magistrsko delo
Klemen Klančič (Author), Mihael Brenčič (Mentor), Joerg Prestor (Co-mentor)

Abstract

Z namenom potrditve ali dopolnitve aktualnega konceptualnega modela vodonosnika Iškega vršaja so bili izvedeni trije črpalni poizkusi v septembru 2018, in sicer na treh globokih vodnjakih: VD Brest-1a, VD Brest-2a in VD Brest-4a, ki segajo v spodnje plasti pleistocenskih aluvialnih nanosov. Med izvedbo črpanj so bile beležene spremembe gladin podzemne vode na bližnjih opazovalnih vrtinah. Po izvedbi črpalnih poizkusov je sledilo kabinetno delo, ki je v prvi fazi obsegalo urejanje podatkov, izmerjenih na terenu, ter prvi izris krivulj znižanj v odvisnosti od časa. Zaradi lažje nadaljnje obdelave so bile krivulje deljene na tri faze: začetno, srednjo in končno. Srednja faza je bila uporabljena za preračun hidravličnih parametrov vodonosnika. Določeni so bili na podlagi Theisove metode z Jacobovimi popravki za vsak črpalni poizkus posamezno in na koncu preračunani v povprečje. Koeficient prepustnosti (K) znaša 4,35?10-4 m/s. Zaradi velikega razpona rezultatov uskladiščenje vodonosnika ni bilo podano za celoten vodonosnik, ampak le za posamezne vodnjake. Končna faza je določala del krivulje, ko depresijski lijak doseže rob vodonosnika, kar se odraža v nihanju gladin podzemne vode, ki je v končnih fazah opazno na vseh vrtinah, torej ni lokalno pogojeno. Depresijski lijak doseže plasti z drugačnimi hidravličnimi parametri, ki povzročijo upad hitrosti njegovega širjenja. Na sama nihanja bi lahko vplivala reka Iška in padavine, vendar zaradi ponikanja reke Iške in premalo podatkov takšne razlage ni bilo mogoče potrditi. Iz predhodnih raziskav je znano, da vodonosnika Iškega vršaja ne omejujejo neprepustne meje. Zaradi tega so pričakovana nihanja na koncu črpalnega poizkusa, saj se hidravlična motnja skozi vodonosnik širi horizontalno in vertikalno.

Keywords

črpalni poizkus;Iški vršaj;konceptualni model;hidravlični parametri vodonosnika;koeficient prepustnosti;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL NTF - Faculty of Natural Sciences and Engineering
Publisher: [K. Klančič]
UDC: 55
COBISS: 53794819 Link will open in a new window
Views: 394
Downloads: 69
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Other data

Secondary language: English
Secondary title: pumping test analysis in the aquifer of Iška River alluvial fan
Secondary abstract: To confirm or update the actual conceptual model of the Iška alluvial fan aquifer, three pumping tests were conducted in September 2018. It was performed in three deep wells: VD Brest-1a, VD Brest-2a and VD Brest-4a, extending into the lower layers of the Pleistocene alluvial deposits. Drawdown in groundwater level at nearby piezometers were recorded during pumping. After the pumping tests were carried out, followed cabinet work, which in the first phase consisted of editing the data taken in the field and the first plotting of the reduction curves as a function of time - s (log t). For ease of further processing, the curves were divided into three phases, namely the first, second and third phases. The second phase was first used to calculate the hydraulic parameters of the aquifer. They were determined based on Theis method with Jacob corrections for each pumping test individually and finally united to average. Hydraulic permeability (K) for the whole aquifer is 4.35⠙10-4 m/s. Storativity was not calculated for the entire aquifer but only for individual wells due to the large range of results. The third phase determined the part of the curve when the cone of depression reaches edge of the aquifer, which is reflected in the fluctuation of groundwater levels. The disorder is noticeable in all wells and is not locally conditioned. Extension velocity drops, when cone of depression reaches layers with different hydraulic parameters. Fluctuations of groundwater level could be affected by the Iška river and rain precipitation, but due to the sinking nature of the Iška river and insufficient data, the idea could not be confirmed. Consequently, a precise interpretation of the pumping tests was ultimately not possible. As previously known, aquifer of Iška alluvial fan is not limited by the impermeable boundary, so fluctuations are expected at the terminal end of the pump test.
Secondary keywords: pumping test;Iška alluvial fan;conceptual model;hydraulic parameters;hydraulic permeability;
Type (COBISS): Master's thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Naravoslovnotehniška fak., Oddelek za geologijo
Pages: XIII, 43 f.
ID: 12548711