÄ veidoÅ”anas etapi un metodika. Modelis tiks iekļauts Latvijas VienotajÄ vides informÄcijas sistÄmÄ, kuru uztur Latvijas Vides, Ä£eoloÄ£ijas un meteoroloÄ£ijas centrs. Par Latvijas HM tika ziÅots ApvienotajÄ Pasaules LatvieÅ”u zinÄtnieku 3. kongresÄ, RÄ«gÄ, 25. oktobrÄ« 2011.g
Joining Pointwise Geological Data to Interpolation Grids if the Data Search Area is a Circle
No full textAbstract ā Pointwise geological data ļ³in are used as initial information for creating hydrogeological models (HM). Interpolation methods are applied to create ļ³-maps on (xy)ļgrids of HM. The maps represent geometrical and physical features of geological layers. If solutions of boundary field problems are used as interpolation results then ļ³in represent boundary conditions. They must be joined to nodes of the interpolation grid. In this paper the case is considered when the local data search region presents a circle. Features of this approach are investigated if the circle radius changes from zero to two plane steps of a uniform (xy)ļgrid
Appliance of Pumping Data of Wells for Obtaining Transmissivity Distributions of Aquifers for Hydrogeological Model of Latvia
No full textAbstract ā In 2010-2012, the hydrogeological model (HM) of Latvia LAMO was established by scientists of Riga Technical University (RTU). LAMO generalizes geological and hydrogeological information accumulated by the Latvian Environment, Geology and Meteorology Centre (LVGMC). The commercial program Groundwater Vistas (GV) is used for running LAMO. In 2013-2014, LAMO was considerably upgraded. Density of the hydrogeological network (rivers, lakes) was increased, cuttings of river valleys into primary geological strata were accounted for, transmissivity distributions for aquifers were refined. To improve transmissivity data of HM aquifers, information provided by pumping tests for wells was used. The refined transmissivity data were applied, to create the permeability maps of aquifers as the variable initial data for the GV system. To accomplish methods of numerical interpolation and digital image processing were used reliability
Comparison of Methods for Joining Pointwise Geological Data to Interpolation Grids
No full textAbstract ā Pointwise geological initial data ļ³in are used for creating hydrogeological models (HM). By processing ļ³in by interpolation methods, ļ³ - maps are created on (x, y) ā grids of HM. The maps represent geometrical and physical features of geological layers. If solutions of boundary field problems are applied as interpolation results (ļ³ - maps) then ļ³in serve as the boundary conditions of the first kind. They must be joined to nodes of the interpolation grid. In this paper, three methods are compared that may be applied to perform this task when the local date search region is a square, a circle, an area enclosed by hyperbola arcs. Features of these methods are examined and recommendations on their optimal use are given
Latvijas hidroÄ£eoloÄ£iskais modelis pazemes dzeramÄ Å«dens krÄjumu pÄrvaldÄ«Å”anai un atveseļoÅ”anai
No full textValstu un to apgabalu hidroÄ£eoloÄ£iskie modeļi tiek veidoti pazemes Å«dens krÄjumu racionÄlas izmantoÅ”anas nodroÅ”inÄÅ”anai. LaikÄ no 1993. gada lÄ«dz 1996. gada RÄ«gas TehniskÄ universitÄte (RTU) kopÄ ar bijuÅ”o Valsts Ä£eoloÄ£ijas dienestu Ä«stenoja reÄ£ionÄlo modeli (REMO) āLielÄ RÄ«gaā Latvijas centrÄlajai daļai. Å is modelis bija paredzÄts hidroÄ£eoloÄ£iskÄs informÄcijas apkopoÅ”anai par te izvietotajÄm dzeramÄ Å«dens ieguves vietÄm (RÄ«ga, JÅ«rmala, Jelgava u.c.). HidroÄ£eoloÄ£iskais modelis (HM) aptvÄra 168kmļ“156km platÄ«bu. AproksimÄcijas režģa solis bija 4000m. VertikÄlÄ virzienÄ REMO saturÄja 10 pazemes Å«dens horizontus, kurus atdalÄ«ja deviÅi sprostslÄÅi. ModelÄÅ”anas rezultÄti apkopoti karÅ”u atlasÄ, kas publicÄts 1996. gadÄ. Modelis tika izmantots RÄ«gas pilsÄtas jauno pazemes Å«dens avotu pÄtÄ«Å”anai (1996. gads), InÄukalna dÄ«Ä·u piesÄrÅojuma areÄla HM veidoÅ”anai (1998. gads) un Å«densgÅ«tnes aprÄÄ·iniem Coca-Cola rÅ«pnÄ«cai (2009. gads).
1996. gadÄ reÄ£ionÄlÄ HM āLielÄ RÄ«gaā izveidoÅ”ana bija ievÄrojams profesionÄls sasniegums. TomÄr Å”is HM neatbilst mÅ«sdienu prasÄ«bÄm, kuras Latvijai nosaka Eiropas SavienÄ«bas Å«dens DirektÄ«vas: nav aptverta visa Latvijas teritorija, pÄrÄk liels HM plaknes režģa solis, modelis veidots oriÄ£inÄlÄ programmatÅ«ras vidÄ, kura nav savietojama ar mÅ«sdienÄ«gÄm komercprogrammatÅ«rÄm u.c.
