1 / 17

Franci Gabrov š ek , Matej Blatnik, Cyril Mayaud

The epiphreatic flow in mature karst aquifers: theory, models and observations. Franci Gabrov š ek , Matej Blatnik, Cyril Mayaud Karst Research Institute , Postojna, Slovenia. The epiphreatic zone. Observations in EZ: Relation : hydrographs <-> geometry. p, T, s. p, T, s.

caryl
Télécharger la présentation

Franci Gabrov š ek , Matej Blatnik, Cyril Mayaud

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The epiphreatic flow in mature karst aquifers: theory, models and observations Franci Gabrovšek, Matej Blatnik, Cyril Mayaud Karst Research Institute, Postojna, Slovenia

  2. The epiphreatic zone • Observations in EZ: • Relation: hydrographs <-> geometry p, T, s p, T, s p, T, s

  3. Characteristicsofthe epiphreatic zone • Speleogenetically most vivid part oftheaquifer. • Large conduitnetworks, major flowpaths. • In youngorogens: • Changingboundaryconditionsandstructure • Highhetereogeneity x-treme changes in geometry • Verticaldevelopment • Speleogenetic disequilibrium = channelscannotaccomodatefloods* *Gabrovšek F, Häuselmann P, Audra P (2014) ‘Looping caves’ versus ‘water table caves’: The role of base-level changes and recharge variations in cave development. Geomorphology 204 (0):683-691.

  4. Freesurfaceandpressurisedflow in conduits Saint-Vennanteqs. for open channel non-stationaryflow. Manning (orsimilar) eqs. for uniform stationaryflow: Rozos E, Koutsoyiannis,D (2006) JOURNAL OF HYDROLOGY n… roughnesscoefficient A… flowcross-section R… hydraulicradius … geometrical parameter …exponent > 1 foropen channelflow = 0.5 forpressurisedflow

  5. Detectionof o verflowchannels Transitionsbetweenflowregimes are recordedbyinflections in hydrographs!

  6. ModellingwiththeSWMM (Storm Water Management Model ) • EPA SWMM • SaintVenant‘s equations (1D, conservation of massandmomentum). • Network of conduits (links) connected at nodes. • Acccountsforpressurisedand open surfaceflow. • Versatility, open source, connectivity. ! Conduitflowonly!

  7. Overflows: a modellinginsight 1) A singleoverflow D2>D1 D1>D2

  8. Overflows: a modellinginsight 2) A doubleoverflow • Overflow (OF) is „seen“ at theObservationPoint (OP): • OF is down-flowfromthe OP, • OF is not back-flooded, • overflowshortcutsconsiderableheaddifference

  9. Case 1: Ljubljanica Catchment Focus on W1, W2, W3 ! • Blatnik et al., (2019) Groundwaterdynamicsbetween Planinsko Polje andspringsofthe Ljubljanica River, Slovenia. ActaCarsologica • (In Print.)

  10. Case 1: Ljubljanica Catchment

  11. Case 2: Kras/Carso • Highrechargevariability: Qmed =8,95 m3/s, Qmin = 0,16 m3/s, Qmax =387 m3/s • Highwaterlevelfluctuations( > 100 m) • Severalcavesreachingepiphreaticlevel. Gabrovšek F, Peric B, Kaufmann G (2018) Hydraulics of epiphreatic flow of a karst aquifer. Journal of Hydrology 560:56-74.

  12. Škocjan Caves- KačnaCave ?

  13. Škocjan Caves- KačnaCave Note thefast rise at P2 (KačnaCave), when Q is above 15 m3/s.

  14. Škocjan Caves- KačnaCave Qmax= 15 m3/s

  15. Škocjan Caves- KačnaCave: SWMM model

  16. Conclusions • Manyothersituationshavebeenobservedandinterpretedthisway: • Identificationandestimationof epiphreatic storage • Gabrovšek et al., (2018) Hydraulics of epiphreatic flow of a karst aquifer. • Journal of Hydrology 560:56-74 ; • Blatnik et al., (2019) Groundwaterdynamicsbetween Planinsko Polje and • springsofthe Ljubljanica River, Slovenia. ActaCarsologica,InPrint. • Mechanismsof polje flooding • Mayaud et al (2019).,.Understandingflooding in poljes : a modellingperspective. JournalofHydrology, vol. 575. • Identificationofflowbarriers • Blatnik et al., (2019) Groundwaterdynamicsbetween Planinsko Polje and • springsofthe Ljubljanica River, Slovenia. ActaCarsologica,InPrint. • Identificationandevaluationofcriticalconstrictions • (KaufmannG, Gabrovsek F, Turk J (2016) Modellingcaveflowhydraulics in Postojnska jama, • Slovenia. ActaCarsologica 45 (1):57-70. ) • Flowdistriburionbetween major springs • Hopeyouhaveheardprevious talk by B. Kogovšek. • Optimalpositioningofloggers

More Related