Sediment production in flysch badlands: A case study from Slovenian Istria

Abstract

This article deals with the results of seven years of measurements of sediment release from the flysch badlands in the Rokava River headwaters. Measurements of sediment production were carried out in erosion plots, and measurements of cliff (or rockwall) retreat using erosion pins. Selected meteorological time series from the Portorož Airport meteorological station were included in the analysis. The calculation showed that from 2008 to 2015 (149 measurements) sediment production was 36 kg/m² per year and the flysch cliff retreated by 146 mm or 21 mm per year. The amount of sediment produced is moderately positively correlated with the number of days between successive measurements (r = 0.51), with a recorded daily transition of air temperature over/below 0 °C (r = 0.56) and slightly more weakly correlated with the precipitation amount (r = 0.45). On the other hand, the amount of sediment produced has a low negative correlation with average air temperature (r = −0.29) and average minimum air temperature (r = −0.30). However, no statistically significant correlation was calculated between the amount of sediment produced and average wind speed.

Naravnogeografski oris slovenske Istre

“…Navedene kamnine so zelo različno odporne na temperaturne spremembe, vlaženje in sušenje, ob morju tudi na izločanje soli, ki povzročajo mehansko preperevanje. V notranjih predelih Koprskih brd, kjer se temperature zraka v hladni polovici leta spustijo pod ledišče, se naštetim procesom mehanskega preperevanja priključi še zmrzal, ki je pomemben dejavnik nastajanja sedimentnega gradiva na erozijskih žariščih (Zorn 2008;Kovačič 2020).…”

“…Za flišno gričevje so značilni izjemno intenzivni erozijsko-denudacijski procesi. Raziskovanje slednjih v dolini Dragonje je pokazalo, da se lahko samo v enem letu površje zniža za več kot centimeter in strma pobočja odmaknejo za več centimetrov (Petkovšek in Mikoš 2003;Zorn 2007;2008;2009;2010;Kovačič 2020). Posledica obilice odnesenega gradiva so debelo prekrita dna dolin ob spodnjem toku rek in dno Tržaškega zaliva z usedlinami.…”

Participatory Approach to Wetland Governance: The Case of The Memorandum of Understanding of the Sečovlje Salina Nature Park

“…Recent measurements show that sedimentation is still active. In the hinterland, sediment production is 36 kg/m 2 per year from the flysch cliffs [28].…”

Geografsko raziskovanje slovenske Istre 1

“…Navedene kamnine so zelo različno odporne na temperaturne spremembe, vlaženje in sušenje, ob morju tudi na izločanje soli, ki povzročajo mehansko preperevanje. V notranjih predelih Koprskih brd, kjer se temperature zraka v hladni polovici leta spustijo pod ledišče, se naštetim procesom mehanskega preperevanja priključi še zmrzal, ki je pomemben dejavnik nastajanja sedimentnega gradiva na erozijskih žariščih (Zorn 2008;Kovačič 2020).…”

“…Za flišno gričevje so značilni izjemno intenzivni erozijsko-denudacijski procesi. Raziskovanje slednjih v dolini Dragonje je pokazalo, da se lahko samo v enem letu površje zniža za več kot centimeter in strma pobočja odmaknejo za več centimetrov (Petkovšek in Mikoš 2003;Zorn 2007;Kovačič 2020). Posledica obilice odnesenega gradiva so debelo prekrita dna dolin ob spodnjem toku rek in dno Tržaškega zaliva z usedlinami.…”