ÄŖstenojot Eiropas ReÄ£ionÄlÄ attÄ«stÄ«bas fonda lÄ«dzfinansÄtu projektu āHidroÄ£eoloÄ£iskÄ modeļa izveidoÅ”ana Latvijas pazemes Å«dens krÄjumu apsaimniekoÅ”anai un vides atveseļoÅ”anaiā, RTU veido reÄ£ionÄla tipa HM Latvijas aktÄ«vajai pazemes Å«deÅu zonai (lÄ«dz PÄrnavas horizontam), no kuras var iegÅ«t dzeramo Å«deni. Projekta Ä«stenoÅ”anas laiks ir 24 mÄneÅ”i (no 2010. gada lÄ«dz 2012. gadam). HM bÅ«s daļa no Latvijas VienotÄs vides informÄcijas sistÄmas, kuru uztur Latvijas Vides, Ä£eoloÄ£ijas un meteoroloÄ£ijas centrs (LVÄ¢MC). Modeļa esamÄ«ba uzlabos Ŕīs sistÄmas kvalitÄti, jo bÅ«s publiski pieejami dati, kas nepiecieÅ”ami pazemes Å«deÅu resursu racionÄlai pÄrvaldÄ«bai un Eiropas SavienÄ«bas direktÄ«vu Ä«stenoÅ”anai LatvijÄ pirmajÄ plÄnoÅ”anas ciklÄ (2004.g.-2015.g).
HidroÄ£eoloÄ£iskos un Ä£eoloÄ£iskos datus HM izveidoÅ”anai nodroÅ”ina LVÄ¢MC. Ar LVÄ¢MC ir saskaÅotas prasÄ«bas, kuras HM jÄnodroÅ”ina kÄ vides informÄcijas sistÄmas elementam.
Latvijas HM aptver 475kmļ“300km plaÅ”u laukumu. Modeļa plaknes režģa aproksimÄcijas solis bÅ«s 500m un Ä£eoloÄ£isko slÄÅu skaits bÅ«s 25 ( no tiem 13 bÅ«s Å«dens horizonti). Modelis tiks realizÄts komercprogrammatÅ«ras āGroundwater Vistasā vidÄ, kura tiek plaÅ”i izmantota pasaules valstÄ«s. Ja nepiecieÅ”ams, uz HM bÄzes varÄs veidot lokÄlus detalizÄtus modeļus pazemes Å«densgÅ«tÅu režīma verifikÄcijai un vides piesÄrÅojuma problÄmu risinÄÅ”anai.
ParedzÄts, ka sadarbojoties RTU un LVÄ¢MC, Ä«stenotÄ Latvijas HM iespÄjas varÄs paplaÅ”inÄt atbilstoÅ”i nÄkoÅ”o plÄnoÅ”anas ciklu prasÄ«bÄm
Finding of Groundwater Recharge, Transit and Discharge Areas
No full textGroundwater recharge, transit and discharge areas for aquifers must be found. Their location depends on the influence of ground surface and hydrographical network (rivers, lakes, sea). It is commonly agreed that the recharge areas are located at hilly places where maximums of infiltration flows and piezometric groundwater levels coincide. Such method was applied for the hydrogeological model of Latvia LAMO. The model provides results for a complex spatial hydrogeological system where conditions even within one aquifer may differ considerably. For this reason, the common method of finding recharge, transit and discharge areas fails to provide accurate results. The new method has been developed. It is based on appliance of the ratio for velocities of vertical to horizontal groundwater flows. The resulting velocity of the vertical flow is found as the difference of velocities of flows on the top and bottom surfaces of the aquifer. The ratio r is the non-dimensional function. Its values r = 1 and r = 0 determine the locations of boundaries for the recharge and discharge areas, accordingly. For the transit area 0 1 and r < 1, correspondingly. The new method provides accurate results even for discontinuous aquifers where the zones of zero thickness appear. Within such zones r = 0. The method will be applied as a tool for investigating complex groundwater processes that are modelled by LAMO. The method was used for extra calibration of LAMO in order to improve its results. The research was supported by the Latvian State Research Program EVIDEnT
Appliance of Pumping Data of Wells for Obtaining Transmissivity Distributions of Aquifers for Hydrogeological Model of Latvia
No full textIn 2010 ā 2012 the hydrogeological model (HM) of Latvia called LAMO was developed by the scientists of Riga Technical University (RTU). LAMO generalizes geological and hydrogeological information accumulated by the Latvian Environment, Geology and Meteorology Centre (LVGMC). The commercial program Groundwater Vistas (GV) was used for running LAMO. In 2013 ā 2014 LAMO was considerably upgraded. Density of the hydrogeological network (rivers and lakes) was increased, cuttings of river valleys into primary geological strata were accounted for, transmissivity distributions for aquifers were refined. To improve transmissivity data of HM aquifers, information provided by pumping tests for wells was used. The refined transmissivity data were applied to create the permeability maps of aquifers as the variable initial data for the GV system. To accomplish these task methods of numerical interpolation and digital image processing were used
- ā¦
