6353 KB0 KB197420252025Benderev, Al.Damyanova, EvelinaDonkova, YordankaGerginov, PeterIvanov, MarinKarastanev, DonchoTchakalova, Borianaštevilka:2-3letnik:54str. 173-187ISSN:0583-6050DOI:10.3986/ac.v54i2.13966COBISSID_HOST:263218691URN:URN:NBN:SI:doc-9AKCFE43enSlovenska akademija znanosti in umetnostiActa carsologicaaquatic resourcesBolgarijaBulgariacave sedimentsjamski sedimentikarst (geology)karst springskras (geologija)kraški izvirivodni viriCharacteristics and reasons for the discharge interruption of the Iskrets karst spring (Western Balkans, Bulgaria)| Značilnosti in vzroki za prekinitev pretoka kraškega izvira Iskrets (Zahodni Balkan, Bolgarija)|The Iskrets spring is one of the most significant karst springs in Bulgaria. ? specific feature of this spring are irregular and abrupt reductions of its discharge after some earthquakes as well as other reasons related to the recharge. This study aims to present a reasonable hypothesis for the reasons of the discharge interruptions. A main feature of the Iskrets karst system is the fact that it is dominated by unconfined water flow in the unsaturated zone with velocities varying in a wide range. This creates conditions for significant erosion, transport and redeposition of the fluvial cave sediments. As a result, in the zones where there is a sharp decrease in the water velocity, a considerable accumulation of sediments occurs which can even fill the entire section of the passage-way and leads to a temporary blocking of the spring discharge. It is supposed that an appropriate section where this happens is located near to the discharge point of the spring. Most likely the main reason for the cave deposit dis-placement is the soil liquefaction caused by the seismic impact. It has been found that the duration of the discharge interrup-tion period is longer at low water flow ratesIzvir Iskrets je eden najpomembnejših kraških izvirov v Bolgariji. Posebnost tega izvira so neenakomerna in nenadna zmanjšanja pretoka po nekaterih potresih, lahko pa tudi kot posledica razmer, povezanih z napajanjem. Namen te študije je postaviti razumno hipotezo o vzrokih za prekinitve pretoka. Glavna značilnost kraškega sistema Iskrets je, da v nenasičenem območju prevladuje tok vode s prosto gladino in velikim razponom hitrosti. To ustvarja pogoje za znatno erozijo, transport in ponovno odlaganje fluvialnih jamskih sedimentov. Posledično se na območjih, kjer pride do močnega zmanjšanja hitrosti vode, usedajo večje količine sedimenta, ki lahko zapolnijo celoten presek kraškega kanala in povzročijo začasno prekinitev pretoka izvira. Domnevamo, da se primeren odsek, kjer se to zgodi, nahaja v bližini izvira. Najverjetneje je glavni razlog za premik jamskih sedimentov utekočinjanje tal zaradi potresnega vpliva. Ugotovili smo, da je trajanje prekinitve pre-toka daljše pri nizkih pretokih izviraTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaZRC SAZU