Geomorphological and hydrological characteristics of Zagorska Mrežnica spring

Izvor-špilja Zagorska Mrežnica nalazi se u selu Desmerice, nedaleko od grada Ogulina. Intenzivno je istraživan od 2006-2011. Cilj rada bio je istražiti potopljene podzemne dijelove izvora, izraditi speleološki nacrt te prikupiti podatke o geomorfološkim i hidrološkim obilježjima. Korištene su speleoronilačke tehnike. Istraživanjem je utvrđeno da se radi o preljevnom krškom izvoru nastalom na kontaktu propusnih i nepropusnih naslaga jurskih vapnenca i dolomita mezozojske starosti s razvijenom mrežom kanala i dvorana tlocrtne duljine 1134 m i maksimalne dubine od 21,5 m. Geomorfološka obilježja odraz su geoloških i hidrogeoloških značajki u freatičkim uvjetima speleogeneze što je jasno vidljivo iz morfologije podzemnog prostora te denudacijskim i akumulacijskim oblicima zabilježenim u izvoru. Hidrološka obilježja izvora u direktnoj su ovisnosti o količini i intenzitetu padalina te o hidrogeološkoj vezi s ponorima u zaleđu.Cave-spring Zagorska Mrežnica is located in the village Desmerice, near the town of Ogulin. It has been intensivly investigated from 2006-2011. The goal was to explore the submerged parts of the spring, make a cave-map and collect data on geomorphological and hydrological characteristics. Cave diving tehniques were used. Research has found that it is owerflow karst spring originated at the contact between permeable and impermeable layers of Jurassic limestone and Mezozoic dolomite with a wide network of passages and halls total horizontal lenght of 1134 meters and maximum depth of 21,5 meters. Geomorphological features are reflection of geological and hidrogeological characteristics in terms of phreatic speleogenisis which is clearly evident from morphology of the underground space and denudation and accumulation forms recordet in the spring. Hydrological connection of the spring are directly dependent on the amount ond intensity of rainfall and hydrogeological connection with sink-holes in hinterland